Purple Urine Bag Syndrome in the Elderly

Purple urine bag syndrome (PUBS) is an uncommon phenomenon among urinary catheterized patients with urinary tract infection. It was first described in 1978 and the explanation of its possible mechanism was proposed in 1988. Bacteria produce phosphatase and sulfatase, which are converted to indoxyl sulfate [IS] in the urine and into indirubin and indigo. Indirubin dissolves in the plastic urine bag and blue indigo deposits on its surface to create a purple discoloration. A higher prevalence of PUBS has been identified in females, those with alkaline urine, those with indwelling urinary catheters, and patients with constipation. Most PUBS patients are catheterized due to significant disability and are chair-bound or bed-bound elderly. Since PUBS is relatively more common in elderly patients than in non-elderly patients, we gathered cases from 1978 onwards from a database and retrospectively analyzed the cases to determine the differences in PUBS between elderly and non-elderly patients.