Medical Education, Board Review, Questions

Board Review Questions: April 2018

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 IX, which made its print debut in June 2017. Order PEER to prepare!

1. A 32-year-old woman who is 3 weeks postpartum presents with lightheadedness, generalized fatigue, and difficulty with her vision. Her blood pressure is 210/107, her pupils are normal and reactive, and she has a bilateral visual field defect. She suffers a generalized tonic-clonic seizure in the ED and is taken for a head CT, which shows ill-defined areas of low attenuation in the bilateral occipital lobes. What is the most likely diagnosis?
A. Adrenergic agonist overdose 
B. Basilar artery aneurysm 
C. Posterior reversible encephalopathy syndrome 
D. Sheehan syndrome

2. Considering the clinical presentation of a patient with suspected infective endocarditis, which of the following antibiotics is the most appropriate initial choice for empiric treatment in the ED?
A. Cefepime
B. Gentamicin
C. Moxifloxacin
D. Vancomycin

3. Which of the following is the most appropriate course of action to manage a 15% stable nontraumatic pneumothorax?
A. Administer oxygen and repeat x-ray in 4 hours
B. Admit for 24-hour observation
C. Insert a 36 Fr chest tube
D. Perform needle aspiration

4. Which of the following, after ingestion, is associated with delayed GI symptoms and hepatic failure?
A. Amanita mushroom
B. Oleander
C. Poison hemlock
D. Water hemlock

5. Which of the following physical examination findings is pathognomonic in flail chest?
A. Bradypnea
B. Hemothorax
C. Paradoxical movement
D. Seatbelt sign

ANSWERS C; 2. D; 3. A; 4. A; 5. C1.

1. The correct answer is C, Posterior reversible encephalopathy syndrome.

Why is this the correct answer?
The posterior reversible encephalopathy syndrome (PRES) was first described in 1996 and is characterized by seizures, altered mental status, hypertension, and vision changes. It is associated with bilateral white matter changes in the posterior temporal and occipital lobes, which are most easily seen on MRI. Patients with PRES are typically those who are prone to sharp spikes in blood pressure, as seen in eclampsia and kidney disease, and those on immunosuppressive therapy such as those with autoimmune disease and transplanted organs. Patients with diabetes and malignancies are also as risk to develop PRES. Patients with this condition typically have days of fluctuating symptoms (hence the term reversible) before presentation. The onset of seizures is the most common presenting sign. Computed tomography usually does not show an abnormality, but if it does, the changes are seen bilaterally in the posterior brain. This is a stark difference from ischemic strokes, which are unilateral, in a single vascular distribution. Magnetic resonance imaging of the brain is a more reliable way to see the characteristic posterior white matter changes in PRES. Treatment consists of the usual antiepileptic treatments for seizures, including benzodiazepines and fosphenytoin or phenobarbital. The hypertension should be managed in the same way any hypertensive emergency is, with intravenous calcium channel blockers or beta blockers.

Why are the other choices wrong?

  • An adrenergic agonist overdose might be associated with tachycardia, hypertension, and seizures, but patients are unlikely to have normal pupils. A patient who is acutely intoxicated with an adrenergic agonist is more likely to be diaphoretic with dilated pupils.
  • A basilar artery aneurysm can be associated with vertigo and vision disturbances and could be more likely to develop in a patient with hypertension; however, a basilar artery aneurysm is not necessarily associated with seizures and is very unlikely to present with bilateral lesions.
  • Sheehan syndrome is the ischemic necrosis of the pituitary gland that can develop following maternal hemorrhage and hypotension in the peripartum period. It leads to hypopituitarism, hypothyroidism, adrenal insufficiency, and amenorrhea. Patients with Sheehan syndrome can initially be asymptomatic; the condition is identified after the patient develops difficulty breastfeeding (agalactorrhea) or amenorrhea.

REFERENCES
Adams JG, Barton ED, Collings JL, et al, eds. Emergency Medicine: Clinical Essentials. 2nd ed. Philadelphia, PA: Elsevier; 2013:1061-1068.e1.
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: 399-409.

2. The correct answer is D, Vancomycin.

Why is this the correct answer?
Vancomycin is the most appropriate initial antibiotic choice for the emergency department treatment of suspected infective endocarditis. Staphylococcus aureus is the most common causative pathogen (over 30% of cases) in all types of infective endocarditis, and vancomycin provides excellent antibiotic coverage. It also is the drug of choice for MRSA infections. Use of combination antibiotic therapy is generally recommended for endocarditis, but vancomycin is the most appropriate first-line antibiotic for an emergency physician to start while considering the possible etiology and assistance from infectious disease consultation. Most patients with endocarditis have either predisposing cardiac abnormalities (prosthetic valve, mitral valve prolapse, bicuspid aortic valve, calcific aortic stenosis) or risk factors for disease (Injected drug use, indwelling catheters, poor dental hygiene, HIV). A history of intravenous drug abuse puts a patient at even higher risk of S. aureus infection (>50% cases). The diagnosis of infective endocarditis can be made using the modified Duke Criteria (sensitivity >90%), which involves the identification of two major criteria or one major and three minor criteria or five minor criteria.

Why are the other choices wrong?

  • Cefepime is a cephalosporin commonly used in the treatment of pneumonia, febrile neutropenia, UTIs, skin infections, and as an adjunct in the treatment of intraabdominal infections. It covers S. aureus infection, but studies indicate that its potential effectiveness against a MRSA infection lies in combination with another antimicrobial. For that reason, it is not a good empiric choice for endocarditis, and certainly not a better choice than vancomycin.
  • Gentamicin is an aminoglycoside and often a first-line choice against infections with gram-negative organisms such as Pseudomonas aeruginosa, Proteus, Escherichia coli, Klebsiella, Enterobacter, Serratia, and Citrobacter, as well as gram-positive staphylococcal infections. But like moxifloxacin, gentamicin does not provide adequate antistaphylococcal coverage for suspected infective endocarditis. Gentamicin is part of the treatment regimen for some types of infective endocarditis but in combination with another antibiotic such as penicillin, nafcillin, or ceftriaxone. In recent years, MRSA infection has become resistant to gentamicin.
  • Moxifloxacin is a fluoroquinolone that has good coverage for streptococcal species and variable susceptibility with MRSA, but it does not provide adequate antistaphylococcal coverage for suspected infective endocarditis. It is typically used in the treatment of community-acquired pneumonia, as well as skin infections, some abdominal infections, and bacterial bronchitis and sinusitis.

REFERENCES
Gilbert DN, Chambers HF, Eliopoulous GM, et al, eds. The Sanford Guide to Antimicrobial Therapy 2015. 2015: 72-76.
Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications (AHA) (Endorsed by IDSA). Circulation. 2015;132:1 -53. http://circ.ahajournals.org/content/circulationaha/early/2015/09/15/CIR.0000000000000296.full.pdf
Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014: 1106-1112.
Mattu A, Brady WJ, et al (eds). Cardiovascular Emergencies. Dallas, TX: American College of Emergency Physicians Publishing; 2014: 209-226.

3. The correct answer is A, Administer oxygen and repeat x-ray in 4 hours.

Why is this the correct answer?
Traditionally, small pneumothoraces were defined as those occupying less than 20% of one hemithorax. Supplemental oxygen increases the rate of resorption of the pneumothorax by a factor of 4 over 3 to 6 hours, so while patients with small pneumothoraces do not require hospitalization, most physicians choose to observe them until repeat films demonstrate improvement of the pneumothorax. Most pneumothoraces estimated at smaller than 15% are regarded as safe to treat with observation only. In small pneumothoraces, there is less likelihood of persistent air leak and less likelihood of recurrence in those managed with observation alone than in those treated with chest tube insertion. Guidelines for the management of primary spontaneous pneumothorax continue to evolve, and there are many and different systems used to estimate pneumothorax volume, such as the analysis of plain PA chest xrays. Recently, the British Thoracic Society published guidelines regarding the differentiation between large and small pneumothoraces to avoid incorrect estimations of size percentages.

Why are the other choices wrong?

  • Successful management of a pneumothorax usually requires a therapeutic intervention using thorax drainage. Observation alone is recommended for only those few patients with pneumothorax with minimal clinical symptoms. In the surgical therapy of pneumothorax, VATS (video-assisted thoracic surgery) is the current effective standard treatment. Open posterolateral thoracotomy is the recommend approach in patient with serious illness or complications. The aim is to reduce the recurrence rate of pneumothorax.
  • Insertion of a large-bore chest tube is the treatment of choice for hemothorax to encourage drainage; a 28 to 32 Fr chest tube is used in most instances. Smokers have a higher risk of developing pneumothorax.
  • Studies have shown that needle aspiration has the same outcomes as the placement of a chest tube with less patient discomfort. However, in most patients with a small pneumothorax, no invasive treatment is needed.

REFERENCES
Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014: 437-440.
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: 464-468.

4. The correct answer is A, Amanita mushroom.

Why is this the correct answer?
Amanita phalloides is a wild growing mushroom, which in addition to a few other Amanita species, is responsible for most of the deaths associated with wild mushroom ingestions in the United States. In general, the onset of GI symptoms in fewer than 6 hours is associated with ingestions of less toxic mushroom species. The delayed onset of vomiting and diarrhea is characteristic of poisoning with hepatotoxic Amanita species and can portend the development of hepatic failure.

Why are the other choices wrong?

  • Poisoning from cardiac glycosides, which are found in the oleander plant (Nerium oleander), is characterized by the rapid (not delayed) onset of GI symptoms (vomiting). Hepatic failure is not an expected feature. Similar to digoxin (a cardiac glycoside), hyperkalemia occurs due to poisoning of sodium-potassium ATPase and can be used as a predictor of possible dysrhythmias.
  • Poison hemlock (Conium maculatum) contains alkaloids that are similar to nicotine. Poisoning is characterized by the rapid (not delayed) onset of GI symptoms (vomiting). Both parasympathetic and sympathetic symptoms can follow. Convulsions and respiratory failure can ensue, but hepatic failure is not an expected feature.
  • Poisoning from water hemlock (Cicuta maculata) is characterized by rapid (not delayed) onset of GI symptoms and convulsions. Most plant ingestions are accidental and typically occur in children; in contrast, ingestions of water hemlock often occur in adults who confuse the plant with similar-appearing edible, nontoxic plants. The toxin present, cicutoxin, is rapidly absorbed, and although not fully characterized, appears to antagonize GABA receptors, explaining why convulsions and status epilepticus are features of poisoning. Hepatic failure is not a feature of this poisoning. Treatment is supportive.

REFERENCES
Hoffman RS, Howland MA, Lewin NA, et al, eds. Goldfrank’s Toxicologic Emergencies. 10th ed. New York, NY: McGraw-Hill; 2015:1500-1502.
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: 1419-1420, 1426-1427.

5. The correct answer is C, Paradoxical movement.

Why is this the correct answer?
Flail chest is defined by fractures in three or more adjacent ribs in two or more places, the result of which is that a segment of the chest wall is not connected to the rest of the thoracic cavity. The flail segment moves paradoxically inward during inspiration; this is the classic finding. Flail chest is a cause of death and significant damage because the flail segment is free to indent the lungs and create significant pulmonary contusion at the time of impact. It is, therefore one of the most critical chest wall injuries. Patients who have a flail segment are more likely to have severe pulmonary contusion than those who have rib fractures but no flail segment. Therefore, patients with a flail segment have higher morbidity and mortality rates. Mechanical ventilation is indicated for respiratory failure, hypoxia, or altered mental status of any cause regardless of whether there is a flail segment. The presence of a flail segment should not influence the decision to withhold mechanical ventilation, although it might influence early institution of mechanical ventilation if a patient is not doing well clinically.

Why are the other choices wrong?

  • Patients with flail chest may demonstrate a wide variation in respiratory insufficiency, but patients typically show tachypnea with decreased tidal volumes and splinting due to pain. Bradypnea, or abnormally slow breathing, is typically not seen in patients with flail chest.
  • Blunt chest trauma can lead to pneumothorax and hemothorax, resulting in decreased breath sounds, but pulmonary contusion is the most common associated lung pathology in flail chest. Pulmonary contusion does not immediately lead to decreased breath sounds. Due to the limitations of trauma plain films, physical examination is useful in identifying clinically significant flail chest.
  • Although flail chest is diagnosed in many patients who exhibit the seatbelt sign, unrestrained passengers in motor vehicle crashes can sustain a flail chest injury and exhibit no seatbelt sign. Flail chest also can occur in a restrained patient who does not present with the seatbelt sign.

REFERENCES
Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. St. Louis, MO: Elsevier; 2014: 433-434.
Wolfson AB, Hendey GW, Ling LJ, et al, eds. Harwood-Nuss’ Clinical Practice of Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2014: 205-206.

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