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.