A 74 year old lady who has had a stroke in the past has an indwelling catheter for 10 months. She presents with bluish-purple discolouration of the catheter bag. What is the SINGLE most likely explanation for this?
A. Normal change due to long use
B. Catheter degradation
C. Acidic urine
D. Alkaline urine
E. Bacterial colonization of the urinary tract
Purple urine bag syndrome
Purple urine bag syndrome is a medical syndrome where purple discoloration of urine occurs in people with urinary catheters and co-existent urinary tract infection. It is a rare phenomenon. Bacteria in the urine produce the enzyme indoxyl phosphatase. This converts indoxyl sulfate in the urine into the red and blue colored compounds indirubin and indigo. One of the most common bacteria implicated is Providencia stuartii.