Purple urine bag syndrome

Purple Urine Bag Syndrome (PUBS) is an uncommon clinical condition that is generally benign but rarely encountered by clinicians. It occurs due to the metabolism of tryptophan by intestinal bacteria, followed by hepatic conjugation. In the urine, bacterial sulfatase and phosphatase enzymes lead to the production of indigo and indirubin pigments, whose oxidation results in the characteristic purple discoloration. We report the case of a 61-year-old female patient with known chronic obstructive pulmonary disease (COPD) and psoriasis. Due to inadequate oral enteral nutrition, a nutritional supplement was prescribed. Approximately seven hours after administration, purple discoloration of the urine bag was observed. Urine culture revealed growth of Proteus mirabilis, and the urine pH was 8.5. As the colony count was low, antibiotic therapy was not initiated. After discontinuation of the nutritional product, the urine color returned to normal. Although PUBS is typically benign, catastrophic outcomes have been reported in delayed cases. Therefore, increasing awareness among healthcare professionals and ensuring early recognition and management are of vital importance.