Hypoglycemia in the elderly

Introduction to hypoglycemia in the elderly Senilehypoglycaemia refers to a group of syndromes in which the plasma glucose concentration is too low for various causes, sympathetic and adrenal medullary excitability and brain dysfunction. Symptoms are generally thought to occur when blood glucose is below 2.8 mmol/L (50 mg/dl). Older people are prone to hypoglycemic brain dysfunction. Hypoglycemia is divided into fasting hypoglycemia and postprandial hypoglycemia (ie, reactive hypoglycemia). The former is mostly pathological and the latter is mostly functional. basic knowledge The proportion of illness: 0.004% - 0.005% (more common in diabetic patients) Susceptible people: the elderly Mode of infection: non-infectious Complications: arrhythmia brain atrophy cerebral infarction

The cause of hypoglycemia in the elderly

Abnormal insulin secretion (35%):

1. Insufficient insulin secretion is increased in fasting state. Hyperinsulinemia such as islet B cell tumor secretes insulin independently and is not inhibited by hypoglycemia; excessive sulfonylureas stimulate insulin secretion from pancreatic islet B cells; and exogenous Excessive use of insulin.

2, after the islet B cell reactive secretion of insulin excess, such as the majority of stomach resection after eating a monosaccharide-rich liquid diet, glucose absorption is too fast, early postpartum (2 ~ 3h) hypoglycemia reaction; type 2 In the early stage of diabetes, especially those with obesity, the B cell response is delayed, the peak of insulin secretion lags behind the peak of blood glucose, and the hypoglycemia reaction occurs in the late postprandial period (4-5 hours).

Reduced glycogen output (10%):

Such as hepatitis, cirrhosis, hepatic congestion and liver cancer, such as liver cell destruction, liver glycogen storage decreased, gluconeogenesis decreased; fasting alcohol (especially patients with liver disease) when ethanol is oxidized to acetic acid, NADH / NAD + ratio increased, acetone The acid is converted into lactic acid, and the gluconeogenesis is reduced, resulting in hypoglycemia.

Pathogenesis

There is no glycogen stored in the brain and nerve cells, and the free fatty acids in the circulation cannot be utilized. Therefore, the energy supply depends entirely on the glucose in the blood circulation. Under normal circumstances, the blood glucose concentration fluctuates within a narrow range, and the fasting blood glucose in the morning is 3.3-5.0 mmol/ L (60 ~ 90mg / dl), mixed diet after blood glucose 6.7 ~ 7.2mmol / L (120 ~ 130mg / dl), glucose load after glucose does not exceed 8.9mmol / L (160mg / dl), fasting blood glucose mainly from glycogen Output (hepatic glycogenolysis and gluconeogenesis), postprandial blood glucose mainly comes from intestinal absorption, insulin secretion is increased or glucose absorption is reduced, blood glucose is lower than the lower limit of normal, hypoglycemia is excited by sympathetic and adrenal medulla, adrenaline, cortex Increased secretion of alcohol, growth hormone and glucagon, compensatory increase in blood sugar levels, such as hypoglycemia persists, impaired brain cell function, severe and long-lasting, can develop irreversible damage, coma, until death.

Elderly hypoglycemia prevention

Actively look for the cause of hypoglycemia, take targeted prevention, and eliminate the pathogenic factors can reduce and prevent the onset of hypoglycemia.

Elderly hypoglycemia complications Complications arrhythmia brain atrophy cerebral infarction

Can be complicated by arrhythmia, brain atrophy, cerebral infarction and so on.

Symptoms of hypoglycemia in the elderly Common symptoms Trembling diabetes fatigue skin pale tachycardia palpitation fasting hypoglycemia triad gangster coma

The clinical manifestations of hypoglycemia, the severity of symptoms and the rate of blood glucose decline, the degree and individual differences have a great relationship, hypoglycemia first excited sympathetic and adrenal medulla, and then impaired brain function, the elderly are poor tolerance to hypoglycemia, and sympathetic The neuronal and adrenal medulla are less reactive or absent, and are prone to varying degrees of brain cell function damage.

1, sympathetic and adrenal medullary excitement

It is characterized by hunger, palpitation, weakness, trembling, sweating, pale skin, tachycardia and elevated blood pressure. These reactions have an "alarm" effect.

2, brain dysfunction

The location of impaired brain function is cortex, subcortical center (basal ganglia, hypothalamus), brain stem (middle brain, medulla), first of all, lack of concentration, fatigue, headache, irritability, slow thinking, Insanity, then hyperalgesia, clonic and dance-like movements, dilated pupils, epileptic seizures, and finally into the coma phase: various reflexes disappear, pupils shrink, muscle tone is low, breathing is weak, blood pressure drops, such as low If the blood sugar is corrected in time, it can be reversed in sequence.

Elderly hypoglycemia check

1, blood sugar

Blood glucose below 2.8mmol / L can be identified as hypoglycemia, but hypoglycemia is often paroxysmal, one or two normal blood glucose can not rule out the disease, so should check the fasting, blood sugar at the time of attack to determine hypoglycemia .

2, plasma insulin

Blood insulin level is an important basis for the diagnosis of etiological factors. In the onset of hypoglycemia, blood should be taken at the same time to detect insulin levels, which is clinically significant when blood sugar is low and insulin levels are high.

(1) blood insulin (U / ml) / blood glucose (mg / dl) ratio: normal value of this value <0.3, if the ratio of blood glucose <50mg / dl > 0.4 means that insulin is not excessively secreted, common in islets Cell tumors should be noted that a negative result does not have a negative meaning, and should be checked and calculated multiple times for suspicious persons.

(2) Insulin release index = [blood insulin (U / ml) × 100] / [glycemic (mg / dl) -30], use the expansion of blood insulin value, reduce blood glucose values to increase the sensitivity and accuracy of diagnosis of hypoglycemia It is more suitable for patients with low blood sugar and low insulin. Normal people <50, obese <80, >80 means that insulin is not properly secreted, especially islet cell tumors are higher than 100 or even 150.

3, blood proinsulin / total insulin

Normal <15%, insulinoma patients due to insulin synthesis is strong, more insulin is not released into insulin, it is released into the blood, so the value is increased.

4, glucose tolerance test

There are two ways to understand the dynamic changes in blood glucose and insulin, namely the 5h oral glucose tolerance test (OGTT) and the 3h intravenous glucose tolerance test (IVGTT).

Oral Glucose Tolerance Test (OGTT): Oral glucose powder 1.75g/kg on a fasting day, the total amount does not exceed 75g, blood glucose and insulin levels before and after taking sugar for 30min and 1, 2, 3, 4, 5h, the whole Test 5h, blood collection 7 times, this method is commonly used.

3h intravenous glucose tolerance test (IVGTT): fasting intravenous glucose 0.5g / kg, the total amount does not exceed 50g, blood glucose and insulin levels before injection and 30min and 1, 2, 3h after injection, the whole experiment 3h, blood collection 5 times , the characteristics of hypoglycemia glucose tolerance blood glucose curves of different causes.

5, starvation test

For patients without typical hypoglycemia, this trial is feasible to induce hypoglycemia. Normal or functional hypoglycemia can tolerate this test, and more than 90% of insulinoma patients increase exercise after 24 hours of fasting or 2 hours before termination. To stimulate hypoglycemia, a few need to delay until 48 ~ 72h to attack, blood sugar <50mg / dl in the presence of hypoglycemia, while insulin levels do not decline, calculate the insulin / blood sugar ratio increased (> 0.4), this experiment is simple and easy, However, this test must be performed under the supervision of a doctor. Once hypoglycemia occurs during the test, blood and insulin should be taken immediately, and the patient should be fed or injected with high-density sugar to terminate the test.

6. Stimulation tests include

Includes D860 and glucagon test.

(1) Tolbutamide (D860) test: There are two methods: 1 oral method: daily carbohydrate intake of not less than 300g on the 3rd day before the test, fasting after dinner on the day before the test, oral D860 on the morning of the test 2.0g, blood glucose and insulin were taken at 0.5, 1, 2, 3h after fasting and taking the drug. The patient's blood glucose decreased to less than 40% of the fasting in 0.5~1h, and still could not be recovered after 2~3h, often induced hypoglycemia, 2 Intravenous method: D860 1g sodium salt is dissolved in 20ml water for injection, intravenous injection within 2min, blood glucose is taken every 5min, insulin is 3 times, such as insulin >195U/ml, suggesting the possibility of insulinoma.

(2) Glucagon stimulation test: 6~8h after fasting or eating, blood is taken first, then insulin is measured every 5 minutes after intravenous injection of glucagon 1mg, such as greater than 135U/ml, suggesting the possibility of insulinoma .

The above-mentioned challenge test induces hypoglycemia by stimulating a large amount of insulin secretion, which is dangerous to the patient. Therefore, the indications should be strictly controlled and performed under the supervision of a doctor.

7, C peptide inhibition test

After intravenous insulin (0.1U/kg), hypoglycemia is caused to inhibit the release of C-peptide, and the inhibition rate is 50%, which is normal. If it is not inhibited, it suggests an insulinoma that is secreted by itself.

Imaging examination: For adenomas with large islets, ultrasound and CT can be used for tumor localization, but most tumor tumors are small (mostly between 5.5 and 10 mm in diameter), selective pancreatic angiography and portal vein, spleen can be used. Intravenous catheter blood was taken to determine insulin and C-peptide content for preoperative localization.

Diagnosis and diagnosis of hypoglycemia in the elderly

Diagnostic criteria

1, determine low blood sugar

Based on the Whipple triad:

(1) Clinical manifestations of hypoglycemia.

(2) The blood glucose at the time of onset is lower than 2.8mmoL/L (50mg/dl), or it is significantly reduced in a short period of time before the onset.

(3) Symptoms are quickly relieved after sugar supply, and Article 2 is essential.

2, the cause of hypoglycemia diagnosis

(1) Islet B cell tumor:

1 Symptoms: Repeated episodes of fasting hypoglycemia, mild obesity.

2 blood sugar: blood sugar at the time of attack is less than 2.8mmol / L (50mg / dl), if suspected islet cell tumor and fasting blood glucose is not obvious, can be used for starvation test, that is, about 2 / 3 patients with low blood sugar after fasting for 12 ~ 18h At 3.3mmol/L (60mg/dl), almost 100% hypoglycemia occurred after fasting for 24~36h, and insulin did not decrease. If the blood glucose was greater than 3.3mmol/L after 72h fasting, no hypoglycemia could rule out insulin. tumor.

3 insulin release index = fasting blood insulin concentration (U / ml) / fasting blood glucose concentration (mg / dl), normal value is less than 0.3, insulinoma patients greater than 0.4, often greater than 1.0.

4 insulin release index correction index = insulin concentration (U / ml) × 100 / [glycemia concentration (mg / dl) -30], the normal value is less than 50U / mg, greater than 85U / mg suggest this disease.

5 imaging examination: pancreatic ultrasonography, CT and selective superior mesenteric artery celiac artery angiography.

6 laparotomy: insulinoma is mostly located in the pancreas, ectopic patients are very few, 84% are benign adenomas, diameter 0.5 ~ 5cm, 83% are single, 13% are multiple, the tumor is mostly gray or purple, blood The supply is rich and soft, and the blood glucose rises obviously within 30 minutes after resection of the tumor. Other pathological types are rare, such as B cell proliferation and B cell carcinoma, and the latter may have hilar lymph nodes and intrahepatic metastasis.

(2) extra-islet tumors

Mainly found in tumors originating from epithelial tissues, such as liver cancer, pancreatic cancer, adrenal cancer, bronchial lung cancer, digestive tract carcinoid, etc., followed by tumors originating from interstitial tissues, such as fibrosarcoma, neurosarcoma, rhabdomyosarcoma, leiomyosarcoma, Lymphoma, leukemia and multiple myeloma can be diagnosed by imaging and specialist examinations.

(3) Other pituitary, adrenal insufficiency diagnosis is seen in the relevant section, in addition to the history of major gastrectomy, drinking history, insulin injection and oral sulfonylurea hypoglycemic history contribute to the diagnosis of hypoglycemia, early type 2 diabetes The hypoglycemic response can be diagnosed by an extended oral glucose tolerance test (OGTT).

Differential diagnosis

1, nervous, mental system diseases

When hypoglycemia is mainly manifested as central nervous system symptoms such as epileptic seizures, disturbance of consciousness, confusion, and abnormal behavior, it is easily misdiagnosed as neurological and psychiatric diseases. If blood glucose can be checked in time, low blood sugar is found to contribute to hypoglycemia. diagnosis.

2, other causes of coma

Hypoglycemia coma can be confused with other causes of coma such as diabetes with ketoacidosis or hyperosmolar coma, cerebrovascular accident, hepatic encephalopathy, etc. It is important to check blood sugar levels.

3, neuropathic weakness

This disease has anxiety, anxiety, fatigue, neuroticism, etc., but the appearance of symptoms has nothing to do with blood sugar levels.

4, non-hypoglycemia syndrome

The patient may have symptoms such as fatigue, apathy, dullness, paralysis, palpitations and the like, but the blood sugar is not low, and the symptoms are not improved after taking the sugar.

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