Urinary retention

How does the urinary system work?

Urinary retention happens when someone can’t completely empty their bladder. Instead of all the urine (wee) being passed out through the urethra, some remains in the bladder. Here we explain the causes and symptoms, the treatment available and where to get help.

Urinary retention can be a short-term or long-term problem and can occur suddenly (acute) or get worse over time (chronic).

If urine stays in your bladder, it can lead to urinary incontinence (leaking urine between wees) and urinary tract infections. In severe cases, urine can start to ‘back up’ towards the kidneys, causing long-term damage.

How does the urinary system work?

The urinary system consists of the kidneys, ureters, the bladder and urethra. The kidneys filter the blood to remove waste products and produce urine. The urine flows from the kidneys down through the ureters to the bladder. A ring of muscle (sphincter) squeezes shut to keep urine in the bladder and relaxes when we need to wee. The urine passes through another tube called the urethra to the outside when urinating (weeing).

What causes urinary retention?

  • Structural problems with the urethra, such as narrowing (stricture) or blockage
  • Structural problems with the bladder neck, sometimes following treatment for a congenital (present at birth) condition, such as posterior urethral valves or bladder exstrophy
  • Weak bladder and pelvic floor muscles
  • Problems with nerve messages travelling between the bladder and brain
  • Side effects of some medications, including anaesthesia
  • Surgery to the urinary system
  • Constipation when the bowel is full of poo and presses on the bladder and urethra

How can I spot the symptoms?

Acute urinary retention is extremely painful and causes abdominal bloating.

There may not be any noticeable symptoms with chronic urinary retention, but symptoms can include urinary incontinence and urinary tract infections, an increased urge to wee more frequently, difficulty getting started and producing a weak or interrupted stream of urine when weeing. There may also be mild abdominal discomfort.

How is urinary retention diagnosed?

First, we record a history of when the problem started and how often it’s been happening. We’ll check if your bladder feels hard (because it’s full of urine) or if there are any signs of constipation. We’ll also do an ultrasound scan of the bladder and kidneys.

We might suggest a bladder function assessment. This is a combination of tests we use to examine your child’s urinary system and how it’s working in close detail. This is usually carried out over a period of up to five hours, using a special ‘uroflow’ toilet, which takes lots of measurements as your child is weeing.

Some children may benefit from having a micturating cystourethrogram (MCUG), which is a scan that shows how well the child’s bladder works. We use this to diagnose why your child may have urinary tract infections, and to see any abnormalities with their urinary system.

Another test that the doctor might suggest is a cystoscopy, a test that allows us to look inside and around your child’s bladder using a cystoscope (a tube containing a small camera and a light).

You can find out more about all these tests here.


Children with acute urinary retention need emergency treatment, to relieve pressure on the bladder and abdomen. Usually, we’ll insert a catheter (small tube) into the urethra so urine can be drained into a collection bag. If the urethra is blocked so the catheter can’t pass through it, we might put the catheter through the skin into the bladder and drain it that way. Once the bladder has been drained, we’ll carry out various tests as described above to find out why the urinary retention occurred.

Chronic urinary retention doesn't usually need emergency treatment but should be evaluated to reduce the risk of infection and damage to the kidneys. Bladder re-training and biofeedback training can help your child understand the messages travelling between the bladder and brain and strengthen the muscles so weeing is easier.

If we think a medicine is causing urinary retention, we might change the prescription to another type or reduce the dose. We may also prescribe other medications that relax the bladder and pelvic floor muscles to make weeing easier.

If we find any structural problems, your child may need surgery. If there is a urethral stricture (a narrowing of the urethra), the urethra may be stretched or dilated, and might need a stent (plastic tube) inserted to keep it open. If the urethra is blocked, we’ll perform an operation to solve this.

We can also use a Mitrofanoff channel (a tube connecting the bladder to the surface of the skin, often using the appendix) to insert a catheter at regular intervals during the day.

What happens next?

Once the underlying cause of urinary retention has been identified and treated, many children won’t experience another episode. If urinary retention is a long-term problem, catheterisation may be a more comfortable way of emptying the bladder.

Compiled by:
The Urodynamics Unit in collaboration with the Child and Family Information Group.
Last review date:
March 2017