OVERACTIVE BLADDER (OAB)

What is an overactive bladder (OAB)?

OAB refers to a group of urinary symptoms which include:

  • Urgency – sudden and compelling desire to urinate

  • Urge incontinence – urgency followed by urinary leakage

  • Frequency – frequent passage of urine (usually > than every 2 hours)

  • Nocturia – need to wake from sleep to pass urine (more than once)

 

What causes OAB?

  • In most cases, no cause is identified (idiopathic).

  • Secondary to bladder obstruction (eg. due to BPH)

  • Neurological conditions – stroke, Multiple sclerosis, Parkinson’s, Dementia

  • Other risk factors:

    • Increasing age

    • Bladder inflammation including recurrent urinary tract infections

    • Pregnancy

    • Post-menopausal state

 

How is OAB diagnosed?

OAB is usually diagnosed after taking a history of your symptoms, preforming an examination of the abdomen and prostate (if applicable) and preforming some or all of the following tests:

  • Urine culture – to exclude infection

  • Blood tests – including kidney function

  • Kidney tract ultrasound looking for:

    • Post void residual volume – remaining urine volume in bladder after voiding

    • Rule out bladder stones and other bladder abnormalities (eg. cancer)

  • Bladder diary – a diary recording the volume of urine passed and  fluids consumed over a 24-48hour period

  • Flow rate/bladder scan – performed in the office at Geelong urology

  • Cystoscopy – if also a history of infections, bleeding, or unusual symptoms

  • Urodynamics – may be used to confirm the diagnosis of OAB or in those not responding adequately to medications before proceeding to surgical treatements

 

How is OAB treated?

There are fortunately numerous treatment options for OAB.  Most patients will have significant improvement with oral medication alone, although a minority will require minimally invasive procedures.  Major surgery is seldom required these days.

 

  1. Lifestyle modifications: in conjunction with other treatments

  • Avoiding foods or fluids that worsen symptoms (caffeine & alcohol in particular)

  • Modifying fluid intake to reduce symptoms at inconvenient times

  • Weight loss

   

   2. Bladder retraining

 

   3. Medications: first line option

  • Anticholinergic medications: Ditropan (Oxybutynin), Vesicare (Solifenacin), Oxytrol patches (Oxybutynin skin patch)

    • Reduce the involuntary nerve reflexes of the bladder and therefore reduce urgency and frequency to void.

    • Side effects may include: dry mouth, constipation and minor blurred vision. Rarely they can cause confusion, dizziness, rapid heart-beat and urinary retention (unable to pass urine).

  • Beta 3 agonists: Mirabegron (Betmiga)

    • Make the bladder more stable and not contract involuntarily and therefore reduce urgency and frequency to void.

    • Side effects may include: slightly raised blood pressure but this is uncommon.

 

   4. Minimally invasive surgery: if medications fail

  • Bladder Botox injections

    • This is performed via a cystoscopy under anaesthesia. 20-30 injections are administered into the bladder wall

    • Although this is usually effective in improving symptoms, Botox will inevitably wear off with time and repeat injections are needed every 6-12 months

  • Sacral Neuromodulation: also often referred to as a “bladder pacemaker”.

    • The first stage is a trial of a small electrode inserted into the lower back (sacral spine) next to the sacral nerve root

    • If symptoms are improved with the trial, a permanent battery is implanted

    • This procedure will require a referral to a subspecialist Urologist

   5. Major surgery: rarely required these days

  • Augmentation cystoplasty – a segment of small intestine is diverted and “patched” onto the bladder to increase the volume

  • Urinary diversion (ileal conduit) – last resort if all else fails. This technique involves diverting the urine away from the bladder to a short segment of small intestine that has been disconnected from the rest of the bowel, which is brought out at the skin as a stoma.  A urine bag is attached at the skin around the stoma to collect the urine. The bladder may or may not be removed at the same time.

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