Questions, Board Review

Board Review Questions: June 2021

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A 22-year-old man presents with watery, non-bloody diarrhea of 2 days' duration that is associated with cramping, abdominal pain, and nausea. He just returned from a 2-week service project in Mexico. What is the most appropriate management?

  1. Give a single dose of ciprofloxacin 750 mg PO
  2. Prescribe metronidazole 500 mg three times daily for 7 days
  3. Provide reassurance and advice on symptomatic therapy
  4. Send stool for examination for WBCs, ova and parasites, and culture

The correct answer is B, Provide reassurance and advice on symptomatic therapy.

Why is this the correct answer?
Traveler's diarrhea is an exceedingly common ailment that affects up to half of all travelers returning from developing countries. Traveler’s diarrhea is self-limited and unlikely to be harmful to an otherwise healthy patient, so reassurance and symptomatic therapy are reasonable treatment options. Mild cases of traveler’s diarrhea can usually be managed with oral rehydration and loperamide administration. Antibiotics are unnecessary for afebrile patients with moderate nonbloody diarrhea, which is more distressing and interferes with planned activities. Enterotoxigenic Escherichia coli (ETEC) is the most common cause of traveler's diarrhea, especially in Mexico, Central America, and the Caribbean — places where travelers from North America are very likely to visit. In southeast Asia, Campylobacter species are the most common cause of traveler’s diarrhea. Antimicrobial treatment is warranted for patients who are nonfunctional with severe symptoms.

Why are the other choices wrong?

  • Multiple randomized controlled trials have proven the efficacy and safety of using single-dose antibiotics for moderate disease if the patient is nonfunctional. If the patient is having severe symptoms or if blood is visible in the stool (dysentery), antibiotics should be started in addition to loperamide. In severe disease, loperamide should be avoided due to the possible increase in colonization with beta-lactamase–producing Enterobacteriaceae. Recently, traveler's diarrhea has developed a high rate of quinolone resistance; a single dose of azithromycin 1,000 mg should be substituted for ciprofloxacin as the first-line antibiotic therapy for traveler's diarrhea. Rifamycin SV is now also recommended for use in nondysenteric traveler's diarrhea.
  • Metronidazole is first-line therapy for amoebiasis, which is characterized by insidious onset of mucus and blood in the stools over a period of several weeks. This patient’s acute symptoms are more likely to have a bacterial or viral origin.
  • Traveler’s diarrhea can be diagnosed clinically. In this case, ordering laboratory stool studies would be an unnecessary expense that is unlikely to affect management decisions. However, laboratory testing can be useful if bloody stools or prolonged symptoms are present.

REFERENCES

  • CDC Yellow Book article on traveler's diarrhea
  • Lazarciuc N. Diarrhea. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 1. 9th ed. Elsevier; 2018: 249-256.
  • D'Andrea SM, De Wulf A. Global travelers. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:1079-1092.

A mother brings in her 30-day-old daughter for difficulty breathing. The baby was born at home at 37 weeks' gestation. The mother received normal prenatal care, and there were no complications during the pregnancy or delivery. The baby only recently returned to her birth weight of 6 pounds. She is formula fed 3 ounces every 2 to 3 hours and is noted to fall asleep during most feeds. The baby is awake and responsive on examination, with a palpable liver edge 2 cm below the costal margin. Her hands and feet are cool and slightly mottled. A 3/4 harsh, holosystolic murmur is noted at the left lower sternal border. Upper and lower extremity blood pressures are symmetric. What is the likely underlying cause of her symptoms?

  1. Coarctation of the aorta
  2. Total anomalous pulmonary venous return
  3. Transposition of the great arteries
  4. Ventricular septal defect

The correct answer is D, Ventricular septal defect.

Why is this the correct answer?
In this case, the initial clinical clues to an underlying congenital cardiac disease include poor weight gain (weight loss in some infants), tiring while feeding (sweating in some cases), and signs of congestive heart failure ("trouble breathing"). Because this patient does not have signs of cyanosis or a ductal-dependent lesion, other types of congenital cardiac disease should be considered. Ventricular septal defect is the most common congenital cardiac lesion, and the degree of disease is dependent on the size of the defect. This can range from no issues to signs of congestive heart failure, such as enlarged liver, which happens as the disease progresses.

Why are the other choices wrong?

  • Coarctation of the aorta would likely show a differential between the upper and lower extremity blood pressures. Given this patient’s presentation, ventricular septal defect is more likely.
  • Total anomalous pulmonary venous return is a cyanotic congenital cardiac disease that would likely present with some degree of cyanosis or alteration in pulse oximetry. Ventricular septal defect is more likely in this case.
  • Transposition of the great arteries is a cyanotic congenital cardiac disease, and it would likely present with some degree of cyanosis or alteration in pulse oximetry. Because this patient does not have signs of cyanosis or a ductal-dependent lesion, other types of congenital cardiac disease, such as ventricular septal defect, are more likely and should be considered.

REFERENCES

Which symptom is reliably found in patients who develop clinical signs of pneumoconiosis?

  1. Acute wheezing 
  2. Chest pain 
  3. Gradual onset dyspnea 
  4. Sputum production

The correct answer is C, Gradual onset dyspnea.

Why is this the correct answer?
Pneumoconiosis is a restrictive lung disease that generally results from inhaling toxic substances, including coal dust (a condition known as coal miner's lung, coal workers' pneumoconiosis, or black lung disease) and silica. It results in pulmonary fibrosis, which limits total lung volume and decreases oxygen perfusion across the alveoli. Obstructive lung diseases, in distinction, cause symptoms due to increased airway resistance. Patients often have symptoms of dyspnea, but wheezing is heard less often due to the nature of restrictive lung disease. Chest x-ray reveals numerous nodules larger than 1 cm, generally in the upper part of the lung lobes. Interstitial lung findings (a fine reticular pattern) can appear similar to interstitial pulmonary edema on initial imaging. Treatment is generally based around steroids to prevent further inflammatory response.

Why are the other choices wrong?

  • Wheezing is not a classic symptom for patients with chronic pneumoconiosis. It can be seen in patients with pneumoconiosis, especially smokers, who generally have worsening disease with a combination of symptoms from COPD and fibrosis. 
  • Chest pain can be caused by numerous pulmonary diseases, but pneumoconiosis is generally not associated with pain. Acute shortness of breath with chest pain in patients with pneumoconiosis might be associated with spontaneous pneumothorax or associated pneumonia. 
  • Productive cough and sputum production can be seen in patients with pneumoconiosis who are smokers and have concomitant chronic bronchitis. Coughing does not distinguish one disease process from another. 

REFERENCES

  • Balmes JR. Occupational and environmental lung disease. In: Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J, eds. Harrison's Principles of Internal Medicine. 20th ed. McGraw-Hill Education; 2018.
  • Blake J, Seamens C, Thurman RJ. Atraumatic conditions of the chest. In: Block J, Jordanov MI, Stack LB, Thurman RJ, eds. The Atlas of Emergency Radiography. McGraw-Hill Education; 2013:141-164.
  • Radiopaedia article on pneumoconiosis

 

Which treatment is contraindicated in the management of an agricultural worker who presents with diaphoresis, fasciculations, hypersalivation, miosis, respiratory distress, and vomiting?

  1. Atropine
  2. Diazepam
  3. Physostigmine
  4. Pralidoxime

The correct answer is C, Physostigmine.

Why is this the correct answer?
The symptoms described in this case are consistent with poisoning from an organophosphorus (OP) compound, which is used most commonly in insecticides. Treatment with atropine, diazepam, and pralidoxime are all appropriate, but physostigmine is an acetylcholinesterase inhibitor that is contraindicated in the treatment of OP poisoning. Physostigmine can be used both diagnostically and therapeutically in patients with antimuscarinic poisoning. Diagnostically, complete reversal of delirium after administration of physostigmine can potentially prevent further workup. Therapeutically, physostigmine administration can be considered to treat agitation in a patient known to be delirious from an antimuscarinic agent.

The presence of convulsions or QRS prolongation should preclude use of physostigmine because asystole has occurred with the presence of these in the setting of tricyclic antidepressant poisoning. Acetylcholinesterase breaks down acetylcholine, and its inhibition leads to the accumulation of acetylcholine in synapses. Accumulation at the neuromuscular junction can manifest with fasciculations and muscle weakness, including respiratory paralysis. Accumulation of acetylcholine at preganglionic synapses occurs in both the parasympathetic and sympathetic nervous system, and at postganglionic parasympathetic synapses. The excess cholinergic activity typically manifests more in the parasympathetic side as evidenced clinically by the presence of diaphoresis, diarrhea, hypersalivation, increased respiratory secretions, miosis, and vomiting. Mnemonics that describe these manifestations include SLUDGE and DUMBELS.

Why are the other choices wrong?

  • In addition to aggressive airway management, atropine is the cornerstone of initial management of OP poisoning. Atropine is a purely antimuscarinic drug that antagonizes excessive acetylcholine at muscarinic receptors in OP poisoning. Atropine should be given liberally until respiratory secretions, bronchospasm, and cardiovascular instability are reversed. Importantly, atropine does not reverse respiratory paralysis that occurs as a result of excess acetylcholine at nicotinic receptors.
  • Diazepam should be used to treat OP–related seizures (not those from hypoxia) that can occur with cholinergic crisis. Although it is currently unclear if diazepam should be routinely administered in OP poisoning, some animal studies have demonstrated benefit, and its use is certainly not contraindicated.
  • The rationale for early pralidoxime administration is to prevent permanent inhibition of acetylcholinesterase by the OP, a process referred to as aging. Although the routine use of pralidoxime in all OP poisonings has been questioned, its use is not contraindicated.

REFERENCES

  • Eddleston M. Insecticides: organic phosphorous compounds and carbamates. In: Nelson LS, Howland MA, Lewin NA, Smith SW, Goldfrank LR, Hoffman RS, eds. Goldfrank’s Toxicologic Emergencies. 11th ed. McGraw-Hill Education; 2019:678,1486-1503.
  • Greene S. Pesticides. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:1300-1309.

Which physical examination finding is reassuring when trying to rule out a mandibular fracture in a patient with facial trauma?

  1. The interdental incisor distance at maximal opening is less than 4 cm
  2. The patient can bite down on and break a tongue blade while the examiner twists it
  3. The patient has a sublingual hematoma on the affected side
  4. The patient’s chin is deviated toward the affected side

The correct answer is B, The patient can bite down on and break a tongue blade while the examiner twists it.

Why is this the correct answer?
The tongue blade test is performed by having a patient attempt to "clamp down on” a tongue blade between the teeth with enough force that the examiner is unable to pull it out from the teeth. When the examiner twists the blade, a patient should be able to generate enough force to break or crack the blade. The test is positive if the patient cannot clench the tongue blade between the teeth or if the examiner cannot break the blade while it is held in the patient’s bite. This test is frequently used in the examination of a patient with blunt trauma to the face; if the result is positive, imaging is indicated. If the blade can be gripped by the patient and be broken by the examiner, fracture of the mandible is much less likely, and additional imaging is likely not needed. Patients with intraoral bleeding, tooth malocclusion, trismus, ecchymosis, and intraoral swelling are at higher risk for fracture.

Why are the other choices wrong?

  • When the interdental incisor distance at maximal mouth opening is less than 4 cm, there is a higher likelihood of mandibular trauma. Imaging would be more likely to reveal fracture in these cases.
  • The presence of a sublingual hematoma is very rare, but when a patient has one, it is suggestive of mandibular fracture. The physician should be highly suspicious for fracture when sublingual hematoma is discovered.
  • Deviation of the chin toward the side of the face that is painful and swollen can indicate mandibular condyle fracture or unilateral dislocation. Dislocation is much more likely to occur as a result of yawning or extreme mouth opening, however, and is rare in trauma. Fracture is more likely in cases of trauma.

REFERENCES

  • Mayersak RJ. Facial trauma. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 1. 9th ed. Elsevier; 2018:330-344.
  • Caputo ND. Maxillofacial injuries. In: Wolfson AB, Cloutier RL, Hendey GW, Ling LJ, Rosen CL, Schaider JJ, eds. Harwood-Nuss’ Clinical Practice of Emergency Medicine. 7th ed. Wolters Kluwer; 2021:161-170,
  • Caputo ND, Raja A, Shields C, Menke N. Re-evaluating the diagnostic accuracy of the tongue blade test: still useful as a screening tool for mandibular fractures? J Emerg Med. 2013 Jul;45(1):8-12.

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