About 80 percent of MS patients experience bladder problems. They either suffer urine leakage or problems emptying their bladder, sometimes both. (However, only about 10% experience bladder problems as the first sign of MS.)
The damage to the nervous system from MS affects the transfer and coordination of neural impulses between the brain, the spinal cord and the bladder.
An overactive bladder is a common consequence, in other words frequent urgings and the need to empty your bladder, even though it isn't full. A person suffering from MS can't control these signals or relieve the urgings.
For 70-80 percent of MS sufferers, even the emptying of the bladder is affected. The muscles in the pelvis and the sphincter muscle around the urethra are contracted during emptying. This results in the urethra closing too early and the bladder not being properly emptied. This is called detrusor external sphincter dyssynergia. This residual urine can lead to the amount of time between bladder emptyings being shorter than if the bladder had been completely emptied.
MS's progress can often swing like a pendulum; during certain periods, urinating will be more problematic than it is during other periods.
It is important that you treat these bladder emptying problems. Residual urine can lead to a UTI, which in turn can cause new attacks or to the return of an attack that had previously receded.