Emergency Medicine Flashcards

A 58-year-old male presents with acute onset chest pain radiating to the back, described as 'tearing.' BP is 190/110 mmHg in the right arm and 155/90 mmHg in the left arm. CT angiography reveals a Type A aortic dissection. Which of the following is the MOST appropriate immediate pharmacologic intervention before surgical consultation?

Answer: Administer IV labetalol or esmolol first to reduce heart rate, then add a vasodilator if needed

In Type A aortic dissection, the priority is reducing aortic wall stress (dP/dt) by first lowering heart rate with a beta-blocker (labetalol or esmolol) before adding a vasodilator. Using a vasodilator like nitroprusside alone causes reflex tachycardia, which increases shear stress on the aortic wall and can worsen the dissection. Heparin is contraindicated as it increases bleeding risk. Nicardipine alone does not adequately control heart rate.

A 34-year-old woman with known epilepsy presents in status epilepticus. She received lorazepam 4 mg IV twice without effect. Levetiracetam 60 mg/kg IV was then administered with no cessation of seizure activity at 20 minutes. Which agent represents the MOST appropriate next step in refractory status epilepticus management per current guidelines?

Answer: Valproic acid 40 mg/kg IV over 10 minutes

Per the Neurocritical Care Society guidelines, after failure of benzodiazepines AND one second-line agent (levetiracetam in this case), the next step for refractory status epilepticus is a third agent. Valproic acid 40 mg/kg IV is a well-supported second-line/third-line option that is rapidly effective. Phenytoin at 50 mg/min risks cardiac arrhythmia and hypotension (fosphenytoin is preferred but not listed). Lacosamide lacks robust evidence in this setting. Repeating benzodiazepines at this stage is not guideline-concordant after two failed doses.

A 72-year-old male on warfarin (INR 3.8) presents with sudden-onset worst headache of his life. Non-contrast CT shows a subarachnoid hemorrhage. His BP is 210/120 mmHg. Which combination of interventions is MOST appropriate in the first 30 minutes?

Answer: 4-factor prothrombin complex concentrate (4F-PCC) + IV nicardipine, target SBP <160 mmHg

In anticoagulant-associated intracranial hemorrhage, rapid reversal is critical. 4F-PCC reverses warfarin within minutes (versus hours for FFP) and does not carry the volume overload risk. IV nicardipine provides titratable BP control targeting SBP <160 mmHg per guidelines for subarachnoid hemorrhage. Vitamin K alone is too slow. FFP takes 30–60 minutes and requires thawing. Platelet transfusion is not indicated unless thrombocytopenia is present.

A 45-year-old scuba diver presents 4 hours after a rapid ascent with joint pain, skin mottling, and new-onset confusion. Oxygen saturation is 91% on room air. Which of the following is the MOST critical early intervention, and what is the primary mechanism of benefit?

Answer: Hyperbaric oxygen therapy — reduces nitrogen bubble size and promotes reabsorption

Decompression sickness (Type II with neurological involvement) requires definitive treatment with hyperbaric oxygen therapy (HBOT), which directly reduces bubble volume (Boyle's Law) and creates a high oxygen gradient to accelerate nitrogen reabsorption. While 100% normobaric oxygen is given as a bridge while arranging HBOT, it does not provide the pressure component necessary to shrink bubbles. IV fluids help prevent hypovolemia but do not treat the gas emboli. Aspirin has no proven role in DCS management.

A 28-year-old presents with fever, nuchal rigidity, and a petechial rash. CSF analysis shows WBC 2,400 cells/µL (95% neutrophils), glucose 28 mg/dL (serum glucose 110 mg/dL), and protein 420 mg/dL. Blood cultures are drawn. The patient has a documented anaphylactic reaction to penicillin. What is the MOST appropriate antibiotic regimen?

Answer: Vancomycin + meropenem + dexamethasone

In bacterial meningitis with severe penicillin allergy (anaphylaxis), cephalosporins are contraindicated due to cross-reactivity risk in true anaphylaxis. Meropenem is the preferred carbapenem for CNS infections (better CNS penetration than imipenem, lower seizure risk). Vancomycin is added to cover resistant pneumococcus. Dexamethasone is added to reduce inflammation. Aztreonam covers gram-negatives but lacks gram-positive coverage and would miss Streptococcus pneumoniae. Chloramphenicol is a historical option but inferior in efficacy and toxicity profile.

A 66-year-old female with ESRD on hemodialysis presents with peaked T-waves, a widened QRS (160 ms), and a sine wave pattern on ECG. She is unresponsive to verbal stimuli. Potassium is 8.2 mEq/L. After calcium gluconate is administered, which agent should be given NEXT to shift potassium intracellularly most rapidly?

Answer: Regular insulin 10 units IV + dextrose 50% 50 mL IV

After membrane stabilization with calcium, the next priority is rapid intracellular potassium shifting. Insulin (with dextrose to prevent hypoglycemia) drives potassium into cells via Na-K-ATPase stimulation and acts within 15–30 minutes, reducing serum K+ by 0.5–1.5 mEq/L. Kayexalate eliminates potassium but takes hours and is not appropriate in this emergent setting. Sodium bicarbonate is slower, less effective in ESRD patients, and works over hours. Furosemide requires residual renal function, which is absent in ESRD patients on dialysis.