What is the appropriate management for a patient with purple urine in their Foley (urinary) catheter tubing?

Purple Urine Bag Syndrome (PUBS) Management

Purple urine in Foley catheter tubing represents Purple Urine Bag Syndrome (PUBS), which signals an underlying urinary tract infection that requires prompt evaluation and treatment, even in asymptomatic patients. 1, 2

Immediate Assessment

Obtain urine culture before initiating antibiotics to identify the causative organism, as PUBS is caused by bacteria possessing indoxyl sulfatase/phosphatase activity (most commonly Proteus mirabilis, Klebsiella pneumoniae, E. coli, Enterococcus faecalis, and Pseudomonas aeruginosa). 3, 4, 5

• Assess for signs of systemic infection including fever, altered mental status, hemodynamic instability, or sepsis, as PUBS can rarely present with severe illness despite its typically benign appearance. 2, 5
• Evaluate for typical predisposing factors: female gender, advanced age, long-term catheterization, constipation, immobility, alkaline urine, and chronic kidney disease. 3

Treatment Algorithm

Replace the current Foley catheter immediately with a new appropriately sized catheter (14-16 Fr) to ensure adequate drainage and remove the discolored tubing/bag. 6, 3, 4

• Initiate antibiotic therapy based on urine culture results and local resistance patterns, as the infection may involve difficult-to-treat organisms including vancomycin-resistant Enterococci. 5
• Address constipation if present, as this is a significant contributing factor to PUBS development. 3
• Consider removing the catheter entirely within 24-48 hours if clinically appropriate, as this minimizes ongoing infection risk. 7, 8

Critical Pitfalls to Avoid

Do not dismiss PUBS as purely benign or cosmetic - while often asymptomatic, it indicates bacteriuria that can progress to severe sepsis and death, particularly in elderly patients with multiple comorbidities. 5

• Avoid delaying treatment in asymptomatic patients, as the underlying UTI requires management given the vulnerable patient population typically affected. 1
• Do not use prophylactic antibiotics routinely for catheterized patients unless specifically indicated. 7, 8
• Recognize that PUBS can recur with varying severity in the same patient, ranging from asymptomatic bacteriuria to life-threatening sepsis. 2

Follow-Up Management

Monitor closely for clinical deterioration over the first 3-5 days, as fatal complications can develop rapidly despite initial asymptomatic presentation. 5

• Reassess the need for continued catheterization and transition to intermittent catheterization if feasible to reduce infection risk. 7
• If prolonged catheterization is unavoidable, consider silver alloy-coated catheters to reduce infection risk. 7, 8