| Popis: |
The diagnosis of Cushing's syndrome remains one of the most challenging tasks in clinical neuroendocrinology. The diagnostic procedure can be divided into two distinct steps: diagnosis of the neuroendocrine disorder and differential diagnosis of the precise aetiology. The goal of the first laboratory tests is to obtain biochemical proof of Cushing's syndrome. Patients with Cushing's syndrome are relatively insensitive to glucocorticoid feedback and exhibit an oversecretion of cortisol devoid of a circadian cycle. In our experience, a low-dose dexamethasone suppression test provides the most reliable confirmation of steroid resistance, a cortisol level of3 to confirm the pituitary origin of the disorder with a 98% sensitivity. Chest or abdominal CT can be helpful to identify an ectopic tumour but very small tumours may go undetected. MRI can detect 60 or 70% of all pituitary adenomas but is virtually non-contributive to the diagnosis of Cushing's disease in children. |
