Questions, Board Review

Board Review Questions: August 2019

PEER (Physician’s Evaluation and Educational Review in Emergency Medicine) is ACEP’s gold standard in self-assessment and educational review. These questions are from PEER, updated continually on its digital platform. Order PEER to prepare!

1. A 56-year-old man presents with pain and “cloudy vision” in his right eye since he woke up. He has had three similar episodes over the past several years that resolved over several days. He has a history of poorly controlled diabetes and occasional cold sores; he does not use contact lenses. Examination reveals decreased visual acuity, no photophobia, and no cell or flare. Slit lamp examination is difficult due to mild diffuse opacification of the cornea with small, white keratoprecipitates over the central inner surface of the cornea. No abrasions or dendritic ulcers are seen. What is the cause of the lesion?
A. Consistently elevated blood sugar levels
B. Exposure to high-intensity ultraviolet light
C. Herpes simplex virus
D. Systemic autoimmune disease 


2. Which of the following therapeutic agents could worsen the hemodynamic status of an infant during a cyanotic tet spell?
A. Bicarbonate
B. Isoproterenol
C. Morphine
D. Phenylephrine 


3. Which characteristic is more commonly seen with an atypical pneumonia than with other causes of pneumonia?
A. Chest pain
B. Dry cough
C. Dyspnea
D. Fever 


4. For which ingested agent is it most appropriate to administer activated charcoal?
A. Aspirin
B. Ethylene glycol
C. Lithium
D. Sodium hydroxide 


5. Which statement regarding pelvic fractures is correct?
A. AP compression most commonly leads to fracture of bony prominences such as the iliac spines
B. Fractures caused by lateral compression forces are associated with bladder injuries and hematuria
C. Injury vectors that decrease pelvic volume are more likely to cause hemodynamic compromise
D. Upper sacral fractures can injure nerve roots and result in loss of perineal sensation and rectal tone

ANSWERS 

1. The correct answer is C, Herpes simplex virus.
Why is this the correct answer?
This case describes the presentation of a less common form of herpes simplex virus (HSV) keratitis, HSV disciform keratitis. Although the most common form of HSV keratitis is epithelial keratitis manifesting with the classic dendrites, other forms, including disciform, stromal, and keratouveitis, are all manifestations of HSV keratitis. Disciform keratitis is a deeper, disc-shaped, localized area of corneal edema. Patients may have pain and decreased vision. In most patients, there is a history of orolabial or genital herpes infections. The slit lamp examination is useful for separately examining the layers of the eye to determine the source of the vision defect. Treatment usually consists of antiviral eye drops and topical steroids.

Why are the other choices wrong?

  • The consistently elevated blood sugar levels in diabetes lead to accelerated cataract formation, but this patient has signs of corneal disease, not lens disease.
  • Exposure to bright sunlight, especially when reflected off sand or snow, can result in ultraviolet keratitis, which is diffuse and bilateral, not one spot in one eye.
  • Several systemic autoimmune diseases present with eye findings, for example, anterior uveitis in reactive arthritis. This patient has no evidence of anterior chamber disease; there is no cell or flare and no irritation with iris constriction (no photophobia).

REFERENCES
Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014:909-930.

Tintinalli JE, Stapczynski JS, Ma OJ, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2012:1504-1512.


2. The correct answer is B, Isoproterenol.
Why is this the correct answer?
Infants who have tetralogy of Fallot can become hypoxic during or after feeding or while crying or agitated and then become cyanotic — an event referred to as a tet spell. The underlying pathophysiology is a worsening of the right ventricular outflow obstruction and decreased pulmonary blood flow characteristic of the disorder; the result is worsening cyanosis. Because the goal of treatment is to correct any hypoxia or acidosis that is present, interventions should increase systemic venous return and peripheral vascular resistance. Medications such as isoproterenol, which decrease pulmonary blood flow and increase right-to-left shunt, should be avoided. Supplemental oxygen should be provided; intravenous access should be established to provide fluid boluses, and the patient should be placed on continuous cardiac monitoring. The knee-to-chest position can be used to increase systemic vascular resistance and thus decrease the magnitude of the right-to-left shunt across the VSD. 

Why are the other choices wrong?

  • Bicarbonate (1 mEq/kg) is part of the treatment for a tet spell. It is used to reverse the acidosis that can lead to an increased respiratory rate and cardiac effort.
  • Morphine (0.1 to 0.2 mg/kg), too, is often used in the management of a cyanotic tet spell because it calms the child and decreases the respiratory rate.
  • If these measures fail, then a phenylephrine infusion (0.1 mcg/kg/min) may be initiated to increase systemic vascular resistance and drive more blood flow across the right ventricular outflow tract obstruction. Beta blockers such as propranolol are also frequently given to decrease cardiac contractility, therefore decreasing infundibular obstruction at the right ventricular outflow tract.

REFERENCES
Adams JG, Barton ED, Collings J, et al, eds. Emergency Medicine: Clinical Essentials. 2nd ed. Philadelphia, PA: Saunders; 2013:117-128, 159-166.

Kato H, Hirose M, Yamaguchi M, et al. Hemodynamic effects of isoproterenol and propranolol in tetralogy of fallot: production and treatment of anoxic spells. Japanese Circulation Journal. 1968;31(12):1857-1863.

Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014:129-134. 

Tintinalli JE, Stapczynski JS, Ma OJ, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2012:823-826. 


3. The correct answer is B, dry cough.
Why is this the correct answer?
Atypical pneumonias are generally characterized as those caused by Legionella pneumophila, Chlamydophila pneumoniae, and Mycoplasma pneumoniae, in addition to viruses. The symptoms include fever, dyspnea, and cough. Patients who have an atypical pneumonia tend to describe the cough as “dry”; this nonproductive cough is unlike the cough associated with other bacterial illnesses, which produces sputum. The symptom of dry cough should be considered when selecting an empiric antibiotic, especially if the patient is to be treated as an outpatient. Because Mycoplasma pneumoniae is one of the most common etiologies of pneumonia in healthy persons, antibiotic coverage for it should be considered: Generally, a macrolide is recommended.

Why are the other choices wrong?

  • Chest pain, often described as pleuritic pain, is present in up to 50% of patients with pneumonia. This can be caused by inflammation of the parietal pleura by the infiltrate. In addition, 25% of patients with Streptococcus pneumoniae infection have a pleural effusion, which can also be symptomatic.
  • Dyspnea is a more common complaint in patients with pneumonia caused by classic bacterial pathogens, including Streptococcus pneumoniae and Staphylococcus aureus. It also is common in elderly and immunocompromised patients at high risk for pneumonia caused by Pseudomonas aeruginosa and Haemophilus influenzae.
  • Fever, in addition to cough and fatigue, is the one of most common symptoms in patients with all types of pneumonia (75%). It does not help make the distinction between atypical pneumonia and other etiologies. Rigors, the shaking and cold feeling associated with spiking a fever, is a typical symptom found in patients with the most common pneumonia, Streptococcus pneumoniae. It can also be common in patients with Klebsiella pneumoniae.

REFERENCES
Tintinalli JE, Stapczynski JS, Ma OJ, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2012:445-456.

Wolfson AB, Hendey GW, Ling LJ, et al, eds. Harwood-Nuss’ Clinical Practice of Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2014:411-418.


4. The correct answer is A, aspirin.
Why is this the correct answer?
The decision to administer activated charcoal to prevent absorption requires multiple considerations: how dangerous an agent is in an overdose, how effectively it is adsorbed by charcoal, the quantity ingested if known, how much time has passed since the ingestion, whether an effective antidote exists, the potential for unknown coingestants, and the presence of contraindications to administration. Of the agents listed, aspirin is the only one for which charcoal administration should be considered. Aspirin is adsorbed well by charcoal. Even non–enteric-coated aspirin can have very delayed absorption in an overdose, making charcoal administration potentially effective even beyond 1 hour after ingestion. 

Why are the other choices wrong?

  • Alcohols such as ethanol, ethylene glycol, and methanol are rapidly absorbed, so such patients are poor candidates for charcoal administration, even if there is some adsorption.
  • Most metals such as iron and lithium demonstrate poor binding to charcoal.
  • Charcoal administration after the ingestion of a caustic agent such as sodium hydroxide is generally contraindicated. Toxicity from most caustic agents is predominantly from local tissue injury (not systemic absorption). Any vomiting precipitated by charcoal administration can be harmful. If an endoscopy is performed, charcoal can obscure visibility.

REFERENCES
Hoffman RS, Howland MA, Lewin NA, et al. Goldfrank’s Toxicologic Emergencies. 10th ed. New York, NY: McGraw-Hill; 2010:83-96.

Tintinalli JE, Stapczynski JS, Ma OJ, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2012:1207-1213.


5. The correct answer is D, Upper sacral fractures can injure nerve roots and result in loss of perineal sensation and rectal tone.
Why is this the correct answer?
Upper sacral fractures can involve the neural foramina of the sacrum, thereby injuring the sacral nerve roots. Sacral nerve root injury can lead to difficulty voiding or sexual dysfunction. Patients may also present with decreased anal sphincter tone and changes in sensation or even loss of sensation in the perineum. There is a rich vascular supply to the pelvis, and sacral injury is commonly associated with pelvic vascular trauma and hemodynamic instability. Upper sacral fractures can be difficult to diagnose clinically and with plain films. Clues to possible injury of the sacrum include asymmetry of the sacral neural foramina and avulsion of the L5 transverse process or ischial spine.

Why are the other choices wrong?

  • Anteroposterior (AP) compression forces most commonly injure the pubic symphysis, leading to disruption or rupture. These forces can also injure the pubic rami, leading to vertical fractures of the rami. Severe AP compression such as that which occurs in a high-speed motor vehicle collision can also disrupt the posterior sacrospinous ligaments and lead to an “open book” fracture.
  • Anterior fractures with AP compression forces are more likely to injure the genitourinary tract than are fractures resulting from lateral compression or from sacral fractures, which are typically caused by a fall from a height in which there is vertical shear. Patients with anterior pelvic trauma may present with hematuria or an inability to void if the urethra is disrupted or obstructed by a hematoma or clot.
  • Injury vectors that increase pelvic volume are much more likely to injure pelvic vessels due to stretching forces on the vessels. Compressive forces leading to decreased volume of the pelvis are less likely to cause significant bleeding, in general.

REFERENCES
Broder J. Diagnostic Imaging for the Emergency Physician. Philadelphia, PA: Saunders; 2011.

Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014:656-663.

Wolfson AB, Hendey GW, Ling LJ, et al, eds. Harwood-Nuss’ Clinical Practice of Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2014:277-284.

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