Bladder problems are among the most disabling and distressing symptoms in MS. Studies of large groups of patients have suggested that bladder dysfunction occurs in at least 70 percent of those with MS, which perhaps is not surprising given that bladder function is regulated at three interconnected levels of the CNS: the frontal lobes, the pontine micturition centre, and the sacral micturition centre. Bladder dysfunction in MS usually, although not invariably, results from spinal cord disease and is therefore often associated with sexual dysfunction and pyramidal symptoms such as weakness and spasticity. Urinary urgency and frequency are the most common symptoms, although hesitancy and nocturia may also be problematic. The underlying problems have been described as difficulty with storage and emptying, the former resulting from detrusor hyper reflexia and the latter from detrusor-sphincter dyssynergia.

The management of bladder dysfunction in MS includes two key components: the use of clean intermittent self-catheterization (CISC) to manage incomplete emptying, and anticholinergic agents such as oxybutynin to reduce the hyperreflexia that results in inadequate storage. However, because oxybutynin may decrease bladder emptying and therefore increase residual volume, it is important to check the residual before embarking on treatment.

CISC, which was initially introduced in the management of spinal injury, usually is taught by an experienced continence advisor but does depend on the patient’s learning a consistently clean technique. Problems may arise if there is severe cognitive impairment. There are potential practical difficulties if hand function is affected by weakness or tremor, or if there is severe adductor spasticity or spasm. Some patients are unhappy about carrying out CISC, and a suprapubic vibrator is a possible alternative for those who are ambulatory. This hand-held, battery operated device has been shown to reduce the residual volume in 80 percent of ambulant patients.

Only when adequate bladder emptying is achieved can drug treatment for detrusor hyperreflexia be initiated. The anticholinergic agent oxybutynin is the first-line treatment and has been shown to be more effective than propantheline in a small randomized trial involving 34 patients. It usually is commenced at 2.5 mg twice daily, but even this dose may cause dry mouth. The maximum recommended dose is 5 mg three times daily. A long acting preparation that is taken once daily is available in some countries. Of the other anticholinergic drugs, tolterodine tartrate is a useful alternative to oxybutynin and is given in a dose of 2 mg twice a day or as a long-acting preparation: tolteridone LA, 4 mg daily. Occasionally, adding imipramine to oxybutynin may be helpful.

If oxybutynin is not helpful or inappropriate, desmopressin may be considered, particularly for nocturia. This synthetic antidiuretic hormone is administered by nasal spray. Several crossover studies involving relatively small numbers of patients (17 and 22, respectively) have shown that one to two puffs (10–20 μg) at bedtime or during the day can reduce urine output for 6 to 8 hours. Benefit over a prolonged period of time has been described recently in a cohort of 19 patients. The expected side effect of hyponatremia is rarely symptomatic, although headache or malaise should be taken as a warning sign. Extreme caution should be exercised in the over-65 age group, who are more likely to become symptomatic. Wheelchair-bound patients with dependent edema are also at risk of developing water retention because their nocturnal frequency may simply be an indication of resorption of edematous fluid. Desmopressin should not be taken more than once every 24 hours.

In more severe disease, interruption of the spinal pathways leads to the emergence of a new reflex at the sacral level mediated by unmyelinated C fibres that stimulates the detrusor, without the control of the normal inhibitory spinal fibres. This detrusor hyperreflexia may be reduced by the neurotoxic effects of capsaicin on the C fibres, and in a small study an instillation of 1 or 2 mmol of capsaicin dissolved in alcohol has shown a beneficial effect lasting up to five months. Repeated instillations may be required and do not appear to be responsible for any long-term side effects. Attempts have been made to evaluate the potential benefits of an ultra-potent capsinoid substance, resiniferotoxin, but these have not been successful. A pilot study of a sublingual cannabis preparation has shown some benefit in 15 patients, but this has not yet been demonstrated in more rigorous studies. Intradetrusor injection of botulinum toxin has recently been shown to be highly effective improving bladder symptoms in patients who were refractory to oral medication. An effect on urgency, incontinence and quality of life was demonstrated in a single centre, prospective open-Iabel study involving 43 patients. Data from randomized controlled trials are awaited.

Biofeedback has also been evaluated in a small study of 20 MS patients, which has suggested some benefit. Pelvic floor rehabilitation combined with electrostimulation was evaluated in an open, controlled, randomized study of two parallel groups with 25 women and 15 men in each group. The treatment arm underwent six sessions of electrostimulation of the pelvic floor muscles followed by regular pelvic floor exercises for 6 months. Symptoms of urinary urgency, frequency, and incontinence were significantly reduced in the treated group; this was particularly striking in the male patients.

Permanent catheterization may be necessary in many patients with severe disease as medical treatments become ineffective or impractical. A long-term urethral catheter is rarely advisable because it is likely to be extruded and destroy the bladder neck mechanism. The preferred alternative is a suprapubic catheter, which should be inserted by a urological surgeon and subsequently changed every 2 months.

In the view of the Committee, bladder symptoms are amenable to management; anticholinergic agents and self-catheterization are two of the most common approaches and there is accumulating evidence for other approaches such as botulinum toxin for those who are refractory to oral treatment.