Black urine due to urobilinogen in a patient with alcoholic pellagra

Abstract

Objectives: Systemic exposure to drugs, chemicals and foods can cause abnormally colored urine. Food exposures are typically benign, but urine discoloration due to chemicals or drugs may indicate a potentially dangerous condition. Discolored urine can also be caused by medical problems. This brief report reviews the laboratory findings leading to lactic acidosis and elevated urine urobilinogen in an alcoholic patient with pellagra.

Design and methods: A 66-year-old male, found unconscious in his hotel room, was brought to the emergency department (ED). Upon arrival he had hypothermia, a diffuse rash and altered mental status. During ED evaluation, a urinary catheter was placed and demonstrated black urine. Medical history noted chronic alcoholism, malnutrition, and poor self-care.

Results: Evaluation in the hospital suggested that his rash and neurologic changes were a result of malnutrition and vitamin deficiency. A thorough biochemical workup demonstrated that elevated urobilinogen was likely causing the patient's black urine. Serum niacin concentration was undetectable. His dermatitis improved with multivitamins, thiamine, and niacin as well as topical steroids. His mental status returned to baseline and he was discharged to a skilled nursing facility following a brief hospital stay.

Conclusions: The patient's abnormal laboratory results were explained by his alcoholism and poor nutrition. Furthermore, urine color returned to normal with decreased concentration of urobilinogen, after vitamin supplementation and supportive medical care.

Keywords: Bilirubin; Black urine; Lactic acidosis; Pellagra; Urobilinogen.