Emergency Medicine EOR practice questions

Why Observation and vascular risk factor control is correct

• An isolated CN VI palsy in an older patient with diabetes and hypertension and a normal MRI is most consistent with microvascular ischemic mononeuropathy
• The standard approach is conservative management with observation and tight control of blood pressure, glucose, and lipids; most cases resolve spontaneously within 3 months
• Symptomatic relief with a temporary eye patch or prism can be offered for diplopia

Why the others are wrong

• B) Urgent neurosurgical posterior fossa decompression — urgent neurosurgical decompression is reserved for compressive lesions such as tumor, aneurysm, or markedly elevated intracranial pressure, none of which are present given the normal imaging
• C) Empiric intravenous acyclovir for viral neuropathy — empiric IV acyclovir would be appropriate if there were evidence of herpes zoster ophthalmicus or a viral cranial neuritis, but there is no rash, pain, or systemic infectious picture here
• D) High-dose intravenous methylprednisolone therapy — high-dose IV methylprednisolone is used for inflammatory or demyelinating optic neuropathy and in giant cell arteritis, not for an isolated ischemic abducens palsy

Why Sympathomimetic toxidrome is correct

• Sympathomimetic toxidrome: mydriasis (dilated reactive pupils), tachycardia, hypertension, hyperthermia, diaphoresis, and agitation — caused by cocaine, amphetamines, MDMA
• Key distinguishing feature from anticholinergic: sympathomimetic = wet (diaphoretic); anticholinergic = dry (no sweating, urinary retention, flushed)

Additional high-yield points

• Management: benzodiazepines (lorazepam) for agitation, hypertension, and seizures
• Avoid beta-blockers alone (unopposed alpha stimulation worsens hypertension)
• Cooling measures for hyperthermia
• Monitor for coronary vasospasm (cocaine)

Why intranasal or intravenous naloxone is correct

• The presentation is the classic opioid toxidrome: miosis (2 mm bilateral pinpoint pupils), respiratory depression (RR 6), bradycardia, hypotension, and decreased consciousness.
• Naloxone (Narcan) is an opioid receptor antagonist and the immediate treatment.
• Routes include IV (fastest onset), IM, or IN (intranasal — easy for bystanders).
• Dose: 0.4–2 mg IV; repeat every 2–3 minutes if no response; titrate to adequate respirations, not full reversal — avoid precipitating acute withdrawal and combative behavior.
• Supportive care includes supplemental oxygen and positioning.

Additional high-yield points

• The half-life of naloxone is shorter than most opioids — monitor for re-narcotization after initial response.

Why N-acetylcysteine infusion is correct

• The 4-hour acetaminophen level is 280 mcg/mL, which falls above the treatment line of the Rumack-Matthew nomogram (150 mcg/mL at 4 hours), so N-acetylcysteine (NAC) infusion is indicated.
• The patient is currently asymptomatic because hepatotoxicity peaks 72–96 hours after ingestion; normal initial labs do not exclude impending injury.
• NAC replenishes hepatic glutathione and detoxifies the reactive metabolite NAPQI.
• NAC is most effective when started within 8 hours; prompt initiation prevents fulminant hepatic failure.

Why the others are wrong

• B) Activated charcoal — Activated charcoal limits absorption only within roughly 1–2 hours of ingestion and would not treat a patient who already has a toxic 4-hour level.
• C) Observation with repeat liver enzymes in 24 hours — Dangerously delays the antidote in a patient whose level mandates treatment; normal initial enzymes are expected this early and do not exclude impending injury.
• D) Psychiatric evaluation and discharge — Ignores a potentially lethal hepatotoxic ingestion; psychiatric assessment is essential but must follow, not replace, NAC.

Why arthrocentesis is correct

• Arthrocentesis with synovial fluid analysis is the single most important next step for an acute, atraumatic, monoarticular effusion, especially when septic arthritis is a concern.
• Synovial fluid analysis distinguishes the underlying cause:
• WBC >50,000/µL with a polymorphonuclear (PMN) predominance suggests septic arthritis — a joint-threatening emergency.
• Positively or negatively birefringent crystals indicate pseudogout or gout.
• Bloody fluid (hemarthrosis) suggests coagulopathy or an occult intra-articular injury.
• Radiographs are already unremarkable here, so imaging has excluded fracture and the priority is to sample the joint before starting antibiotics.

Why the others are wrong

• A) Magnetic resonance imaging of the knee — MRI evaluates soft-tissue structures but does not identify infection or crystals and delays the definitive diagnostic tap.
• C) Empiric intravenous antibiotic therapy — Antibiotics should not be started before arthrocentesis in suspected septic arthritis because doing so lowers synovial culture yield.
• D) Measurement of the serum uric acid level — Serum uric acid is frequently normal during an acute gout flare and cannot confirm or exclude septic arthritis; joint aspiration is required.

Why Acute airway obstruction is correct

• The most feared and most common serious complication of recurrent respiratory papillomatosis is acute airway obstruction from papilloma growth in the larynx and trachea
• Children present with worsening stridor, retractions, and hypoxia
• May require urgent operative microlaryngoscopy and debulking; some need temporizing tracheostomy

Why the others are wrong

• A) Esophageal perforation — esophageal perforation is not a recognized complication of laryngeal papillomatosis; it would cause chest pain, subcutaneous emphysema, and mediastinitis, not the airway picture described
• B) Spontaneous pneumothorax — spontaneous pneumothorax is uncommon in this age group, usually occurs in tall thin adolescents or those with bullous disease, and presents with unilateral decreased breath sounds and pleuritic pain rather than stridor and retractions
• C) Pulmonary embolism — pulmonary embolism is rare in healthy young children without thrombophilia or prolonged immobility and does not produce biphasic stridor; it would present with pleuritic chest pain and unilateral findings

Additional high-yield points

• About 1-3% of cases undergo malignant transformation to squamous cell carcinoma, typically when disease extends to the lungs, but this is a late complication, not an acute presentation