Post-Obstructive Diuresis: Physiopathology, Diagnosis and Management after Urological Treatment of Obstructive Renal Failure

Abstract

Obstructive acute renal failure is both a medical and a surgical emergency. The first treatment modality is urological by relief of obstruction. Post-obstructive diuresis is an abnormal condition of prolonged polyuria, involving both excessive solute and water loss, after acute drainage of obstructed urinary tract system. Physiopathology mechanisms are multiples. In most patients, diuresis will resolve once the kidneys normalize the volume and solute status and homeostasis is achieved. Post-obstructive diuresis can occur in up to 50% of patients with substantial urinary tract obstruction and can be life-threatening if it becomes pathologic. It can be detected by hourly monitoring of diuresis. Medical treatment of post-obstructive diuresis consists of oral or intravenous fluids adjusted to the findings of clinical examination, diuresis (volume and electrolytes) and close monitoring of patient. Fluid compensation should be tapered off over several days. Patients at high risk of post-obstructive diuresis should be identified and appropriately monitored.