Acute urinary retention is a condition where the bladder fails to empty completely, or at all. It can manifest suddenly (acute) or develop over time (chronic). The acute form is a medical emergency that requires prompt medical attention. This condition is more prevalent in men, particularly those between 60 and 80 years old. Statistics show that about 10% of men over 70 and up to 30% of men over 80 may be affected.
Recognizing the Symptoms
Acute urinary retention (AUR) is defined by a sudden and distressing inability to pass any urine, despite having a full bladder and an intense feeling of needing to go. The primary experience is not just difficulty, but a total cessation of urine flow.
This sudden inability to urinate is almost always accompanied by significant pain and a feeling of pressure in the lower abdomen. As the bladder continues to fill with urine from the kidneys, it stretches beyond its normal capacity. This overstretching causes a noticeable swelling or a bloated, firm feeling in the area between the navel and the pubic bone. The pain can become severe as the bladder expands.
Underlying Causes of Retention
One of the most frequent reasons for acute urinary retention is a physical blockage in the urinary tract. In men, the most common cause is an enlarged prostate, known as benign prostatic hyperplasia (BPH), which can squeeze the urethra and impede urine flow. Other obstructions for both men and women can include bladder stones, tumors, or a narrowing of the urethra called a urethral stricture. In women specifically, a pelvic organ prolapse, where the bladder or uterus shifts position, can also create a blockage.
Disruptions in the nerve signals that control the bladder are another major cause. For the bladder to empty, nerves must carry coordinated signals from the brain to the bladder muscle, telling it to contract, and to the sphincter muscle, telling it to relax. Conditions that damage these nerve pathways, such as a spinal cord injury, stroke, multiple sclerosis, or complications from long-term diabetes, can interfere with this process.
Certain medications are known to contribute to AUR. Drugs with anticholinergic properties, like some antidepressants and antihistamines found in common cold and allergy remedies, can reduce the bladder muscle’s ability to contract. Opioid pain medications, often used after surgery, can also interfere with bladder function and contribute to postoperative urinary retention.
Infections and significant inflammation can also trigger an episode of AUR. A severe urinary tract infection (UTI), or inflammation of the prostate in men (prostatitis), can cause enough swelling to obstruct the urinary path. Additionally, AUR is a recognized temporary complication following surgery, as the effects of anesthesia and pain medications can prevent the bladder from functioning properly.
Medical Evaluation and Treatment
When a person seeks help for acute urinary retention, the medical evaluation is focused and immediate. A healthcare provider will typically perform a physical examination, which includes gently pressing on the lower abdomen to feel for a distended, full bladder. To confirm the diagnosis, a bladder scanner is often used. This non-invasive device uses ultrasound waves to quickly measure the volume of urine in the bladder.
The primary treatment for AUR is to drain the bladder, a procedure called bladder decompression. This is accomplished by inserting a thin, flexible tube known as a catheter. A urethral catheter is inserted through the urethra and into the bladder, providing immediate relief as urine flows out.
If a urethral catheter cannot be inserted due to a blockage, a different approach is used. A suprapubic catheter is inserted directly into the bladder through a small incision in the lower abdomen. This catheterization is the emergency intervention, while further tests are done later to identify and manage the underlying cause of the retention.
Risks of Untreated Retention
Seeking immediate medical care for acute urinary retention is necessary to avoid serious complications. When the bladder remains overfilled for an extended period, the pressure can cause significant harm. One of the primary risks is lasting damage to the bladder muscle, which can be stretched to a point where it loses its tone and ability to contract effectively, potentially leading to long-term bladder dysfunction.
The pressure from a full bladder can also back up into the urinary tract, affecting the kidneys. This backflow, known as hydronephrosis, can prevent the kidneys from filtering waste properly, leading to acute kidney injury or, over time, chronic kidney disease.
If the urinary retention is caused by a severe infection, the stagnant urine in the bladder can become a breeding ground for bacteria. This increases the risk of the infection spreading into the bloodstream, a life-threatening condition called sepsis. Sepsis can cause widespread inflammation and organ failure, underscoring the urgency of draining the bladder and treating the infection.