Hypothyroid heart disease in the elderly

Introduction to hypothyroid heart disease in the elderly Hypothyroidism (hypothyroidism) is an endocrine disorder caused by a series of symptoms and signs such as decreased thyroxine synthesis, insufficient secretion or insufficient biological effects, decreased myocardial contractility, decreased cardiac output and decreased peripheral blood flow. Sexual heart disease. basic knowledge The proportion of illness: 0.005% Susceptible people: the elderly Mode of infection: non-infectious Complications: pericardial effusion, angina pectoris, myocardial infarction

The cause of hypothyroidism in the elderly

Low basal metabolism (30%):

In patients with insufficient synthesis or secretion of thyroxine, the metabolic rate of various organs and tissues of the body is reduced, resulting in retention of water and sodium, increased capillary permeability of the tissue and slowing of local lymphatic reflux, and hydrophilic mucopolysaccharide due to local mucinous edema. Mucin accumulation, causing myocardial edema and serous effusion, of which the most important is pericardial effusion, the incidence of hypothyroidism in the early years reported 30% to 80%, in recent years, with the improvement of analytical techniques can be found early Light or even asymptomatic hypothyroidism patients, so the incidence of pericardial effusion decreased, but there are still many patients with hypothyroidism with pericardial effusion as the first symptom, hypothyroidism pericardial effusion is mostly small, can be medium to large, Slow growth, even if a large amount of pericardial effusion, less pericardial tamponade, patient heart rate slowdown and stroke volume reduction, cardiac output decreased, peripheral blood volume decreased, blood flow velocity slowed, cycle time extended, in order to maintain heat The skin blood vessels are in a contracted state and the peripheral resistance is increased.

Myocardial lesions and heart failure (15%):

Hypothyroidism, thyroid hormone deficiency, myocardial many enzyme activities are inhibited, and others found that myocardial sarcoplasmic reticulum function and sarcoplasmic globulin adenosine triphosphate activity decreased during hypothyroidism, resulting in myocardial invariability, variable shifting effect, myocardial pair Decreased sensitivity of catecholamines or decreased myocardial catecholamine receptors causes non-specific myocardial lesions in the myocardium, and the heart expands into a globular shape, which promotes hypothyroidism.

Hyperlipidemia and arteriosclerosis (15%):

Fat metabolism changes during hypothyroidism. The normal cholesterol half-life is about 75 days, and the hypothyroidism is extended to 150 days. This may be the cause of the increase in blood cholesterol in this disease, and it is also a risk factor for coronary heart disease.

High blood pressure (10%):

Among the patients with hypothyroidism, 7.8% to 25% of the patients have elevated blood pressure, and after treatment with thyroxine, the blood pressure is significantly reduced. The cause of hypertension is presumed to be related to the following factors:

(1) Hyperlipidemia promotes arteriosclerosis leading to the formation of hypertension.

(2) The basal metabolic rate is reduced, the effective circulating blood volume is insufficient, and the peripheral vascular compensatory contraction.

Arrhythmia (10%):

Myocardial sensitivity to adrenaline and norepinephrine decreased during hypothyroidism, and tissue oxygen consumption decreased and metabolic rate decreased, bradycardia was more common, followed by atrioventricular block, in addition, hypothyroidism can cause QT Prolonged period, severe cases of ventricular arrhythmia, such as torsade ventricular tachycardia, recurrent atrial fibrillation, hypothyroidism corrected, QT interval can return to normal.

Elderly hypothyroidism prevention

Primary prevention

Avoid hypothyroidism by preventing various causes, including prevention of Hashimoto's thyroiditis, avoiding iodine deficiency or iodine deficiency, proper amount of radioactive iodine treatment for Graves' disease, avoiding antithyroid drug overdose, and other hypothyroidism Long-term overdose of drugs such as p-aminosalicylic acid, phenylbutazone, potassium perchlorate, cobalt, lithium and amiodarone, in recent years, amiodarone is common in the treatment of arrhythmias in the elderly, amiodarone versus thyroid The function has three functions: first, it is combined with thyroid receptors in the nucleus to counteract thyroxine; secondly, it inhibits the conversion of peripheral T4 to T3, so long-term medication can cause a decrease in serum T3 levels and transient TSH. High; third, the drug contains 35% iodine (by weight), which produces a large amount of inorganic iodine when metabolized in the body, leading to inhibition of organic iodine iodine. Patients taking this drug may have hypothyroidism (more US) See), there are many reports in the country, so the elderly patients with long-term amiodarone should be reviewed regularly for thyroid function.

2. Secondary prevention

Early detection, diagnosis of sick elderly, regular (six months to 1 year) physical examination is very important, especially for receiving radioactive iodine treatment and taking anti-thyroid drugs or taking p-aminosalicylic acid, phenylbutazone, potassium perchlorate, amine iodine High-risk elderly people with ketones should be tested for thyroid function regularly (3 months to 6 months).

3. Three levels of prevention

For the elderly with a clear diagnosis, thyroxine replacement therapy should be given to reduce the incidence of morbidity and hypothyroidism, and the incidence of cardiac complications.

In patients with senile hypothyroidism, if the course of disease is longer, the heart performance is very prominent, the incidence rate is 70% to 80%. In addition to sinus bradycardia, there is still heart enlargement, pericardial effusion, far heart sound, and high blood pressure. Concurrent atherosclerosis, etc., often resembles hypertension, coronary heart disease or cardiomyopathy, which is easily misdiagnosed, resulting in untimely treatment, sometimes life-threatening, and once diagnosed and treated promptly, the prognosis is good.

Complications of hypothyroidism in the elderly Complications, pericardial angina, myocardial infarction

Concurrent pericardial effusion is common, a small number of myocardial oxygen consumption increased after treatment, but induced angina pectoris, myocardial infarction and so on.

Symptoms of hypothyroidism in the elderly Common symptoms Fatigue loss of appetite, chest tightness, weakness, sleepiness, arrhythmia, slow response, dyspnea, ataxia, dry skin

Age-related hypothyroidism is insidious, slow progress, sometimes advanced, and clinical manifestations are not obvious. Only a small number of patients have characteristic clinical manifestations and signs, such as fatigue, dullness, depression, myalgia, constipation and dry skin, but Sometimes even if the above performance is often considered to be caused by aging, it is easy to miss diagnosis and misdiagnosis.

General symptoms

Activity ability decline, dullness, depression, lack of lazy words, stomach cold and sweat, body temperature is lower than normal, hoarseness, deafness and taste loss, loss of appetite and weight loss or increase.

2. Face and skin

Typical mucinous edema often presents apathy, pale complexion, edema of the eyelids, thick lips and thick tongue, dry and thickened skin, and rough and desquamation. It is non-invasive edema. The skin can be pale yellow due to anemia and caroteneemia. Because of the increase of cholesterol in the blood, occasionally yellow tumors appear, the hair is sparse and dry, brittle and dull, slow growth, and even stop growing, the eyebrows are sparse, the outer 1/3 falls off, and a few patients have thick and brittle nails and many cracks.

3. Mental nervous system

Memory loss, mental retardation, unresponsiveness, lethargy, depression, sometimes worrying and neurotic manifestations, severe cases can appear mental disorders, stupor and dementia, and even coma, sensitive to sedatives, can induce coma after taking, mucin deposition When cerebellar dysfunction occurs, ataxia, nystagmus, etc. occur.

4. Muscle and joint system

Mainly manifested as weak muscle weakness, but also temporary muscle rigidity, sputum, pain, etc. Occasionally myasthenia gravis, muscle rigidity and myalgia are common, muscle relaxation after flaccid delay, loosening after fist fisting, bone metabolism is reduced, bone Both formation and absorption are reduced, bone density is increased, and patients with mucinous edema may be associated with joint disease and occasional joint effusion.

5. Cardiovascular system

(1) general cardiovascular manifestations of palpitations, chest tightness, fatigue, labor dyspnea, severe cases may occur in sitting breathing, bradycardia common, generally 50 times / min, heart expansion, heart sounds low blunt, heart shadow enlargement It can be caused by interstitial edema, pericardial effusion or heart dilatation. It can also be the common result of the above three reasons. Sometimes the heart enlargement is not obvious at the time of initial diagnosis, but after thyroxine replacement therapy, the heart is obviously reduced, and the cardia has been enlarged before. .

(2) pericardial effusion: 80% of hypothyroidism has pericardial effusion, large amount of effusion, but because of its slow, generally does not cause pericardial tamponade, high proportion of pericardial effusion, containing high concentrations of protein and Cholesterol, with a small number of cells, sometimes accompanied by pleural effusion and ascites, is a non-inflammatory effusion, which may be due to increased capillary permeability and accumulation of local mucinous mucopolysaccharides and mucins. It is confirmed that the pericardium is particularly sensitive to thyroxine. Once the thyroxine is deficient, the mucopolysaccharide is exuded out of the blood vessels, and effusion occurs soon. After thyroidectomy in patients with thyroid cancer, if thyroid hormone replacement therapy is not used, the pericardial dysfunction is obtained after 2 weeks. liquid.

(3) secondary cardiomyopathy: patients with hypothyroidism may have enlarged heart, due to cardiac mucinous edema, interstitial edema, myocardial fibrosis, resulting in myocardial relaxation, contraction weakness, the formation of so-called myocardial pseudohypertrophy, clinically There may be arrhythmia, atrioventricular block or heart failure. Older patients with hypertension and arteriosclerosis are more difficult to distinguish from coronary heart disease. After treatment with thyroxine, the heart can be significantly reduced.

(4) Heart failure: People with hypothyroidism rarely have congestive heart failure. This is because although the myocardial contractility is reduced and the cardiac output is reduced, it can still meet the already reduced metabolic needs of the body, sometimes the performance of heart failure. Mucinous edema is very similar, such as difficulty breathing, edema, serous effusion, heart enlargement, etc. If there is obvious heart failure, consider the presence of other organic heart disease.

(5) angina pectoris and myocardial infarction: patients with obvious coronary atherosclerosis, due to the parallel reduction of tissue oxygen consumption and cardiac output, angina and myocardial infarction rarely occur even if myocardial oxygen supply is reduced, but In the elderly, especially those with hypertension, the incidence should be increased. If angina pectoris occurs in thyroxine replacement therapy, it should be highly suspected of drug, and the dose must be reduced.

6. Digestive system

Patients with frequent tongue hypertrophy, decreased gastrointestinal motility caused by loss of appetite, anorexia, bloating, constipation, severe cases may have paralytic ileus or mucous edema of the megacolon, due to lack of stomach acid or vitamin B12 malabsorption, can cause iron deficiency anemia or Pernicious anemia.

Examination of hypothyroidism in the elderly

1. General examination: often have mild to moderate normal cell type and positive pigmented anemia, a small number can also see small cell hypopigmentation and large cell anemia, but hemoglobin is rarely <100g / L, the common cause of anemia may be iron, folic acid It is related to the deficiency of vitamin B12. In addition, thyroxine can stimulate bone marrow hematopoiesis to a certain extent. The lack of thyroxine will make the bone marrow hematopoietic function relatively inhibited, triglyceride increased, and HDL increased.

2. Thyroid function test

(1) Determination of basal metabolic rate: often less than -20%, about 80% of patients have a basal metabolic rate of -20% to 40%, and the degree of decline is often proportional to the severity of the disease. After the treatment is obtained, the basal metabolic rate increases. To the normal range.

(2) 131I rate of thyroid gland: hypothyroidism patients rarely have radioactive iodine accumulation, the 131I rate is lower than normal, showing a low flat curve, while the 131I excretion in urine increases.

(3) TSH measurement: due to the reduction of thyroid hormone, the feedback inhibition of pituitary TSH is reduced, so the secretion of TSH is increased, and the degree of increase reflects the degree of thyroxine decline in blood. It is the most sensitive indicator for the diagnosis of hypothyroidism. TSH is measured by radioimmunoassay. Normal people more <10U / ml, if TSH is normal, it can basically rule out hypothyroidism, mild hypothyroidism (subclinical hypothyroidism or compensatory hypothyroidism: increased TSH, normal T3 and T4, no hypothyroidism The performance of TSH is 5 ~ 15U / ml, the clinical hypothyroidism TSH is more than 20U / ml, in addition, TSH measurement is also valuable for the identification of primary hypothyroidism and secondary hypothyroidism, the primary hypothyroidism TSH increased, and Secondary hypothyroidism TSH is reduced or normal.

(4) T3 and T4 determination: including TT4, TT3, FT4, FT3 determination TT4 can be measured by radioimmunoassay, which includes binding and free T4, which is a direct measurement of thyroxine, and TT4 is often <3g/dl when hypothyroidism As early as the decline of TT3, the TT3 measurement has little value in the diagnosis of hypothyroidism. About 30% of patients with clinical hypothyroidism have normal TT3. In the late and severe cases, TT3 is reduced by <100g/dl, and anti-T3 is obviously decreased. Normal The value is (47±10)g/dl. The T4 and T3 secretion are insufficient in this disease, and the T4 is converted to T3 tends to increase to compensate for hypothyroidism, so that the anti-T3 decreases, often <20g/dl; FT4 can directly respond Thyroid function is the most reliable indicator for the diagnosis of hypothyroidism. The diagnostic coincidence rate is 100%. The diagnostic value of FT3 for hypothyroidism is lower than the diagnostic sensitivity of FT3 for hypothyroidism:

TSH FT4 > TT4 > FT3 > TT3.

3.TRH excitement test

It is mainly used to identify secondary or primary hypothyroidism. After intravenous injection of TRH 200-500g, TSH increases rapidly by 5~25U/ml under normal conditions, reaches a peak at 30min, and returns to normal at 120min, such as a delayed increase in TSH. , suggesting that the lesion may be at the level of the hypothalamus. If there is no increase in the response, the lesion may be in the pituitary, such as TSH is higher, and after TRH stimulation, it is suggestive of primary hypothyroidism.

4. Determination of thyroid autoantibodies

Serum TGAb, TPOAb and TBAb were positive in patients with autoimmune thyroiditis, TGAAb, TPOAb positive rate was 50%-90%, and TBAB positive rate was 20%-30%.

Thyroid B ultrasound

In general, the clinical value of hypothyroidism is limited, and thyroid blood flow can be found to decrease.

2. Echocardiography

It can show pericardial effusion, decreased left ventricular diastolic and systolic function, and asymmetrical ventricular septal hypertrophy.

3. X-ray inspection

See the general increase in heart shadow, the perspective can be seen that the amplitude of the heart beat is reduced, or there is a sign of pericardial effusion.

Thyroid nuclides examination: There is a certain clinical value in the observation of hypothyroidism with thyroid enlargement. For example, the thyroid nuclide uptake in Hashimoto's thyroiditis is unevenly distributed.

In addition, the electrocardiogram showed sinus bradycardia, low voltage, T wave low or inverted, and the PR interval or QRS time limit was sometimes extended, sometimes with atrioventricular block.

Diagnosis and diagnosis of hypothyroidism in the elderly

Diagnostic criteria

A person who meets the following four criteria can be diagnosed with hypothyroidism:

1. Meet the diagnostic criteria for hypothyroidism.

2. Heart enlargement, pericardial effusion, performance of heart failure and abnormal electrocardiogram.

3. Cardiology other than other causes.

4. After thyroid hormone replacement therapy, it obviously improved or even recovered.

Because the elderly have a mild onset of hypothyroidism, many symptoms are often attributed to senile changes without paying attention. The cardiovascular system changes like heart disease, coronary heart disease or high heart disease, so it is easy to be misdiagnosed, so for the elderly People, especially women, with unexplained heart enlargement, pericardial effusion and electrocardiogram showed QRS low voltage and heart rate is not fast, should consider the possibility of hypothyroidism, need to do the corresponding examination.

Differential diagnosis

1. Identification of low thyroid hormone syndrome

Mainly need to be identified with less than T3 syndrome and adrenal insufficiency.

2. Identification of the cause of hypothyroidism

That is to distinguish between primary, central and peripheral hypothyroidism.

3. Identification of hypothyroidism and subclinical hypothyroidism

It is mainly determined based on the results of FT3, FT4 and TSH inspections.

4. Identification of common symptoms of hypothyroidism

It mainly includes edema, anemia, hypertension, serous effusion and abnormal liver function.

5. Identification with other system diseases

Such as delayed puberty, pituitary dwarf, nephrotic syndrome, coronary heart disease and pituitary tumors.

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