Toxicology, Environmental & Infectious Diseases Flashcards

A patient on warfarin presents with an INR of 9.8 and active intracranial hemorrhage. Which is the FASTEST and most appropriate reversal strategy?

Answer: 4-factor prothrombin complex concentrate (4F-PCC)

4-factor PCC reverses warfarin-related INR within minutes, contains all vitamin K-dependent factors, requires small volume, and is superior to FFP for emergent reversal.

A patient presents with fever, hepatosplenomegaly, and pancytopenia after returning from a tropical trip; a bone marrow biopsy shows macrophages engulfing red blood cells and platelets. What is the diagnosis?

Answer: Visceral leishmaniasis (kala-azar)

Visceral leishmaniasis (kala-azar) causes macrophage invasion of the reticuloendothelial system, presenting with fever, massive splenomegaly, and pancytopenia in a returning traveler.

Which ECG finding in a patient with digoxin toxicity is MOST specific for toxicity rather than therapeutic effect?

Answer: Bidirectional ventricular tachycardia

Bidirectional ventricular tachycardia is highly specific for digoxin (and aconitine) toxicity and is not a therapeutic ECG change.

A patient presents with fever, cough, and bilateral hilar lymphadenopathy after disturbing bat guano in an Ohio cave. Bronchoalveolar lavage reveals intracellular yeast within macrophages. What is the treatment for severe pulmonary disease?

Answer: Amphotericin B lipid complex

Severe or disseminated histoplasmosis requires amphotericin B lipid formulation as initial therapy, followed by step-down to itraconazole after clinical improvement.

A construction worker collapses on a hot summer day with core temperature of 41.5°C, anhidrosis, and delirium. What is the MOST effective cooling method to reduce core temperature rapidly?

Answer: Ice water immersion

Ice water immersion provides the fastest rate of core cooling (0.2°C/min) for exertional heat stroke and is the gold standard cooling method.

A patient presents with ascending flaccid paralysis, areflexia, and respiratory insufficiency 10 days after a gastroenteritis illness. CSF shows elevated protein with normal glucose and no pleocytosis. What is the most appropriate emergency intervention?

Answer: Intubation and mechanical ventilation if FVC < 20 mL/kg

In Guillain-Barré syndrome, the most critical emergency intervention is airway management; intubation is indicated when FVC falls below 20 mL/kg or the patient cannot complete a sentence.

A patient presents with septic shock from suspected gram-negative bacteremia. Which of the following represents the BEST evidence-based initial fluid resuscitation target in the first 3 hours per surviving sepsis guidelines?

Answer: 30 mL/kg of crystalloid IV, then reassess

The Surviving Sepsis Campaign recommends at least 30 mL/kg of IV crystalloid within the first 3 hours of sepsis-induced hypoperfusion recognition.