A 68-year-old man with coronary artery disease was admitted for chest pain and ventricular tachycardia. After electric cardioversion, therapeutic heparinization was started for myocardial ischemia and nontransmural infarction. On day 3, headache and fever developed, followed by an altered sensorium and hyponatremia. Infectious etiology for the fever was excluded, and results of computed tomography of the brain were normal. Later magnetic resonance imaging (Day 10) demonstrated a pituitary macroadenoma with hemorrhage. Treatment for panhypopituitarism with stress-dose steroids stabilized the patient, and the fever and hyponatremia resolved. Transsphenoidal resection of the pituitary adenoma was performed without incident. This is the first reported case of pituitary apoplexy after heparin anticoagulation for acute myocardial infarction, although chronic anticoagulation in other settings has been reported as a precipitant of apoplexy. The uncommon presentation of a "central" fever and confusion in a patient with previously undiagnosed adenoma posed a diagnostic challenge. Subtle presentations of panhypopituitarism, knowledge of which should lead to suspicion and early diagnosis of pituitary apoplexy, will prevent anticoagulant-induced central nervous system catastrophes and potential fatalities.