Глікемічний скринінг і вторинні порушення вуглеводного обміну при ендокринній патології

The use of glycated hemoglobin for diabetes mellitus (DM) diagnosis is recommended by World Health Organization as of 2011. The level of glycated hemoglobin (HbA1c) ≥ 6.5 % is a diagnostic criterion for DM but HbA1c level of 6.0–6.4 % does not exclude diabetes mellitus diagnosis with hyperglycemia. Moreover, when diagnosing, evaluation of this criterion is a must, since decision about the nature and the scope of sugar-reducing therapy is based on the level of HbA1c. Counterregulatory hormones are glucagon, adre­nalin, somatotropin, glucocorticoids and thyroid hormones. Pathogenic mechanism of carbohydrate metabolism disorders with hypersecretion of counterregulatory hormones is caused by peripheral insulin resistance, decrease in insulin secretion, increase in gluconeogenesis and glycogenolysis in liver and increase in the absorption of intestinal glucose with insulin being the only hormone decreasing the blood glucose. So, the endocrine diseases (hypercorticism, acromegalia, pheochromocytoma, hyperparathyroidism and hyperthyroidism) with excessive secretion of counterregulatory hormones suggest the necessity of secondary diabetes diagnosis. Screening tests with quite high sensitivity and specificity have been developed for early diagnosis of endocrynopathies. Screening tests for hypercorticism diagnosis are dexamethasone (1 mg) suppression test, daily urinary cortisol excretion and nighttime salivary cortisol. Optimal test for screening acromegalia is considered to be insulin-like growth factor 1 which shows the secretion of somatotropic hormone during previous day and is not subject to significant fluctuations. One-time detection of increased insulin-like growth factor 1 level compared to referential values for specific sex and age is enough for confirmation of hypersomatotropinemia. Thyroid-stimulating hormone is recommended as a screening test for thyrotoxicosis diagnosis. When choosing this test, doctor should consider the parameter of analytical sensitivity of test system for thyroid-stimulating hormone. Screening for hyperparathyroidism is the detection of blood ionized calcium level. This examination is particularly relevant for patients from risk group for initial hyperparathyroidism — patients with gallstone disease, urolithiasis, stomach ulcer and/or duodenal ulcer, essential hypertension, etc. Free metanephrines of blood plasma and conjugated urine metanephrines are the screening tests for pheochromocytoma diagnosis. The level of methylated secondary catecholamines (metanephrines, normetanephrines) shows the daily tumor activity of pheochromocytoma. Thus, glycemic screening and endocrynopathies screening with hypersecretion of counterregulatory hormones should be conducted together. This will allow detecting secondary forms of diabetes mellitus and compensating glycemic state of the patient.