Overactive Bladder

Overview

Overactive bladder (OAB) is a syndrome characterised by urinary urgency, usually accompanied by increased daytime frequency and nocturia, with or without urge urinary incontinence. It is caused by involuntary contractions of the detrusor (bladder wall muscle) that occur before the bladder is full.

OAB is a common condition, affecting a significant proportion of both men and women, with prevalence rising with age. It can have a considerable impact on quality of life — disrupting sleep, limiting social activities, and causing anxiety about access to toilets.

It is important to note that in men, overactive bladder symptoms frequently overlap with, and may be caused by, benign prostatic hyperplasia (BPH). For this reason, the prostate is assessed as part of the evaluation of OAB in male patients, and treating the prostate can sometimes resolve the bladder symptoms.

Symptoms

The four cardinal symptoms of OAB are:

• Urgency — a sudden, compelling urge to urinate that is difficult to defer; this is the defining feature of OAB
• Frequency — passing urine more than eight times in 24 hours
• Nocturia — waking from sleep to pass urine two or more times per night
• Urge urinary incontinence — involuntary leakage of urine associated with a sudden urge; this is present in “wet OAB” but not all patients

Symptoms are often assessed using validated questionnaires (such as the OAB-V8 or ICIQ) and a three-day bladder diary, which records fluid intake, voiding times, and leakage episodes.

Diagnosis

OAB is a clinical diagnosis based on the symptom pattern, but investigations are needed to exclude other causes:

• Urine dipstick and culture — to exclude urinary tract infection, which can mimic OAB
• Post-void residual ultrasound — to ensure the bladder is emptying adequately (retained urine can cause irritative symptoms)
• Frequency/volume chart (bladder diary) — provides objective data on voiding frequency, volumes, and episodes of leakage
• Uroflowmetry — flow rate measurement, particularly in men, to assess for obstructive element
• Urodynamics — more detailed assessment of bladder function; considered when the diagnosis is uncertain or when surgical treatment is planned

In men, assessment of the prostate (prostate examination, PSA, flow rate, post-void residual) is part of the evaluation.

Treatment

Treatment follows a stepwise approach:

First-line: lifestyle and behavioural measures

• Fluid management — aiming for 1.5–2 litres per day; reducing caffeine, alcohol, and carbonated drinks
• Bladder training — gradually extending the time between voids to increase bladder capacity
• Timed voiding and double voiding
• Weight management in those with obesity

Second-line: medication

• Antimuscarinic drugs (oxybutynin, solifenacin, tolterodine, trospium) — the established drug class for OAB; reduce involuntary detrusor contractions
• Mirabegron (beta-3 adrenoceptor agonist) — an alternative to antimuscarinics with a different side-effect profile; can be combined with an antimuscarinic in selected patients
• In men with concurrent BPH, an alpha-blocker may be added or used as the primary medication

Third-line: surgical and interventional options When first- and second-line treatments have not provided adequate relief:

• Botulinum toxin A (Botox) injection into the bladder wall — performed cystoscopically; reduces detrusor overactivity; effects last approximately 6–12 months and injections can be repeated
• Sacral neuromodulation (SNM) — an implantable device that modulates sacral nerve signals to the bladder; suitable for carefully selected patients with refractory OAB
• Percutaneous tibial nerve stimulation (PTNS) — a non-surgical nerve stimulation technique

Dr Hadjipavlou manages OAB including botulinum toxin injections and assessment for neuromodulation. In men, evaluation and treatment of any concurrent prostatic obstruction is incorporated into the management plan.