From the Research
Definition and Pathophysiology
- Post obstructive diuresis (POD) is a polyuric response initiated by the kidneys after the relief of a substantial bladder outlet obstruction 1.
- The condition occurs after relief of bilateral ureteral obstruction, despite persistent decrease in renal cortical perfusion and glomerular filtration rate (GFR) 2.
- Mechanisms of polyuria following relief from bilateral chronic obstruction include enhanced PGE-mediated medullary blood flow, structural and functional tubular damage, decreased sodium reabsorption, and impaired renal concentrating ability 2.
Clinical Presentation and Complications
- POD can become pathologic, resulting in dehydration, electrolyte imbalances, and death if not adequately treated 1.
- The post-obstruction diuresis syndrome can lead to dehydration, or even shock and acute renal failure 3.
- Serious electrolyte disturbances can occur after relief of urinary tract obstruction, including excessive urinary excretion of potassium, bicarbonate, calcium, phosphate, magnesium, and urate 4.
Diagnosis and Management
- Primary care physicians should be familiar with this potential clinical entity, especially as they are generally the first to encounter and treat these patients 1.
- Prompt diagnosis is required to avoid complications, and restoration of renal homeostasis requires correction of blood volume and electrolyte disturbances 5.
- Medical management is designed to avoid serious haemodynamic and metabolic disorders, and strict and specialized monitoring is required during the post-obstruction phase 3.