Severe Methotrexate toxicity after ectopic pregnancy: a case report managed with continuous renal replacement therapy

Methotrexate (MTX) is a cornerstone non-surgical therapy for ectopic pregnancy, but its narrow therapeutic window necessitates strict dose verification to prevent toxicity. We report a case of severe MTX intoxication in a 31-year-old woman following salpingostomy, resulting from a dosing error. After receiving an excessive intramuscular dose, the patient developed severe gastrointestinal symptoms and acute kidney injury (AKI). Initial management included prompt leucovorin rescue, urine alkalinization, and intensive supportive care; however, renal dysfunction progressed with impaired MTX clearance. In the absence of glucarpidase, the patient was transferred to the intensive care unit (ICU) and treated with continuous renal replacement therapy (CRRT), which facilitated sustained MTX removal and was followed by gradual clinical and biochemical recovery. This case highlights the critical importance of dose verification in MTX administration and illustrates that, when conventional measures are insufficient and glucarpidase is unavailable, CRRT may serve as a viable salvage therapy for life-threatening MTX toxicity complicated by AKI.