Case Report: Purple urine bag syndrome in woman with neurogenic bladder.

Purple urine bag syndrome (PUBS) is a rare phenomenon in patients that is associated with the use of a long-term/indwelling urinary catheter. The purple color results from indigo and indirubin, accumulated from bacteria-mediated tryptophan conversion. High risk patients include: the elderly; women; immobilized patients; patients with an indwelling catheter, chronic constipation, alkaline urine or poor hygiene; and those with catheter bags and tubes made of certain types of plastic.