Purple Urine Bag Syndrome in a 26-Year-Old Woman Living with HIV and Metastatic Spinal Cord Compression: A Case Report

Abstract

Background: Purple urine bag syndrome (PUBS) is a rare complication of urinary catheterization in which urine, catheter and collection bag develop a characteristic purple discoloration from bacterial metabolism of dietary tryptophan to indigo and indirubin. It is reported almost exclusively in elderly, chronically catheterized women, with very few reports from sub-Saharan Africa. Case Presentation: A 26-year-old para 2+0 woman, six months postpartum and living with HIV (CD4 = 194 cells/µL), presented with a two-month history of progressive lower-limb weakness, urinary and fecal incontinence and chronic constipation, with three days of fever and loin pain, having been catheterized three times in the preceding four weeks. She was febrile and paraplegic with a T12 sensory level. Empirical ceftriaxone was started for presumed urosepsis; two days later the urine and bag turned purple. Urine culture grew Escherichia coli at > 10 5 CFU/mL, multidrug-resistant but sensitive to piperacillin/tazobactam. Therapy was escalated and the catheter exchanged; the urine cleared within 24 hours with symptomatic improvement. MRI showed a lytic T10/T11 lesion with cord compression and hepatic and pulmonary nodules consistent with metastatic disease; tumor markers were within normal limits, narrowing but not excluding the primary. Discussion: Recognized PUBS risk factors include prolonged catheterization, female sex, neurogenic bladder, immobility, chronic constipation and renal disease, occurring mostly in elderly women. Our patient was young but had several of these factors, plus multidrug-resistant bacteriuria and HIV-related immunosuppression that may have increased her susceptibility to infection. Cumulative risk-factor burden, rather than age alone, appears to drive the syndrome; empirical ceftriaxone failed, reflecting rising regional cephalosporin resistance. Conclusion: PUBS is a visible indicator of catheter-associated urinary tract infection that can occur outside the typical elderly demographic when risk factors converge and should prompt urgent culture, catheter exchange and culture-directed antibiotics to prevent progression to urosepsis: to our knowledge, the first reported case from Uganda. Keywords: purple urine bag syndrome, urinary tract infection, Escherichia coli, HIV, metastatic spinal cord compression, case report