A Case Report on Cesarean Scar Pregnancy and Methotrexate Toxicity Following Intragestational Sac Instillation

Aim and background: A significant number of ectopic pregnancies are now being diagnosed early with the advances in imaging technologies, enabling the timely administration of medical treatment, whether local or systemic.Methotrexate (MTX) is being used as a first-line drug in the medical management of ectopic pregnancy due to its excellent efficacy and limited side effects.Adverse effects of MTX during treatment of ectopic pregnancy, though very rare, may range from mild to severe forms.Here, we report a case involving a middle-aged woman with cesarean scar pregnancy (CSP) who experienced a sudden and fatal deterioration in her health because of MTX toxicity following intrasac instillation of MTX.With this article, we want to bring to the attention of the readers the importance of careful monitoring during and after MTX therapy, a high index of suspicion for toxicity, and its management if it occurs at all.Case description: A gravida three, para one, living one and one first trimester medical abortion with one previous cesarean section was referred to our institution with a transvaginal scan (TVS) report suggesting a CSP extending into the lower uterine cavity with a single live gestation corresponding to 7 weeks for further treatment in a tertiary care setup.Upon ultrasound confirmation of the same, she received two doses of intrasac MTX with a gap of four days.On day 10 after the second dose of intrasac MTX therapy, the woman presented to the emergency room with fever, abdominal distension, diffuse abdominal pain, and loose stools.Examination revealed pallor, icterus, multiple mucosal ulcers, tachycardia, and tachypnea.Lab investigations revealed pancytopenia, deranged liver function tests (LFTs), hypokalemia, and elevated levels of serum MTX.After a thorough evaluation by a multidisciplinary team, the woman was diagnosed with MTX-induced myelosuppression with acute liver injury and mucositis.A treatment plan was devised, which included noninvasive ventilation for respiratory support, blood and blood product transfusions to correct pancytopenia, intravenous (IV) fluids, sodium bicarbonate infusions, intramuscular folinic acid, subcutaneous granulocyte colony-stimulating factor, broad-spectrum antibiotics, parenteral potassium correction, IV N-acetyl cysteine, and sodium bicarbonate mouthwashes.With the help of a multidisciplinary team, early diagnosis, treatment, and strict monitoring were possible, and the woman showed clinical improvement along with a decrease in serum MTX levels to a nontoxic range.By day 4 of ICU stay, she was weaned off from the noninvasive ventilation and discharged after a week in stable condition.Conclusion: Unexpected toxicity with local instillation of intrasac MTX should be kept in mind during use for ectopic pregnancies.Folinic acid treatment is to be considered in women being treated not only with multiple doses of MTX but also with a single dose.Strict vigilance for signs and symptoms of MTX toxicity must be inculcated in every clinician using MTX as a treatment option.Clinical significance: Cesarean scar pregnancy poses a significant challenge for obstetricians; however, recent evidence supporting the effectiveness of MTX therapy has made its management more feasible.While systemic MTX toxicity is well-documented and managed, there is limited literature addressing toxicity following local MTX administration at the low doses typically used in CSP treatment.In this article, we emphasized the importance of careful monitoring during and after MTX therapy, a high index of suspicion for toxicity, and its management in case of its occurrence.