An 84‐year‐old white woman was admitted for fracture of her right hip. She underwent hemiarthroplasty and was transferred to the rehabilitation unit. It was noted that the patient's urine bag was turning purple but the color of urine entering the catheter and urine bag was clear. She was asymptomatic otherwise. She had been catheterized for 18 days during her stay in the hospital. There was no history of intake of medication or food items that may alter the color of urine. She had an extensive past history that was significant for hypertension, CHF, DVT, bladder cancer with surgery, frequent UTI, ambulatory dysfunction, CKD, adrenal insufficiency, coronary artery disease, bladder fistula, lumbar laminectomy, knee replacement, left hip repair and cholecystectomy. Urine analysis revealed yellow cloudy alkaline urine with pH of 8.5, WBC of 3–5, RBC of 0–2, positive nitrites, negative leukocyte esterase and many bacteria. Urine culture revealed > 10,000 colony forming unit of Citrobacter freundii. No antibiotic was prescribed for her asymptomatic bacteruria. Renal ultrasound revealed mild medical renal disease. In view of the clinical findings and urine analysis, a diagnosis of purple urine bag syndrome (PUBS) was made. The catheter and the urine bag were changed and the purple discoloration resolved.
PUBS was first reported in 1978. A prevalence of 9.8% has been reported in institutionalized patients. It is commonly associated with elderly women, alkaline urine, chronic constipation, institutionalization, use of PVC catheter and certain species of gram negative bacteria in urine. The organisms most commonly associated with PUBS include Kleibsiella pneumoniae, Providencia, Enterobacter, Proteus, Morganella, E. coli, and Pseudomonas species. Most PUBS‐affected patients are bedridden and exhibit cognitive impairment. Constipation alters the gut motility and promotes bacterial overgrowth in the bowel where dietary tryptophan is converted to indole, pyruvic acid and ammonia by tryptophanase of gut flora. Indole is absorbed into the portal circulation and then converted to Indoxyl sulfate in the liver. Indoxyl sulfate is then excreted in urine. Urinary bacteria possess sulfatase activity to convert indoxyl sulfate to indoxyl. In alkaline urine, the indoxyl is converted to indigo and indirubin, which gives the purple color. Our patient had most of the risk factors for PUBS — elderly catheterized woman with limited mobility in intermediate care facility. Citrobacter fruendii isolated in our patient is less commonly reported. In addition, PUBS resolved without any treatment.
In conclusion, PUBS is a relatively benign condition, and most patients with PUBS are asymptomatic. Not all cases are of infectious etiology, although UTI is commonly seen. Frequent urine bag and regular catheter change prevents both PUBS and catheter‐associated urinary tract infection. The purpose of reporting this case is to raise awareness of this condition and provide pertinent literature review.
To cite this abstract:Somasundaram A, Ogunde S, Falkowitz D. Purple Urine Bag: A Case Report and Literature Review. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 386. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/purple-urine-bag-a-case-report-and-literature-review/. Accessed March 31, 2020.