Presumed hydrochlorothiazide-associated immunologic-hypersensitivity-induced pericardial effusion.

A 50-year-old Caucasian female presented for a second opinion regarding a newly diagnosed pericardial effusion. Seven months previously, hydrochlorothiazide was introduced into her pharmacologic regimen to aid in the management of her hypertension. A routine echocardiogram indicated a large pericardial effusion with signs of early cardiac tamponade. The patient subsequently underwent successful pericardiocentesis with complete drainage of the pericardial effusion. The effusion was empirically attributed to a viral etiology. Repeat echocardiograms showed recurrence of the pericardial effusion. Prior to undergoing a second pericardiocentesis with pericardial biopsy, as her physicians recommended, the patient sought a second opinion. While obtaining the patient's history, an allergy to sulfa was elicited. The possibility that the pericardial effusion may be secondary to an immunologic-hypersensitivity reaction was considered. It was recommended the patient discontinue the use of hydrochlorothiazide. Nine days following discontinuation of hydrochlorothiazide and without any other intervention, an echocardiogram was reported to show the size of the pericardial effusion had subsided substantially. Nine weeks following discontinuation, almost complete resolution of the pericardial effusion was reported. It is hypothesized that when treated with hydrochlorothiazide, the patient had an immune response leading to the pericardial effusion.