Question: A 64-year-old man presents to the emergency room with a headache and nausea. He reports that he was rocking his grandson to sleep when the symptoms began. He states the pain is constant and is primarily located on his right side. When asked to indicate the area of pain, he says that it surrounds his eye and upper forehead. He had one episode of vomiting. The patient also reports difficulty seeing out of his right eye, which he attributes to excessive tearing. The patient’s past medical history is significant for hypertension. His medications include hydrochlorothiazide. His temperature is 98.6°F (37°C), blood pressure is 135/91 mmHg, pulse is 72/min, and respirations are 12/min. The patient’s right eye is shown in Figure A. Upon physical examination, the right pupil is minimally responsive to light and the globe feels firm. A right-sided carotid bruit is appreciated. Which of the following is the most appropriate prophylaxis for this patient’s condition?

Answer: Acetazolamide

Explanation:
This patient is presenting with sudden-onset unilateral vision loss and an orbitofrontal headache with a dilated pupil and a hard ocular globe suggesting a diagnosis of acute angle-closure glaucoma. Long-term management of angle-closure glaucoma can include acetazolamide.

Examination of the eye in a patient with acute-closure glaucoma will reveal a red eye that is rock-hard and a mid-dilated pupil which is minimally reactive to light. The fundoscopic exam will show an increased optic cup-to-disk ratio (>0.4) and tonometry will show increased intraocular pressure. Gonioscopy is the diagnostic gold standard. Acute treatment and long-term management involve the administration of beta-blockers, alpha-2-agonists, and carbonic anhydrase inhibitors such as acetazolamide to decrease intraocular pressure. The definitive treatment is iridotomy.

Airaksinen et al. review the treatment of closed-angle glaucoma. They discuss how a combination of acetazolamide and beta-blockers can terminate an attack. They recommend using 1 drop of pilocarpine 3 hours after intravenous acetazolamide administration.

Figure/Illustration A is a clinical photograph showing an eye with injected conjunctiva (red circles) and a mid-dilated pupil. These findings are consistent with angle-closure glaucoma.

Incorrect Answers:
Answer B: Amitriptyline can be used as prophylaxis for migraines. Migraines present as unilateral, pulsating headaches that may be associated with nausea or photophobia. Patients with migraines can sometimes experience an aura with visual field changes; however, they would not have exam findings of a rock-hard eye or injection.

Answer C: Clopidogrel may be used as a conservative treatment for carotid atherosclerosis, which can be an embolic source for central retinal artery occlusion (CRAO). CRAO presents as acute, painless, monocular vision loss. A fundoscopic exam will demonstrate ischemia of the retina.

Answer D: Epinephrine is contraindicated in the treatment of angle-closure glaucoma as it increases pupillary dilation. It is used in the management of open-angle glaucoma. This would present with gradually patchy loss of vision and is generally painless.

Answer E: Verapamil is used as prophylaxis for cluster headaches. Cluster headaches present as unilateral, repetitive, brief headaches associated with severe peri-orbital pain, lacrimation, rhinorrhea, and Horner syndrome (miosis, ptosis, and anhidrosis).

Bullet Summary:
Pharmacologic management of acute angle-closure glaucoma involves beta-blockers, alpha-2 agonists, and carbonic anhydrase inhibitors.


Question: A 42-year-old woman is enrolled in a randomized controlled trial to study cardiac function in the setting of several different drugs. She is started on verapamil and instructed to exercise at 50% of her VO2 max while several cardiac parameters are being measured. During this experiment, which of the following represents the relative conduction speed through the heart from fastest to slowest?

Atria > Purkinje fibers > ventricles > AV node

AV node > ventricles > atria > Purkinje fibers

Purkinje fibers > ventricles > atria > AV node

Purkinje fibers > AV node > ventricles > atria

Answer: Purkinje fibers > atria > ventricles > AV node

Explanation:
The conduction velocity of the structures of the heart are in the following order: Purkinje fibers > atria > ventricles > AV node. A calcium channel blocker such as verapamil would only slow conduction in the AV node.

The conduction velocity of cardiac tissue is determined by a wide variety of factors, including the number and identity of various ion channels, the number and type of gap junctions, and the size and composition of muscle fibers. Conduction through the Purkinje system is the fastest within the heart, allowing for coordinated contraction of the ventricles, and atrial muscle conducts faster than ventricular muscle. Conduction through the AV node is the slowest, to allow the ventricles enough time to fill with blood.

Bonke et al. review the evidence regarding the conduction velocity of parts of the heart. They discuss how the AV node is slower than the SA node. They recommend understanding how different parts of the heart conducts electricity.

Incorrect Answers:
Answers A-C & E: These choices do not correspond to the correct conduction velocities in each part of the cardiac conduction system. A calcium channel blocker would not change the relative velocities of conduction in Purkinje fibers, atria, and ventricles.

Bullet Summary:
The conduction velocity through the heart in order of speed is Purkinje fibers > atria > ventricles > AV node.


Question: A 3-year-old girl is brought to the office for a routine well-child appointment. She was delivered preterm at 35 weeks, and her medical history is significant for several ear infections over the last year. Her older brother has been diagnosed with attention-deficit hyperactivity disorder (ADHD), but the rest of her family history is otherwise unremarkable. The patient has become more withdrawn lately and has sometimes been ignoring her parents when asked to perform tasks at home. This seems to have worsened over the last 8 weeks. Otherwise, the patient is energetic and started preschool 3 months ago. Her temperature is 98.6°F (37°C), blood pressure is 98/62 mmHg, pulse is 97/min, and respirations are 26/min. The patient successfully draws a square and can stand on 1 foot. Her language skills are unchanged from her appointment 6 months ago. Her neurological examination is normal, and she is at the 50th percentile for height and weight. She seems distracted during the interview and responds only intermittently to the physician’s directions. Which of the following is the most appropriate next step in management?

Answer: Audiometry testing

Explanation:
This patient who presents with trouble following directions, inconsistent response to the physician's questions, and lack of progression in her language skills may have an acquired hearing impairment. The patient should undergo audiometry testing.

Hearing impairment in children can be genetic or acquired. In a patient with a history of recurrent ear infections, conductive hearing loss is the most common underlying cause of hearing impairment. Hearing impairment can often present similarly to behavioral or persistent developmental disorders. In a child with poor language skills, social skills, and self-isolation, hearing loss should be ruled out first before considering other diagnoses. Undetected hearing loss can progress with poor academic performance, personal-social maladjustment, and emotional difficulties as children progress through critical development stages. The treatment for hearing loss is the restoration of hearing through hearing aids, cochlear implants, and other supportive measures.

Dammeyer et al. studied the impact of childhood hearing loss on family life. They found that children with additional disabilities were more likely to be ignored by parents. They recommend understanding family dynamics in order to better support patients and families.

Incorrect Answers
Answer B: Autism spectrum screening questionnaire is useful in the diagnosis of autism spectrum disorder in children presenting with social isolation and poor communication skills. Autism spectrum disorder often presents with repetitive behaviors and fixed interests, which are absent in this child. Hearing loss should be ruled out first before pursuing this diagnosis. Treatment of autism spectrum disorders is early intervention and counseling.

Answer C: Parent and teacher ADHD rating scales should be obtained to aid in the diagnosis of attention-deficit hyperactivity disorder (ADHD). While children with ADHD often appear inattentive and impulsive in multiple domains, poor language development, and social isolation are not features of ADHD. This patient should first undergo an audiometry test. ADHD can be treated with stimulants such as methylphenidate.

Answer D: Referral for genetic testing is an incorrect first step in the management of this patient. While delayed language can be seen with several genetic conditions, there are usually signs of other global motor, cognitive, and social delays. Additional genetic testing can be pursued if the patient’s audiometry testing results are normal.

Answer E: Referral for speech and language assessment is an incorrect first step. A formal assessment should be obtained in the diagnosis of communication and language disorders. However, this should only be done after ruling out hearing loss. Therefore audiometric testing should be performed first.

Bullet Summary:
Children with a history of recurrent ear infections presenting with signs of social or language development delays should be evaluated for hearing impairment with an audiometry test.


Question: A 64-year-old man presents with nausea, vomiting, and weakness. He states that his wife made him come in when he fainted today while attempting to stand up. He otherwise states he has noticed some visual changes, including noting a yellow tint to objects. He has a history of heart failure with reduced ejection fraction, obesity, diabetes, hypertension, acute coronary syndrome, atrial fibrillation, and peripheral vascular disease. His temperature is 98.5°F (36.9°C), blood pressure is 153/91 mmHg, pulse is 40/min, respirations are 15/min, and oxygen saturation is 97% on room air. Physical exam reveals a frail man who is unable to ambulate secondary to lightheadedness. His neurological exam is otherwise non-focal. An ECG is performed as seen in Figure A. Which of the following is the most likely etiology of this patient’s symptoms?

Answer: Digoxin

Explanation:
This patient with a history of heart failure with reduced ejection fraction and atrial fibrillation is presenting with nausea, vomiting, visual changes, bradycardia, and premature ventricular complexes, which are concerning for digoxin toxicity. Note that digoxin can be given in patients with poor cardiac function and atrial fibrillation; thus it is a plausible home medication for this patient.

Digoxin is a cardiac glycoside that is used in conditions such as heart failure with reduced ejection fraction and atrial fibrillation. While it does not lower mortality, it may reduce symptoms of heart failure. Digoxin toxicity classically presents with gastrointestinal symptoms (nausea/vomiting), blurred vision or yellow halos, and cardiac dysrhythmias. While there is a myriad of dysrhythmias, digoxin can cause bradycardia, atrioventricular block, and premature ventricular contractions. ST-segment scooping can be seen with digoxin use both in toxicity but also with regular therapeutic use. Toxicity is treated with anti-digoxin antibodies.

Patocka et al review digoxin toxicity. They note that this medication has a narrow therapeutic range and recommend close monitoring. Toxicity depends on severity and can be treated with anti-digoxin antibodies.

Figure/Illustration A is an ECG demonstrating bradycardia and premature ventricular complexes (red circles). This is consistent with digoxin toxicity.

Incorrect Answers:
Answer A: Amiodarone is an antidyshythmic agent with toxicities including bradycardia, heart block, a prolonged QT interval, hepatitis, interstitial lung disease, hypothyroidism, corneal deposits and optic neuropathy. This patient could use amiodarone for his atrial fibrillation, but the visual disturbances are more typical of digoxin toxicity.

Answer C: Diltiazem is a calcium channel blocker that would cause hypotension, bradycardia, and hyperglycemia. Treatment would involve immediate administration of calcium and vasopressors such as epinephrine. Other treatments in severe toxicity may include glucagon, dextrose, and insulin (to increase cardiac contractility).

Answer D: Procainamide is the preferred antidysrhythmic in tachydysrhythmias associated with Wolff Parkinson White syndrome. It may cause drug-induced lupus and other dysrhythmias in overdose but would not cause this patient’s constellation of symptoms. Procainiamide is used rarely for atrial fibrillation and is only available for intravenous infusion in the US.

Answer E: Propranolol toxicity would present with bradycardia, hypotension, confusion, seizures, and hypoglycemia. Treatment is centered on glucagon, calcium, and vasopressors such as epinephrine. In severe toxicity, lipid emulsion therapy and insulin/dextrose should be administered.

Bullet Summary:
Digoxin toxicity may present with nausea, vomiting, visual changes, bradycardia, and premature ventricular complexes.


Question:
A 23-year-old woman presents to the emergency department complaining of a worsening headache. The headache started 1 month ago. It is constant and “all over” but gets worse when she is lying down or in the setting of bright lights. A review of systems is significant for a low-grade fever, night sweats, cough, malaise, poor appetite, and unintentional weight loss of 12 pounds in the last 2 months. The patient is sexually active with multiple male partners and reports inconsistent condom use. She has a history of intravenous drug use and has not been to a doctor in the last 2 years. Her temperature is 100.4°F (38.0°C), blood pressure is 110/78 mmHg, pulse is 88/min, and respirations are 14/min with an oxygen saturation of 98% O2 on room air. On physical exam, pain is elicited upon passive flexion of the patient’s neck. A CT scan shows ventricular enlargement. A CD4+ count is 57 cells/µL blood. A lumbar puncture is performed with the following findings:

Cerebrospinal fluid:
Opening pressure: 210 mmH2O
Glucose: 32 mg/dL
Protein: 204 mg/dL
India ink stain: Positive

Leukocyte count and differential:
Leukocyte count: 200/mm^3
Lymphocytes: 100%
Red blood cell count: 2/mm^3

Which of the following treatments most directly addresses the underlying cause of this patient's symptoms?

Answer: Amphotericin B and 5-flucytosine

Explanation:
The patient with a history of unprotected sex and intravenous drug use who presents with sub-acute fever, meningismus, photophobia, a low CD4+ count, and a positive India ink-stained lumbar puncture most likely has cryptococcal meningitis. Acute treatment for cryptococcal meningitis is intrathecal amphotericin B and 5-flucytosine.

Cryptococcal meningitis is the most common fungal meningeal infection in patients with HIV, especially those with a CD4+ count < 100/mm^3. Symptoms are normally gradual in onset and can include headache, fever, neck stiffness, and photophobia. The most appropriate initial test is a lumbar puncture with an India ink stain. Cerebrospinal fluid in fungal meningitis would have low glucose, elevated protein, and an elevated lymphocyte-dominant leukocyte count. The most accurate diagnostic test is latex particle agglutination. Intrathecal amphotericin B and 5-flucytosine are the first-line treatments for acute management. Once the patient is treated, fluconazole is given for life or until the patient’s CD4+ count is > 100/mm^3.

Badali et al. present a case of a patient with cryptococcal meningitis. They discuss how despite immediate antifungal therapy, the patient died due to a rapidly progressive infection. They recommend aggressive intrathecal therapy to treat this disease.

Incorrect Answers:
Answer A: Acyclovir is used to treat Herpes simplex virus encephalitis. Cerebrospinal fluid would show normal protein and glucose, an elevated lymphocyte-dominant leukocyte count, and an elevated red blood cell count. The Herpes virus can lead to a hemorrhage of the temporal lobes.

Answer C: Dexamethasone is given in addition to IV antibiotics if Streptococcus pneumoniae meningitis is suspected. This is the most common cause of meningitis in adults, elderly, and asplenic patients, and can spread to cause sinusitis, otitis media, or bacteremia.

Answer D: Fluconazole is used for prophylaxis against cryptococcal meningitis after a person is treated acutely. It is either given for life, or until the patient’s CD4+ count is > 100/mm^3. This treatment is not sufficient for patients with acute meningitis with neurological changes.

Answer E: Vancomycin and ceftriaxone are given to a patient suspected of having bacterial meningitis until culture results confirm the bacterial organism. Bacterial meningitis would have decreased glucose, elevated protein, and an elevated neutrophil-dominant leukocyte count.

Bullet Summary:
Cryptococcal meningitis classically presents in a patient with a CD4+ count < 100/mm^3 and should be treated acutely with intrathecal amphotericin B and 5-flucytosine.


Question: A 9-year-old girl presents to the emergency department with a fever and a change in her behavior. She presented with similar symptoms 6 weeks ago and was treated for an Escherchia coli infection. She also was treated for a urinary tract infection 10 weeks ago. Her mother says that last night her daughter felt ill, and her condition has been worsening. Her daughter experienced a severe headache and had a stiff neck. This morning she was minimally responsive, vomited several times, and produced a small amount of dark cloudy urine. The patient was born at 39 weeks and met all her developmental milestones. She is currently up to date on her vaccinations and did not have infections during early childhood. Her parents are divorced and her father has noted she does not seem to get sick when he takes care of her. Her temperature is 99.5°F (37.5°C), blood pressure is 60/35 mmHg, pulse is 190/min, respirations are 33/min, and oxygen saturation is 98% on room air. The patient is started on intravenous fluids, vasopressors, and broad-spectrum antibiotics. Which of the following is the most appropriate underlying explanation for this patient's presentation?

Answer: Intentional contamination

Explanation:
This patient is presenting with repeat sepsis, which is uncommon in a pediatric patient with no significant medical history. This abnormal concentration of infections when the patient is with her mother suggests a diagnosis of intentional contamination.

Factitious disorder by proxy (formerly Munchausen syndrome) occurs when 1 individual creates symptoms in another for attention. Typically, this is a parent feigning or creating symptoms in a child in order to receive the psychiatric gain of attention from healthcare personnel. The patient should be treated and removed from the parents as this is considered child abuse. Factitious disorder by proxy should be suspected in any pediatric patient who has repeat infections that are atypical or not expected epidemiologically. Patients should also be evaluated for organic causes of symptoms such as immunodeficiency syndromes.

Abeln and Love review the evidence regarding the diagnosis of factitious disorder by proxy. They discuss how these disorders have high morbidity and mortality when not accurately recognized. They recommend paying attention to red flags such as abnormal constellations of symptoms.

Incorrect Answers:
Answer A: Gastroenteritis would present with nausea, vomiting, and diarrhea; however, it would not present with sepsis routinely. Gastroenteritis does not best explain the most likely underlying cause of this patient's presentation.

Answer B: Immunodeficiency such as severe combined immunodeficiency (SCID) would present with lifelong infections from birth that are bacterial, viral, and fungal. Immunodeficiency would not present with repeat infections in a pediatric patient only when they are with one patient.

Answer D: Meningitis would present with headache, altered mental status, and meningeal signs. In the setting of repeat sepsis in a healthy pediatric patient, intentional contamination is more likely. Similarly, an absence of photophobia and no further history/physical exam supporting this diagnosis suggests an alternative diagnosis.

Answer E: Urinary tract infection would present with dysuria rather than repeat episodes of sepsis. Though a urinary tract infection could lead to sepsis, this would be rare and more likely to occur in an immunosuppressed patient, the elderly, or a neonate. UTIs are a common cause of infection and fever in pediatric patients.

Bullet Summary:
Factitious disorder by proxy occurs when 1 individual feigns or creates symptoms in another.


Question: A 55-year-old man presents to the emergency department with right knee pain. He woke last night with sudden-onset, sharp, 10/10 non-radiating pain in his right knee. He denies recent trauma and he has no known medical problems. He denies tobacco use and will often drink 6-8 beers or spirits on weekend nights. His temperature is 98.6°F (37.0°C), pulse is 90/min, blood pressure is 140/90 mmHg, respirations are 16/min, and oxygen saturation is 97% on room air. Physical exam reveals an erythematous, edematous right knee. Passive extension of the knee is limited by pain. Synovial fluid aspiration is performed and sent for analysis, which reveals 20,000 leukocytes/mm^3, and no organisms visualized. Microscopic examination of synovial fluid is shown in Figure A. Which of the following is the most likely diagnosis?

Answer: Gout

Explanation:
The patient’s sudden-onset knee pain with effusion and synovial fluid findings are characteristic of gout.

Gout is caused by monosodium urate crystal deposition in joint spaces, most commonly in the big toe, ankle, or knee. Crystal deposition in the joint space leads to an intense inflammatory reaction that causes severe pain and joint effusion. Gout is most commonly due to lifestyle factors including a diet high in red meat and alcohol. Medications that cause elevated uric acid levels (such as thiazide diuretics) may also play a role. Conditions resulting in high cell turnover and therefore excessive purine release such as hematologic malignancies may also lead to the development of gout. Patients typically present with sudden-onset, severe pain, erythema, and joint effusion. Synovial fluid analysis will reveal an elevated leukocyte count and negatively birefringent, needle-shaped crystals. Treatment of acute gout is with NSAID medications, colchicine, or steroids depending on presentation and patient-specific factors. Prevention of further attacks is centered around lifestyle changes such as avoidance of red meat and alcohol. Xanthine oxidase inhibitors such as allopurinol are also often used for prevention of further episodes.

Neogi discusses the management of acute gout. She comments that, while synovial fluid analysis is the gold standard of diagnosis, many physicians do not routinely perform it, instead relying on clinical judgment to diagnose gout. The differential diagnosis for a gout-like presentation includes pseudogout, septic arthritis, Lyme arthritis, reactive arthritis, and rheumatoid arthritis.

Figure A shows monosodium urate crystals, which appear as negatively birefringent, needle-shaped crystals under polarized light.

Incorrect Answers:
Answer B: Lyme disease may also presents as a monoarticular arthritis in later stages. However, a recent history of tick exposure and preceding flu-like illness would also be expected.

Answer C: Pseudogout presents similar to gout, but is caused by calcium pyrophosphate deposition. Crystals appear rhomboid shaped and are positively birefringent under polarized light.

Answer D: Septic arthritis typically has higher leukocyte counts (> 50,000/mm^3) in the synovial fluid with organisms visualized on gram stain. Fever would also be expected.

Answer E: Rheumatoid arthritis may present as a monoarticular arthritis with acute flairs. However, crystals visualized in synovial fluid are more suggestive of acute gout.

Bullet Summary:
Acute gout presents with sudden-onset, severe joint pain and is characterized by needle-shaped negatively birefringent crystals visualized under polarized light.


Question:
A 44-year-old nurse presents to the emergency department with confusion. This has happened several times this past month with increasing frequency. Each time her symptoms improved with eating. She is otherwise healthy. She lives with her mother who has diabetes whose medications include metformin, insulin, lisinopril, amlodipine, and glyburide. Her temperature is 98.0°F (36.7°C), blood pressure is 132/81 mmHg, pulse is 85/min, respirations are 16/min, and oxygen saturation is 98% on room air. Physical exam reveals a confused woman. She is moving all her extremities but follows commands poorly. Laboratory studies are ordered as seen below.

Hemoglobin: 14 g/dL
Hematocrit: 41%
Leukocyte count: 7,500/mm^3 with normal differential
Platelet count: 199,000/mm^3

Serum:
Na+: 140 mEq/L
Cl-: 102 mEq/L
K+: 4.0 mEq/L
HCO3-: 23 mEq/L
BUN: 30 mg/dL
Glucose: 29 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Sulfonylurea level: undetectable
C-peptide level: 55 ng/mL (normal < 5 ng/mL)

Which of the following is the most likely etiology of this patient’s symptoms?

Answer: Beta cell tumor

Explanation:
This patient is presenting with confusion, profound hypoglycemia, an elevated C-peptide level, and a negative sulfonylurea level, which are concerning for an insulinoma. An insulinoma is a beta cell tumor that secretes insulin.

An insulinoma is a beta cell tumor of the pancreas. The beta cells normally secrete insulin in response to increased circulating fuel substrate (such as glucose or fat). In the setting of an insulinoma, insulin is pathologically and continuously secreted. This leads to profound, recurrent episodes of hypoglycemia. When a patient presents with hypoglycemia of unclear etiology; a blood glucose level, C-peptide level, and sulfonylurea level should be ordered. An infectious workup may be indicated as sepsis can also cause hypoglycemia. In an insulinoma, patients will be hypoglycemic, have an elevated C-peptide level (as this is a marker of endogenous insulin release), and a negative sulfonylurea level (important to rule out as a sulfonylurea overdose can also cause hypoglycemia in the setting of an elevated C-peptide level). Further workup will involve imaging of the abdomen such as a CT scan or MRI (more accurate) to delineate this insulin-secreting mass.

Mathur et al. discuss insulinoma. They note that it is a rare endocrine tumor, and note its association with multiple endocrine neoplasia type 1. They recommend workup for an insulinoma should occur in patients with recurrent episodes of hypoglycemia without a clear cause.

Incorrect Answers:
Answer A: Alpha cell tumor describes a glucagonoma, which pathologically secretes glucagon leading to profound hyperglycemia, a classic rash termed necrolytic migratory erythema (presents with painful, erythematous papules and plaques), and gastrointestinal symptoms including anorexia, abdominal pain, and diarrhea.

Answer B: Beta cell destruction describes the pathophysiology of type I diabetes mellitus, which presents in pediatric patients (most commonly) with hyperglycemia, weight loss, polydipsia, and polyuria. Treatment involves the administration of insulin. An initial presentation of type I diabetes may be diabetic ketoacidosis which presents with dehydration, abdominal pain, nausea, vomiting, Kussmaul respirations, and an anion gap acidosis.

Answer D: Insulin overdose would present with hypoglycemia, somnolence, confusion, and tremulousness. Note that exogenous insulin administration would not elevate the C-peptide level, which is a marker of endogenous insulin production.

Answer E: Sulfonylurea overdose would cause hypoglycemia that is often persistent given the long half-life of sulfonylureas. It would also elevate the C-peptide level as these medications increase the endogenous release of insulin. However, the sulfonylurea level was negative in this patient. While iatrogenic use of medications is plausible in this patient who has knowledge of medications (as she is a nurse), her repeat episodes and her workup suggesting against an iatrogenic etiology makes an insulinoma a more likely diagnosis.

Bullet Summary:
Insulinomas are beta cell tumors of the pancreas and lead to severe hypoglycemia and an elevated insulin and C-peptide level.


Question: A 67-year-old man presents to the emergency department after fainting. He was outside tending to his lawn for several hours in the heat, when he stood up suddenly from pulling weeds and fainted. He denies any preceding symptoms and returned to baseline within 1 minute. The patient is not aware of any medical problems and just started seeing a primary care physician last week. He recently used a friend's prescription for ondansetron for nausea. His temperature is 99.3°F (37.4°C), blood pressure is 142/88 mmHg, pulse is 107/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam reveals intact cranial nerves, normal strength and sensation, and a stable gait. His abdomen is soft and nontender. An ECG is performed as seen in Figure A. Which of the following is the most likely diagnosis based on this patient’s ECG?

Answer: Previous myocardial ischemia

Explanation:
This patient is presenting after syncope, likely secondary to dehydration and orthostatic hypotension given his outdoor gardening in the heat and symptoms when standing up rapidly. The patient’s ECG reveals deep, pathologic Q waves, which in this case are an incidental finding indicative of a previous myocardial infarction or a previous ischemic event.

The Q wave is a negative deflection just prior to the R wave. Q waves are a normal finding when they are small and are seen on most ECGs. However, pathologic Q waves are indicative of myocardial ischemia. Pathologic Q waves are generally diagnosed when they are >2 mm deep, >1 mm wide, >25% of the QRS complex height, or are seen in leads V1-V3. The interpretation of Q waves depends on other findings on ECG and the patient's symptoms. Deep Q waves in the setting of ST elevation indicate an acute myocardial infarction. On the other hand, pathologic Q waves found incidentally indicate a previous myocardial infarction or previous ischemic event.

Rovai et al. review Q waves. They discuss how Q waves can be used to predict the location and size of a myocardial infarction as correlated with MRI. They recommend testing such as cardiac MRI to assess for previous infarction in the appropriate patient population.

Figure/Illustration A is an ECG demonstrating pathologic Q waves (red arrows). Note the deep and wide Q waves; this raises concern for a past ischemic event.

Incorrect Answers:
Answer A: Acute myocardial infarctions would present with ST elevation in a vascular distribution on ECG with possible reciprocal depressions. While T wave inversions may be indicative of new or acute ischemia, deep pathologic Q waves without ST elevation are indicative of previous infarction.

Answer B: Hypokalemia would cause U waves on ECG, which appear as a small, "second T wave" after the initial T wave. Note they are not U-shaped despite their name. Management is centered on repletion of potassium and often magnesium as well.

Answer C: Intermittent torsades de pointes can cause syncope and should be suspected in a patient with syncope in the setting of a prolonged QT interval. This patient’s QT interval is not particularly prolonged, and his syncope seems to be secondary to orthostatic hypotension. Management is centered on cessation of QT-prolonging medications and magnesium administration. Note that while ondansetron does prolong the QT interval, it is unlikely to cause torsades given the patient took it a week ago.

Answer E: Pulmonary emboli would present on ECG with sinus tachycardia in addition to pleuritic chest pain and hypoxia. Note that the ECG is a nonspecific test for pulmonary emboli, and CT angiography is the preferred confirmatory test for this condition. Syncope is a possible presentation of larger pulmonary emboli (though the patient would also be hemodynamically unstable).

Bullet Summary:
Pathologic Q waves are indicative of a previous myocardial infarction.


Question: A 34-year-old man is brought to a rural emergency department by ambulance after being involved in a motor vehicle accident. Paramedics report that the patient was driving the car and crashed into a tree at roughly 25 miles per hour. There were no passengers and he was awake but disoriented at the scene. His temperature is 97.9°F (36.6°C), blood pressure is 131/88 mmHg, pulse is 89/min, and respirations are 14/min. He is speaking but is confused, opens his eyes to voice commands, and follows simple commands. He has multiple lacerations on his face and arms and smells of alcohol and marijuana. His cardiac exam is normal and his lungs are clear to auscultation bilaterally. He has bruising over his abdomen without any tenderness to palpation, distension, or rigidity. Which of the following is the most appropriate next step in management?

Chest radiograph anterior-posterior and lateral

Focused abdominal sonography for trauma exam

Answer: Abdominal and chest CT

Explanation:
This patient presents following a motor vehicle accident with a tender abdomen and stable vital signs. Given his stability, the most appropriate next step is an abdominal and chest CT.

In blunt abdominal trauma, the next step in management depends upon whether the patient is hemodynamically stable. With a normal blood pressure and pulse within the normal range, patients can undergo imaging to evaluate for injury to the abdominal organs with the most appropriate study being an abdominal CT with contrast. This study can accurately localize bleeding and aid in operative planning. A bedside ultrasound known as the FAST exam is often performed in unstable patients. Unstable patients, patients with abdominal tenderness, and patients with a severe mechanism of trauma may have a bedside FAST exam performed. If the free fluid is localized, the patient can be transferred directly to the operating room. Note that in many hospitals, the FAST exam is done simultaneously with the primary and secondary survey; however, if asked to choose which exam to perform on a trauma patient who is stable with no signs of a surgical abdomen, a CT scan should be performed to more accurately assess the patient's injuries and assess for injuries that may be missed by a FAST exam.

Feliciano reviewed the evidence surrounding the current diagnosis and management of abdominal trauma. He discusses how contrast-enhanced CT of the abdomen and pelvis is an important method for evaluating the etiology of intra-abdominal bleeding. He recommends considering damage control methods in the polytrauma patient.

Incorrect Answers:
Answer B: Chest radiography has limited utility in the setting of blunt abdominal trauma; however, a portable anterior-posterior film is often taken in trauma, in particular, when the patient is intoxicated. However, an anterior-posterior and lateral film would involve transporting the patient to radiology and positioning the patient. Thus it would be both difficult to obtain and less useful when compared to a CT scan given his traumatic injuries. Findings on chest radiograph could suggest abdominal injury, such as lower rib fractures or free air under the diaphragm, which would suggest intestinal perforation.

Answer C: Diagnostic laparoscopy may play a role in evaluating for injury in penetrating traumas such as gunshot wounds or stabbing wounds but would not be indicated as the most appropriate initial step in management in a stable patient. Unstable patients, surgical abdomens, and positive FAST exams or CT scans warrant transfer to the operating room.

Answer D: Diagnostic peritoneal lavage is a historical test to assess for intra-abdominal injury that was typically used with ambiguous FAST exams or patients where it was unclear whether there was abdominal bleeding; however, it has almost entirely been supplanted by the FAST exam.

Answer E: FAST exams are often performed with the primary or secondary survey in large institutions where resources are available. However, in small hospitals with limited resources, the most appropriate next step in management when deciding between a FAST exam or a CT scan should be made based on the mechanism and concern for bleeding. This stable patient with a benign exam can undergo a CT scan, which will offer more data than a FAST exam and would be performed regardless of whether a FAST exam was positive or negative given this patient's intoxication and abdominal bruising.

Bullet Summary:
In a patient who has experienced blunt abdominal trauma the most appropriate initial step in a stable patient is an abdominal CT scan.


Question: A 26-year-old man presents to the emergency department with fatigue and dark urine over the past day. He was recently diagnosed with cellulitis of his left leg, for which he was prescribed trimethoprim-sulfamethoxazole. He denies having nausea, vomiting, or diarrhea. He has no significant medical history and does not currently take any medications. His temperature is 98.6°F (37°C), blood pressure is 115/72 mmHg, pulse is 98/min, and respirations are 14/min. Physical exam reveals conjunctival icterus, bilateral flank tenderness, and erythema of the left leg. Laboratory workup is performed, and the results are shown below: Serum: Hemoglobin: 7.2 g/dL Total bilirubin: 2.1 mg/dL Direct bilirubin: 0.8 mg/dL Lactate dehydrogenase: 470 U/L Glucose-6-phosphate dehydrogenase: 7 U/gHb (normal: 6-20 U/gHb) Which of the following would most likely be seen on a peripheral blood smear in this patient?

Answer: Degmacytes

Explanation:
This patient presents with hemolytic anemia (low hemoglobin, elevated indirect bilirubin, and elevated lactate dehydrogenase) shortly after starting a sulfa medication (trimethoprim-sulfamethoxazole) in the setting of likely glucose-6-phosphate dehydrogenase deficiency. Degmacytes ("bite cells") will be seen on peripheral blood smears in these patients.

Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency will experience hemolytic anemia when exposed to an oxidizing substance such as sulfa drugs or fava beans. Laboratory tests will show a decrease in hemoglobin and hematocrit levels. Since hemolysis releases intracellular enzymes into the bloodstream, serum levels of lactate dehydrogenase will be increased. Hemoglobin is then metabolized in the spleen into unconjugated bilirubin, which will cause an elevated bilirubin level that is primarily indirect. In the acute setting, G6PD levels will be normal because the most compromised cells have all been hemolyzed. Obtaining a G6PD level in between episodes of hemolysis is therefore required to observe the chronically decreased G6PD in these patients. A peripheral blood smear will reveal degmacytes ("bite cells") and Heinz bodies. Avoidance of oxidative stress to red blood cells is the most important component of management in these patients.

Belfield and Tichy discuss the classic presentation of G6PD deficiency in patients. The authors review oxidizing medications such as rasburicase, primaquine, dapsone, pegloticase, and methylene blue. The authors recommend avoiding initiation of these medications whenever possible until a G6PD diagnostic test has been performed.

Incorrect Answers:
Answer A: Acanthocytes can be seen in patients with liver disease due to defective production of lipoproteins; however, these cells do not undergo acute hemolytic destruction. Patients with abetalipoproteinemia usually present with symptoms consistent with fat-soluble vitamin deficiency such as bleeding (vitamin K) or osteoporosis (vitamin D).

Answer B: Codocytes are most commonly seen in patients with thalassemia but can also generally be seen in all microcytic anemias. Patients with thalassemia will present with chronic anemia without acute episodes of hemolysis. The increased lactate dehydrogenase and bilirubin levels in this patient indicate an acute hemolytic event.

Answer D: Schistocytes can be seen in thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular coagulation (DIC). Patients with TTP present with thrombocytopenia, microangiopathic hemolytic anemia, fever, neurologic symptoms, and acute kidney injury. DIC is a common downstream pathway for many processes such as sepsis, malignancy, and eclampsia; however, it would present with diffuse clotting and bleeding from all sites.

Answer E: Spherocytes can be seen in hereditary spherocytosis, which may result in hemolysis during times of acute stress; however, this patient denies symptoms of nausea, vomiting, or diarrhea. Instead, the hemolysis in response to new foods is most likely due to exposure to oxidizing substances such as trimethoprim-sulfamethoxazole.

Bullet Summary:
Patients with glucose-6-phosphate dehydrogenase deficiency will experience hemolytic anemia in response to oxidizing substances and will have degmacytes (bite cells) on peripheral blood smear.


Question:
A 45-year-old man with history of IV drug use presents to the outpatient clinic with a history of fever for 5 days. He also endorses sweats, headache behind the eyes, sore throat, muscle and joint pain, and a new rash seen in Figure A. He reports that he traveled to Africa last year and returned from a vacation to Thailand 10 days ago. His immunizations are up to date, although he missed the pre-departure travel medicine consult before his trip to Thailand. His temperature is 101.5°F (38.6°C), blood pressure is 125/80 mmHg, pulse is 105/min, and respirations are 14/min. Laboratory testing reveals the following:

Leukocyte count: 2,400/mm^3
Hemoglobin: 13.4 g/dL
Hematocrit: 40%
Mean corpuscular volume: 81 µm^3
Platelets: 92,000/mm^3

Serum:
AST: 112 IU/L
ALT: 69 IU/L
ALP: 78 IU/L
Bilirubin: 0.9 mg/dL

Which of the following is the diagnostic test of choice for this disease?

Answer: Serologic testing

Explanation:
This patient is presenting with fever, headache with retro-orbital pain, muscle aches, joint pain, rash, leukopenia and thrombocytopenia, which are classic findings for dengue fever. The diagnostic test of choice for dengue is serology.

Dengue is a viral infection endemic to South Asia, Central and South America, and the Caribbean. Although most infections are asymptomatic, notable characteristics include headache with retro-orbital pain, bone pain ("break-bone fever"), leukopenia, and thrombocytopenia (< 100,000 /µL). Symptoms typically develop several days to 2 weeks following the bite of an infected mosquito. The diagnostic test of choice is a serologic antibody test, although PCR can also be used in the acute (< 3 days) phase of illness. Treatment is with supportive care including rehydration.

Jasamai et al. present the current treatment options for dengue fever. They discuss how supportive therapy is the mainstay of treatment as no antibody or antiviral treatments have been effective at this time. They recommend using effective preventive measures such as mosquito control in endemic areas.

Figure A is a clinical photograph demonstrating the maculopapular rash seen in dengue fever.

Incorrect Answers:
Answer A: Blood culture is used for the detection of bacterial infections of the blood. This patient's IV drug use puts him at risk for bacterial endocarditis, but he does not have other expected findings, such as new murmur, Janeway lesions, Roth spots, or Osler nodes. Endocarditis should be treated with intravenous antibiotics.

Answer B: Blood smear is the diagnostic test of choice for other mosquito-borne diseases such as malaria. It is not used in the detection of dengue. Malaria presents with cyclical fevers and organisms on blood smear. It can be treated with chloroquine and artesunate.

Answer D: Sputum with acid fast stain is the test of choice for tuberculosis. This patient has a risk factor of TB as he recently traveled to Africa, but he does not have any pulmonary symptoms. Treatment for tuberculosis is rifampin, isoniazid, pyrazinamide, and ethambutol therapy (among other possible regimens).

Answer E: Stool culture may be used to diagnose typhoid fever. Typhoid fever presents with many of the same non-specific symptoms as dengue but would also present with prominent abdominal pain and gastrointestinal symptoms. Typhoid can be treated with antibiotics such as ciprofloxacin.

Bullet Summary:
Dengue fever is characterized by fever, headache with retro-orbital pain, muscle and joint pain, rash, leukopenia and thrombocytopenia that can be diagnosed through serologic testing.


Question: A 30-year-old woman presents to the emergency department for palpitations. For 2 months, she has experienced intermittent palpitations along with menstrual irregularity and hair loss. At home, the air conditioner is at its coldest setting, but the patient still feels overheated. Her temperature is 99.5°F (37.5°C), blood pressure is 135/90 mmHg, pulse is 120/min, and respirations are 22/min. The patient is diaphoretic with tremulous hands, demonstrates thyromegaly, and protrusion of her eyes is noted. She is given atenolol in the emergency department with improvement of her palpitations and is instructed to follow up with her primary doctor for further management. Which of the following is most likely to be found in this patient after definitive treatment of her condition?

Answer: Exophthalmos

Explanation:
This patient presents with palpitations, tachycardia, tremor, heat intolerance, hair loss, menstrual irregularity, goiter, and exophthalmos concerning for hyperthyroidism due to Graves disease. Radioiodine ablation is the preferred definitive management for Graves disease, which can worsen exophthalmos.

Graves disease is an autoimmune hyperthyroid disorder caused by antibodies to the thyroid stimulating hormone receptor (TSHR), which induce production of T4 and triiodothyronine (T3). Overstimulation of the thyroid gland by TSHR antibodies results in diffuse enlargement of the thyroid gland, termed “goiter.” TSHR is also highly expressed in retro-ocular adipocytes and fibroblasts, where overstimulation by TSHR antibodies (and activated T-cells) leads to the expansion of retro-ocular connective tissue and extra-ocular muscle volume. This causes exophthalmos (bulging eyes) and is referred to as Graves ophthalmopathy or orbitopathy. Beta blockers are used to achieve acute sympathetic control in hyperthyroid Graves patients, and antithyroid medications (propylthiouracil or methimazole) are initiated to achieve a euthyroid state. Radioactive iodine ablation is first-line definitive management, particularly, for individuals with unsuccessful anti-thyroid medication management. Radioiodine ablation has been known to increase TSHR-antibodies, likely secondary to the leakage of thyroid antigens, and thus exophthalmos is often worsened after treatment. For this reason, corticosteroids are often co-administrated as a prophylactic measure.

Davies et al. review Graves disease including the pathophysiology and management. They note that Graves orbitopathy may be worsened by radioiodine ablation. They recommend further studies and advancements in care given this lasting complication.

Incorrect Answers:
Answer B: Hair loss can occur in hyperthyroid and hypothyroid states due to altered hair follicle stem cell function. However, this process is typically reversed, not worsened, after achieving a euthyroid state.

Answer C: Heat intolerance occurs in Graves disease due to hyperthyroid-induced sympathetic overactivity, which resolves after successful treatment.

Answer D: Menstrual irregularity occurs in hyperthyroidism through altered levels of sex hormone binding globulin, gonadotropin-releasing hormone, and prolactin. However, treatment of hyperthyroidism typically restores menstrual regularity. After ablation, patients will be hypothyroid; however, the standard of care is to start the patient on levothyroxine which should prevent this complication.

Answer E: Thyromegaly in Graves disease is caused by diffuse overactivation of the thyroid gland by the TSHR antibodies. Once treated with radioactive iodine (I-131), the thyroid gland gradually shrinks in size. Patients who undergo radioactive iodine ablation will later require life-long thyroxine supplementation due to resulting hypothyroidism.

Bullet Summary:
Definitive therapy for Graves disease is radioiodine ablation, which leads to increased TSHR antibodies and worsened exophthalmos from overactivation of TSHR-rich retro-ocular adipocytes and fibroblasts.


Question: A 1-year-old girl is brought to a neurologist due to increasing seizure frequency over the past 2 months. She recently underwent a neurology evaluation which revealed hypsarrhythmia on electroencephalography (EEG) with a mix of slow waves, multifocal spikes, and asynchrony. Her parents have noticed the patient occasionally stiffens and spreads her arms at home. She was born at 38-weeks gestational age without complications. She has no other medical problems. Her medications consist of lamotrigine and valproic acid. Her temperature is 98.3°F (36.8°C), blood pressure is 90/75 mmHg, pulse is 94/min, and respirations are 22/min. Physical exam reveals innumerable hypopigmented macules on the skin and an irregularly shaped, thickened, and elevated plaque on the lower back. Which of the following is most strongly associated with this patient's condition?

Answer: Cardiac rhabdomyoma

Explanation:
This patient with a seizure disorder, ash-leaf spots (innumerable hypopigmented macules), Shagreen patch (elevated irregular plaque on the lower back), and West syndrome (hypsarrhythmia on EEG and movements consistent with infantile spasms) likely has tuberous sclerosis. Tuberous sclerosis is associated with cardiac rhabdomyomas.

Tuberous sclerosis is a neurocutaneous disorder that is inherited in an autosomal dominant fashion. Mutations in TSC1 and TSC2 lead to unregulated cell growth, leading to the formation of hamartomas in various locations. Manifestations of tuberous sclerosis include seizures (secondary to subependymal nodules and cortical dysplasia), mental retardation, renal angiomyolipomas, facial angiofibromas, mitral regurgitation, and hypomelanotic macules (ash-leaf spots). Cardiac rhabdomyoma is strongly associated with tuberous sclerosis and can lead to arrhythmias. West syndrome, which is characterized by infantile spasms, intellectual disability, and hypsarrhythmia (a chaotic mixture of high-amplitude slow waves, multifocal spikes, and intrahemispheric-interhemispheric asynchrony) on EEG, is also associated with tuberous sclerosis. Diagnosis of tuberous sclerosis is made with genetic testing. Advanced imaging (CT or MRI) may reveal cortical tubers and lesions in the third and fourth ventricles. Abdominal imaging may reveal renal angiomyolipomas. The management of seizures in tuberous sclerosis includes anti-seizure medications, though surgery may also be pursued in select cases.

Hinton et al. studied the cardiac manifestations of tuberous sclerosis. They found that cardiac rhabdomyomas can lead to arrhythmia later in life. They recommended that infantile spasms in tuberous sclerosis be treated with vigabatrin but other seizure types should be treated similar to other epileptic disorders.

Incorrect Answers:
Answer B: Glaucoma may occur in patients with Sturge-Weber syndrome, which is characterized by "tram-track" calcifications in the brain, port-wine stains of the face, mental retardation, and epilepsy. Diagnosis is with MRI of the brain with contrast to demonstrate leptomeningeal vascular malformations that are characteristic of the disease.

Answer C: Optic glioma is associated with neurofibromatosis type 1 (NF1), which presents with hyperpigmented macules (cafe-au-lait spots), axillary freckling, and cutaneous neurofibromas. Neurofibromas in NF1 may also grow on peripheral nerves, leading to malignant peripheral nerve sheath tumors. Lisch nodules, or benign growths of the iris, may also be seen in NF1. Diagnosis of NF1 is clinical, but can be aided by genetic testing.

Answer D: Polyostotic fibrous dysplasia is associated with McCune-Albright syndrome. Polyostotic fibrous dysplasia causes fibrous tissue in bones, leading to growth abnormalities and pathologic fractures. McCune-Albright syndrome is also associated with cafe-au-lait macules, which have irregular borders, and endocrine abnormalities such as precocious puberty and hyperthyroidism. Diagnosis is supported with endocrine tests as well as genetic testing.

Answer E: Renal cell carcinoma is associated with Von-Hippel-Lindau syndrome (VHL), which presents with tumors arising in multiple organs. Patients with VHL present with hemangioblastomas in the brain, spinal cord, cerebellum, and retina, and pheochromocytoma. Pheochromocytomas release catecholamines, leading to episodic hypertension, diaphoresis, and palpitations. Diagnosis of VHL is with genetic testing.

Bullet Summary:
Tuberous sclerosis has numerous manifestations including seizures, angiofibromas, mitral regurgitation, renal angiomyolipoma, ash-leaf spots, mental retardation, and cardiac rhabdomyoma.


Question: A 17-year-old boy presents to his primary care physician with a chief concern of "bad" skin that has not improved despite home remedies. The patient has had lesions on his face that have persisted since he was 13 years of age. He has a diet high in refined carbohydrates and has gained 20 pounds since starting high school. Physical exam is notable for the findings in Figure A. The patient is started on benzoyl peroxide and topical retinoids. He returns 1 month later stating that his symptoms are roughly the same. Which of the following is the most appropriate next step in management?

Continue current therapy for 1 more month

Answer: Topical antibiotics

Explanation:
This patient is presenting with persistent acne vulgaris that is refractory to topical benzoyl peroxide and retinoids. The next step in management is topical antibiotics.

Acne vulgaris is caused by blockage or outlet obstruction of the pilosebaceous unit. It presents with erythema, pustules, and comedones typically in young men going through puberty. Risk factors include stress, excessive sweating, greasy skin care products, and steroid use. The management of acne vulgaris, in order, is to start with topical benzoyl peroxide and topical retinoids, topical antibiotics, oral antibiotics, and isoretinoin. It is important to try a therapy for a proper duration before switching to a more invasive therapy.

Eichenfield et al. review the evidence regarding the treatment of patients with acne vulgaris. They discuss how this disease can be treated with benzoyl peroxide. They recommend using antibiotics or isotretinoin for refractory cases.

Figure/Illustration A is a clinical photograph demonstrating diffuse comedones over the forehead (red circle). These findings are classically seen in patients with acne vulgaris.

Incorrect Answers:
Answer A: Continuing current therapy for 1 more month is unnecessary as this patient's symptoms have not improved at all with 1 month of therapy. Continuing current therapy would be appropriate if the patient had only tried therapy for a few days.

Answer B: Dietary interventions have not been shown to improve outcomes in acne vulgaris. Stopping illicit substances such as performance enhancing steroids can be effective in reducing acne symptoms but there is no evidence this patient has been using steroids.

Answer C: Isoretinoin is the last-line therapy for acne vulgaris. It should not be given to pregnant women as it is teratogenic. Women taking isoretinoin should be on reliable birth control. Topical and oral antibiotics should be used first.

Answer D: Oral antibiotics would be indicated after topical antibiotics fail. Topical antibiotics should be tried first as these do not have systemic side effects.

Bullet Summary:
The management of acne vulgaris is to start with topical benzoyl peroxide and topical retinoids, followed by topical antibiotics, oral antibiotics, and isoretinoin in increasing order of severity.


Question: A 55-year-old woman is brought to the emergency department by her husband with a 1 hour history of an unremitting headache. The headache started suddenly while she was eating dinner and she says it feels like the “worst headache of my life.” An emergent CT scan of the head without contrast confirms the diagnosis, and a CT angiogram identifies the source of bleeding. The patient undergoes surgical management of her condition. On hospital day 3, she is found to be disoriented to person, place, and time. She also develops nausea and vomiting. Her medical problems consist of heart failure for which she takes furosemide, spironolactone, and metoprolol, which were continued at admission. Her temperature is 99.6°F (37.6°C), blood pressure is 100/60 mmHg, pulse is 112/min, and respirations are 16/min. Physical examination shows poor skin turgor. Capillary refill time is 4 seconds. Serum laboratory results are shown below: Na+: 120 mEq/L Cl-: 92 mEq/L K+: 3.9 mEq/L HCO3-: 26 mEq/L BUN: 32 mg/dL Creatinine: 1.0 mg/dL Serum osmolality is 265 mEq/L and urine osmolality is 340 mEq/L. Urine sodium is 44 mEq/L. Which of the following is the most likely diagnosis?

Answer: Cerebral salt wasting

Explanation:
This patient presents with a subarachnoid hemorrhage (“worst headache of my life”) which is treated and then subsequently develops nausea, vomiting, and altered mental status with reduced serum sodium concentration, indicative of symptomatic hyponatremia. In the setting of serum hypo-osmolality, urine hyper-osmolality, urine sodium concentration > 20 mEq/L, and hypovolemia (low blood pressure, decreased skin turgor, and prolonged capillary refill), this is indicative of cerebral salt wasting.

The mechanism of cerebral salt wasting is unclear, although some hypotheses point to increased release of brain natriuretic peptide after injury leading to suppression of renal sodium reabsorption, or sympathetic nervous system injury resulting in an impaired renin response. Patients classically present several days after cerebral injury or neurosurgery with hypovolemic hyponatremia and hypochloremia. Water retention results in serum hypo-osmolality, hyponatremia, and hypochloremia with urine hyper-osmolality and increased urine sodium excretion. In patients with prolonged cerebral salt wasting, hypokalemia can also occur (potassium may be normal in acute states). Treatment in mild or moderate cases consists of normal saline infusion to correct both volume status and hyponatremia. Treatment in severe cases consists of hypertonic saline. During correction, serum sodium must be monitored closely to prevent central pontine myelinolysis.

Cui et al. describe the differences between syndrome of inappropriate anti-diuretic hormone (SIADH) and cerebral salt wasting. They discuss how volume status serves as the key differentiator between these conditions. They recommend paying closer attention to total body electrolyte balance in understanding these conditions.

Incorrect Answers:
Answer A: Addison disease, also known as primary adrenal insufficiency, results in salt wasting due to decreased mineralocorticoid activity. Because of reduced aldosterone release, patients also have hyperkalemia and metabolic acidosis. In contrast, this patient’s potassium and bicarbonate levels are normal. Treatment is with steroids.

Answer C: Diuretic overuse is occasionally observed in patients using loop diuretics. Overuse of loop diuretics can cause hyponatremia, hypokalemia, and hypochloremia. Metabolic alkalosis is commonly seen due to volume contraction. Cerebral salt wasting is more likely in this patient presenting after a recent cerebral injury. Treatment is the cessation of the causative medication.

Answer D: Primary polydipsia can cause symptomatic hyponatremia. The urine would be maximally diluted (urine osmolality < 100 mEq/L) due to an appropriate physiological response to hyponatremia and excess free water intake. Treatment is cessation of excessive water consumption.

Answer E: Syndrome of inappropriate anti-diuretic hormone (SIADH) presents with identical findings as cerebral salt wasting with the exception of euvolemia as opposed to hypovolemia. An assessment of volume status is essential to differentiate. This patient has clear signs of hypovolemia. Treatment of SIADH is fluid restriction followed by ADH inhibitors, if needed.

Bullet Summary:
Cerebral salt wasting presents with hyponatremia, hypochloremia, and hypovolemia in the setting of recent cerebral injury or neurosurgery.


Question: A 69-year-old man passes away after a 3-week hospitalization for liver failure, complicated by a myocardial infarction. A medical student rotating in the intensive care unit asked if she can practice performing intubations during her rotation. The resident suggests performing one on the deceased patient, as the student cannot harm him. Which of the following is the most appropriate course of action for the medical student?

Ask the resident if the patient’s family or the patient has been consented for this procedure

Contact the patient's family to ask for permission to perform the procedure

Intubate the patient with the resident's supervision

Report the resident to hospital administration

Answer: Ask the resident if the patient’s family or the patient has been consented for this procedure

Explanation:
This medical student wants to perform a procedure on a deceased patient for educational purposes. Before proceeding, the student should ensure that permission has been obtained from the patient's family or the patient when he was alive.

Performing procedures on deceased patients is ethically permissible with appropriate consent and consideration of risks and benefits for patients, families, learners, staff, and the field of medicine. Supervising physicians must obtain informed consent from the patient while alive and with capacity or from a newly deceased patient’s healthcare proxy or family. During the consent process, the supervisor should outline the patient's and family's rights, wider educational and societal benefits, potential risks, and ensure that performing the procedure would be consistent with the patient's values and wishes. Additionally, the supervising physician has a responsibility to ensure that a medical examiner has cleared the patient and that the patient is not an organ donor before proceeding. Finally, the procedure should be documented in the patient's chart.

Berger and Cassell review the ethics of practicing procedures on deceased patients. They note that some ethical norms may suggest this practice is not appropriate. They recommend performing procedures when consent is obtained and it is ethically acceptable to do so.

Incorrect Answers:
Answer B: Consulting the hospital ethics committee is not necessary, for with proper permission, trainees may perform procedures on deceased patients for educational purposes. The ethics committee should only be consulted when there is no clear course of action (an example may be no advanced directive with family members disagreeing on what the patient's wishes would have been for a critically ill patient).

Answer C: Contacting the patient's family to ask for permission to perform the procedure is incorrect, as the supervising physician needs to verify and document consent. Medical students cannot consent patients and family members. Moreover, the family should not be contacted if the patient has already approved or refused this when he had capacity.

Answer D: Intubating the patient with the resident's supervision is incorrect because proper permission must be ensured prior to performing educational procedures on deceased patients.

Answer E: Reporting the resident to hospital administration is incorrect because it is ethically permissible to perform an intubation on a deceased patient provided there is proper permission. The resident is not asking the medical student to do anything illegal or against hospital policy. Reporting the resident may be indicated if the resident was performing procedures against the patient's will.

Bullet Summary:
Trainees may perform procedures for educational purposes on deceased patients if permission is obtained from the patient prior to death, the patient's family, or a healthcare proxy.


Question:
A 26-year-old man presents to his primary care physician with a 6-month history of increasing lower back pain. He first felt the pain while lifting boxes at work but thought that he had just strained a muscle. The pain appears to be worse in the mornings and after rest. Exercise and physical activity appear to temporarily make the pain better. He has taken acetaminophen and ibuprofen for the pain. He has no significant medical history and takes no medications. His temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 70/min, and respirations are 12/min. On physical exam, he is found to have limited flexion and extension of his spine as well as tenderness to palpation over the insertion of his patellar tendons bilaterally. Results from laboratory tests are shown below:

Serum:
Erythrocyte sedimentation rate (ESR): 61 mm/hr
C-reactive protein (CRP): 36 mg/L (normal <10 mg/L)

Which of the following is the most accurate test for this patient's condition?

Answer: Magnetic resonance imaging

Explanation:
This young man presents with low back pain that is relieved by physical activity, decreased spinal mobility, enthesitis of his patellar tendons, and elevated ESR/CRP values most likely has ankylosing spondylitis (AS). The most accurate diagnostic test for early ankylosing spondylitis is MRI.

Multiple imaging tests can diagnose ankylosing spondylitis. Radiographs of the spine will show squaring of vertebrae with vertical or marginal syndesmophytes resulting in a "bamboo spine" appearance. The earliest radiographic sign is the erosion of the iliac side of the sacroiliac joint, but this finding is not sensitive in the early stages of the disease. MRI is sensitive in detecting sacroiliac inflammation, which makes this the best modality for early detection of ankylosing spondylitis in young patients. Initial therapy for ankylosing spondylitis includes lifestyle modifications (exercise, smoking cessation, physical therapy) and non-steroidal anti-inflammatory drugs (NSAIDs). Therapy for patients with inadequate response to NSAIDs includes tumor necrosis factor inhibitors (etanercept, infliximab, adalimumab) and interleukin 17 inhibitors (secukinumab, ixekizumab).

Jung et al. studied whether signs of inflammation on MRI are correlated with bone quality in patients with ankylosing spondylitis. The authors find that bone marrow edema is negatively correlated with the trabecular bone score. The authors recommend control of active bone inflammation to prevent osteoporosis in patients with ankylosing spondylitis.

Incorrect Answers:
Answer A: Bone scan will show inflammation in the sacroiliac joints, but this study lacks specificity for this disease compared with other inflammatory forms of arthritis.

Answer B: CT will show bony changes but not active inflammation, so it is most commonly used to diagnose cervical fractures in patients with ankylosing spondylitis. While it can support the diagnosis, it is less accurate than an MRI.

Answer D: Radiographs will show erosion of the iliac side of the sacroiliac joint, but this finding is not sensitive in the early stages of the disease when bony ankylosis has not yet occurred. Radiographs may be an appropriate initial test.

Answer E: Ultrasound is useful in evaluating muscle strains or tendon tears; however, it is not able to detect bony abnormalities and is therefore of limited use in ankylosing spondylitis.

Bullet Summary:
MRI is the most sensitive and accurate test for the early detection of ankylosing spondylitis.


Question: A 62-year-old man presents to the emergency department with chest pain and shortness of breath that he experienced while barbecuing. The pain is over his chest and in his left arm. The patient has a medical history of obesity, type 2 diabetes mellitus, and hypertension. His current medications include insulin, metformin, lisinopril, and hydrochlorothiazide. An ECG is performed and is seen in Figure A. His temperature is 99.5°F (37.5°C), pulse is 112/min, blood pressure is 100/70 mmHg, respirations are 18/min, and oxygen saturation is 95% on room air. The patient is appropriately managed and is admitted to the step-down unit. 2 days later, he complains of chest pain. A repeat ECG is performed and is seen in Figure B. Which of the following is the most appropriate next step in management for this patient's underlying condition?

Answer: Aspirin

Explanation:
This patient is presenting with chest pain several days after sustaining a myocardial infarction and has an ECG suggestive of pericarditis. This presentation is consistent with Dressler syndrome and the most appropriate initial step in management is aspirin.

Dressler syndrome is pericarditis that can occur after a myocardial infarction (MI). It most commonly occurs weeks to months after the MI, but can also occur within 1 week from an MI in rare cases. It is believed to result from an autoimmune reaction that occurs after damage to the heart (surgery and MI). It presents with chest pain, fever, pleuritic pain, and a pericardial friction rub. ECG demonstrates diffuse ST elevation with PR depression consistent with pericarditis. The most appropriate initial step in the management of this condition is symptomatic management with aspirin.

Leib et al. review the evidence regarding the diagnosis and treatment of Dressler syndrome. They discuss how this condition is secondary pericarditis with or without pericardial effusion resulting from injury to the heart or pericardium. They recommend considering this syndrome in all patients with chest pain after a myocardial infarction.

Figure/Illustration A demonstrates an ECG with ST elevation in leads II, III, and aVF (blue circles) suggesting a diagnosis of right-sided MI.

Figure/Illustration B demonstrates an ECG with diffuse ST elevation and PR depression (blue circles) suggesting a diagnosis of pericarditis.

Incorrect Answers:
Answers 1 & 5: Angiography and stenting would be appropriate management if this patient were experiencing a repeat MI. The diffuse ST elevation and PR depression seen several days after his myocardial infarction are more indicative of pericarditis rather than a repeat MI. In addition, the chest pain the patient is experiencing can also occur in pericarditis and obfuscates the diagnosis of repeat MI.

Answers 3 & 4: Ibuprofen, other NSAIDs, and corticosteroids such as prednisone are not first-line therapy in post-MI pericarditis as they can hinder the healing and remodeling process of the myocardium. Current guidelines dictate that they may be used in cases that are refractory to initial therapy.

Bullet Summary:
Dressler syndrome (post-MI pericarditis) presents with chest pain, pericardial friction rub, fever, and diffuse ST elevation with PR depression on ECG, and should be treated initially with aspirin.


Question:
A 6-year-old boy presents to the emergency department after falling from his scooter. He has dull, aching pain along his left side where he hit the ground. He fell sideways off the scooter as he rounded a curve in the road. He has never had any serious injuries but that he always seems to bruise easily, especially after he started playing soccer this fall. His parents deny that he has an abnormal number of nosebleeds or bleeding from the gums. They have never seen blood in his stool or urine. His mother notes that her brother has had similar problems. His temperature is 98.6°F (37°C), blood pressure is 112/74 mmHg, pulse is 82/min, and respirations are 11/min. On physical exam, the patient has extensive bruising of the lateral left thigh and tenderness to palpation. Laboratory tests are performed and reveal the following:

Hemoglobin: 14 g/dL
Hematocrit: 41%
Mean corpuscular volume: 89 µm3
Reticulocyte count: 0.8%
Leukocyte count: 4,700/mm3
Prothrombin time (PT): 13 seconds
Partial thromboplastin time (PTT): 56 seconds
Bleeding time (BT): 4 minutes

Which of the following is the most likely underlying pathophysiology?

Answer: Factor 8 deficiency

Explanation:
This young patient presents with extensive bruising following an injury, a family history of blood disorder, and a prolonged partial thromboplastin time (PTT) with a normal prothrombin time (PT) and bleeding time. These findings suggest a diagnosis of hemophilia A caused by factor 8 deficiency.

Hemophilia is a deficiency of factor 8 (hemophilia A) or factor 9 (hemophilia B). Common symptoms of hemophilia include hemarthrosis, intramuscular hematoma, and gastrointestinal or genitourinary bleeding. Laboratory testing is helpful in confirming the diagnosis, as hemophilia is characterized by an isolated prolongation of PTT without a change in PT. The factors involved in hemophilia participate only in the indirect cascade of coagulation factor activation. Similarly, since bleeding time depends only upon platelet function and not coagulation factors, hemophilia presents with a normal bleeding time. Treatment of hemophilia includes desmopressin in mild cases and factor replacement in moderate to severe disease.

Berntorp et al. present a review of the evidence regarding the diagnosis and treatment of hemophilia. They discuss how these patients now have normal life expectancies with the advent of factor replacement therapy. They recommend being vigilant for the development of anti-factor antibodies.

Incorrect Answers:
Answer A: Anti-platelet antibodies are responsible for idiopathic thrombocytopenic purpura (ITP). This disease is caused by autoimmune antibody formation that damages platelets and causes them to be removed by splenic macrophages in the reticuloendothelial system. It usually occurs in children after an acute viral infection and it presents with bleeding from mucosal surfaces with laboratory findings showing an increased bleeding time, decreased platelets, and a normal PT/PTT.

Answer C: Factor 9 deficiency (hemophilia B) presents nearly identically to hemophilia A with a normal PT, prolonged PTT, and normal bleeding time with a history of bleeding in male relatives. However, because hemophilia B is epidemiologically less common than hemophilia A, hemophilia A is a more likely diagnosis.

Answer D: GP1b deficiency causes Bernard-Soulier syndrome, which is a bleeding disorder characterized by unusually large platelets and a low platelet count. Like von Willebrand disease (vWD), patients often present with cutaneous and mucosal bleeding, abnormal bleeding from minor trauma, and a prolonged bleeding time, which this patient does not have. It can be distinguished from vWD by a ristocetin assay. Treatment can include tranexamic acid.

Answer E: Von Willebrand factor deficiency results in vWD, which is a bleeding disorder characterized by cutaneous and mucosal bleeding, menorrhagia, and gastrointestinal bleeding. Unlike this patient, patients with vWD also present with a prolonged bleeding time. Patients with vWD will also have an increased PT because this factor is responsible for stabilizing coagulation factor 8.

Bullet Summary:
Hemophilia A is caused by factor 8 deficiency and presents with hemarthrosis, frequent bruising, intramuscular hematoma, and gastrointestinal bleeding with a prolonged PTT with a normal PT and bleeding time.


Question: A 4-week-old boy is brought to the pediatrician by his parents for an initial evaluation. His parents are concerned that he is not feeding well and has lost weight over the last 2 weeks. He was born at home via spontaneous vaginal delivery at 37 weeks of gestation to a G1P1 mother. His mother did not receive prenatal care. His blood pressure is 70/44 mmHg, pulse is 151/min, and respirations are 41/min. His weight is 3 kg (4th percentile) compared with 3.5 kg at birth (45th percentile). On physical exam, he is jaundiced with an enlarged liver and spleen. He does not appear to respond to visual stimuli, and further examination reveals bilateral clouding of the lens. Which of the following interventions could have avoided this patient's symptoms?

Removing phenylalanine from maternal diet during pregnancy

Answer: Changing to a soy based formula

Explanation:
This patient who presents with failure to thrive, hepatosplenomegaly, and bilateral cataracts most likely has classic galactosemia. Patients with this disorder should avoid lactose-containing products by changing to a soy-based formula.

Classic galactosemia is an autosomal recessive defect in galactose-1-phosphate uridyltransferase. This enzyme is involved in the conversion of galactose to glucose, and a deficiency of this enzyme results in the accumulation of galactose 1-phosphate in the liver, kidney, and brain. This metabolite acts as a phosphate sink, meaning that it traps all free phosphate in the cytosol and inhibits the formation of other phosphate-dependent metabolites such as adenosine triphosphate. This results in failure to thrive, vomiting, lethargy, and hepatosplenomegaly after ingestion of galactose-containing products such as milk. Patients will also develop bilateral cataracts if the deficit is not detected in the first few weeks after birth. Avoiding galactose by changing to a soy-based formula will avoid the complications of this disorder.

Turck discusses using soy protein for infant feeding. The author notes that there are safety concerns with regards to the high phyto-estrogenic isoflavone content of these formulas. The author recommends that despite these safety concerns, these formulas should still be used in patients with classic galactosemia.

Incorrect Answers:
Answer A: Avoiding fruit juice and sweetened foods would be effective in the treatment of hereditary fructose intolerance. This disease presents similarly to classic galactosemia, but cataracts would not be seen in patients with this disease.

Answer C: Providing imiglucerase enzyme replacement would be effective in the treatment of patients with Gaucher disease, which can also present with failure to thrive. However, associated findings in this disease would be anemia and avascular necrosis of the bones.

Answer D: Removing phenylalanine from the maternal diet during pregnancy would be effective in the treatment of patients with phenylketonuria, which can also present with failure to thrive. However, these patients classically present with a "musty smell" and eczema.

Answer E: Vitamin B6 supplementation may be effective in mitigating the negative symptoms of homocystinuria. This disease may also present with cataracts or lens dislocations. Associated findings in this disorder would be marfanoid appearance and arachnodactyly.

Bullet Summary:
Patients with classic galactosemia should not be breastfed and should receive a galactose-free and lactose-free diet such as soy-based formulas.


Question: A 25-year-old man presents to his gastroenterologist for trouble swallowing. Whenever he eats solids, he regurgitates them back up. Given this patient's suspected diagnosis, the gastroenterologist performs a diagnostic test. Several hours later, the patient presents to the emergency department with chest pain and shortness of breath. His temperature is 99.5°F (37.5°C), blood pressure is 130/85 mmHg, pulse is 60/min, respirations are 12/min, and oxygen saturation is 99% on room air. On physical exam, the patient demonstrates a normal cardiopulmonary exam. His physical exam demonstrates no tenderness of the neck, a normal oropharynx, palpable crepitus above the clavicles, and minor lymphadenopathy. Which of the following is the most appropriate next step in management?

Answer: Gastrografin swallow

Explanation:
This patient is presenting with chest pain and palpable crepitus after endoscopy suggesting a diagnosis of esophageal perforation. The most appropriate next step in management is a gastrografin swallow.

Esophageal perforation presents with severe chest pain and palpable crepitus typically occurring after endoscopy or repeated forceful vomiting. The most appropriate initial step in management is a water-soluble contrast image (gastrografin) in order to confirm the diagnosis. Alternatively, a CT scan or radiograph may also be appropriate initially. Once the diagnosis is confirmed, surgical correction is necessary in order to prevent gastric contents from continuing to enter the mediastinum. Broad-spectrum antibiotics and proton pump inhibitors should also be administered.

Kim reviews the factors associated with esophageal perforation and rupture. They discuss how causes include foreign body, iatrogenic, trauma, and forceful vomiting. They recommend urgent surgical treatment.

Incorrect Answers:
Answer A: Barium swallow would be inappropriate as it is an irritating substance and could travel out of the perforated esophagus. This substance is only used in rare cases when gastrografin is not revealing, per the discretion of the surgeon.

Answer C: MRI would appropriately diagnose the condition but acquiring such imaging would take too long for such an urgent presentation. A gastrografin swallow is a more appropriate initial test.

Answer D: Ultrasound is inappropriate as it does not demonstrate the location of the perforation and the information obtained is dependent on the habitus of the patient and the operator.

Answer E: Urgent surgery would be necessary once the diagnosis is confirmed. Performing a rapid diagnostic step is necessary in order to establish the diagnosis first.

Bullet Summary:
The most appropriate initial step in the management of esophageal perforation is a gastrografin swallow followed by surgery.


Question: A 25-year-old woman is brought to the emergency department by her family. They found her somnolent next to her computer with an empty pill bottle around 3 hours ago. The family cannot recall the types of pill bottles that they found and did not bring them to the ED. The patient's medical history is notable for anxiety, obesity, hypertension, and polycystic ovarian syndrome. She is currently not on any medications. She was given an exercise program but she has not been compliant with these exercises. Her temperature is 99.5°F (37.5°C), pulse is 82/min, blood pressure is 125/85 mmHg, respirations are 11/min, and oxygen saturation is 97% on room air. Physical exam is within normal limits. The patient begins communicating with the physician and states that she did take acetaminophen but it was only a few pills. Her parents are certain the bottle was new. Which of the following is the most appropriate next step in management?

Answer: N-acetylcysteine

Explanation:
This patient is presenting with acute acetaminophen intoxication. The most appropriate next step in management is to administer the antidote N-acetyl cysteine (NAC).

In a toxicology case where the ingestion is unknown, the most appropriate initial step in management is to begin treatment empirically with IV fluids, charcoal, NAC, naloxone, and glucose if needed. These agents are effective against the most common causes of intoxication. In cases where there is known acetaminophen ingestion, the most important treatment is prompt administration of NAC. This medication works by increasing the hepatic production of glutathione, which detoxifies the toxic metabolite of acetaminophen N-acetyl-p-benzoquinone imine (NAPQI). NAC is a safe, cheap, and effective treatment that could be life-saving if administered in a timely fashion. In massive overdoses, it is appropriate to start treatment empirically as it can be discontinued later. Otherwise, a 4 hour acetaminophen level should be collected and the level should be plotted on the Rumack Matthew nomogram to determine treatment. In chronic acetaminophen toxicity, the acute serum level play no role in guiding treatment.

Chiew et al. performed a meta-analysis regarding the treatment of acetaminophen overdose. They found that the administration of charcoal immediately after ingestion can decrease the rate of absorption of acetaminophen. They recommend early administration of N-acetyl cysteine in order to decrease the hepatotoxicity of this substance.

Incorrect Answers:
Answer A: Blood acetaminophen levels should be ordered, but it is much less dire to confirm the diagnosis than it is to begin treatment given the high fatality rate with untreated acetaminophen overdose. Testing for all common intoxication should proceed while treatment is being administered. In this case, the concern for consumption of an entire bottle of acetaminophen would make it reasonable to treat first.

Answer B: Charcoal is an appropriate intervention if it is given in a timely manner; however, this patient consumed acetaminophen over 2 hours ago. In general, if the patient's airway is secure, it does no harm and could offer some benefit by decreasing the absorption of the substance of interest.

Answer C: IV fluid administration is the most appropriate initial step in the management of trauma when there is suspected bleeding and vitals are unstable (hypotension and tachycardia). Fluids are not urgently needed in this toxicity case with a patient who has stable vitals.

Answer E: Syrup of ipecac induces emesis in patients and was previously used in an attempt to have the patient vomit the toxic substance. This is no longer a preferred method of managing toxicities as patients can aspirate the vomitus or the toxic substance can induce more tissue damage during vomiting. In general, syrup of ipecac is the wrong answer choice for all toxicity cases.

Bullet Summary:
Acetaminophen toxicity should be treated immediately with N-acetyl cysteine followed by further diagnostic workup including serum acetaminophen levels.


Question: A 22-year-old woman presents to the emergency department with shortness of breath. She was hiking when she suddenly felt unable to breathe and had to take slow deep breaths to improve her symptoms. The patient is a Swedish foreign exchange student and does not speak any English. Her medical history and current medications are unknown. Her temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 120/min, respirations are 22/min, and oxygen saturation is 90% on room air. Physical exam is notable for poor air movement bilaterally and tachycardia. The patient is started on treatment. Which of the following parameters including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and diffusing capacity of carbon monoxide (DLCO) most appropriately describes this patient's underlying pathology?

Answer: Normal DLCO

Explanation:
This patient who presents with dyspnea and poor air movement bilaterally most likely has an acute asthma exacerbation. DLCO is the one parameter that is normal in these episodes.

Asthma is an obstructive lung disease that results in intermittent episodes of respiratory compromise. Asthma presents with shortness of breath typically secondary to an allergen/antigen or with exposure to exercise or cold air that causes bronchospasm. Pulmonary function testing will typically reveal a decreased FEV1, a decreased FVC, and a decreased FEV1/FVC in both asthma and emphysema. The DLCO will be normal in asthma in contrast to emphysema where the DLCO is decreased. Patients should be treated with inhaled beta-adrenergic agonists and corticosteroids for acute exacerbations.

Peng et al. review the evidence regarding patients who have COPD versus asthma. They discuss how patients with COPD have reduced DLCO. They recommend measuring parameters to distinguish between these entities.

Incorrect Answers:
Answer A: Decreased airway tone does not describe asthma. Rather, hyperreactive airways with increased tone describes an asthma attack. Decreased airway tone may be seen in patients with connective tissue diseases such as Ehlers-Danlos syndrome.

Answers 2-4: Increased FEV1, FEV1/FVC, and FVC do not describe asthma. All of these laboratory values are decreased in asthma and emphysema. Increased respiratory performance can be seen in patients who are athletes or training for marathons.

Bullet Summary:
Both asthma and emphysema present with a decreased FEV1, FVC, and FEV1/FVC; however, asthma has a normal DLCO while COPD has a reduced DLCO.


Question: A 7-year-old boy presents to the emergency department after an episode of jerking his extremities followed by confusion. This has happened in the past, but his mother thought he was fabricating his symptoms. She has taken him to a free health clinic to have him seen by a doctor who prescribed medication; however, she has been unable to fill the prescription. He has had an MRI of the brain with no acute findings in the past. The mother states this episode lasted about 3 minutes and involved full-body jerking. After the episode, the child was non-responsive but was breathing on his own. The child has a history of migraine headaches with aura that resolve with ibuprofen. He is otherwise healthy and has no medical problems or recent illness and is up to date on his vaccinations. His temperature is 97.6°F (36.4°C), blood pressure is 100/64 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 99% on room air. The patient is protecting his airway but is unable to answer questions. He is able to move the right upper and lower extremity. He initially is unable to move his left upper and lower extremity and has a left facial droop; however, after a few minutes, he has 4/5 strength in the affected side with resolution of his facial weakness. The mother notes that this is similar to his past episodes. Which of the following is the most appropriate management?

Answer: Observation

Explanation:
This patient is presenting after a seizure (tonic-clonic jerking of his extremities) and is currently postictal given that he is obtunded. Given that the patient is not moving the left side of his body, he is likely suffering from Todd paralysis, which can occur after seizures and resolves on its own with only observation.

A generalized tonic-clonic seizure may present with full-body tonic-clonic activity with altered mental status. After a generalized tonic-clonic seizure, patients can be postictal and appear to be obtunded. Other than ensuring adequate oxygenation/ventilation and evaluating for the cause of the seizure, there is no further intervention needed as this postictal state will improve with time. After seizures, some patients present with Todd paralysis, which is a focal paralysis after a seizure. This may mimic a stroke, and thus the patient’s risk factors and known seizure history should be factored into the decision. Todd paralysis does not require any intervention and will improve with time and observation only.

Xu et al. review Todd paralysis. They note that Todd paralysis is characterized by temporary limb weakness or hemiplegia and usually occurs following a seizure. They recommend that it can be difficult to differentiate Todd paralysis from a stroke in certain patient populations.

Bullet Summary:
Answer A: Alteplase is a thrombolytic that could be used in an acute ischemic stroke if given within 4.5 hours of symptom onset without any contraindications to its use. It would only be given after the CT scan of the head has been performed and other reversible causes have been addressed in the setting of acute ischemic stroke. Alteplase is not given when neurologic symptoms are thought to be secondary to Todd paralysis. In fact, seizure and Todd paralysis would be a contraindication to thrombolytic use in stroke.

Answer B: CT head, in addition to a fingerstick blood glucose, should immediately be performed in all patients with sudden onset focal neurologic deficits thought to be secondary to a stroke. A stroke would present with sudden onset focal neurologic deficits. However, it is common for patients to be obtunded and have focal neurologic deficits after a seizure and this would not warrant a stroke workup unless clinical suspicion exists. This patient has no risk factors for stroke and his improving strength suggests against a stroke. Moreover, he has a history of a normal MRI of the brain.

Answer C: Diazepam would only be given for a patient who is actively seizing as it is a benzodiazepine with a long half-life. Note that it is not indicated in a postictal patient as there is no ongoing seizure. Benzodiazepines are not given as preventive measures for seizures.

Answer E: Sumatriptan may be indicated to treat a migraine, which presents with a pulsatile, unilateral headache and is more common in women. Hemiplegic migraine can cause focal neurologic deficits, and it would be reasonable to treat a migraine headache if a patient had focal neurologic deficits and a history of known hemiplegic migraines. Patients will either have a frequent history of hemiplegic migraines themselves or in their family.

Bullet Summary:
Focal neurologic deficits (Todd paralysis) can be seen after a seizure and will resolve with observation.


Question: A 44-year-old man presents to the emergency department acutely confused. The patient’s wife states she found him lethargic at home. He has been sick the past week with diarrhea and has been staying home from work. He is otherwise healthy and does not take any medications. His temperature is 97.5°F (36.4°C), blood pressure is 62/32 mmHg, pulse is 185/min, respirations are 25/min, and oxygen saturation is 98% on room air. The patient has profuse, bloody diarrhea while in the emergency department. The patient is given 3L of ringer lactate and subsequently appears less confused, with a blood pressure of 100/70 mmHg. He is able to drink oral fluids and protect his airway. An ECG is performed as seen in Figure A. He continues to have diarrhea while in the emergency department. Which of the following is contraindicated in the management of this patient?

Answer: Loperamide

Explanation:
This patient is presenting with infectious diarrhea (given his bloody diarrhea and hypotension) with unstable vitals that improve with fluids. In bloody diarrhea, loperamide is contraindicated and could worsen illness.

Bacterial diarrhea is commonly caused by organisms such as Campylobacter, Shigella, and Escherichia coli. It may present with bloody or purulent diarrhea and fever and may progress to sepsis or septic shock. Immediate management is centered on hydration. Unstable patients or those who cannot tolerate PO require IV fluids immediately. Otherwise, patients can rehydrate orally. Loperamide is an antimotility agent that decreases diarrheal output. It is contraindicated in bloody diarrhea as it can decrease the rate of fecal shedding and lead to bacteremia and a worsening clinical picture. Loperamide may be appropriate in controlling diarrhea in milder infectious forms of diarrhea, or in non-infectious conditions such as irritable bowel syndrome.

Baker reviews loperamide. He discusses its indications, contraindications, and mechanism of action. They recommend that loperamide should not be given in invasive diarrhea.

Figure/Illustration A demonstrates U waves on ECG (red arrows) that are significant for hypokalemia, which would be expected in a dehydrated patient with profuse diarrhea.

Incorrect Answers:
Answer A: Ceftriaxone would be appropriate in this patient who has bacterial diarrhea and appears septic as his critically ill state warrants antibiotics. Note that this patient may receive broader antibiotics than ceftriaxone given how ill he appears. Antibiotics should not be routinely used for bacterial diarrhea in young, healthy patients with stable vitals.

Answer C: Magnesium could be appropriate in this patient even though his magnesium level is not stated as he is hypokalemic given his ECG is demonstrating U waves. The serum magnesium level does not adequately reflect intracellular magnesium levels. It requires replacement in many cases of hypokalemia.

Answer D: Norepinephrine could be appropriate in this patient if he remained persistently hypotensive despite fluid administration. Note that this patient could receive more fluids and is not frankly unstable. While norepinephrine may not be appropriate at this time, it is not contraindicated.

Answer E: Normal saline is generally avoided in diarrheal illness in patients who can tolerate PO as oral hydration is preferred to IV. However, IV fluids are not contraindicated and would be appropriate in this persistently hypotensive patient. Normal saline has a very high sodium and chloride load and can cause a hyperchloremic metabolic acidosis. For this reason, a lower-chloride solution may be preferred (e.g, Lactated Ringer).

Bullet Summary:
Loperamide is contraindicated in bloody diarrhea.