Renin/angiotensin system in hypertension after traumatic renal-artery thrombosis.

Hypertension was found in four patients after unilateral renal-artery thrombosis following blunt abdominal trauma. In one patient, who was followed up from the time of injury, renin hypersecretion and secondary aldosteronism developed within a few days, and hypertension was present 12 weeks later. Increasing haemoglobin and raised blood-erythropoietin concentrations were also found. In the three other patients, hypertension was found casually within 3 years of trauma. In all patients, unilateral renin production by the affected kidney was significantly increased. Nephrectomy of the diseased kidney corrected hypertension and endocrine abnormalities in all patients. The delayed onset of hypertension despite early activation of the renin/angiotensin/aldosterone axis accords with the course of events observed in experimentally induced hypertension in rats, and suggests that several weeks or even months are required for hypertension to develop after sudden renal-artery occlusion in man. Slowly acting mechanisms, probably initiated by hypersecretion of renin, may be responsible for the hypertension.