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Box 3. Important diagnoses to exclude
• Neurogenic detrusor overactivity.
• Malignancy of the urinary tract.
• Recurrent urinary tract infections.
• Bladder outlet obstruction( urethral stricture, prior continence surgery).
• Overflow incontinence due to voiding dysfunction.
• Obstructive sleep apnoea.
• Congestive heart failure.
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Left: The current size of available implantable pulse generators— the top is rechargeable and the lower non-rechargeable.
Box 4. OAB— when to refer
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and requires insertion of an electrode adjacent to the nerve. 11 PTNS is reserved as a third-line treatment. Both require maintenance
therapy for ongoing efficacy.
— Intravesical botulinum toxin A This is an effective third-line treatment which is performed under cystoscopy, either under local or general anaesthesia. The standard dose for treatment of idiopathic detrusor overactivity( DO) is 100IU, usually injected in 10 sites in the bladder mucosa. Botox has a 60-80 % response rate demonstrated across multiple studies, along with continence achieved in up to 30 %. 12, 13 There is a risk of urinary retention and the need for clean intermittent self-catheterisation in 5 % of patients, which on average lasts for eight weeks. Patient ability and willingness to self-catheterise, if required, should therefore be discussed prior to undergoing treatment. There is also an increased risk of urinary tract infections. In general, most patients require repeat treatments every 6-12 months.
— Sacral neuromodulation This alternative third-line treatment has similar efficacy to intravesical Botox and is also beneficial for the treatment of faecal incontinence. 14 Under general anaesthesia, an electrode is implanted into the S3 sacral
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foramen and connected to an implantable pulse generator( IPG). The technology has improved in recent years such that newer devices are smaller( see figure 1), with both rechargeable and non-rechargeable battery options. For rechargeable batteries, the IPG needs to be replaced approximately every 15 years. Non-rechargeable devices must be replaced every 5-8 years. Newer devices are also now MRI compatible. 15 Sacral neuromodulation can be useful for patients with more than one condition, for those who have not benefited from other treatments or in whom there are contraindications for intravesical Botox. There is currently limited access to the procedure in the public setting in Australia because of the cost of the devices.
Invasive surgical treatment such as augmentation cystoplasty or urinary diversion may be considered in select cases but are infrequently utilised. For some patients,
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the use of a suprapubic catheter may be beneficial; this is often used in conjunction with intravesical Botox for refractory cases to prevent ongoing urinary leakage from detrusor contractions.
When to refer?
Box 4 outlines cases that warrant consideration
for referral to a urogynaecologist or urologist.
Conclusion
Overactive bladder is common in the female population and can be a challenging condition to manage because it is a chronic condition in most patients. Thankfully there are treatments that can substantially improve patients’ quality of life when implemented.
References on request from kate. kelso @ adg. com. au
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• Patients who do not respond to first- and second-line treatment options( conservative and medication therapy).
• If there is suspicion of other causative factors( eg, recurrent UTIs, haematuria, concern about malignancy risk requiring specialist investigation).
• Contribution from co-existing prolapse or voiding issues.
• Severe symptoms warrant consideration for early referral, as these patients are less likely to respond to initial treatments.
Resources
• Continence Foundation of Australia— Overactive Bladder and
Urgency bit. ly / 41NIDaA
• Urogynaecological Society of Australasia— Overactive Bladder www. ugsa. com. au / oab
• International Urogynecological Association— Overactive bladder bit. ly / 3FrnqMl
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