Emergency Medicine Flashcards

A 34-year-old woman presents with 3 days of progressive ascending weakness starting in her legs, now with difficulty swallowing and a heart rate alternating between 48 and 130 bpm. Lumbar puncture reveals protein of 420 mg/dL with 3 WBCs/mm³. Which intervention is most likely to reduce ICU length of stay in this patient?

Answer: Plasmapheresis initiated within 4 weeks of symptom onset

This is Guillain-Barré syndrome with autonomic instability (hallmark: fluctuating HR) and albuminocytologic dissociation on LP. Plasmapheresis initiated within 4 weeks of onset reduces time on ventilator and ICU stay. IV IgG is equally efficacious to plasmapheresis alone but combining them sequentially (option C) offers no additive benefit per trials. Steroids (option B) are contraindicated in GBS — they worsen outcomes. Rituximab is not established therapy for classic GBS.

A 58-year-old man on warfarin (INR 3.8) for atrial fibrillation presents after a witnessed fall with a GCS of 14. CT head shows a 4 mm subdural hematoma with no midline shift. He is on no antiplatelet agents. Thirty minutes later his GCS drops to 10. Which is the most appropriate next step?

Answer: 4-factor prothrombin complex concentrate (4F-PCC) and emergent neurosurgical consultation

Clinical deterioration (GCS drop of 4 points) signals expanding hematoma requiring immediate warfarin reversal and neurosurgical evaluation. 4F-PCC (Kcentra) achieves INR reversal within minutes versus 6–12 hours for Vitamin K and 30–60 minutes for FFP, making it the preferred agent for life-threatening warfarin-associated intracranial hemorrhage. FFP requires large volumes and is slower. Andexanet alfa reverses factor Xa inhibitors (rivaroxaban, apixaban), not warfarin. Watchful waiting with repeat CT is inappropriate given active neurological decline.

A 72-year-old man with COPD is brought in for acute respiratory failure. ABG on room air: pH 7.18, PaCO2 88 mmHg, PaO2 48 mmHg, HCO3 32 mEq/L. He is placed on BiPAP. After 90 minutes his SpO2 is 94% but he remains somnolent with a pH of 7.21 and PaCO2 of 82 mmHg. What is the most appropriate next step?

Answer: Intubate and initiate volume-controlled ventilation with a low tidal volume strategy

BiPAP failure criteria include persistent or worsening encephalopathy, failure to improve pH to above 7.25 after 1–2 hours, and hemodynamic instability. This patient has not improved sufficiently and remains somnolent — a contraindication to ongoing NIV (aspiration risk, inability to protect airway). Intubation with volume-controlled ventilation using permissive hypercapnia strategy is now indicated. Increasing IPAP further without clinical response is unlikely to succeed and delays definitive airway management. Heliox has modest evidence in COPD exacerbations but is not appropriate as a bridge when NIV is failing. Doxapram is rarely used in modern practice and is not a first-line rescue agent.

A 26-year-old woman presents with sudden-onset severe headache described as 'the worst of her life,' photophobia, and a stiff neck. Non-contrast CT head is negative. Lumbar puncture shows: opening pressure 240 mmH2O, 2200 RBCs in tube 1, 2100 RBCs in tube 4, xanthochromia present, protein 110 mg/dL, glucose 55 mg/dL. Which of the following is the most accurate interpretation?

Answer: Subarachnoid hemorrhage — the RBC count not clearing between tubes 1 and 4, combined with xanthochromia, confirms true hemorrhage

Xanthochromia (yellow discoloration from oxyhemoglobin/bilirubin formed in vivo) is the definitive marker of subarachnoid hemorrhage in CSF analysis — it cannot result from a traumatic tap. RBC count that does NOT clear between tube 1 and tube 4 further supports true SAH rather than traumatic tap (in which counts typically fall by 25–50%). The presentation (thunderclap headache, meningismus, CT-negative) with these LP findings is classic SAH until proven otherwise. Bacterial meningitis would show neutrophilic pleocytosis and low glucose. Xanthochromia from elevated protein alone is a clinical myth; it requires hemolysis in vivo over time.

A 44-year-old male beekeeper is brought by EMS 10 minutes after approximately 200 bee stings. He received epinephrine 0.3 mg IM en route. In the ED: BP 70/40, HR 128, SpO2 88% on 15L NRM, diffuse urticaria, and severe bronchospasm. Despite a second dose of epinephrine 0.5 mg IM, BP is 68/38. He takes metoprolol 50 mg daily for hypertension. What is the most appropriate pharmacologic intervention?

Answer: Glucagon 1–2 mg IV followed by an epinephrine infusion

Beta-blocker use (metoprolol) is the critical modifier here — it competitively blocks the beta-adrenergic effects of epinephrine, causing refractory anaphylaxis. Glucagon bypasses beta receptors by increasing cAMP through a G-protein–coupled mechanism independent of adrenergic receptors, restoring heart rate and contractility. It should be followed by an epinephrine infusion to maintain systemic vascular resistance. Vasopressin can be used as an adjunct in refractory anaphylaxis but is not the first rescue agent when beta-blockade is the mechanism. Norepinephrine addresses vasodilation but does not overcome bronchospasm or beta-blocked myocardial depression. Antihistamines and steroids have no role in acute hemodynamic rescue.

A 67-year-old woman with end-stage renal disease on hemodialysis misses two sessions and presents with weakness and palpitations. ECG shows peaked T-waves and a PR interval of 240 ms. Her K⁺ is 7.1 mEq/L. She receives calcium gluconate 1g IV, sodium bicarbonate 50 mEq IV, and insulin 10 units IV with D50. Thirty minutes later, repeat ECG shows new sine wave pattern and her K⁺ is 6.8 mEq/L. What is the definitive next step?

Answer: Emergent hemodialysis

A sine wave pattern on ECG represents pre-fibrillatory hyperkalemia and is a true cardiac emergency requiring immediate definitive treatment. In ESRD, the kidneys cannot excrete potassium, so all medical interventions (insulin/glucose, bicarbonate, albuterol) only temporarily redistribute K⁺ — they do not remove it from the body. Only hemodialysis actually removes potassium. Kayexalate has a delayed onset of 2–6 hours, variable efficacy, and carries risk of intestinal necrosis. Patiromer also has delayed onset (hours to days) and is appropriate for outpatient chronic hyperkalemia, not acute emergencies. Repeating insulin without dialysis risks hypoglycemia while failing to reduce total body potassium.