Acute urinary retention: a case-based approach

The presentation

"George" (an illustrative example) is 72 and arrives at an urgent treatment centre unable to pass urine since the morning. For months he has noticed a weaker stream, needing to go more often, and getting up several times at night. Today, despite feeling a strong, painful urge, nothing will come. His lower tummy feels swollen and tender, and he is restless with discomfort. The clinician recognises a classic picture: a build-up of long-standing prostate-related urinary symptoms, then a sudden complete block. The first job is to confirm the bladder is full and blocked, relieve the pain quickly, and then work out why it happened — because the cause guides everything that follows.

Why it happens

Acute retention has several common causes. In older men, an enlarged prostate gland squeezing the water pipe (urethra) is the leading reason, sometimes tipped over the edge by constipation, a urine infection, or certain medicines that affect the bladder. It can also follow surgery or be triggered by holding on too long. In women and younger people it is less common but can be caused by infection, severe constipation, nerve problems, or after childbirth. A particularly important cause to spot is pressure on the nerves at the base of the spine — cauda equina syndrome — which can cause retention alongside back pain, numbness around the back passage and leg weakness, and is a surgical emergency in its own right.

Immediate treatment

The priority is to relieve the full bladder, which quickly eases the pain. This is done by passing a thin, soft tube called a catheter into the bladder to drain the urine — a procedure most people find a huge relief once it is done. The team notes how much urine drains, which helps judge how severe the retention was. They examine the tummy, check the prostate where relevant, test the urine for infection, and take blood tests to check how the kidneys are coping. Depending on the cause and the person's health, they may start a medicine that relaxes the prostate and bladder outlet to improve the chance of passing urine normally once the catheter is later removed.

What happens next

After the bladder is drained, attention turns to the underlying cause and the plan for recovery. Many people go home with the catheter in place for a short time, with a district nurse or clinic follow-up and a planned attempt to remove it — sometimes called a trial without catheter — to see if normal urination returns. Treating contributing factors matters: relieving constipation, treating any infection, and reviewing medicines. If an enlarged prostate is the driver, the person is referred to urology to discuss longer-term options. Blood tests guide whether the kidneys were affected. Some people need admission to hospital, especially if the kidneys are involved, there is infection in the blood, or the cause is uncertain.

Safety-netting and follow-up

Anyone who suddenly cannot pass urine, or can only pass tiny amounts while feeling a painful, full bladder, should seek urgent medical help the same day — through NHS 111, an urgent treatment centre or A&E — because the bladder needs draining. Seek emergency help straight away if urinary retention comes with new back pain, numbness or tingling around the back passage or genitals, or weakness in the legs, as this can signal a spinal emergency. Warning signs of a serious infection — high fever, shivering, confusion or feeling very unwell — also need urgent care. If you go home with a catheter, you will be told what to watch for and who to contact if it stops draining or causes problems.