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Male overactive bladder (OAB)

What is male overactive bladder (OAB)?

Overactive bladder is characterised by urinary urgency (the sudden need to pass urine), urinary frequency (passing urine often) and nocturia (increased urination at night) with or without urge incontinence (the leakage of urine on the way to the toilet preceded by a feeling of urgency).

What are the causes of male overactive bladder (OAB)?

Overactive bladder (OAB) is caused by abnormal messages in the nerves that supply the bladder that causes the bladder muscle to contract out of a man’s control.

In men the commonest cause of OAB is blockage i.e. due to prostate enlargement (usually benign or non-cancerous) that makes it harder for the urine to be passed and as a result the bladder has to work harder and becomes overactive.

Some cases of male overactive bladder (OAB) are “idiopathic” i.e. the man does not have a defined or identifiable neurological abnormality but the bladder nerve pathways are nevertheless misbehaving.

Other cases of OAB are due to “neurogenic” detrusor overactivity i.e. the person has a definite neurological problem identified e.g. a spinal cord injury, past stroke or neurological condition such as Multiple Sclerosis (MS) or Parkinson’s disease.

How is male overactive bladder (OAB) assessed?

The assessment of male overactive bladder (OAB) is very similar to that of female OAB and includes:

  • History
    • Details of bladder habits e.g. how many times in a 24-hour period toileting occurs
    • Details of incontinence such as triggers, frequency, severity, pad usage, effects on quality of life
    • Other medical history e.g. of conditions that can affect bladder control such as diabetes, heart failure
    • Medications – both prescribed and over the counter
    • Fluid intake – especially that of bladder irritants such as coffee, tea, cola drinks, alcohol
    • Past history – urological surgery (e.g. radical prostatectomy surgery for prostate cancer, benign prostate surgery with TURP and open prostatectomy), pelvic radiotherapy, other pelvic surgery, neurological problems
  • Physical examination
    • The examination includes an examination of the abdomen looking for a distended or enlarged bladder.
    • In men the examination includes a prostate assessment (also known as digital rectal examination).
    • The digital rectal examination also assesses the ability to perform a pelvic floor contraction and its strength
  • Basic investigations
    • Bladder diary – the bladder diary documents frequency of urination and volumes of urine passed over three 24- hour periods (not necessarily consecutive). It is an important tool in quantifying urinary symptoms, helping establish a baseline of symptoms and assessing the effectiveness of treatments.
    • Urine testing with MSU
    • Bladder ultrasound to assess bladder emptying (post void residual ultrasound) and prostate size
  • Cystoscopy – may be used to assess the prostate and exclude bladder pathology
  • Urodynamic testing
    • Urodynamic testing and cystoscopy are particularly important in men to help differentiate the overactive bladder caused by blockage from prostate enlargement versus idiopathic or neurological causes of overactive bladder (without blockage).
    • Urodynamic testing helps define if obstruction from the prostate is present.

What are the treatment options for male overactive bladder (OAB)?

Both conservative and surgical treatment options are available for men with overactive bladder (OAB).

Initial treatment includes conservative measures such as

If the cause of a man’s overactive bladder (OAB) is due to prostate enlargement, then treatment is focussed on relieving the obstruction caused by the prostate.

Treatments for prostate obstruction include:

  • Medical therapy with drugs including classes of drugs such as
    • Alpha blockers e.g. tamsulosin (marketed as Flomaxtra®)
    • 5-alpha-reductase inhibitors e.g. dutasteride, finasteride
    • A combination of an alpha blocker and 5-alpha-reductase inhibitor e.g. tamsulosin combined with dutasteride (marketed as Duodart®)
  • Surgery
    • TURP – transurethral resection of the prostate (“prostate rebore”)
    • Laser ablation of the prostate

If the cause of a man’s overactive bladder (OAB) is unrelated to prostate enlargement, then it can be treated with therapies directed at the bladder.