A unique case of purple urine: A case report and literature review.

Pigmented urine in a hospitalized patient has a broad differential diagnosis including urinary tract infection or bacterial colonization, hemolysis, rhabdomyolysis, and drugs. We present a case of purple urine in a patient who received methylene blue and hydroxocobalamin for catecholamine-refractory vasodilatory shock. The patient's purple urinary discoloration is presumed to have resulted from a combination of the blue and red pigments of methylene blue and hydroxocobalamin, respectively. As these drugs are increasingly being used to treat vasoplegia in cardiopulmonary bypass, it is important for clinicians to be aware of this benign cause of urine discoloration.