Acute Kidney Injury and Hemolytic Anemia Secondary to <b><i>Mycoplasma pneumoniae</i></b> Infection

Glomerulonephritis as well as kidney injury secondary to fulminant intravascular hemolysis are rare extrapulmonary manifestations of Mycoplasma pneumoniae infection. We describe a 50-year-old female diagnosed with M. pneumoniae infection-associated hemolytic anemia, characterized by negative cold agglutinin tests but with laboratory evidence of complement alternative pathway activation. The patient presented both with anemia and severe kidney failure and she was treated with steroids and red blood cell transfusions along with plasmapheresis. She also received a short course of antibiotics. Renal biopsy showed combined features of resolving postinfectious glomerulonephritis and hemolysis-associated extensive acute tubular injury characterized by renal hemosiderosis and intratubular hemoglobin casts. Electron microscopy revealed features of glomerular microangiopathic injury. The treatment led to complete disease remission and a favorable renal outcome at the first year follow-up.