Two Decades of Endocrine Silence: Severe Hyponatremia Presenting as Late-Onset Sheehan Syndrome

Sheehan syndrome is a rare but potentially fatal complication of postpartum hemorrhage caused by ischemic necrosis of the anterior pituitary gland. Although its incidence has decreased in countries with comprehensive obstetric care systems, it remains a significant cause of panhypopituitarism in regions lacking timely and adequate access to perinatal care. The clinical challenge lies in its insidious presentation: symptoms develop slowly and gradually, and the diagnosis may remain unrecognized for decades. We report the case of a 52-year-old woman who presented with a one-year history of progressive decline in general health, characterized by debilitating asthenia, somnolence, decreased appetite, and an unintentional 13-kg weight loss. Her obstetric history provided the crucial diagnostic clue: 21 years prior, her last delivery - an initially unattended home birth - was complicated by a retained placenta and severe hemorrhage, followed by total agalactia and permanent secondary amenorrhea. Initial laboratory evaluation revealed severe hyponatremia (119 mmol/L), normocytic anemia, and biochemical evidence of central hypothyroidism and adrenal insufficiency. Magnetic resonance imaging (MRI) confirmed an empty sella turcica. Sequential hormone replacement therapy was initiated - administering glucocorticoids before levothyroxine - resulting in the normalization of serum sodium levels and significant clinical improvement. The clinical triad of postpartum hemorrhage, agalactia, and secondary amenorrhea constitutes a critical diagnostic red flag. Timely recognition of Sheehan syndrome is essential not only for resolving acute complications such as hyponatremia, driven by secondary hypothyroidism and hypocortisolism, but also for preventing cardiometabolic complications and severe osteoporosis with a high fracture risk associated with untreated chronic hypopituitarism.