Кушинг синдромы: себептері, диагностикасы және эпидемиологиясы

the equine form of the disease

Cushing's disease is one cause of Cushing's syndrome characterised by increased secretion of adrenocorticotropic hormone (ACTH) from the anterior pituitary (secondary hypercortisolism). This is most often as a result of a pituitary adenoma (specifically pituitary basophilism) or due to excess production of hypothalamus CRH (corticotropin releasing hormone) (tertiary hypercortisolism/hypercorticism) that stimulates the synthesis of cortisol by the adrenal glands. Pituitary adenomas are responsible for 80% of endogenous Cushing's syndrome,

Once Cushing's syndrome has been diagnosed, the first step towards finding the cause is measuring plasma adrenocorticotropic hormone (ACTH) concentration. A concentration consistently below 1.1 pmol/L is classified as corticotropin independent and does not lead to a diagnosis of Cushing's disease. In such cases, the next step is adrenal imaging with CT. If plasma corticotropin concentrations are consistently above 3.3 pmol/L, then corticotropin dependent Cushing's syndrome is most likely. Any intermediate values need to be cautiously interpreted and a corticotropin releasing hormone (CRH) test is advised in order to confirm corticotropin dependency. If corticotropin dependent Cushing's syndrome is determined then the next step is to distinguish between Cushing's disease and ectopic corticotropin syndrome. This is done via a combination of techniques including CRH, high dose DST, pituitary MRI and bilateral inferior petrosal sinus sampling (IPSS).

Two dexamethasone suppression tests (DSTs) are generally used, the overnight test and the 48 hour test.

IPSS (inferior petrosal sinus sampling) or BIPSS (bilateral IPSS) is a more accurate but invasive test used to differentiate pituitary from ectopic or adrenal Cushing's syndrome. A corticotropin gradient sample via BIPSS is required to confirm diagnosis when pituitary MRI imaging and biochemical diagnostic tests have been inconclusive.

Cases of Cushing's disease are rare, and little epidemiological data is available on the disease. An 18 year study conducted on the population of Vizcaya, Spain reported a 0.004% prevalence of Cushing's disease. The average incidence of newly diagnosed cases was 2.4 cases per million inhabitants per year. The disease is often diagnosed 3–6 years after the onset of illness. Moreover, most women affected were between the ages of 50 and 60 years. The prevalence of hypertension, and abnormalities in glucose metabolism are major predictors of mortality and morbidity in untreated cases of the disease. with the majority of deaths due to vascular disease. a 23 year old woman called Minnie G. whose symptoms included painful obesity, amenorrhea, hypertrichosis (abnormal hair growth), underdevelopment of secondary sexual characteristics, hydrocephalus and cerebral tension. This combination of symptoms was not yet described by any medical disorder at the time. Out of the 12 cases with hypercortisolism described in Cushing's monograph on the pituitary body, 67% died within a few years after symptom presentation, whereas Minnie G. survived for more than 40 years after symptom presentation, despite the fact that she did not receive any treatments for a pituitary tumor. The prolonged survival made Minnie's case unique at the time. The reason behind this survival remains a mystery since an autopsy of Minnie was refused after her death. However, the most likely explanation, proposed by J. Aidan Carney and based on statistical evidence, was that the basophil adenoma Minnie might have harbored underwent partial infarction, leading to symptom regression. The other hypothesis was that Minnie might have had Primary Pigmented Nodular Adrenocortical Disease (PPNAD), which when associated with Cushing's syndrome (Carney complex) can infrequently cause spontaneous symptom regression of the latter. In 1924, the Soviet neurologist Nikolai Itsenko reported two patients with pituitary adenoma. The resulting excessive adrenocorticotropic hormone secretion led to the production of large amounts of cortisol by the adrenal glands. Considering this impact, the name of Itsenko was added to the title in some East European and Asian countries, and the disease is called Itsenko Kushing disease.