Cavitating Osmotic Demyelination Syndrome Following Correction of Chronic Hyponatremia in Sheehan's Syndrome: A Novel Case Report

Introduction: Rapid correction of hyponatremia can result in osmotic demyelination syndrome (ODS). Sheehan's syndrome, a rare pituitary disorder caused by severe postpartum hemorrhage, is a potential cause of chronic hyponatremia. This case report describes a rare progression of extrapontine myelinolysis to central pontine myelinolysis, ultimately leading to ODS, following the correction of chronic hyponatremia associated with Sheehan's syndrome. Notably, this event occurred a decade after the initial postpartum hemorrhage due to placenta previa.

Case report: A 40-year-old woman from rural West Bengal, India, presented in a comatose state after five years of progressively worsening symptoms, including fatigue, gastrointestinal disturbances, cold intolerance, hair loss, and severe apathy, which had been misdiagnosed as psychogenic and treated with selective serotonin reuptake inhibitors. Two days before her admission to our hospital, she was diagnosed with a lower respiratory tract infection, dehydration, and severe hyponatremia (118 mEq/L) at a local private healthcare facility. Despite treatment with 3% sodium chloride and intravenous antibiotics, her condition deteriorated, prompting her transfer. At the time of hospitalization, the patient was diagnosed with chronic hyponatremia and hypopituitarism consistent with Sheehan's syndrome. This condition was attributed to a severe postpartum hemorrhage that occurred a decade prior, resulting from placenta previa. Initial MRI revealed extrapontine myelinolysis, and the correction of her "compensated" hyponatremia was identified as the cause of her neurological decline. Follow-up MRIs at 7 and 14 weeks confirmed the development of cavitating ODS.

Discussion: This case highlights several key points: First, even a relatively gradual correction of hyponatremia can precipitate ODS, especially in patients with chronic conditions like Sheehan's syndrome. Second, it underscores the importance of meticulous management of chronic hyponatremia to prevent severe neurological outcomes. Third, it illustrates the diagnostic challenges of differentiating Sheehan's syndrome from primary psychiatric disorders, particularly in low-resource settings where the syndrome remains prevalent. The case also emphasizes the need for awareness among healthcare providers about the potential for severe complications arising from even minor corrections in serum sodium levels in such patients.