Reversible Central Adrenal Insufficiency Without Identifiable Cause: A Diagnostic Challenge.

Reversible central adrenal insufficiency (CAI) is a rare disorder characterized by transient impairment of cortisol secretion due to reduced adrenocorticotropic hormone (ACTH) production. It is commonly associated with exogenous glucocorticoid use, acute illness, or certain medications; however, transient CAI can also occur without identifiable triggers. We report the case of a 45-year-old female patient with transient CAI in whom no systemic illness, medication exposure, or pituitary abnormality was identified. Laboratory evaluation revealed a markedly low morning cortisol level (1.3 µg/dL) and suppressed plasma ACTH (3.13 pg/mL). Pituitary magnetic resonance imaging (MRI) was unremarkable, and other pituitary hormones were within reference ranges. The patient received hydrocortisone therapy led to rapid symptomatic improvement and normalization of cortisol levels within three months, after which treatment was discontinued. Long-term follow-up showed sustained recovery of adrenal function. This case highlights the potential for transient CAI without apparent precipitating factors and emphasizes the importance of careful diagnostic evaluation and follow-up. Early recognition, appropriate treatment, and periodic reassessment are essential to guide therapy and confirm recovery. Recognizing such idiopathic presentations can help prevent misdiagnosis and unnecessary lifelong glucocorticoid therapy.