Benign Prostatic Hyperplasia (BPH) is a common, non-cancerous condition where the prostate gland enlarges as men age. This growth frequently leads to lower urinary tract symptoms, including a weak stream and difficulty starting urination. Urinary retention is the inability to completely empty the bladder. BPH is the most frequent cause of urinary retention in aging men, creating a health concern that requires prompt attention. The connection stems from the prostate’s anatomical position surrounding the urethra.
How BPH Leads to Urinary Retention
The prostate gland wraps around the urethra, the tube that carries urine from the bladder. As BPH causes the prostate tissue to proliferate, it mechanically compresses this tube, creating an obstruction to the flow of urine. This physical narrowing forces the bladder muscle, known as the detrusor, to work harder to push urine past the blockage.
This increased effort results in a temporary thickening and strengthening of the bladder wall. Over time, the constant strain against the obstruction weakens the detrusor muscle, leading to decompensation or failure. The bladder can no longer contract effectively, and it retains a volume of urine after voiding, which results in urinary retention.
Acute Versus Chronic Retention
Urinary retention manifests in two distinct ways: acute and chronic. Acute urinary retention (AUR) is a sudden condition where the man cannot pass any urine despite a strong urge. AUR is a medical emergency because the rapid over-distension of the bladder causes severe pain and discomfort in the lower abdomen.
In contrast, chronic urinary retention (CUR) develops gradually and is often painless; an individual can urinate but is unable to empty the bladder completely. Symptoms of CUR are subtle and may include a weak or inconsistent stream, urinary hesitation, or the feeling of needing to urinate again immediately after finishing. Because the onset is gradual, the symptoms are sometimes mistaken for an overactive bladder.
The long-term risks associated with chronic retention are significant. Residual urine in the bladder is a breeding ground for bacteria, leading to recurrent urinary tract infections (UTIs). Continuous pressure on the bladder wall can damage the organ’s structure and function. The back-pressure from the retained urine can travel up the ureters to the kidneys, a condition called hydronephrosis, which can lead to permanent kidney damage or chronic kidney failure.
Immediate Relief Measures
When acute urinary retention occurs, the immediate priority is to relieve the obstruction and drain the urine to prevent further damage and alleviate pain. This is achieved through bladder decompression, primarily using catheterization. A flexible tube, such as a Foley catheter, is inserted through the urethra into the bladder to allow the retained urine to flow out.
This procedure offers instantaneous relief from the pressure caused by the full bladder. If a standard urethral catheter cannot be inserted due to a severe blockage, a physician may use a firmer, angled Coude catheter or a suprapubic catheter. The latter is inserted directly into the bladder through the abdominal wall. Quickly decompressing the bladder also reduces the risk of acute kidney injury.
Managing BPH to Prevent Recurrence
Long-term management of BPH focuses on treating the underlying prostatic obstruction to reduce the risk of future urinary retention episodes. The first line of pharmacological treatment involves alpha-blockers, such as tamsulosin or alfuzosin. These drugs relax the smooth muscles in the prostate and bladder neck, decreasing resistance to urine flow and providing rapid symptom improvement.
Another class of drugs, 5-alpha reductase inhibitors (5-ARIs) like finasteride and dutasteride, address the physical size of the prostate. These medications prevent the hormonal conversion that drives prostate growth, causing the gland to shrink over several months. For men with larger prostates, a combination of an alpha-blocker and a 5-ARI is often prescribed to reduce the long-term risk of retention.
If medications fail to control symptoms, or if retention recurs, surgical intervention is considered. Transurethral resection of the prostate (TURP) involves removing excess prostate tissue through the urethra. Minimally invasive options, such as laser therapies or water vapor thermal therapy, are also available to reduce prostatic volume and restore unobstructed flow.