PURPLE URINE BAG SYNDROME IN GERIATRIC PATIENTS

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.

Trends in the epidemiology of purple urine bag syndrome: A systematic review

Purple urine bag syndrome (PUBS) is rarely observed in clinical practice. The present study aimed to identify the epidemiological trends in PUBS in recent decades. A search of PubMed articles published between 1980 October and 2016 August was conducted, in which 106 articles (174 cases) described PUBS. Of these cases, 58 cases were excluded: 14 cases without mention of gender, 4 cases without description of age, 37 cases without mention of white blood cell (WBC) count, shock status, fever status or description of etiology, and 3 cases without information on mortality. The remaining 116 PUBS cases were collected and analyzed in the present study. The articles were divided into three groups by publication year: 1991 to 2000, 2001 to 2010 and 2011 to 2016. The χ² test was used for statistical analysis, with P<0.05 (two-tailed) defined as the threshold for significance. Of the total enrolled cases, there were 47 men (40.5%) and 69 women (59.5%), with a mean age ± standard deviation of 75.6±12.8 years. Of these, 98 cases (84.5%) were elderly (≥65 years old). A total of 93.1% of cases had a urine pH >7 while 6.9% of cases had acidic urine (pH <7). Furthermore, although WBC count elevated progressively, the mortality rate of patients with PUBS decreased over subsequent decades. This necessitates the advancement of antibiotics and application of early goal-directed therapy. Additionally, the overall mortality rate of PUBS (1980-2016) was 6.8%, which decreased to 4.3% in the last 5 years (2011-2016). In conclusion, although PUBS has previously been considered a benign process in the majority of indwelling catheterized patients, emphasis is required on early examination and aggressive antibiotic administration.

Trends in the epidemiology of purple urine bag syndrome: A systematic review

Purple urine bag syndrome (PUBS) is rarely observed in clinical practice. The present study aimed to identify the epidemiological trends in PUBS in recent decades. A search of PubMed articles published between 1980 October and 2016 August was conducted, in which 106 articles (174 cases) described PUBS. Of these cases, 58 cases were excluded: 14 cases without mention of gender, 4 cases without description of age, 37 cases without mention of white blood cell (WBC) count, shock status, fever status or description of etiology, and 3 cases without information on mortality. The remaining 116 PUBS cases were collected and analyzed in the present study. The articles were divided into three groups by publication year: 1991 to 2000, 2001 to 2010 and 2011 to 2016. The χ² test was used for statistical analysis, with P<0.05 (two-tailed) defined as the threshold for significance. Of the total enrolled cases, there were 47 men (40.5%) and 69 women (59.5%), with a mean age ± standard deviation of 75.6±12.8 years. Of these, 98 cases (84.5%) were elderly (≥65 years old). A total of 93.1% of cases had a urine pH >7 while 6.9% of cases had acidic urine (pH <7). Furthermore, although WBC count elevated progressively, the mortality rate of patients with PUBS decreased over subsequent decades. This necessitates the advancement of antibiotics and application of early goal-directed therapy. Additionally, the overall mortality rate of PUBS (1980-2016) was 6.8%, which decreased to 4.3% in the last 5 years (2011-2016). In conclusion, although PUBS has previously been considered a benign process in the majority of indwelling catheterized patients, emphasis is required on early examination and aggressive antibiotic administration.

Two Cases of the Purple Urine Bag Syndrome

The purple urine bag syndrome, purple discoloration of urine, is an uncommon and alarming condition in patients requiring long-term urinary catheterization but the clinical course is usually benign. We report two cases of the syndrome with a literature review on its aetiology and management.

An Elderly with Purple Urine

Purple discolouration of urine is not commonly encountered in accident and emergency departments. We report a case of an elderly gentleman on long-term urinary catheter who presented with purple discolouration of urine. He was found to have urinary tract infection caused by the bacteria Proteus mirabilis. The urine became clear after urinary catheter change and antibiotic treatment. This is called the purple urine bag syndrome and emergency physicians should be aware of this uncommon condition and the associated potentially dangerous conditions in order to initiate appropriate management.

[Biochemical and bacteriological investigation of six cases of purple urine bag syndrome (PUBS) in a geriatric ward for dementia]

AIM

Purple urine bag syndrome is a condition in which the urinary catheter bag turns purple. A tryptophan-indigo hypothesis has been proposed as the mechanism of PUBS, in which bacterial decomposition of tryptophan in gut associated with chronic constipation, bacterial overgrowth in the urinary tract and alkaline urine causes production of indigo and discoloration. We considered that further investigation of cases was needed.

METHODS

We investigated 6 cases exhibiting PUBS (3 males and 3 females).

RESULTS

All cases had chronic constipation. Oral ingestion was impossible in one case. PUBS disappeared after antibiotic treatment (3 cases) or spontaneously (one case). Alkaline urine and indicanuria were not found in all cases that showed the disappearance of PUBS. In bacterial culture of urine during the exhibition of PUBS, Enterococcus faecalis was isolated together with Morganella morganii (3 cases) and Pseudomonas aeruginosa (one case). Single infections by Klebsiella pneumoniae or Citrobacter species were also found. After disappearance of PUBS, infected bacterial species changed but no cases showed sterile urine. Urine and blood alpha-amino-n-butyric acid levels reduced after the disappearance of PUBS whereas tryptophan levels did not show related changes. In one case, blood protein concentration increased after the spontaneous disappearance of PUBS. Indicanuria and alkalization of urine from urinary catheter bag were more intense than of fresh urine.

CONCLUSIONS

The present results generally support the 'Tryptophan-indigo hypothesis'. Furthermore, it was suggested that additional factors associated with the occurrence of PUBS are an environment that facilitates specific bacterial growth in a hospital as well as abnormal metabolism relating to alpha-amino-n-butyric acid and reduced protein synthesis in patients.

An association of purple urine bag syndrome with intussusception

We report a case of an elderly lady with a long-term suprapubic catheter who developed purple discoloration of urine around the same time as she developed intussusception. Purple urine bag syndrome is a benign condition known to be associated with intestinal stasis. However, this association with intussusception should be kept in mind before the patient is reassured.