MS is an inflammatory disease that affects the central nervous system, the brain and the spinal cord. The isolating layer surrounding the nerves (myelin) is lost, leaving scar tissue called sclerosis (also known as plaques or lesions). These damaged areas slow down nerve impulses.
The symptoms are quite varied, depending on where the plaques or lesions form. MS often presents in recurring attacks, in which the symptoms become worse or new symptoms appear. Between attacks, the symptoms can improve or remain constant. A first sign is often an inflammation of the eye nerve.
Over time, about 80% of MS patients will experience bladder problems. An overactive bladder is common, where the nerve damage results in frequent, uncontrollable urges to empty, even though the bladder isn't full.
Problems emptying the bladder completely are also very common. The muscles in the pelvic floor and the sphincter muscle around the urethra contract spontaneously during emptying. This closes the urethra, resulting in the bladder not being properly emptied. The residual urine then leads to the feeling of needing to urinate again, leading to more bathroom trips than if the bladder had been completely emptied.
The progression of MS can swing wildly; urinating will be more problematic in some periods, relatively easy in others. It is still very important to treat bladder emptying problems consistently. Residual urine can lead to urinary tract infections, which in turn can cause new attacks or the return of an attack that had previously receded.