Plasma renin activity in patients after a subarachnoid hemorrhage--a possible predictor of outcome

Plasma renin activity (PRA) was estimated in 23 patients during the 1st week after a subarachnoid hemorrhage (SAH) and in a control group of 6 postlaminectomy patients. Patients with altered levels of consciousness and neurological deficits had significantly higher levels of PRA than did patients who were alert and neurologically intact. The SAH patients were divided into three groups: (a) low renin (13 patients with a PRA of less than 1.77 pmol/ml/hour), (b) normal renin (2 patients with normal renin levels), and (c) high renin (8 patients with a PRA of greater than 2.5 pmol/ml/hour). Patients with high renin levels had a significantly higher incidence of morbidity and mortality than did those with low renin levels. There were also higher levels of urinary catecholamines in the high renin group of patients. The combination of altered consciousness, high levels of urinary catecholamines, particularly adrenaline; and a high PRA in the 1st week after a SAH indicates a poor prognosis.