Hyperreninemic hypoaldosteronism: a possible etiological factor of septic shock-induced acute renal failure

Objective. Hyperreninemic hypoaldosteronism has been described in critically ill patients. The present study investigated the plasma aldosterone concentration (PAC) in septic shock patients and its relationship with clinical course. Design and setting. Prospective descriptive study in a medical intensive care unit (ICU) of a university hospital. Patients. Forty-six consecutive patients with septic shock as defined by the ACCP/SCCM criteria. Intervention. A corticotropin stimulation test, followed by treatment with low doses of hydrocortisone and fludrocortisone. Measurements and results. Plasma renin activity, PAC, and cortisol levels were measured before and after the test. PAC measurements were repeated for 1 week. Relevant clinical and laboratory variables were recorded for ICU stay. Patients were divided into two groups according to PAC/renin activity ratio: above 2 (n=24 patients) and below 2 (n=22). Patients with PAC/renin activity less than 2 had higher total volume of infused fluid, serum creatinine level, and fractional excretion of sodium values; aldosterone and serum creatinine were negatively correlated. Hypoaldosteronism was reversible within 1 week. Duration of ICU stay (p=0.0026) and the need for renal replacement therapy (p=0.0021) were greater in the group with PAC/renin less than 2. Conclusions. Transient hyperreninemic hypoaldosteronism is common in patients with septic shock. These abnormal aldosterone levels are associated with greater sodium and fluid depletion and are followed by enhanced incidence of acute renal failure requiring renal replacement therapy and prolonged length of stay in ICU.