LAUSR

S moke inhalation is the leading cause of death from fire-related events because it can result in thermal injury to the lungs and upper airways; chemical injury from byproducts of burned items; and poisonings, such as carbon monoxide and cyanide. Cyanide is a potent toxin that inhibits numerous enzymes, including cytochrome oxidases leading to cellular hypoxia, cardiovascular collapse, and death. Hydroxocobalamin, a natural form of vitamin B12 that chelates cyanide leading to formation of cyanocobalamin that is excreted by the kidneys, has been increasingly used as an antidote of cyanide poisoning. However, a retrospective French study found that hydroxocobalamin use for smoke inhalation was associated with an increased risk of acute kidney injury (AKI) and a need for renal replacement therapy. Moreover, another study reported high urine oxalate levels in patients treated with hydroxocobalamin. There is a paucity of reports regarding hydroxocobalamin-induced AKI from oxalate nephropathy. We present a case of biopsy-proven hydroxocobalamin-induced oxalate nephropathy in a patient admitted for smoke inhalation.