Doctor: Why Has Her Urine Turned Purple?

We present the case of an elderly woman with long-term indwelling urinary catheter use whose urine turned purple due to a urinary tract infection. LEARNING POINTS: Purple urine bag syndrome is secondary to urinary tract infections with indigo- and indirubin-producing bacteria and affects typically institutionalized and chronically catheterized patients. Escherichia coli, Citrobacter and Proteus spp are the main culprit. It may reflect only asymptomatic bacteriuria and therefore the need for antibiotic treatment must be carefully addressed and individualized. Catheter sanitation, constipation avoidance and prompt removal of unnecessary catheters are key to prevention.