Flavonoid-induced acute nephropathy.

We report two cases of acute renal failure induced by sciadopitysin, a type of flavonoid, and review related papers of flavonoid-induced acute nephropathy in the literature. A total of eight patients were studied. The purpose of this report is to alert physicians to consider this cause of acute renal failure with hemolysis, because flavonoids are widely used in the world. All patients initially presented with fever and gastrointestinal upset after the ingestion of a single large dose or long-term small doses. Symptoms that followed were cola-colored urine and jaundice. Elevation of blood nitrogen and serum creatinine lasted for 2 to 9 weeks. Hemolysis (100%), cholestatic hepatitis (50%), and disseminated intravascular coagulopathy (50%) were also noted in flavonoid-induced oliguric acute renal failure patients. All of these patients required hemodialysis and all but one who died completely recovered within 2 to 9 weeks. Renal biopsy was performed and showed acute interstitial nephritis with acute tubular necrosis. Moreover, we first demonstrated multiple polymorphous inclusion bodies within tubular epithelial cells in electron microscopic examinations. The definite pathogenetic mechanism of flavonoid-induced acute nephropathy needs further elucidation.