Hyperglycemia is an increase in the concentration of glucose in the blood plasma of more than 6.1 mmol / l. The causes of this condition can be stress, a high-carbohydrate diet, medication, as well as diseases of the endocrine system and internal organs. The main clinical manifestations include dry mouth, profuse urination, and muscle weakness. The level of glycemia is examined by venous or capillary blood before meals and medications. To normalize blood sugar levels, diet, medications (insulin, hypoglycemic agents), and treatment of the underlying disease are used.
According to the severity of hyperglycemia is divided into:
- Light - up to 8.2 mmol / l.
- Moderate - from 8.3 to 11 mmol / l.
- Heavy - over 11 mmol / l.
This numerical division is considered very conditional, since it is not the level of glycemia that matters more, but the rate of increase. By nature, physiological (stress, carbohydrate intake) and pathological hyperglycemia are distinguished. According to the origin of hyperglycemia are:
- Hormonally determined. An increase in sugar is caused by various endocrine pathologies (diabetes, hypercortisolism, etc.).
- central genesis. An increase in glucose levels occurs with diseases of the central nervous system and brain injuries.
- Alimentary-conditioned. Hyperglycemia develops as a result of rare hereditary constitutional and metabolic disorders.
Causes of hyperglycemia
A short-term increase in blood sugar can be observed during pregnancy, when taking carbohydrate-containing food on the eve of a biochemical analysis. Under stress, hyperglycemia occurs due to the activation of the sympathetic-adrenal and hypothalamic-pituitary-adrenal systems and the production of contrainsular hormones. In these conditions, hyperglycemia is transient (reversible) and does not require any intervention.
Diabetes mellitus (DM) is the leading cause of high blood glucose levels. The pathogenetic mechanisms of the development of hyperglycemia are somewhat different in different types of diabetes. Type 1 diabetes is characterized by a decrease in insulin production by beta cells of the islets of Langerhans of the pancreas (absolute insulin deficiency), which leads to a violation of the utilization of glucose as an energy substrate by peripheral tissues (fat, muscle) and, accordingly, its retention in the blood.
In type 2 diabetes, on the contrary, due to long-term hyperinsulinemia, insulin resistance occurs (an increase in the threshold of insulin sensitivity) due to a decrease in the number of insulin receptors on the surfaces of muscle and adipose tissue cells (relative insulin deficiency). Gestational diabetes mellitus (GDM) is caused by a decrease in insulin clearance, as well as the action of fetoplacental hormones (placental lactogen, progesterone).
- Type 1 diabetes. The spasmodic nature of hyperglycemia is typical. A sharp increase in blood sugar levels can also occur at the time of the clinical manifestation of the disease, and, most often, when dosages are not observed or insulin injections are missed. Lifelong insulin therapy is necessary to maintain glucose within normal limits.
- Type 2 diabetes. It is characterized by a slow and steady increase in the concentration of glucose, due to which it can reach very high values (30-4 mmol / l). The level of glycemia decreases under the influence of diet and the intake of hypoglycemic agents. Normalization of body weight and bariatric surgery can reduce or completely eliminate the need for treatment.
- GSD. With gestational diabetes, blood sugar gradually rises in the II-III trimesters of pregnancy. Specific treatment is carried out before the onset of childbirth or operative delivery. In the postpartum period, spontaneous remission is often observed, but hyperglycemia may persist with the transition to type 2 diabetes mellitus.
Other endocrine disorders
In addition to diabetes, other diseases of the endocrine system can lead to hyperglycemia. This mainly concerns endocrinopathies, accompanied by an increased production of contrainsular hormones, i.e. hormones that increase the concentration of glucose by influencing various stages of carbohydrate metabolism:
- thyrotoxicosis. With diffuse toxic goiter or toxic adenoma, thyroid hormones activate glycogenolysis, gluconeogenesis, and stimulate the absorption of glucose in the intestine. Hyperglycemia is moderate, resolved after normalization of the level of thyroid hormones.
- Hypercortisolism. Glucocorticosteroids (cortisol) increase gluconeogenesis and inhibit glucose breakdown. With Itsenko-Cushing's disease / syndrome, the so-called "steroid diabetes" often develops.
- Pheochromocytoma. Catecholamines (adrenaline, norepinephrine) stimulate the breakdown of glycogen in the liver. Hyperglycemia proceeds paroxysmally, the glucose level increases sharply at the time of the sympathetic-adrenal crisis. In the interictal period, glycemia remains within the normal range.
- Acromegaly. The growth hormone produced by the pituitary tumor somatotropinoma, in addition to the direct hyperglycemic effect, inhibits the utilization of glucose by peripheral tissues, i.e. creates insulin resistance. Therefore, hyperglycemia in acromegaly is of a special nature. Unlike other endocrinopathies, in which impaired glucose tolerance occurs more often, acromegaly quite often leads to the development of type 2 diabetes.
- Glucagonoma. Glucagon, as the main antagonist of insulin, stimulates the formation of glucose from amino acids in the liver. Hyperglycemia is mild. In most cases, changes in diet are enough to normalize blood sugar.
- Convulsive conditions.
- Organic lesions of the central nervous system: encephalitis, brain tumors, hemorrhages in the IV ventricle.
- Liver failure.
- Severe diseases of the pancreas : pancreatic necrosis, cystic fibrosis.
- Taking medications: thiazide diuretics, glucocorticosteroids, beta-adrenergic blockers.
- Severe somatic disorders: sepsis, extensive burns.
- Autoimmune polyglandular syndromes: Schmidt's syndrome.
- Rare hereditary syndromes : Sipe-Lawrence lipodystrophy, Prader-Willi syndrome, Wiedemann-Beckwith syndrome.
- HIV infection.
Initially, hyperglycemia is detected during a preventive or targeted laboratory blood test for sugar. However, patients who have a portable glucometer can independently detect a regular increase in glucose in the morning on an empty stomach. In this case, you should immediately visit a general practitioner or endocrinologist. In the future, to clarify the nature of the pathological process, the following can be carried out:
- Study of carbohydrate metabolism. A patient with hyperglycemia undergoes a urine test for sugar, an oral glucose tolerance test, and daily monitoring of the glycemic profile. Together with glucose tests, the determination of the level of glycated hemoglobin, blood insulin, and the HOMA index (insulin resistance) is often additionally prescribed.
- Hormonal studies. If a pathology of the endocrine system is suspected, a blood test is performed for thyroid hormones (TSH, free T4, T3), insulin-like growth factor-1, measurement of the level of metanephrines in daily urine. If the patient has clinical signs of hypercorticism, measure the concentration of cortisol in saliva, as well as in plasma after performing small and large dexamethasone tests.
- ultrasound. In the case of hyperglycemia of pancreatogenic origin, ultrasound of the abdominal organs reveals a decrease in the echogenic density of the pancreas, its swelling, fuzzy contours, the presence of cysts, etc. In hyperthyroidism, ultrasound of the thyroid gland shows a decrease in the echogenicity of the parenchyma, the presence of nodular formations.
- CT. With laboratory confirmation of hyperproduction of hormones of the adrenal cortex, a CT scan of the adrenal glands is performed to search for a tumor formation - corticosteroma.
- MRI. With acromegaly and Itsenko-Cushing's disease, an MRI of the brain shows a benign pituitary tumor - an adenoma.
Since prolonged hyperglycemia in itself has an adverse effect on the entire human body, if it is detected, especially after repeated measurement of blood sugar, an examination is prescribed to assess the state of target organs, which includes:
- study of total cholesterol and lipid profile;
- measurement of blood pressure;
- taking an electrocardiogram;
- determination of the level of creatinine in the blood serum, urea, in the urine - total protein, albumin-creatinine ratio, if necessary, the calculation of the glomerular filtration rate is performed;
- eye examination.
Insulin therapy is the leading treatment for diabetes mellitus
After receiving tests with an excess of reference glucose values, you should consult a doctor. A short-term increase in glycemia due to physiological factors does not require treatment. With drug-induced hyperglycemia, it is necessary to cancel the causative drug, as well as consult a specialist who prescribed this drug in order to replace it.
In some cases, to normalize glycemia, competent therapy of the underlying disease is sufficient (prescription of thyreostatic drugs, steroidogenesis inhibitors, somatostatin analogs). For the treatment of patients with pathological hyperglycemia, especially caused by diabetes mellitus, the following measures are used:
- Diet. Compliance with a low-carbohydrate diet is one of the main conditions for the successful correction of hyperglycemia. First of all, easily digestible carbohydrates are limited - chocolate, pastries, cakes. Preference is given to whole grain products (buckwheat, oatmeal).
- Physical exercise. Due to the regular performance of various physical exercises, there is an increased utilization of glucose by the muscles, which makes it possible to achieve a decrease in glycemia.
- insulin therapy. Insulin injections are indicated for all type 1 diabetic patients and pregnant women with gestational diabetes. Insulin is also prescribed for decompensated type 2 diabetes. The effectiveness of therapy is the achievement of target levels of glycated hemoglobin (HbA1c).
- Hypoglycemic agents. In type II diabetes, as well as hyperglycemia caused by other endocrinopathies, hypoglycemic drugs are considered drugs of choice - biguanides (metformin), sulfonylurea derivatives (glibenclamide), DPP-4 inhibitors (vildagliptin).
In some cases, when hyperglycemia cannot be corrected by conservative methods (for example, in patients with morbid obesity and type II diabetes), bariatric surgery is resorted to - gastric bypass, resection, gastric banding. For the successful treatment of many endocrinopathies, a surgical operation is required - thyroidectomy for thyrotoxicosis, transnasal adenomectomy for acromegaly, bilateral adrenalectomy for Cushing's syndrome.
Pathological hyperglycemia is an extremely unfavorable prognostic factor. High glucose levels can cause acute life-threatening conditions - hyperosmolar hyperglycemic and lactic acid coma. Hyperglycemia inhibits the phagocytic activity of leukocytes, resulting in an increased susceptibility to infectious diseases.
Prolonged hyperglycemia due to glycosylation of lipoproteins and the endothelium of the vascular walls rapidly accelerates the progression of atherosclerosis. Subsequently, this can lead to the early development of cardiovascular disasters (acute myocardial infarction, stroke), as well as chronic renal failure, loss of vision, gangrene of the extremities.