Questions, Board Review

Board Review Questions: October 2021

Provided by PEERprep for Physicians

PEERprep for Physicians is ACEP's gold standard in self-assessment and educational review. Order PEERprep at acep.org/peerprep.


A 73-year-old man presents with tightness in his chest after eating a pulled pork sandwich. He is unable to tolerate liquid by mouth; anything ingested is almost immediately regurgitated. An ECG is normal. What is the most effective management for this condition?

  1. Esophagogastroduodenoscopy
  2. Glucagon 1 to 2 mg IV
  3. Ingestion of an effervescent beverage
  4. Papain PO

The correct answer is A, Esophagogastroduodenoscopy.

Why is this the correct answer?
This patient has food impaction, which most often occurs in the distal esophagus. The best management for food impaction is esophagogastroduodenoscopy (EGD) and manual retrieval or advancement of the food bolus. Medical approaches to encourage esophageal relaxation are unlikely to be successful, and feeding agents to dissolve the food can be harmful. Esophageal food impaction may develop for multiple reasons, aside from simply trying to swallow a mouthful that is too large. Patients might have structural abnormalities (eg, strictures, a Schatzki ring, esophageal webs, or a Zenker diverticulum). The narrowest point in the esophagus is the cricopharyngeus muscle or upper esophageal sphincter. Children account for 80% of cases of swallowed foreign bodies, and they tend to get objects trapped in the upper esophagus. Adults, especially prisoners and psychiatry patients, who ingest foreign bodies most often get theirs stuck at the lower esophageal sphincter. Anything that passes through the pylorus is likely to complete transit of the GI tract. Although expectant management is reasonable for a patient who is tolerating the obstruction, food impactions should not be allowed to persist for more than 24 hours because they can lead to esophageal perforation. Dangerous objects, such as sharp objects or button batteries, need to be removed immediately.

Why are the other choices wrong?

  • Glucagon has been widely advocated for use in food bolus impaction to relax the esophageal smooth muscle and allow passage of the material. However, glucagon was shown to be ineffective when studied against a control and may be associated with vomiting. Although glucagon is likely nonharmful and could be offered while awaiting the availability of an EGD, it is not the most effective treatment approach in this case.
  • Effervescent beverages (ie, sodium bicarbonate plus a mild acid such as lemon juice or a brand-name cola) can dislodge food impactions by generating carbon dioxide in the esophagus to push the food bolus along, and there are case reports of this approach occasionally being effective. However, effervescent beverages are difficult to administer and prone to induce aspiration in patients with complete obstructions, as in this case.
  • Papain, a trypsin-like enzyme, is used as a meat tenderizer. Although it has previously been suggested as an option for dissolving food boluses, it can dissolve the esophagus itself, leading to perforation. Papain has been associated with fatal outcomes and should never be considered as a potential therapy for food impaction.

REFERENCES
Emergency Medicine International article on removing food impactions
https://www.hindawi.com/journals/emi/2013/924015/ 

Lee AW, Hess JM. Esophagus, stomach and duodenum. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 1. 9th ed. Elsevier; 2018:1067-1082.

O'Mara SR, Wiesner L. Hepatic disorders. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:516-523.


A 45-year-old man presents with multiple episodes of bloody stool over the past 2 hours. His medical history includes hepatitis C with ascites, alcohol dependency, and a recent endoscopy showing peptic ulcers. His vital signs are BP 66/45, P 134, R 24, and T 36.6°C (97.9°F); SpO2is 93%. The physical examination is notable for a nontender, distended, and firm abdomen and melena. After starting resuscitation with intravenous fluids and blood, what is the most appropriate pharmacotherapy?

A. Dopamine and ceftriaxone
B. Norepinephrine and octreotide
C. Octreotide and ceftriaxone
D. Pantoprazole and ciprofloxacin

The correct answer is D, Pantoprazole and ciprofloxacin.

Why is this the correct answer?
Cirrhosis patients who present with upper GI bleeding that is not attributed to varices should receive proton pump inhibitors (PPIs) in addition to prophylactic antibiotics to address immunocompromise. Standard antibiotic choices include ciprofloxacin 400 mg IV or ceftriaxone 1 g IV; the PPI of choice is pantoprazole 80-mg bolus IV, followed by an infusion of 8 mg/hr. Cirrhosis patients have an increased risk of translocation of gut bacteria in the setting of acute bleeding. Antibiotic prophylaxis is associated with reduced mortality rates, decreased bacterial infection, lowered risk of rebleeding, and shortened length of hospitalization. The delivery of a PPI is aimed at increasing gastric pH to allow for clot formation. It has been shown to reduce the need for surgical intervention and hospital length of stay.

Why are the other choices wrong?

  • Vasopressor agents such as dopamine may be required in severe cases of GI bleeding. However, volume and blood resuscitation should be the initial therapy provided. Vasopressin is optimal for reducing splanchnic blood flow and portal hypertension.
  • Vasopressor agents such as norepinephrine may be required in severe cases of GI bleeding, but volume and blood resuscitation should be the initial therapy provided. Vasopressin is optimal for reducing splanchnic blood flow and portal hypertension. However, this patient had a recent endoscopy that showed peptic ulcers; since varices are not mentioned, splanchnic vasoconstrictors such as octreotide are not indicated.
  • Octreotide, a somatostatin analogue and splanchnic vasoconstrictor, is indicated for patients with variceal bleeding. This patient's recent endoscopy showed peptic ulcers with no known varices, so splanchnic vasoconstrictors are not indicated.

REFERENCES
Maguerdichian DA, Goralnick E. Gastrointestinal bleeding. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 1. 9th ed. Elsevier; 2018: 242-258.

Ziebell CM, Kitlowski AD, Welch J, Friesen P. Upper gastrointestinal bleeding. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:495-498.

UpToDate article on upper GI bleeding, available in full with a subscription
https://www.uptodate.com/contents/approach-to-acute-upper-gastrointestinal-bleeding-in-adults

Barkun AN, Bardou M, Kuipers EJ, et al; International Consensus Upper Gastrointestinal Bleeding Conference Group. International consensus recommendations on the management of patients with nonvariceal upper gastrointestinal bleeding. Ann Intern Med. 2010 Jan 19;152(2):101-113.


Which patient requires immediate postexposure prophylaxis for rabies?

A. Farmer who was bitten on the hand by their horse
B. Teenager who was bitten on the leg by a neighbor's dog
C. Toddler who woke up in the same room as a bat
D. Woman who had contact with a raccoon but no injury

The correct answer is C, Toddler who woke up in the same room as a bat.

Why is this the correct answer?
Rabies postexposure prophylaxis (PEP) is indicated for individuals who are bitten by or experience other mucous membrane exposure to a bat. Sometimes, patients are unsure or unaware that they have been bitten by a bat, which might be the case with a small child or with someone who was sleeping at the time. These cases should be considered equivalent to a known exposure. Other high-risk exposures requiring immediate PEP include bites or other mucous membrane exposures from raccoons, skunks, and foxes. If the animal can be captured, PEP can be started on the patient until definitive testing can be obtained on the animal. The PEP process has three steps. First, early and aggressive irrigation of the wound is performed with soap, water, and povidone-iodine solution. Second, human rabies immune globulin (HRIG) is administered surrounding the wound. Third, human diploid cell vaccine is administered away from the HRIG and repeated on days 3, 7, and 14, with a dose at day 28 if the patient is immunocompromised.

Why are the other choices wrong?

  • There has never been a reported case of human rabies as a result of a bite from farm livestock. If there is reasonable doubt, the clinician should contact an infectious disease specialist or the CDC to discuss the case.
  • In the case of a bite from a domestic dog or cat, the animal can be quarantined and observed for 10 days for behavior suggestive of rabies. If suspicious behavior is identified, the animal can be killed and tested, and PEP can be initiated pending the results. If the dog or cat cannot be quarantined for 10 days, the clinician should review local public health guidelines and act accordingly; recommendations vary among states depending on local prevalence of disease.
  • Rabies is spread through the saliva of an infected animal. A person who has general contact with a rabid animal or a high-risk animal is not considered at risk if they know that there was no animal saliva exposure to mucous membranes. Exposure to animal blood, urine, or feces also does not create risk for contracting rabies. Other insignificant exposures are bites from birds, reptiles, or rodents. Being able to differentiate the risk of exposure is crucial for an emergency physician, as it is estimated that 30% to 60% of PEP is avoidable.

REFERENCES
Bullard-Berent J. Rabies. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Elsevier; 2018:1619-1625.

Willis ZI, Weber DJ. Rabies. Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:1051-1057.

CDC information on rabies
https://www.cdc.gov/rabies/ 

CDC information on the rabies vaccine
https://www.cdc.gov/rabies/medical_care/vaccine.html


Which finding is most accurate for confirming rupture of the amniotic sac?

A. Crystallization of fluid on microscopic examination
B. Fluid turning brown when flamed
C. Nitrazine strip turning blue
D. Pooling of fluid in the vaginal vault

The correct answer is A, Crystallization of fluid on microscopic examination.

Why is this the correct answer?
The approach to confirming rupture of membranes has three components: pooling of amniotic fluid in the vaginal vault, a positive nitrazine test result, and crystallization (or "ferning") revealed on microscopic analysis of amniotic fluid. Of the three findings, ferning is the most specific for amniotic sac rupture. Ferning occurs when amniotic fluid dries and sodium chloride crystals precipitate.

Why are the other choices wrong?

  • When exposed to a flame, vaginal secretions, not amniotic fluid, turn brown. Amniotic fluid turns white and displays the crystallized ferning pattern.
  • Nitrazine is a pH indicator that is more sensitive than litmus and is often used in the emergency department. Vaginal fluid is mildly acidic with a pH of approximately 4 to 5 and causes a nitrazine strip to either remain yellow or turn slightly red (acidic). Amniotic fluid is basic with a pH of 7 to 7.5 and turns a nitrazine strip blue. For several reasons, a nitrazine test can have a false-positive result, such as lubricant use during speculum examination; the presence of semen, blood, or cervical mucus; or concurrent Trichomonas vaginalis
  • When membrane rupture is suspected, a speculum examination must be performed. Pooling fluid can have various sources (eg, amniotic, vaginal, or urinary), so visualization of pooling is not specific.

REFERENCES
Vasquez V, Desai S. Labor and delivery and their complications. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 2. 9th ed. Elsevier; 2018:2296-2312.

Young JS. Maternal emergencies after 20 weeks of pregnancy and in the peripartum period. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:631-637.


In which scenario is succinylcholine a safe alternative to rocuronium?

A. Amyotrophic lateral sclerosis
B. History of malignant hyperthermia
C. Known cocaine use 30 minutes before arrival
D. Left-sided weakness for the past 2 hours

The correct answer is D, Left-sided weakness for the past 2 hours.

Why is this the correct answer?
Succinylcholine is a depolarizing neuromuscular blocking agent that is used in rapid sequence intubation. Succinylcholine has a more rapid onset and shorter duration of action than nondepolarizing neuromuscular blocking agents, but it carries the risks of bradycardia, hyperkalemia, masseter spasm, and malignant hyperthermia. Contraindications to succinylcholine administration include risk factors for hyperkalemia, history of malignant hyperthermia, and recent amphetamine use. Notably, the risk for severe hyperkalemia is insignificant until after the first 5 days for burns, crush injuries, spinal cord injuries, strokes, and intra-abdominal sepsis. The severe hyperkalemic response is due to acetylcholine receptor upregulation at the neuromuscular junction, which takes several days to develop. Thus, a patient with an acute stroke may be given succinylcholine without increased risk for hyperkalemia. Bradycardia is more common in children and is typically self-limiting, but it may be treated with atropine. Masseter spasm may be treated with dantrolene or a nondepolarizing neuromuscular blocking agent.

Why are the other choices wrong?

  • Neuromuscular diseases (including amyotrophic lateral sclerosis and multiple sclerosis) result in upregulation of acetylcholine receptors at the neuromuscular junction, which can cause an exaggerated hyperkalemic response to succinylcholine. Succinylcholine is contraindicated in these patients regardless of time of diagnosis or severity of disease.
  • Succinylcholine is a known cause of malignant hyperthermia, and patients with a prior diagnosis of malignant hyperthermia should receive nondepolarizing neuromuscular blocking agents. Due to a pathophysiologic overlap between masseter spasm and malignant hyperthermia, all patients who develop masseter spasm should undergo future testing for susceptibility to malignant hyperthermia.
  • Patients who have recently used amphetamines (including cocaine) might have a prolonged duration of neuromuscular blockade because these agents competitively inhibit plasma cholinesterase, which reduces the amount of enzyme available for succinylcholine metabolism.

REFERENCES
Brown CA, Walls RM. Airway. In: Walls RM, Hockberger RS, Gausche-Hill M, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 1. 9th ed. Elsevier; 2018:3-24.

Wang HE, Carlson JN. Tracheal intubation. In: Tintinalli JE, Ma OJ, Yealy DM, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 9th ed. McGraw-Hill Education; 2020:179-190.

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