This is one of the most difficult issues to deal with in MS, despite being a very common symptom. Research has suggested that between 80–90% of people with MS have urinary problems of some kind, although they vary widely in type and seriousness. More expertise and resources are now being devoted to dealing with it.
If particular nerves in the spinal cord are damaged by Multiple Sclerosis, then urinary control will be affected. There are several kinds of urinary control in people with MS that might then be affected:

• They may urinate involuntarily – either just dribbling a little, or sometimes even more (a problem of ‘incontinence’).
• They may wish to urinate immediately (a problem of ‘urgency’).
• People may wish to urinate more often than before (a problem of frequency). When people have frequency at night, i.e. needing to urinate several times during the night, it is called ‘nocturia’.
• They may fail to empty their bladder (a problem of ‘voiding’).
• They may find it difficult to begin to, or to continue to urinate (a problem of ‘hesitancy’).

The major bladder problems in Multiple Sclerosis can be summarized as either:

• a failure to store
• a failure to empty, or
• a combination of both.

In general the more serious the MS, the more serious your urinary symptoms are likely to be. About 65% of people with urinary problems have difficulties with urgency, or frequency and incontinence resulting from urgency. About 25% have difficulties in relation to urine retention and bladder emptying, and the remaining 10% may have both sets of problems.
Whilst many of the common urinary problems above that people with MS experience are indeed a result of damage to the nervous system caused by the disease, others may be caused by ‘urinary tract infections’. Urinary tract infections are not caused directly by the MS itself, but are more likely in people with MS because of some of its functional effects – for example through infections from a failure to empty the bladder. Thus it is very important that you are regularly tested for urinary infections. This is particularly important if the bladder problems you have are significant.