Hydralazine-Associated Pericardial Effusion Causing Cardiac Tamponade Without Hypotension

Drug-induced pericardial effusion is an uncommon but clinically significant cause of cardiac tamponade. Hydralazine is strongly associated with autoimmune phenomena, yet cardiovascular manifestations remain under-recognized.

A 42-year-old man receiving high-dose hydralazine presented with progressive dyspnea, dizziness, and palpitations. Transthoracic echocardiography demonstrated a large circumferential pericardial effusion with right ventricular diastolic collapse and a plethoric inferior vena cava, consistent with tamponade physiology despite preserved blood pressure. Emergent pericardiocentesis drained 1,860 mL of serosanguinous exudative fluid, with immediate symptom relief. Serologic testing revealed antinuclear antibody positivity, markedly elevated perinuclear antineutrophil cytoplasmic antibodies, and borderline myeloperoxidase antibodies. Hydralazine withdrawal and corticosteroid therapy resulted in sustained clinical and echocardiographic resolution.

This case highlights hydralazine as a reversible cause of autoimmune-mediated pericardial effusion and illustrates that tamponade may occur without hypotension.

Medication-induced autoimmunity should be considered in unexplained pericardial effusions. Early recognition and drug withdrawal can prevent life-threatening complications.