[Differential diagnosis of hypothalamic-hypophyseal Cushing's syndrome and ectopic ACTH syndrome (author's transl)]

Endocrinological symptoms of, on the one hand, hypothalamic-hypophyseal Cushing's syndrome and, on the other, ectopic ACTH syndrome (usually caused by bronchial carcinoma) can often not be distinguished. Reliable differentiation of these two forms of secondary hypercortisolism is necessary, because in hypothalamic-hypophyseal Cushing's syndrome therapy is more and more frequently directed at the anterior pituitary and hypothalamus rather than attempted by bilateral adrenalectomy. The following method was used for distinguishing between the two in six patients: blood was withdrawn by catheter from the jugular vein and the inferior petrosal sinus and the ACTH concentrations measured. Compared with ACTH concentration in a peripheral vein (e.g. cubital vein) that in the jugular vein was higher in five patients by a factor of 1.47 +/- 0.1 and in the inferior petrosal sinus by 2.39 +/- 0.64. A positive diagnosis of hypothalamic-hypophyseal Cushing's syndrome can thus be made. In one patient the diagnosis of ectopic ACTH syndrome could be made from the gradient of ACTH concentration between the cardiac right ventricle and the bronchial artery (1 : 3.75), before there was radiological demonstration of the bronchial carcinoma.