Hmmm. Never seen this color in urine bag !

CASE: 

• We were rounding on a middle aged male patient, h/o pelvic trauma (has a chronic suprapubic catheter). The catheter is connected to a urine bag, picture of it is pasted below : 

 

• PURPLE COLOR URINE in the bag. What is this? 

• I have never seen this before. I point this out to my intern, and she goes, " Yea! I know this; it is PURPLE URINE BAG SYNDROME." 

Q. What is purple urine bag syndrome? 

• Rare syndrome where purple discoloration of urine occurs in people with urinary catheters and co-existent urinary tract infection.
• The purple color of the urine is due to metabolic products of biochemical reactions formed by bacterial enzymes in the urine. 

• Geeky stuff, try not to read it : Tryptophan in the diet is 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. Indoxyl sulfate is excreted in the urine. In purple urine bag syndrome, bacteria that colonize the urinary catheter convert the indoxyl sulfate to indirubin and indigo; and hence purple discoloration of the urine, collecting bag, and tubing. 
• Bacteria capable of producing these enzymes include Providencia stuartii, Providencia rettgeri, Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Morganella morganii, and Pseudomonas aeruginosa. 

• People with purple urine bag syndrome usually do not complain of any symptoms. Purple discoloration of urine 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

• Medical management of purple urine bag syndrome does not require any special treatment apart from changing the catheter and administering appropriate antimicrobial therapy to treat the underlying bacterial infection.