The standard test for suppression

The standard test for suppression by dexamethasone [227] assumes the collecting of consecutive portions of urine within days before introduction of dexamethasone and during everyone 2 its introductions in a dose of 2 and 8 mg/days At healthy faces the small dose of dexamethasone reduces the maintenance of a free hydrocortisone in urine xenical orlistat to level less than 20 mkg/sut, and 17-Construction Department - to level less than 3 mg/days At patients with AkTg-sekretirujushchimi tumours depression of these indicators at a small dose is absent, but at big still makes not less than 50 . Absence of depression at introduction even the big dose specifies in a tumour of adrenals. It is necessary to underline however, that this rule has exceptions. At some patients with AkTg-sekretirujushchimi tumours suppression manages to be observed only at dexamethasone use in a dose of 32 mg/days Stimulation of an axis a hypothalamus - a pituitary body finds out at illness the raised reaction of a cortex of adrenals that is shown by rising of sensitivity of all this system as to the signals mediated , and to deenergizing of a negative feedback. Reaction of a hydrocortisone to an insulinic hypoglycaemia, on the contrary, decreases. In case of occurrence of doubts concerning the diagnosis the help in differentiation of a bilateral adrenal struma owing to AkTg-sekretirujushchih tumours and adenomas of adrenals can render scanning of adrenals with radioactive . Usually in it there is no necessity.
At patients with suspicion on AKTG-PRODUCING tumour it is necessary to make a tomography of a Turkish saddle though it is necessary to remember, almost at 40 of such patients thus, and changes in general can not be found out in patients at whom radiological changes are taped, tumour localisation can mismatch their site [225]. The differential diagnosis Approximately at 80 of patients with syndrome (without patients at whom the semiology is caused by introduction of exogenous hormones) last is a consequence AkTg-sekretirujushchej of a pituitary body tumour. Approximately 15 of patients have a tumour of adrenals, and at the others this syndrome is bound to production an ectopic tumour. The diagnosis is put on the basis of acceleration of secretion of a hydrocortisone, change of results of the test for suppression by dexamethasone, by risings of level of a hydrocortisone in plasma and a hyperreactivity of gipotalamo-gipofizarno-adrenal system for lack of any signs of other neoplasm and irrespective of data of a tomography of a Turkish saddle. Diagnostics passes two basic stages. The first consists in differentiation maxalt or maxalt mlt from the conditions characterised by clinical signs of this disease, but without disturbance of secretion of steroids, and the second - in an exception of conditions at which does not depend on a hypothalamus or pituitary body pathology. One of the conditions deserving special treating, the syndrome of ectopic production is. More often ectopic production is carried out by cancers of lungs, carcinoid tumours and tumours of islets of a pancreas. Disease by the clinical and biological features can imitate illness dependent on a pituitary body though at patients with malignant tumours often is absent augmentation of mass of a body and the leading part the hypopotassemia gets. Assay with dexamethasone finds out various degree of inhibition. Some of tumours cosecrete not (or not only ), and [228], that can explain similarity of dynamic reactions. Excision of tumours completely eliminates biochemical and clinical disturbances. Loss of periodicity of secretion of a hydrocortisone, absence of braking effect of dexamethasone and often some rising of level of a hydrocortisone in plasma is observed at stress, during the periods of serious experiences and at emotional disorders, especially depressions. From biochemical positions it can appear impossible to distinguish such patients from persons with AkTg-sekretirujushchimi tumours though clinical signs, as a rule, are absent. Genesis AkTg-sekretirujushchih of tumours: a hypothalamus or pituitary body pathology Many arguments stated in connection with STG - and tumours, are valid and concerning AkTg-sekretirujushchih tumours. considered, that this disease has a parentage, but the subsequent nabljude - The hypothesis of a subthalamic genesis is based on following observations: 1 - on autopsy at died as a result of illness damages and kernels of a hypothalamus [229] are taped; there are also reports on illness bound to tumours and raised intracranial pressure which symptoms disappeared after an oncotomy; 2 - on autopsy at died as a result of illness in 10-25 of cases in a pituitary body find a hyperplasia