Central Adrenal Insufficiency Unmasked After Pneumonia-Associated Asthma Exacerbation Leading to the Diagnosis of Rathke's Cleft Cyst in an Elderly Woman: A Case Report.

Rathke's cleft cyst (RCC) is a benign pituitary lesion that is often asymptomatic but can cause hypopituitarism, including central adrenal insufficiency, which may become clinically apparent under physiological stress. However, RCC presenting with adrenal insufficiency unmasked by acute respiratory illness is rare, particularly in elderly patients. We report a case of RCC diagnosed after adrenal insufficiency became evident following pneumonia-associated asthma exacerbation. An 89-year-old woman presented with fever, productive cough, and generalized fatigue and was diagnosed with pneumonia-triggered asthma exacerbation. Initial laboratory evaluation revealed hyponatremia (serum sodium 126 mEq/L). She was treated with bronchodilators, systemic corticosteroids, and antibiotics, resulting in prompt improvement of respiratory symptoms and normalization of serum sodium levels. After discontinuation of corticosteroids and discharge, she developed persistent fatigue, anorexia, and right eyelid ptosis. Brain magnetic resonance imaging revealed a 22-mm cystic lesion in the pituitary gland consistent with RCC. Endocrine evaluation demonstrated markedly reduced adrenocorticotropic hormone and cortisol levels, along with central hypothyroidism, hypogonadism, and growth hormone deficiency, confirming panhypopituitarism with central adrenal insufficiency. Hydrocortisone replacement therapy was initiated, leading to clinical stabilization. Surgical intervention was deferred due to advanced age and absence of visual field defects, and the patient was managed conservatively with hormone replacement and follow-up imaging. This case highlights that acute respiratory illness may precipitate overt adrenal insufficiency in patients with previously unrecognized RCC. Transient improvement with corticosteroids during acute treatment may mask the underlying endocrine disorder, delaying diagnosis. Persistent fatigue, hyponatremia, or neurological findings after resolution of respiratory illness should prompt evaluation for central adrenal insufficiency and pituitary pathology, as early recognition and hormone replacement are essential to prevent life-threatening complications.