Euglycemic Diabetic Ketoacidosis Presenting With Intraoperative Cardiac Arrest in Late Pregnancy.

Euglycemic diabetic ketoacidosis (EDKA) is an uncommon but serious metabolic complication in pregnancy, where physiologic changes promote ketone production even without marked hyperglycemia. We report the case of an 18-year-old woman at 35 weeks and 4 days of gestation with type 1 diabetes mellitus and severe preeclampsia who developed intraoperative cardiac arrest during an emergent cesarean delivery. She had been nonadherent with insulin therapy for more than seven days before admission. Initial laboratory evaluation demonstrated metabolic abnormalities despite normoglycemia. During cesarean delivery, inadequate epidural anesthesia required rapid sequence intubation. Following delivery and administration of tranexamic acid for hemorrhage control, the patient developed progressive bradycardia, hypotension, and pulselessness. Cardiopulmonary resuscitation was initiated, and return of spontaneous circulation occurred within one minute. Post-arrest laboratory studies revealed severe metabolic acidosis, markedly low bicarbonate, elevated anion gap, and ketonuria consistent with EDKA. Magnesium levels were elevated but below thresholds typically associated with severe toxicity. This case highlights how overlapping obstetric, anesthetic, and metabolic stressors can obscure the diagnosis of EDKA and precipitate acute cardiovascular instability. Early recognition of acid-base disturbances and prompt multidisciplinary management are essential in high-risk obstetric patients, particularly when insulin omission and advanced gestation increase susceptibility to ketosis.