Decreased viral load and symptoms of polyomavirus-associated chronic interstitial cystitis after intravesical cidofovir treatment.

Interstitial cystitis causes disabling bladder pain and is usually diagnosed in the absence of infection. We describe a patient with interstitial cystitis who had high urinary levels of polyomavirus that decreased dramatically after initiation of intravesical cidofovir treatment; the patient also showed substantial improvement in symptoms. Another patient had milder symptoms of cystitis and intermittent polyomavirus shedding. Polyomaviruses, particularly BK virus, may cause some cases of interstitial cystitis.