More than Just a Bag—Purple Urine Bag Syndrome as a Manifestation of Vulnerability in Geriatric Patients: A Case Report

INTRODUCTION: Purple urine bag syndrome (PUBS) is an uncommon yet visually striking condition observed in patients with long-term urinary catheters. It is associated with urinary tract infections caused by bacteria that metabolize tryptophan into indigo and indirubin pigments. Although typically benign, PUBS can signal underlying medical and social vulnerability. CASE REPORT: We describe a 78-year-old woman with multiple sclerosis and chronic suprapubic catheterization who presented with failure to thrive and concerns for caregiver fatigue. A striking finding on arrival was the deep purple discoloration of her urine in the Foley bag, consistent with PUBS. Additionally, she was tachycardic and had extensive, unstageable pressure ulcers. Laboratory studies revealed leukocytosis, lactic acidosis, and acute kidney injury. Imaging suggested sacral osteomyelitis, stercoral colitis, and aspiration pneumonia. Blood cultures grew Streptococcus dysgalactiae, and she was treated empirically with broad-spectrum antibiotics. After goals-of-care discussions, she was transitioned to hospice and died shortly after discharge. CONCLUSION: While purple urine bag syndrome is often benign, its presence should prompt clinicians to evaluate for serious underlying disease, particularly in debilitated or high-risk patients. It is classically associated with chronic catheterization, alkaline urine, and infections involving organisms such as Providencia stuartii, Klebsiella pneumoniae, and Proteus mirabilis. This case highlights PUBS as a visible marker of potentially severe, multisystem pathology requiring timely and comprehensive assessment. Moreover, it underscores the role of social determinants of health such as inadequate home support, caregiver strain, and fragmented post-discharge care in exacerbating clinical decline. Recognition of these factors is essential for holistic care planning in frail older adults.