Purple urine bag syndrome (PUBS) is a medical syndrome where purple discoloration of urine collection bag occurs in people with urinary catheters and co-existent urinary tract infections. PUBS is most prevalent in elderly females with constipation. Constipation alters the gut bacteria, reducing gastrointestinal motility and leading to increased growth of bacteria in the colon. High bacterial counts in urine are the most important factor causing purple urine bag syndrome. Bacteria in urine produce the enzyme indoxyl sulfatase. This converts indoxyl sulfate in the urine into the red and blue colored compounds indirubin and indigo. People with urinary tract infections using catheters will increase the conversion of indoxyl sulfatase to indirubin and indigo. Indirubin dissolves in plastic and therefore causes urine discoloration. The purple discoloration is the result of reaction between indirubin and plastic urine bags, as well as the presence of indigo. Bacteria in the urine can be found through bacteria culture test. People with purple urine bag syndrome may present with elevated bacterial loads on their culture tests when compared to those who are not affected by this syndrome. The most commonly implicated bacteria are Providencia stuartii, Providencia rettgeri, Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Morganella morganii, and Pseudomonas aeruginosa. Purple urine bag syndrome treatment should aim for underlying issues rather than the condition itself. The purple discoloration is harmless and can be resolved with treatments targeted to specific bacteria or any underlying medical conditions. Treatment also consists of providing comfort to both patients and their family, administering antibiotics and performing regular catheter changes. The prognosis is good, however, the morbidity and mortality rates associated with PUBS are elevated depending on patient's underlying health status.
Signs and symptoms People with purple urine bag syndrome usually do not complain of any symptoms. Purple discoloration of urine bag is often the only finding, frequently noted by caregivers. It is usually considered a benign condition, although in the setting of recurrent or chronic urinary tract infection, it may be associated with drug-resistant bacteria. Purple urine bag syndrome is an asymptomatic condition, however, symptoms of urinary tract infections may be similar to those of purple urine bag syndrome. Some signs and symptoms of urinary tract infection may include abdominal pain, pain during urination, fever or chills, nausea or vomiting, and an increased frequency of urination.
Pathophysiology
Purple urine bag syndrome (PUBS) is thought to be caused by tryptophan from the diet being metabolized by bacteria in the gastrointestinal tract to produce indole. Indole is absorbed into the blood by the intestine and passes to the liver. There, indole is converted to indoxyl sulfate, which is then excreted in the urine. In purple urine bag syndrome, bacterial enzymes that colonize the urinary catheter, specifically sulfatases and phosphatases, convert indoxyl sulfate to the colored compounds indirubin and indigo. When oxidized, indirubin becomes a reddish color while indigo becomes blue. Combined, they react with the plastics in the polyvinylchloride (PVC) in the catheter bag and create the signature purple seen in PUBS. The change in tryptophan metabolism is theorized to be due to diminished gut motility resulting in prolonged transit times. The additional time will lead to a bacterial overgrowth in the bowel. The overabundance of bacterial will facilitate the conversion of tryptophan into indole. PUBS has also been linked to long term laxative use. A common side effect of overuse of laxatives is damage to the colorectal mucosal lining and changes to the normal intestinal microbiota. This will once again allow bacteria to accumulate and facilitate tryptophan conversion. The most common bacteria found to be responsible are Providencia stuartti and rettgeri, Proteus mirabilis, Pseudomonas auruginosa, Klebsiella pneumoniae, Escherichia coli, Morganella, and citrobacter species, Enterococci, and Group B Streptococci.
Causes and risk factors Many risk factors can increase how likely it is for someone to develop a urinary tract infection. While using a catheter for a prolonged period of time is a potential risk factor, some other risk factors for a urinary tract infection include being female, constipation, and chronic renal failure. Pregnant women are also at higher risk of developing UTIs. Purple urine bag syndrome can be a side effect of having a urinary tract infection while using a catheter for a long period of time. A catheter is a small, flexible tube that can be inserted into a patient's bladder by a medical professional to allow the patient to easily and constantly empty their bladder. This is commonly used before/after surgeries, for those who have a blockage preventing them from urinating, to assist those with bladder weakness that is impacting their ability to urinate, etc. While a patient has a catheter inserted, the chemicals produced by their body can react with the chemicals in the tubing and bag of the catheter. Purple urine bag syndrome has greater prevalence among those who have trouble with making bowel movements or are dehydrated (lacking adequate fluid). It is also associated with longer periods using a catheter. Other significant risk factors include being female, being elderly, and/or being immobile, which refers to the inability to move.
… excerpt ends here. Continue reading the full article.
