Hypotensive response to angiotensin II analogue and angiotensin I converting enzyme inhibitor in pseudo-Bartter's syndrome.

We studied the effect of angiotensin II analogue (AII-A) and angiotensin I converting enzyme inhibitor (SQ 14,225) on blood pressure and the renin-angiotensin-aldosterone system in a patient with pseudo-Bartter's syndrome, who was a 26-year-old unmarried Japanese woman taking furosemide surreptitiously. The intravenous infusion of AII-A decreased blood pressure from 85/35 to 68/28 mmHg. This decrease in blood pressure was associated with an increment of plasma renin activity (PRA) and a decrement of plasma aldosterone concentration (PAC). Similarly, SQ 14,225 given orally decreased blood pressure to the same extent. An increment of PRA and a decrement of PAC were also observed. These results suggest that the renin-angiotensin system plays a considerable role in maintaining blood pressure in pseudo-Bartter's syndrome. Again, attention has to be paid to the possibility of surreptitious use of diuretics in an adult patient with persistent hypokalemic alkalosis, hyperactivity of the renin-angiotensin-aldosterone system and angiotensin II insensitivity simulating "true" Bartter's syndrome.