[Purple Urine Bag Syndrome: A Rare Clinical Case]

Purple urine bag syndrome (PUBS) is a rare syndrome characterized by production of indigo (blue) and indirubin (red) pigments due to bacterial colonization in urinary catheter. The pathogenesis of PUBS is related to the combination of these two pigments produced from the metabolism of tryptophan. Tryptophan turns into indole by deamination, indole turns into indoxyl sulphate by hepatic conjugation and indoxyl sulphate is secreted into urine. Sulphatases and phosphatases enzymes produced by bacteria like Providencia stuartii and Providencia rettgeri, Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Enterococcus spp., Morganella morganii, Pseudomonas aeruginosa, Citrobacter spp. and group B streptococci convert indoxyl sulphate to indoxyl. In the urinary tract, oxidation of indoxyl results in the production of indigo and indirubin pigments. These pigments react with polyvinyl chloride (PVC) lining of the urinary catheter bag and the reaction results purple discoloration of urine. Urine discoloration is very important clinical sign in the differential diagnosis of several pathological conditions such as hematuria, urinary system tumors and drug side effects and may be disquieting for patients, families and healthcare workers. Purple urine discoloration is rarely reported in the literature and it is generally associated with urinary tract infection. In this report, a 60 years old woman with a past medical history of significant chronic kidney disease undergoing regular hemodialysis, chronic constipation and hepatitis B was admitted to our neurology clinic because of acute intracerebral hemorrhage. She had confusion and right hemiplegia in her neurological examination and required urinary catheterization due to immobilization. Red coloration was observed in urine on the tenth hospital day. Although this coloration was thought to be hematuria, according to urine examination it was not hematuria. Then urine color turned into purple within two days. The next day, because of fever, full blood count and other blood investigations were performed and urine was sent to the laboratory for culture. Empirical piperacillin-tazobactam and teicoplanin antibiotic treatments were commenced. In the urine culture, 105 cfu/ml Enterococcus faecalis was isolated. According to the antibiotic susceptibility results the therapy was changed and meropenem was added to the treatment. For her constipation, supportive managements such as hydration, nutrition and laxative treatment were applied. After all the treatments, the patient's constipation regressed, the urine had become normal colored and the following urine cultures were not revealed any bacterial growth. As in this case, when the urine discoloration occurs, PUBS should be kept in mind which is especially seen in elderly female patients with chronic constipation, urinary catheterization, urinary tract infection and renal failure.