Is Adrenocorticotropic Hormone Deficiency Really Rare in Patients with Idiopathic Growth Hormone Deficiency and Normal Thyroid Function Tests

BACKGROUND/AIM: It was the aim of this study to evaluate subtle adrenocorticotropic hormone deficiencies in a group of patients with idiopathic growth hormone deficiency and without thyroid-stimulating hormone deficiency. METHODS: Growth hormone and cortisol responses to an insulin tolerance test of 25 patients (15 males and 10 females) were evaluated at diagnosis (11.8 ± 2.5 years) and at the time of retesting (14.6 ± 1.6 years). A cortisol response <416, 416-555 and >555 nmol/l was defined as inadequate, blunted and normal, respectively. RESULTS: Baseline cortisol responses to the insulin tolerance test were subnormal in 10 of the 25 patients (6 had blunted responses and 4 had inadequate responses). The mean ± SD of normal, blunted and inadequate cortisol response at diagnosis was 722.2 ± 127.8, 480.4 ± 37.4 and 317.7 ± 81.7 nmol/l, respectively. Five of these patients showed improved cortisol response at retesting. Three of the 15 patients who had a normal baseline cortisol response developed blunted cortisol response at re-evaluation. The mean ± SD of normal and blunted plus inadequate cortisol response at retesting was 668.1 ± 116.1 and 467.3 ± 64 nmol/l, respectively. All patients with a subnormal cortisol level were asymptomatic. CONCLUSION: Asymptomatic adrenocorticotropic hormone deficiency patients should be followed up closely, and treatment should be considered in a stress situation after re-evaluation of the hypothalamic-pituitary-adrenal axis.