Urinary tract infections may trigger relapse in multiple sclerosis.

: Multiple Sclerosis (MS), a demyelinating disease of the central nervous system, is the most common neurological disease affecting young adults in North America and, in the majority of cases, is associated with accumulating disability. Urinary tract dysfunction affects up to 90% of the MS population, and urinary tract infections are encountered in up to 74% of the tested population. Viral infections have previously been shown to trigger acute exacerbation and it is our experience that urinary tract infection also commonly precedes relapse, and, when recurrent, is associated with neurologic progression. We present three case studies from our MS Clinic where recurrent UTI was associated with acute exacerbation and neurologic progression refractory to intravenous steroid treatment. Interferons, protein signaling molecules, have recently been found to play a role in acute exacerbation and disease progression in individuals with MS. Viral infections induce interferon release which may activate T cells to produce gamma-interferon. Interferon-gamma precipitates relapse and stimulates production of tumour necrosis factor-alpha, a cytokine directly toxic to oligodendrocytes. Bacterial infections similarly induce interferon release and may activate immune pathways that result in MS exacerbation and neurologic progression.