Reversible hypertension associated with unrecognised high pressure chronic retention of urine.

The cardiovascular effects of relief of obstruction were examined in 21 patients with painless urinary retention and hydronephrosis and hydroureter associated with hypertension (diastolic blood pressure 95-120 mm Hg, mean 107, 11 patients), severe peripheral oedema (8 patients), raised jugular venous pressure (5 patients), or clinical evidence of pulmonary oedema (5 patients). Before relief of obstruction fractional sodium excretion was appropriate for the reduced rate of glomerular filtration. After urethral catheterisation blood pressure fell (p less than 0.001) and the other cardiovascular abnormalities were rapidly reversed without further therapeutic measures. This improvement was associated with an increase (p less than 0.05) in both absolute and fractional urinary sodium excretion that was greatest at 24 h. 5% of patients undergoing surgery for obstructive disorders of the lower urinary tract have hydronephrosis and hydroureter. Hypertension related to chronic urinary tract obstruction may be the commonest form of surgically correctable renal hypertension.