Characteristics of the Early Manifestations and the Sequential Changes of Magnetic Resonance Imaging in Acute Sheehan's Syndrome: A Case Report and Literature Review.

Acute Sheehan's syndrome (ASS) is a rare condition that causes pituitary insufficiency in the early postpartum period. In this article, we report a case of early diagnosis of ASS with hyponatremia as the initial symptom. In addition, we review the characteristics of the initial symptoms and sequential changes on magnetic resonance imaging (MRI) based on previous related cases. The patient was a 33-year-old pregnant woman, gravida 2, para 1. She had a vaginal delivery at 40 weeks of gestation, with a total blood loss of 12,700 mL due to atonic bleeding, and, subsequently, she developed a vulvar hematoma. She had a mild comatose, headache, and nausea 30 hours after delivery. The laboratory evaluation revealed hyponatremia (sodium: 128 mEq/L) and mild hypopituitarism (low adrenocorticotropic hormone and low cortisol). The patient was diagnosed with ASS and treated with hormone replacement therapy. MRI examination showed marginal enhancement of the pituitary gland at one week postpartum, normalization at three months, and atrophy at eight months. ASS should be considered when hyponatremia occurs after massive postpartum hemorrhage. It is also important to note that MRI findings in ASS can change during the postpartum period.