Hypoglycemia : Causes, Symptoms, Diagnosis & Treatment

Last Updated: 21/07/2022

Hypoglycemia is a decrease in plasma glucose concentration less than 2.8 mmol / l. Causes include non-compliance with insulin therapy in diabetes (skipping meals, exercise, alcohol consumption), various endocrine and metabolic disorders, and cancer. The clinical symptom complex is represented by vegetative and neuropsychiatric disorders of varying severity. Diagnosis is based on the detection of low fasting or postprandial plasma glucose. To stop hypoglycemia, oral fast-digesting carbohydrates, the introduction of glucose or glucagon are used.

Hypoglycemia is not an independent disease, but a clinical and laboratory syndrome. In diabetes, this condition occurs in approximately 40-60% of patients. Among people with type 1 diabetes, the percentage of cases of hypoglycemia is slightly higher, however, due to the much higher prevalence of type 2 diabetes, the predominant number of episodes of hypoglycemia occurs in this form of diabetes. Moreover, in diabetic patients with prolonged hyperglycemia (decompensation), symptoms begin to appear already at a glucose level of 5-6 mmol / l. In the process of maturation, the nervous system of children (especially newborns) consumes more glucose and therefore reacts more acutely to hypoglycemia.

Causes of hypoglycemia

The condition has many etiological factors. In a healthy person, the reasons for lowering glucose below normal values ​​\u200b\u200bare pregnancy, intense physical activity, and prolonged fasting. However, such cases are extremely rare. Most often, hypoglycemia develops in various diseases and pathological conditions:

  • Errors in insulin therapy in diabetes . They are considered the most common cause of hypoglycemia. Basically, it develops if a patient who regularly injects himself with insulin skips meals, drinks alcohol, and begins to exercise. Sometimes the cause is a violation of the injection technique, an accidental or deliberate overdose of insulin.
  • Hyperinsulinism. Secretion into the blood of an inadequately large amount of insulin by pancreatic beta cells occurs with insulinoma, hyperplasia of the islets of Langerhans (nesidioblastosis). Also, the causes of excessive production of insulin and insulin-like growth factor are some malignant tumors (carcinoma, mesothelioma). Hypoglycemia can occur in the presence of insulin autoantibodies that bind to insulin receptors (Hirata disease).
  • Endocrine Disorders . Deficiency of the so-called contrainsular hormones, i.e. hormones with an antagonistic effect on insulin (cortisol, thyroxine, somatotropin) is observed in hypothyroidism, adrenal insufficiency, pituitary dwarfism.
  • Taking medication . In addition to insulin, other drugs can cause a decrease in glucose concentration. First of all, these include medicines used in type 2 diabetes (hyperglycemic agents), which stimulate the production of insulin by the pancreas - sulfonylurea derivatives (glibenclamide), glinides (repaglinide).
  • Operations on the digestive tract . Such surgical interventions on the digestive organs, such as resection of the stomach or the initial section of the small intestine, lead to dumping syndrome, due to the accelerated entry of undigested food into the intestine. As a result, there is insufficient breakdown and absorption of carbohydrates.
  • Hereditary diseases . These are severe metabolic diseases (glycogenosis, galactosemia, fructosemia), characterized by a genetically determined defect in the enzymes involved in the metabolism of carbohydrates (glycogen, fructose, galactose). As a result of enzyme deficiency, there is a violation of the conversion of glucose from other carbohydrates or the difficulty of its release from glycogen, which causes a drop in glycemia.

Chronic diseases predispose to the development of hypoglycemia, in which the clearance of hypoglycemic drugs that regulate blood glucose levels slows down - renal, hepatic insufficiency. The hypoglycemic effect of sulfonylurea derivatives is enhanced when they are taken simultaneously with sulfonamides, salicylates, and synthetic antimalarials. Hypoglycemia also contributes to slow gastric emptying (diabetic gastroparesis).

Pathogenesis

Glucose is the main energy substrate for the central nervous system. Therefore, the CNS is very sensitive to hypoglycemia. First, as a compensatory reaction, contra-insular hormones are released into the blood, including catecholamines (adrenaline, norepinephrine), which cause autonomic symptoms. If glucose continues to be low, neuroglycopenia occurs.

Brain cells (mainly the cerebral cortex, diencephalic structures) begin to experience energy starvation, all metabolic processes, redox reactions, etc. are inhibited in them. Persistent hypoglycemia affects the medulla oblongata, the upper parts of the spinal cord, which leads to inhibition of reflexes, convulsive readiness of the brain, impaired consciousness, coma. Pathological changes include edema, necrosis of certain parts of the brain.

Classification

The detection of hypoglycemia in a blood test is not always true. False, or pseudohypoglycemia, can occur with leukocytosis, erythrocytosis. Separately, transient hypoglycemia of newborns born from mothers with diabetes is distinguished. By severity, hypoglycemia is divided into mild, moderate, severe, along the course - into acute, subacute, chronic. According to etiopathogenesis, the following types of hypoglycemia are distinguished:

  • Skinny (spontaneous) . It develops with excessive secretion of insulin, an insulin-like factor and diseases accompanied by a deficiency of contrainsular hormones.
  • Reactive (postprandial) . Occurs 2-4 hours after eating. The reason is the early stage of diabetes, hereditary metabolic disorders, post-resection syndromes, autoimmune insulin syndrome.
  • induced . It develops in diabetes, is caused by the intake of alcohol, drugs.

 

Symptoms of hypoglycemia

The presence of symptoms and their severity may not correlate with the level of glycemia. The first symptoms are due to the activation of the sympathetic-adrenal system (release of adrenaline, norepinephrine). There is a sharp and strong feeling of hunger, muscle tremors, sweating. The cardiovascular system reacts with increased heart rate, increased blood pressure, angina pectoris pain in the heart. Neuropsychic symptoms join: anxiety, motor agitation, depressed mood or, conversely, a feeling of euphoria.

Characterized by paresthesia (tingling sensation of the lips, tongue, fingertips). This is the so-called adrenergic or vegetative syndrome. If hypoglycemia continues, neuroglycopenia develops. Concentration of attention, coordination of movements (ataxia) worsens, speech becomes slurred, blurry. The patient begins to fall asleep, he reacts poorly to external stimuli, sometimes there are photopsies (flashes of lightning before the eyes), visual hallucinations.

Tonic-clonic convulsive seizures, resembling epilepsy, indicate a deep depression of the nervous system and an extremely serious condition of the patient. The development of seizures precedes hypoglycemic coma. In individuals with chronic hypoglycemia (with insulinoma), the only clinical manifestation may be intermittent headache, which quickly stops after ingestion of a carbohydrate meal. With a decrease in glucose concentration at night, some patients experience disturbed sleep or nightmares. There are also atypical hypoglycemic symptoms - nausea, vomiting, bradycardia.

Complications

Severe hypoglycemia is characterized by a wide range of adverse effects with a high rate of death. The most common of these include cardiovascular complications (hypertensive crisis, myocardial infarction, stroke) due to the release of large amounts of catecholamines into the blood. Hypoglycemia can also cause life-threatening cardiac arrhythmias, such as paroxysmal ventricular tachycardia, which is caused by prolongation of the QT interval. Complications of profound hypoglycemia include cerebral edema, coma, respiratory arrest, and palpitations.

Diagnostics

Patients with hypoglycemia are managed by endocrinologists. At the initial appointment, the doctor asks the patient what medications he is taking, whether he has undergone any operations. During a general examination of the patient, attention is drawn to the moisture content of the skin, dilated pupils (mydriasis), inhibition of physiological reflexes (tendon, skin) and the appearance of pathological ones (Babinski's reflex).

Organic hyperinsulinism (insulinoma, nesidioblastosis) is characterized by Whipple's triad: attacks of spontaneous hypoglycemia, a decrease in glucose during an attack below 2.8, a rapid cessation of an attack by the administration of glucose or carbohydrate intake. The most difficult task is to establish the cause of hypoglycemia. For this, an additional examination is assigned, including:

  • Laboratory Research . Blood tests measure C-peptide, glucose-insulin ratio. In diabetes, a glucose tolerance test is performed, an analysis of glycated hemoglobin. The presence of anti-insulin antibodies, antibodies to insulin receptors is checked. The concentration of contrainsular hormones (thyroid stimulating hormone, free thyroxine, somatotropin) is being studied, an ACTH test is performed. The activity of enzymes of carbohydrate metabolism (glucose-6-phosphatase, phosphofructokinase, glycogen synthetase) is being studied.
  • provocative tests . Diagnosis with insulin is extremely difficult, so various provocative tests are often performed. The most informative is the test with a 72-hour fast. Stimulation tests for suppression of the C-peptide are also carried out after the administration of glucagon, leucine, tolbutamide.
  • ECG. On the electrocardiogram, sinus tachycardia, atrial, ventricular extrasystoles, lengthening of the QT interval are detected, sometimes paroxysmal ventricular tachycardia can be recorded. With the development of myocardial ischemia due to an excess of catecholamines, depression of the ST segment, a negative T wave is noted.
  • Visualization of insulinoma . Approximately 50% of patients insulinoma can be visualized using ultrasound and CT of the abdominal cavity. Multispiral tomography, intraoperative ultrasound have greater sensitivity. Selective pancreatic arteriography with the introduction of calcium gluconate and subsequent blood sampling to measure the level of insulin and glucose is recognized as a very effective diagnostic method.

Hypoglycemia should be differentiated from alcohol intoxication, epilepsy, autonomic crisis (panic attacks). It is also necessary to exclude ONMK. An excited mental state, pronounced motor restlessness must be distinguished from mental disorders (hysteria, psychosis). In diabetes, according to clinical signs, it can be quite difficult to differentiate a hypoglycemic coma from a hyperglycemic one.

 

Treatment of hypoglycemia

Conservative therapy

For the treatment of mild hypoglycemia, it is enough to take easily digestible carbohydrates - fruit juice, sweet tea, a few pieces of refined sugar. With a moderate and severe degree, the patient must be hospitalized in the endocrinology department, and with depressed consciousness and coma - in the intensive care unit, where the following is performed:

  • Relief of hypoglycemia . A glucose solution is injected intravenously, if the patient does not regain consciousness, its drip administration continues. Intramuscular administration of glucagon is also effective (except for hypoglycemia caused by alcohol and sulfonylurea derivatives). Ascorbic acid is used to improve the utilization of glucose by neurons. In order to prevent cerebral edema in severe patients, magnesium sulfate, dexamethasone, diuretics (mannitol or furosemide) are used.
  • Treatment of the underlying disease . If the cause of hypoglycemia is a deficiency of contrainsular hormones, hormone replacement therapy (hydrocortisone, fludrocortisone, L-thyroxine) is performed. In autoimmune insulin syndrome, glucocorticosteroids, immunosuppressants, and plasmapheresis sessions are used. For the treatment of malignant insulin in the presence of contraindications to surgery, the drug streptozocin is prescribed, which causes the death of pancreatic beta cells. To improve the motor-evacuation function of the stomach in diabetes, prokinetics (itopride) are used.

Surgery

The most effective treatment for insulin and nesidioblastosis is surgery. In 90% of cases, the operation can achieve a complete cure for the disease. The method of choice is tumor enucleation. Sometimes resection of the head, body or tail of the pancreas is performed. As a preoperative preparation, a powerful inhibitor of insulin secretion, diazoxide, is prescribed. Hyperglycemia is possible within 72 hours after surgery. To prevent it, short-acting insulin is administered. After removal of extrapancreatic tumors, the level of glycemia normalizes very quickly.

Forecast and prevention

Despite a significant number of complications, in most cases, hypoglycemia has a mild or moderate severity. In diabetes, it occupies only 3-4% in the structure of mortality. Cardiovascular accidents (heart attack, stroke) are the main cause of death. To prevent hypoglycemia in diabetes, the patient must strictly observe the dosage, technique and frequency of insulin administration, do not skip meals, and avoid drinking alcohol.

When conducting insulin therapy, you need to regularly monitor the level of blood glucose with a glucometer, have fast-digesting carbohydrates with you for self-treatment of hypoglycemia. It is also necessary to correctly select the dose of hypoglycemic drugs, taking into account the function of the patient's liver and kidneys, and possible drug interactions. Patients with metabolic disorders (glycogenoses, galactosemia) are recommended to have frequent fractional meals with a large amount of carbohydrates.

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