Board Review Questions in Emergency Medicine

John F. O'Brien, MD, Assistant Residency Director, Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, Fla; Associate Clinical Professor, University of Florida School of Medicine, Gainesville, Fla

1. A 27-year-old man with severe asthma requires endotracheal intubation in the emergency department after rapid sequence induction with ketamine HCl (Ketalar) and succinylcholine chloride (Anectine, Quelicin). Although the resuscitation initially goes well, within several minutes his blood pressure (BP) drops to 70/40 mm Hg, and his pulse rate increases to 156 beats per minute (bpm). Breath sounds are equal. What should your first intervention be?

1. order chest x-ray immediately
2. administer 10 cc intravenous (IV) calcium chloride 10%
3. insert bilateral chest thoracostomy tubes
4. disconnect endotracheal tube from respirator and facilitate prolonged exhalation
5. use volume infusion with 500 cc of normal saline

2. A 63-year-old woman with chronic myelocytic leukemia had been taking hydroxyurea (Hydrea, Mylocel) as daily chemotherapy to control her white blood cell (WBC) count levels. She admits to stopping her medications for about 2 months, then restarting with a double dose about 8 hours ago. She feels very weak now and short of breath. Laboratory studies are likely to reveal all the following conditions, except:

1. hypercalcemia
2. hyperuricemia
3. hyperphosphatemia
4. hyperkalemia

3. A 13-year-old girl presents with severe menorrhagia, which she has had since menarche. Her hemoglobin level is 7.2 g/dL (normal, 12-16 g/dL) with hypochromic microcytic indices. A pregnancy test is negative. The most common coagulopathy associated with menorrhagia in adolescents is:

1. hemophilia A
2. hemophilia B
3. von Willebrand's disease
4. factor V Leiden mutation

4. A 27-year-old man presents after a syncopal event following a long run. He complains of lightheadedness and itching, along with swelling of his hands and feet. His BP is 68/36 mm Hg and pulse is 160 bpm. Lung examination shows he has diffuse wheezing. His blood glucose is 95 mg/dL. The most important initial IV therapy would be:

1. epinephrine (Adrenalin)
2. diphenhydramine HCl
3. methylprednisolone sodium succinate (A-Methapred, Solu-Medrol)
4. normal saline
5. cimetidine (Tagamet)

5. A 64-year-old man with chronic hypertension has been experiencing 90 minutes of severe chest pain and shortness of breath. His BP is 86/60 mm Hg and his pulse is 104 bpm. Electrocardiograph (ECG) shows ST-segment elevation in leads V₁ through V₆, and a chest radiograph reveals marked pulmonary edema. All the following treatments, used concomitantly, represent optimal therapy for this patient, except:

1. aspirin
2. low-molecular-weight heparin
3. percutaneous angioplasty
4. thrombolytic therapy

6. What is the most common cause of acute hepatic failure in the United States?

1. acetaminophen overdose
2. alcohol use
3. hepatitis A
4. hepatitis B

7. After his first hemodialysis treatment, a 23-year-old man with diabetes presents to the emergency department with altered mental status and a new-onset generalized seizure. His blood glucose level is 154 mg/dL. Computed tomography (CT) scan of his head is normal and lumbar puncture reveals only an opening pressure of 280 mm H₂O. Initial treatment for this patient should include:

1. immediate repeat hemodialysis
2. mannitol (Osmitrol)
3. thiamine (Thiamine HCl, Thiamilate)
4. pyridoxine HCl (vitamin B6)

8. A 63-year-old man presents with abrupt onset of regular palpitations. He saw his cardiologist 3 days ago for a regularly scheduled evaluation of his dual chamber pacemaker. His BP is 150/84 mm Hg and pulse is 164 bpm. His ECG reveals a paced rhythm at that rate. All the following interventions are appropriate, except:

1. adenosine (Adenocard)
2. magnet application to pulse generator
3. lidocaine HCl
4. vagal maneuvers

9. A 24-year-old college student complains of repeated severe extensor spasms in all extremities along with a bizarre arching of his back. He has a history of substance abuse. Immediate treatment should include:

1. tetanus immunoglobulin (BayTet)
2. vitamin B₁ (thiamine)
3. benzodiazepines
4. lumbar puncture

10. A 17-year-old adolescent comes to the emergency department with severe left-leg pain after falling off a roof. Radiographs revealed a badly comminuted left-leg fracture. Pain medications were initially effective, but even higher doses are now ineffective. Your most important intervention would be:

1. applying traction to the left ankle
2. applying ice to the left leg
3. compartment pressure measurements
4. lower extremity venous Doppler studies

11. Because of a tenuous blood supply, all the following bones are prone to avascular necrosis after fracture except:

1. talus
2. capitate
3. femoral head
4. scaphoid
5. cuboid

12. A 32-year-old alcoholic man presents with a temperature of 103?F, severe headache, and neck stiffness. Lumbar puncture is done. Analysis of cerebrospinal fluid (CSF) shows a glucose level of 22 mg/dL, protein of 126 mg/dL, and WBC count of 26.1 x 10⁹/L with 93% polymorphonuclear neutrophils. Gram stain of the CSF reveals gram-positive diplococci in pairs. These findings suggest the diagnosis of meningitis. Which of the following statements about treatment in adults with meningitis is true?

1. dexamethasone reduces morbidity but not mortality in bacterial meningitis
2. dexamethasone reduces morbidity and mortality in pneumococcal meningitis but not in other causes of bacterial meningitis
3. dexamethasone reduces mortality in pneumococcal as well as other types of bacterial meningitis
4. dexamethasone shows no benefit in the medical therapy of bacterial meningitis

13. A tall, 24-year-old pregnant woman presents at 36 weeks' gestation with acute chest pain radiating to her back. Physical examination shows her BP is 160/90 mm Hg and her pulse is 124 bpm, as well as a pulse deficit in her left arm. She is noted to have pectus excavatum and a high-arched palate. What is the necessary next step in her management?

1. administer esmolol HCl (Brevibloc) and titrate to achieve a pulse rate of 50 to 60 bpm
2. administer IV magnesium, 4 g
3. administer IV nitroprusside sodium (Nitropress) and titrate to achieve a mean arterial pressure of 70 to 80 mm Hg
4. order an immediate imaging study with magnetic resonance imaging (MRI), high-resolution, contrast-enhanced CT scan, or 2-dimensional (2D) echocardiography before medical therapy

14. A 1-week-old infant born at 38 weeks' gestation is brought to the emergency department with cyanosis and shock. She has no appreciable heart murmur, and her heart rate is 188 bpm. All the following interventions are indicated, except:

1. ampicillin (Principen) and cefotaxime sodium (Claforan)
2. adenosine
3. prostaglandin E₁ (Alprostadil)
4. normal saline, 20 cc/kg

15. A 62-year-old woman presents with a prolonged history of dyspnea on exertion along with severe peripheral edema and chronic diarrhea. Her chest radiograph reveals cardiac silhouette calcifications. What is the likely diagnosis?

1. asbestosis
2. hypothyroidism
3. constrictive pericarditis
4. ventricular aneurysm

16. Which of the following fractures is most suggestive of nonaccidental trauma in a 1-year-old child?

1. oblique nondisplaced fracture of the tibia
2. buckle fracture of the distal radius
3. metaphyseal fracture of the proximal tibia
4. midclavicular fracture

17. A 5-year-old boy sustained a large laceration in his left thigh after a mirror fell on him. He weighs 55 lb. What is the maximal number of milliliters of 1% lidocaine with epinephrine that could safely be injected intradermally at one time to repair this wound?

1. 12.5 cc
2. 15 cc
3. 17.5 cc
4. 20 cc

18. A 57-year-old man returns from a long trip to India and presents to the emergency department with a history of 3 days' fever as high as 104.2?F and diffuse muscle aches. He now has severe cough, which produces yellow sputum streaked with blood, and severe chest pain, and he is hypotensive. Chest radiography reveals a right lower infiltrate with right pleural effusion. Sputum gram stain reveals sheets of gram-negative bacillary organisms. Which of the following agents is the antibiotic of choice in this clinical setting?

1. clarithromycin (Biaxin)
2. ceftriaxone sodium (Rocephin)
3. ciprofloxacin (Cipro)
4. trimethoprim/sulfamethoxazole (Bactrim, Septra)

19. A 35-year-old man with diabetes mellitus and end-stage renal disease (ESRD) presents after a motor vehicle accident with an open, badly contaminated fracture of the tibia and fibula. Which of the following medications is contraindicated in this setting?

1. meperidine HCl (Demerol)
2. gentamicin (Garamycin)
3. hydromorphone HCl (Dilaudid)
4. cefazolin sodium (Ancef)

20. Which of the following medications has NOT been demonstrated to reduce mortality in patients with ischemic cardiomyopathy?

1. beta-blockers
2. calcium channel blockers
3. spironolactone (Aldactone)
4. angiotensin-converting enzyme (ACE) inhibitors

21. Which of the following conditions is NOT a cause of a low anion gap?

1. lithium toxicity
2. bromide poisoning
3. multiple myeloma
4. iron poisoning

ANSWERS

1?D. In this patient, hypotension is almost certainly secondary to increased intrathoracic pressure caused by an inability to exhale the respirator's minute ventilation. This problem is called "stacking" and is best managed by disconnecting the respirator and gently compressing the chest to evacuate the lungs. The use of small tidal volumes (6 to 8 mL/kg) and low ventilator rates (6 to 8 breaths per minute), a method called permissive hypercapnia, has greatly reduced mortality in mechanically ventilated bronchospasm patients. Although barotrauma is another consideration, it is less likely.

Unless overwhelming evidence of tension pneumothorax prompts emergency chest tube placement on the side of the problem, a chest radiograph should be performed if disconnecting the mechanical ventilation does not promptly restore perfusion.

Many asthmatic patients are hypovolemic, and ketamine as well as sympatholytic agents may induce hypotension. Thus, volume loading is indicated, but hypovolemia is unlikely to be the main problem. Calcium chloride is effective treatment for succinylcholine-related hyperkalemia, a condition that is unlikely in this patient.

Source

Rosen's Emergency Medicine: Concepts and Clinical Practice

Nowak RM, Tokarski G. Asthma. In: Marx JA, Hockberger R, Walls R, eds. . 5th ed. St Louis, Mo: Mosby; 2002: 938-956.

2?A. Tumor lysis syndrome occurs when malignancies with large tumor burdens or rapid proliferation? such as leukemias with high WBC counts, lymphomas, or a variety of solid tumors?are subjected to rapid cell lysis. This results in the rapid release of intracellular contents into the bloodstream, precipitating hyperuricemia, hyperphosphatemia (with secondary hypocalcemia), and hyperkalemia, with life-threatening consequences.

Source

Semin Hematol.

Jeha S. Tumor lysis syndrome. 2001;38(suppl 10):4-8.

3?C. von Willebrand's disease is the most common hereditary bleeding disorder with an estimated prevalence of 1%. It is the leading coagulopathy associated with adolescent menorrhagia, which may be treated with intranasal or IV desmopressin acetate if mild, or Cryoprecipitate transfusion if severe. Oral contraceptives may provide long-term control of menorrhagia in von Willebrand's disease.

Source

Haemophilia

Kouides PA. Menorrhagia from a haematologist's point of view. Part I: initial evaluation. . 2002;8:330-338.

4?A. This patient has exercise-induced anaphylaxis, a type of distributive shock that should be considered in the differential diagnosis of syncope. Exercise in susceptible patients may precipitate allergic manifestations ranging from cholinergic urticaria to fatal anaphylaxis. Although all the listed therapies have benefit here, IV epinephrine is the treatment of choice in this life-threatening situation.

Source

Curr Allergy Asthma Rep

Castells MC, Horan RF, Sheffer AL. Exercise- induced anaphylaxis. . 2003;3:15-21.

5?D. This patient is in cardiogenic shock. The Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial examined the outcomes of patients with acute myocardial infarction (MI) in cardiogenic shock. It showed that emergency revascularization (primary percutaneous coronary angioplasty or emergent coronary artery bypass grafting) reduced 30-day mortality by a not statistically significant 9% but reduced 6-month and 1-year mortality by a significant 13%, compared with medical stabilization that included thrombolytic therapy. Based on this trial, the American College of Cardiology and American Heart Association guidelines now recommend emergency revascularization for patients younger than 75 years with acute MI and cardiogenic shock.

Source

Congest Heart Fail

Menon V, Flincke R. Cardiogenic shock: a summary of the randomized SHOCK trial. . 2003;9:35-39.

6?A. Acetaminophen overdose is the most common cause of acute hepatic failure in the United States, with one study finding that it accounted for 39% of cases. Nacetylcysteine has benefit even after hepatotoxicity is evident, and the recent approval of its IV form (Acetadote) adds to our armamentarium in this setting.

Source

Ann Intern Med

Ostapowicz G, Fontana RJ, Schoidt FV, et al. Results of a prospective study of acute liver failure at 17 tertiary care centers in the United States. . 2002;137:947-954.

7?B. Dialysis disequilibrium syndrome is an acute condition that occurs during or shortly after hemodialysis, usually the initial sessions. It may present with mild symptoms, including headache, nausea, vomiting, and muscle cramps or more severe symptoms, such as disorientation, seizures, and coma. Dialysis disequilibrium is thought to be caused by a more rapid removal of urea from plasma than from the brain, causing an acute osmotic gradient and cerebral edema. Although this phenomenon is usually self-limiting, increasing serum osmolality with mannitol, hypertonic saline, or dextrose 50% may provide rapid symptomatic improvement.

Source

Kidney Int

Arieff AI. Dialysis disequilibrium syndrome: current concepts on pathogenesis and prevention. . 1994;45:629-635.

8?C. This patient has a pacemaker-mediated tachycardia, a reentry dysrhythmia that occurs in dual-chamber pacemakers with atrial sensing. The pacemaker acts as part of the reentry circuit, with the arrhythmia usually initiated by a premature ventricular contraction with retrograde conduction through the atrioventricular node. This causes atrial depolarization, which the pacemaker senses, prompting a ventricular pacing spike and an endless loop. The rate is limited to the programmed upper rate limit of the pulse generator. Magnet application to the pulse generator turns off sensing and may break the tachyarrhythmia. Interventions that slow conduction through the AV node, including vagal maneuvers and adenosine, may also resolve this dysrhythmia.

Source

Postgrad Med J

Menon S, Hafeez H, Verjee T, et al. Tachycardia in the presence of a pacemaker. . 2004;80:119, 122.

9?C. Strychnine poisoning and tetanus may both be present in an alert patient with recurrent extensor spasms and even opisthotonos. Both are seen more often in individuals with substance abuse problems. In the United States, college students are required to have tetanus immunization. Strychnine antagonizes the postsynaptic uptake of the central inhibitory neurotransmitter glycine. Benzodiazepines are effective adjunctive therapy for both strychnine poisoning and tetanus.

Source

Pediatr Emerg Care

Flood RG. Strychnine poisoning. . 1999;15:286-287.

10?C. Compartment syndrome is a dreaded complication of lower extremity fractures. The leg has 4 compartments?anterior, lateral, superficial, and deep posterior. Clinical findings are of limited benefit, as the problem is the elevation of tissue pressures to levels that close the capillary beds (30-40 mm Hg). Arterial pulses are usually maintained. A high index of suspicion along with prompt measurement and monitoring of compartment pressures is the best strategy for early recognition.

Source

J Ortho Trauma

Ulmer T. The clinical diagnosis of compartment syndrome of the lower leg: are clinical findings predictive of the disorder? . 2002;16:572-577.

11?E. Human bones that are more likely to develop avascular necrosis after fracture because of blood supply issues include the femoral head, talus, scaphoid, and capitate. The cuboid bone is blessed with a better blood supply.

Source

Rosen's Emergency Medicine: Concepts and Clinical Practice

Eisenhauer MA. Forearm and wrist. In: Marx JA, Hockberger R, Walls R, eds. . 5th ed. St Louis, Mo: Mosby; 2002:467-492.

12?C. A prospective, double-blind, multicenter trial randomized 301 patients with bacterial meningitis to placebo or dexamethasone, 10 mg, administered 15 to 20 minutes before or concomitant to antibiotic therapy and then every 6 hours for 4 days. Dexamethasone reduced risk of unfavorable outcomes and mortality in all patients, including those with pneumococcal meningitis.

Source

N Engl J Med

de Gans J, van de Beek D, for the European Dexamethasone in Adulthood Bacterial Meningitis Study Investigators. Dexamethasone in adults with bacterial meningitis. . 2002;347:1549-1556.

13?A. This patient is likely to have Marfan's syndrome, and her clinical presentation is very suggestive of aortic dissection. Treatment for her elevated BP and tachycardia should be initiated immediately, even before confirmation with emergency imaging studies. Beta-blockers are the drugs of choice, as they help normalize the factors that contribute to aortic dissection?increased BP, heart rate, and contractility. Magnesium is effective in preeclampsia but not in aortic dissection. Nitroprusside sodium (Nitropress) alone causes reflex tachycardia and increased contractility, effects that are counterproductive in aortic dissection. Nitroprusside is also associated with fetal cyanide toxicity; MRI, high-resolution, contrast-enhanced CT, and 2D echocardiography are all very accurate in confirming the diagnosis.

Source

Ann Thorac Surg

Immer FF, Bansi AG, Immer-Bansi AS, et al. Aortic dissection in pregnancy: analysis of risk factors and outcome.. 2003;76:309-314.

14?B. This 1-week-old neonate has cardiovascular collapse despite an apparently normal birth. A sepsis workup with appropriate empiric antibiotic therapy and volume resuscitation is indicated. The clinical situation is suggestive of acute closure of a patent ductus arteriosis in a neonate with ductal-dependent congenital heart disease. Prostaglandin E¹ represents a potentially lifesaving intervention to reopen the ductus arteriosus and improve cardiovascular function. It should be initiated in this setting even before definitive confirmation. Adenosine is unlikely to be helpful, as the heart rate does not suggest supraventricular tachycardia.

Source

Anesthesiol Clin North America

Lee C, Mason LJ. Pediatric cardiac emergencies. . 2001;19:287-308.

15?C. Constrictive pericarditis occurs when thickened pericardium restricts cardiac chamber filling. Usually idiopathic, tuberculosis is the most commonly recognized cause. Constrictive pericarditis may also occur after cardiovascular surgery or radiation therapy to the chest. Symptoms and signs are the result of low cardiac output with both left-sided and right-sided venous congestion. Constrictive pericarditis is difficult to distinguish from restrictive cardiomyopathy; CT and MRI help define increased pericardial thickness. Pericardial calcifications are common. Cardiac calcifications are also seen in asbestosis but without significant cardiac consequences.

Source

Cardiol Rev

Asher CR, Klein AL. Diastolic heart failure: restrictive cardiomyopathy, constrictive pericarditis, and cardiac tamponade: clinical and echocardiographic evaluation. . 2002;10:218-229.

16?C. The clavicle is the most often fractured bone in childhood, with most fractures occurring at midshaft. Toddlers' fractures are oblique, nondisplaced fractures of the tibia, usually in children aged 9 to 36 months. The mechanism of injury can be as simple as torque applied to the leg while walking or a fall from a small height. Buckle fractures of the distal radius, often termed torus fractures, frequently occur when falling on an outstretched hand. Metaphyseal fractures are very suggestive of child abuse, as they result from violent shaking, twisting, or pulling of a small child's limb. They most often involve the femur, tibia, or proximal humerus.

Source

Rosen's Emergency Medicine: Concepts and Clinical Practice

Bachman DT, McQuillen K. Musculoskeletal disorders. In: Marx JA, Hockberger R, Walls R, eds. . 5th ed. St Louis, Mo: Mosby; 2002:2370-2392.

17?C. Knowledge of safe maximal doses of lidocaine is important to avoid central nervous system complications such as seizures. Lidocaine with epinephrine can be administered in doses up to 7 mg/kg, while the maximal dose of lidocaine without epinephrine is 3 to 5 mg/kg. A patient who weighs 55 lb can safely receive up to 175 mg of lidocaine with epinephrine intradermally; since a 1% solution contains 10 mg/mL, this corresponds to 17.5 cc. As 0.5% lidocaine with epinephrine provides adequate anesthesia intradermally, it could be diluted in a 1:1 ratio with sterile water to yield 35 cc of local anesthetic.

Source

Best Pract Res Clin Anaesthesiol

Cox B, Durieux ME, Marcus MA. Toxicity of local anaesthetics. . 2003;17:111-136.

18?C. In many regions of the world, particularly Asia and India, as well as the western United States, Yersinia pestis, a gram-negative bacillus-causing plague, is endemic. Primary pneumonic plague occurs when organisms are inhaled into the lungs. After an incubation period of 2 to 3 days, patients develop a flulike illness followed rapidly by a fulminant pneumonia with hemoptysis, respiratory failure, circulatory collapse, and death. The chest radiograph in this plague usually reveals lobar pneumonia, with frequent pleural effusions. Death is almost certain unless the condition is recognized and treated early. Pneumonic plague is sensitive to many antibiotics, including streptomycin sulfate, gentamicin, doxycycline (Periostat), ciprofloxacin, and chloramphenicol (Chloromycetin Sodium Succinate).

Source

Semin Respir Infect

Krishna G, Chitkara RK. Pneumonic plague. . 2003;18:159-167.

19?A. Loading doses of an aminoglycoside, such as gentamicin, are not contraindicated in ESRD, but subsequent dosing must be adjusted based on the degree of renal insufficiency. Meperidine is metabolized to normeperidine, which lowers the seizure threshold and has a long half-life in renal insufficiency. This drug is contraindicated because it may cause altered mental status and seizures in ESRD.

Source

Am J Kidney Dis

Kurella M, Bennett WM, Chertow GM. Analgesia in patients with ESRD: a review of available evidence. . 2003;42:217-228.

20?B. Calcium channel blockers have not been demonstrated to reduce mortality in heart failure and may actually increase risk of death in ischemic cardiomyopathy. Beta-blockers, ACE inhibitors, and spironolactone are among the medications clearly demonstrated to reduce mortality in this setting.

Source

Am J Med

DiBianco R. Update on therapy for heart failure. . 2003;115:480-488.

21?D. Although much has been taught about a high anion gap and the famous mnemonic MUDPILES (Methanol, Uremia, Diabetic ketoacidosis, Paraldehyde, Infection, Lactic acidosis, Ethylene glycol, and Salicylates), a low anion gap may also be a subtle clinical sign of multiple myeloma and other paraproteinemias, such as Waldenstr?m's macroglobulinemia. Bromide intoxication and lithium toxicity are other important etiologies. Reduced albumin levels also lower the anion gap.

Source

South Med J

Jurado RL, del Rio C, Nassar G, et al. Low anion gap.. 1998;91:624-629.