Purple urine bags: a geriatric presentation of lower urinary tract infection

Purple Urine Bag Syndrome: More Than Eyes Can See

BACKGROUND/AIMS

Purple urine bag syndrome (PUBS) is an uncommon clinical entity characterized by purple urine discoloration in the setting of urinary tract infections. Pa-thophysiology of PUBS has been correlated to aberrant metabolism of tryptophan. Multiple predisposing factors have been recognized, namely: female gender, advanced age, constipation, institutionalization, long-term catheter-ization, dementia and chronic kidney disease. Herein, we present a comprehensive review of all PUBS cases reported in PubMed, focusing on the predisposing factors and the microorganisms related to PUBS.

METHODS

We performed a search in PubMed database for articles referring to PUBS, published in English, French, Spanish and German from January 1978 until November 2017. The literature recruitment strategy was based on several keywords and Medical Subject Heading combination such as "purple urine bag syndrome" or PUBS or "urine discoloration". The finally selected articles were categorized into case reports/series (88 articles including 112 patients) and studies (10 articles including 134 patients). Demographical data as well as predisposing factors were recorded and further analyzed.

RESULTS

According to our findings, mean age of PUBS patients was 78.9 ± 12.3 years, 70.7% were female while 90.1% were suffering from constipation, 76.1% were in a bedridden situation, 45.1% were experiencing long-term catheterization, 42.8% had been diagnosed with dementia, 14.3% had recurrent urinary tract infections and 14.1% were chronic kidney disease patients. 91.3% of patients presenting with PUBS alkaline urine were observed while the most common microbe in urine cultures was E. coli.

CONCLUSIONS

PUBS is considered benign process in the majority of catheterized patients. Clinicians should be aware of the syndrome that may indicate serious comorbidities.

Purple urine bag syndrome with acidic urine

Purple discoloration of a urinary catheter bag is very rare. This phenomenon is known as the purple urine bag syndrome. It is associated with urinary tract infections occurring in catheterized patients, generally elderly females with significant co-morbidities and constipation. The urine is usually alkaline. We present a unique case of this rare and interesting phenomenon occurring in acidic urine and discuss the pathophysiology.

Purple urine bag syndrome

The purple urine bag syndrome (PUBS) is a rare condition associated with chronic urinary catheterization. It is characterized by the purple discoloration of the urine, collecting bag, and tubing. A number of factors are involved, but not always present, in its development including female sex, urinary tract infection, constipation, indicanuria, and alkaline urine. Despite multiple theories that involve the complex tryptophan metabolism to the tubing dye, the cause remains elusive. The syndrome resolves usually after treatment of urinary tract infection or changing of the collecting bag. We present a case of a patient with purple urine bag syndrome and a pertinent literature review.

A case-control study of purple urine bag syndrome in geriatric wards

The clinical background of purple urine bag syndrome (PUBS) has not yet been well characterized. In previous reports, clinical, biochemical, or bacteriological analyses were carried out using urine or bacteria from a limited number of patients. Other than one report, we are not aware of any case-control studies that compared the clinical, biochemical, or bacteriological background between patients with and without PUBS. To examine the risk of PUBS, we carried out a case-control study. Twenty-six patients, in three long-term care wards, who had been catheterized for more than 3 months with the same types of balloon catheters and who had the same type of disposable plastic urine bags were enrolled as the PUBS-positive case group (14 patients; 2 men and 12 women), and as the PUBS-negative control group (12 patients; 4 men and 8 women) were enrolled. The data for urine tests (pH, sugar, protein, leukocyte counts, and bacterial yields and species) were compared for the two groups. A relatively higher prevalence of PUBS was observed in female and alkaline-urine-producing patients. Bacteriological studies, using fresh urine collected through the catheter, showed that the bacterial counts were significantly higher, by 1 to 2 logs, in most samples from the case group than those from the control group (P = 0.012). Although a total of 66 bacterial strains, belonging to 12 separate species, were isolated from the urine accumulated in bags, no causative relationship between bacterial species and PUBS was observed. These data suggest that a higher bacterial yield in urine acts as the most important factor in PUBS, in combination with other facilitating factors, such as female-specific ones and the alkaline condition of urine.