Cephalexin-Induced Hemolytic Anemia and Renal Failure: A Case Report and Review of the Literature

Hemolytic anemia is a rare adverse reaction to cephalosporins, and its occurrence in response to cephalexin is even rarer. Cephalexin is a commonly prescribed empiric oral antibiotic for a variety of infections, particularly in the outpatient setting. It is, therefore, important to be aware of this possible adverse reaction to cephalexin for timely intervention and prompt discontinuation of the offending agent. We present a case of a 48-year-old female with no significant past medical history who presented with intermittent hematuria for two days and anuria for one day. She had been seen in the emergency department three days prior for a urinary tract infection and discharged on cephalexin. Her renal function was normal at the time. Upon re-presentation with anuria, her creatinine and hemoglobin had acutely worsened, lactate dehydrogenase was elevated, and haptoglobin was low. Her renal function rapidly deteriorated, and the patient required hemodialysis. Her renal biopsy revealed acute tubular injury with numerous intraluminal hemoglobin casts supporting the diagnosis of drug-induced hemolysis resulting in acute renal failure. The patient achieved full renal recovery within four weeks following prompt discontinuation of cephalexin and timely renal replacement support. This case highlights the importance of considering this rare adverse reaction to cephalexin when a patient presents with findings suggestive of intrarenal acute kidney injury. Early recognition can expedite the diagnostic workup and treatment, potentially improving outcomes.