Idiopathic ACTH Deficiency: Stomach Pain, Not Low Blood Sugar, Signals Rare Disorder

Adrenocorticotropic hormone (ACTH), produced by the pituitary gland, stimulates the adrenal glands to produce cortisol, a vital stress hormone. Deficiency in ACTH typically leads to secondary adrenal insufficiency, a condition where the adrenal glands don't produce enough cortisol, often presenting with symptoms like fatigue, weight loss, and crucially, hypoglycemia (low blood sugar). This case report highlights an unusual presentation of idiopathic and isolated ACTH deficiency (meaning the cause is unknown and it's not part of a broader pituitary issue) where a patient experienced continuous epigastric discomfort without any signs of hypoglycemia, challenging typical diagnostic assumptions.

Diagnostic tests revealed profoundly low hormone levels: morning plasma cortisol was <1.0 µg/dL (normal range typically 5-25 µg/dL), and plasma ACTH was critically low at <5 pg/mL (normal range typically 10-60 pg/mL). Pituitary MRI showed no structural abnormalities, confirming the "idiopathic" and "isolated" nature of the deficiency. The most striking finding was the complete resolution of the patient's continuous epigastric discomfort within just 72 hours following the initiation of hydrocortisone 10 mg daily treatment. This rapid and complete symptom reversal strongly linked the gastrointestinal distress to the underlying ACTH deficiency, despite the absence of typical hypoglycemia symptoms. The patient's blood glucose levels remained stable throughout the diagnostic and treatment phases, further emphasizing the atypical presentation.