Overflow Incontinence

How overflow incontinence happens

A healthy bladder holds about 400 to 600 ml (13 to 20 oz) and empties almost completely each time. In overflow incontinence, the bladder empties only partly. The leftover urine (post-void residual) builds up over days and weeks until the bladder is chronically overstretched, sometimes holding a liter or more. Once it is full to capacity, small amounts spill out with any extra filling, movement, coughing or lying down.

This is why it is sometimes called paradoxical incontinence: the person leaks because they cannot empty, not because the bladder empties too easily. It is the leaking form of chronic urinary retention.

Symptoms

• frequent or constant dribbling of small amounts of urine, day and night
• a weak, slow or interrupted stream
• straining or pushing on the belly to pass urine
• a feeling that the bladder never empties
• passing urine often but only small amounts
• waking at night with a wet bed
• little or no sensation of the bladder being full
• recurrent urinary tract infections
• sometimes a swelling in the lower belly that can be felt

Overflow incontinence vs other types

The difference matters because treatments for urge incontinence (bladder-relaxing medicines) can make overflow incontinence worse.

Causes

Blockage of the bladder outlet

• Benign prostatic hyperplasia (enlarged prostate): the most common cause in men over 50.
• Urethral stricture: scar tissue narrowing the urethra after infection, injury or catheters.
• Prostate cancer.
• Severe constipation: a full rectum presses on the bladder neck, a common cause in older adults and children.
• Pelvic organ prolapse in women, which can kink the urethra.
• After surgery for incontinence in women, if a sling is too tight.

Weak bladder muscle

• Diabetes: long-term high blood sugar damages bladder nerves (diabetic cystopathy).
• Nerve damage: spinal cord injury, multiple sclerosis, a slipped disc or spinal stenosis, spina bifida, and nerve damage after pelvic surgery. See neurogenic bladder.
• Long-term overstretching: an outlet blockage that has gone on for years can leave the muscle permanently weak, called an atonic bladder.

Medicines

Anticholinergics (for overactive bladder, some antihistamines and travel sickness pills), tricyclic antidepressants, opioid painkillers, some antipsychotics, and decongestants such as pseudoephedrine can all tip a borderline bladder into retention.

Diagnosis

1. History: urinary symptoms, diabetes, back problems, surgery, constipation and all medicines.
2. Examination: feeling the lower belly for a full bladder, a rectal exam to assess the prostate and check for constipation, and a check of sensation and reflexes in the legs and saddle area. Women may have a pelvic exam for prolapse.
3. Bladder scan: a quick ultrasound straight after you pass urine. A residual of more than about 200 to 300 ml points to significant retention.
4. Urine test for infection and blood.
5. Blood tests: kidney function (creatinine) and sometimes PSA in men.
6. Further tests: kidney ultrasound to look for back-pressure (hydronephrosis), urodynamic studies to tell blockage from a weak bladder, and cystoscopy to look inside the urethra.

Treatment

The first priority is emptying the bladder to protect the kidneys and stop the leaking.

Draining the bladder

• Catheter: a catheter is often placed at first to drain the bladder fully and let it rest. Large volumes are drained under monitoring.
• Clean intermittent self-catheterization: passing a thin catheter several times a day to empty the bladder, then removing it. It is the preferred long-term option when the bladder muscle is weak.
• Long-term indwelling or suprapubic catheter if self-catheterization is not possible.

Treating the cause

• Enlarged prostate: alpha-blockers relax the prostate and bladder neck, and 5-alpha reductase inhibitors shrink the prostate over months. Surgery such as transurethral resection (TURP) or newer laser procedures relieves the blockage when medicines are not enough.
• Urethral stricture: stretching (dilation), cutting through the scar, or reconstructive surgery.
• Constipation: laxatives and a regular bowel routine often resolve overflow in older adults.
• Medicines: your doctor may stop or switch any that weaken the bladder.
• Nerve-related causes: good blood sugar control, treatment of the spinal problem, and catheter drainage.

Helpful habits

• Double voiding: after passing urine, wait a minute, then try again.
• Timed voiding: go every 2 to 3 hours rather than waiting for an urge you may not feel.
• Sit to pass urine if it helps you relax and empty fully.
• Use absorbent pads and protect your skin with barrier cream while treatment takes effect.

Complications

If the bladder is left overfull, complications include repeated infections, bladder stones, skin breakdown from constant wetness, and back-pressure on the kidneys leading to kidney damage. These are largely preventable with regular drainage and follow-up.

Frequently asked questions

What is overflow incontinence?

It is leaking of urine from a bladder that is always too full because it does not empty properly. Urine dribbles out frequently or constantly, often without any urge. It is caused by a blockage such as an enlarged prostate, or by a weak bladder muscle from nerve damage, diabetes or medicines.

What are the symptoms of overflow incontinence?

Typical symptoms are frequent dribbling, a weak or stop-start stream, straining, a feeling of incomplete emptying, passing small amounts often, wetting at night and repeated urinary infections. Many people do not feel a strong urge to go, because the stretched bladder loses sensation.

Is overflow incontinence more common in men or women?

It is much more common in men, because an enlarged prostate is its leading cause. Women can develop it from nerve damage, diabetes, severe prolapse, constipation or after incontinence surgery.

Can overflow incontinence be cured?

Often, yes. If the cause is a blockage such as an enlarged prostate, constipation or a medicine, treating it can restore normal emptying. When the bladder muscle is permanently weakened, the leaking can still be controlled with intermittent self-catheterization.

How is overflow incontinence different from urge incontinence?

Urge incontinence comes from an overactive bladder that squeezes suddenly, causing a strong urge and leaks. Overflow incontinence comes from a bladder that does not empty, causing dribbling without warning. Medicines for urge incontinence can make overflow worse, so a bladder scan is used to tell them apart.