Introduction
Purple urine bag syndrome (PUBS) occurs when purple urine discoloration is noticed in chronically debilitated institutionalized persons with long-term urinary catheters and urinary tract infections.
Pathogenesis was first described by Barlow and Dickson (Reference Barlow and Dickson1978) and later studied by Dealler et al. (Reference Dealler, Hawkey and Millar1988), establishing that recurrent urinary tract infections with bacteria containing sulfatase and phosphatase enzymes metabolize products of tryptophan, resulting in the formation of red pigments (indirubin) and blue (indigo), the mixture of which gives the purple color to urine. There are several identified predisposing risk factors to PUBS, namely female gender (due to female urinary anatomy), increased dietary tryptophan, constipation, chronic urinary catheterization using polyvinylchloride (PVC) plastic catheters, renal failure, recurrent urinary tract infections, high urinary bacterial load, alkaline urine (although there are reports of PUBS in acidic urine), elderly and bedridden/chair-bound nursing-home persons with Alzheimer’s dementia and multiple comorbidities requiring long-term indwelling catheters (Khan et al. Reference Khan, Chaudhry and Qureshi2011; Yang and Su Reference Yang and Su2018). PUBS may become more prevalent with increased life expectancy and chronic diseases leading to increased dependency and long-term institutionalization (Goyal et al. Reference Goyal, Garg and Jindal2018; Lin et al. Reference Lin, Huang and Chien2008). PUBS is a condition that causes great alarm and distress in patients and family members, friends, and health professionals (Goyal et al. Reference Goyal, Garg and Jindal2018; Kalsi et al. Reference Kalsi, Ward and Lee2017; Khan et al. Reference Khan, Chaudhry and Qureshi2011). Therefore, early identification and management of PUBS are warranted, avoiding misdiagnosis and patient and caregiver distress, particularly in those who are fragile, vulnerable, and terminally-ill.
Case presentation
Mrs. B. was a long-term 98-year-old bedridden resident with Alzheimer’s dementia, hypertension, hypercholesterolemia, chronic constipation, duodenal ulcer, macular degeneration, and hip fracture treated with hemiarthroplasty. She presented with recurrent urinary tract infections for the past 2 years. Because of severe groin maceration and sacral ulcer, she was chronically catheterized. After nearly 10 years of urinary catheterization, she presented with PUBS (Fig. 1A). She remained clinically stable (heart rate: 64 bpm; blood pressure: 115/65 mmHg), with no abdominal pain, fever, or mental confusion during this episode. When confronted with the purple color of her urine, she was slightly agitated and frightened that something severe was happening to her body. The nurses assisting her were also anxious and wanted to send her to the emergency department for examination. The urine culture showed a high bacterial load of Escherichia coli (>105) and leukocyturia (>500 cells/μL). Ciprofloxacin 500 mg, twice daily, was empirically initiated and switched to fosfomycin 3 g, once daily, after the urine culture result. Non-PVC catheter and urine bag were changed, and good urologic sanitation was achieved. Laxative medication was increased, hence normalizing bowel movements. Urine in both tubing and urine bag became amber/pale yellow 24 hours after PUBS’s management (Fig. 1B). After replacing the urinary catheter and observing the typical coloration of her urine (Fig. 1B), the resident became calmer, and no medication for agitation was necessary.
Figure 1. (A) Dark purple discoloration in urine bag and tubing. (B) Clear, amber/pale yellow urine after 24 hours, both in urine bag and tubing.
Discussion
Due to the increasing number of dependent and chronically catheterized persons, PUBS is likely to become more frequent in nursing homes and the home-care setting. Persons living with life-limiting conditions (oncological or advanced organ failure, such as dementia) and cared for by palliative care are also at risk. PUBS is commonly seen as benign and harmless, but given its strangeness and rarity, can be alarming and distressing for health professionals, patients, and caregivers. PUBS is a bedside diagnosis, with medical history, examination, and urinary analysis being essential to achieving good outcomes (Kalsi et al. Reference Kalsi, Ward and Lee2017). As seen in our case report, clinical awareness is essential for diagnosing this uncommon condition, helping to allay health-care professionals’ anxiety, patients’ suffering and fear, and caregivers’ unnecessary distress while caring for their loved ones. Properly managing the case avoided an unnecessary and disturbing emergency department visit. Because there are no specific guidelines for the management of PUBS, individualized care is essential. There is a consensus that treatment should address some modifiable underlying risk factors (e.g. diet, constipation), catheter replacement, and urological sanitation. The use of antibiotics still calls for further research (Khan et al. Reference Khan, Chaudhry and Qureshi2011; Yang and Su Reference Yang and Su2018). Although our resident was asymptomatic, antibiotics were initiated given her recurrent urinary tract infections and severe groin maceration to avoid possible complications such as Fournier’s Gangrene among others (Bhattarai et al. Reference Bhattarai, Bin Mukhtar and Davis2013; Tasi et al. Reference Tasi, Huang and Yang2009). PUBS is most relevant in home-based palliative care, where limited access to health teams may mean lack of immediate clinical support. The importance of PUBS diagnosis extends beyond managing the condition itself, and it often follows a relatively benign clinical course, although it does not always have a harmless course (Su and Yang Reference Su and Yang2019; Tasi et al. Reference Tasi, Huang and Yang2009). Health-care teams and burdened and tired caregivers dealing with dependent, bedridden, and frail persons with urinary catheters should be provided with information on the nature of this complication to minimize their unnecessary distress and concerns, should they happen to see the color purple.
Author contributions
MJ and MC were responsible for the initial draft’s conception, design, and writing. All authors made the revision of the final report and had full access to all the data.
Funding
This study received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
None exist.
