Halbgewachs C & Domes T. Can Fam Physician. 2015 Feb; 61(2): 137–142.
"Urinary retention is a common clinical condition encountered by all physicians at some point in their careers. As described above, the initial medical approach involves decompressing the bladder with the placement of a urethral catheter, followed by a workup to identify the underlying cause. However, how often do primary care physicians consider the potential effects of rapidly draining a patient’s bladder on the rest of the body? One might argue there is little effect, as doing so mimics urination, the normal physiologic process that has been perfected over thousands of years of natural selection. However, in some situations, acute drainage of an obstructed urinary tract can unmask deranged renal mechanisms and result in uncontrolled, unregulated urine production known as postobstructive diuresis. Postobstructive diuresis is important because it can occur in up to 50% of patients with substantial urinary tract obstruction and can be life-threatening if it becomes pathologic and is not adequately treated. The goal of this article is to make primary care physicians aware of this clinical entity and help them confidently identify individuals at risk, initiate appropriate monitoring to allow for early diagnosis, and provide adequate treatment to avoid any adverse outcomes.
EDITOR’S KEY POINTS
- Acute drainage of an obstructed urinary tract can unmask deranged renal mechanisms and result in uncontrolled, unregulated urine production known as postobstructive diuresis (POD).
- Postobstructive diuresis can occur in up to 50% of patients with substantial urinary tract obstruction and can be life-threatening if it becomes pathologic.
- Patients with decompressed urinary obstruction might have to be admitted for a 24-hour observation period. If pathologic POD ensues, then polyuria will continue even after a euvolemic state is reached. Patients with pathologic POD require strict monitoring of vital signs, fluid status, and serum electrolyte levels, and benefit from consultation with a nephrologist."