[Pastel in the urine bag].

Purple urine bag syndrome is a relatively unknown phenomenon in which the urine bag and the collector of chronically catheterized patients turn purple or blue. It affects predominantly women, and is mainly reported in elderly patients. The mechanism seems to be related to the appearance in the urine of two compounds that have been identified as indigo (blue) and indirubin (red) which bind to the urine bag and the collector. Several associated factors are usually mentioned such as constipation, alkaline urine, bed rest, institutionalization or cognitive impairment. They are risk factor of this phenomenon. On the other hand, an infection or a urinary bacterial colonization is necessary and high bacterial counts seem to be the critical step in the development of the purple urine bag syndrome. We report on two cases of purple urine bag syndrome observed in two patients being treated in a long-term care unit. Both of whom were diagnosed with indwelling urinary bacterial colonization, with Escherichia coli and Pseudomonas aeruginosa respectively.