Amyloid cardiomyopathy

Introduction to amyloidosis Amyloidosis is a disease in which myocardial dysfunction caused by the deposition of amyloid protein uniformly stained with hematoxylin-eosin in myocardial tissue. basic knowledge The proportion of illness: 0.0006%--0.0007% Susceptible people: no special people Mode of infection: non-infectious Complications: congestive heart failure, arrhythmia, angina

Causes of amyloidosis

(1) Causes of the disease

Clinically, it is generally divided into primary and secondary: it occurs in tuberculosis, rheumatoid arthritis, ulcerative colitis, chronic osteomyelitis, chronic suppurative and wasting disorders, or occurs in multiple myeloma. Secondary amyloidosis; if there is no above cause, it is a primary amyloidosis, which is mostly related to heredity.

Amyloidosis is a pathological noun. It refers to the accumulation of a large number of fibrous substances with glycoprotein properties. The main protein components are immunological light chain protein (AC), non-immune amyloid (AA), calcitonin-like protein. (AEI) and four types of plasma pre-protein (SA) of senile amyloidosis.

1. AC-induced amyloidosis is the most common amyloidosis in clinical practice, more common in primary, systemic amyloidosis, caused by immunoglobulin degradation defects or synthetic defects, such amyloids are abnormal clones. Secreted by beta cells; mainly involving the heart, tongue, stomach, muscles, tendons and skin, in addition, liver, spleen, kidney, adrenal gland and thyroid can also be affected.

2. AA-induced amyloidosis is called secondary amyloidosis, often caused by tuberculosis, rheumatoid arthritis, ulcerative colitis, chronic osteomyelitis, chronic suppurative diseases and other chronic infectious diseases, or multiple myeloma It is caused by the inflammatory reaction of macrophages phagocytizing serum AA protein and causing it to be decomposed, mainly involving kidney, liver, spleen and adrenal gland. In addition, it is still associated with atrial myxoma formation.

3. AEI-induced amyloidosis is more common in medullary thyroid carcinoma.

4.SA-induced amyloidosis of the heart, pancreas, prostate and brain are the main affected parts, especially in the elderly, so the clinical is called senile systemic amyloidosis.

(two) pathogenesis

Pathogenesis

(1) Optical microscopy (light microscopy) of starch-like deposits: light-mirror-like starch deposits showed no qualitative, hematoxylin and eosin staining was eosinophilic, and stained with crystal violet, Congo Red has affinity, and it can produce specific green birefringence by observation with a polarizing microscope of Congo red stained specimens.

(2) Ultrastructure of starch-like deposits: Electron microscopic observation of amyloidosis has two different forms of components: one is a small fiber component; the other is a pentagonal substance (referred to as P component), and the small fiber is about 10 nm ( 100Å), broad, unbranched, thin and hard, laterally arranged into fibrils, all amyloid proteins in a beta-folded configuration, explaining the green birefringence characteristics of amyloid deposition under Congo red staining.

The P component of amyloid deposits is a dough-like structure formed by five globular subunits around a central cavity. It has a diameter of 8 nm (80 Å) and has a circumference of 4 nm (40 Å). The composition may be immunoglobulin, endocrine, senile, familial and unidentified sources, etc., can be divided into systemic, focal, or hereditary, acquired, hereditary can be systemic, also It can be focal; so is acquired.

2. Pathological ventricular hypertrophy, amyloid deposits are diffusely deposited in cardiomyocytes, causing dystrophies in cardiomyocytes, atrophy or cardiomyocytes completely replaced by amyloid-like substances, electron microscopy shows that amyloid-like fibers are loosely distributed in the extracellular space. Away from the arrangement of cell fibers, the fibers and cell membranes close to the cardiomyocytes are oriented vertically or parallel. The involvement of small coronary arteries can cause angina pectoris. The heart valve can be thickened after being affected. The heart involvement is more common in primary amyloidosis. Secondary systemic amyloidosis and familial myocardial amyloidosis.

Histological infiltration of starch can cause pressure atrophy and organ dysfunction of substantial cells, regardless of whether the cause of amyloidosis is primary, secondary or with myeloma or familial, the formation of amyloid deposits The effects on organs are consistent, and the manifestation of restrictive cardiomyopathy can be manifested by significant myosin infiltration caused by which type of amyloidosis syndrome.

Amyloidosis cardiomyopathy prevention

prevention:

1. Because the cause of amyloidosis is unclear, there is no way to prevent primary amyloidosis.

2. Secondary amyloidosis can only cause inflammatory diseases of amyloidosis by prevention or effective treatment.

Amyloidosis cardiomyopathy Complications congestive heart failure arrhythmia angina

The disease may have complications such as congestive heart failure, arrhythmia and angina pectoris.

Symptoms of amyloidosis cardiomyopathy Common symptoms Atrioventricular block Pathological Q wave dyspnea conduction block Amyloidosis transition zone R wave increasing poor

A small amount of amyloid deposits in the heart is quite common, clinically asymptomatic, and has little effect on cardiac function. In many depositions, cardiac systolic and diastolic dysfunction can be caused by cardiac stiffness. The following clinical manifestations can be seen:

1 restricted cardiomyopathy: the most common, manifested as right heart dysfunction and peripheral edema, no paroxysmal paroxysmal dyspnea and sitting breathing, due to ventricular stiffness, can cause left ventricular diastolic early filling speed slowed, but different In the case of constrictive pericarditis, the latter's left ventricular diastolic early filling often increases, which can be identified.

2 congestive heart failure: more common, common people have palpitations, shortness of breath, wet sounds of the two lungs, caused by decreased myocardial contractile function, with the disease worsening, heart failure symptoms can be progressively worse, more than conventional treatment can not Work,

3 orthostatic hypotension: about 10% of patients may have orthostatic hypotension, mostly caused by vascular and autonomic amyloidosis. In addition, studies have found that it is associated with cardiac and adrenal amyloidosis.

4 arrhythmia: quite common, the detection rate is about 50% to 85%, the lesions involving the conduction system, mostly manifested as bundle branch block, high atrioventricular block and paroxysmal sinus rest, in addition, and Detection of paroxysmal supraventricular tachycardia, atrial fibrillation, frequent ventricular premature contractions, and even ventricular tachycardia and ventricular fibrillation,

5 angina pectoris: amyloidosis involving the coronary artery can cause angina pectoris, about 80% of patients with chest lead lead pathological Q wave or transition zone R wave is poor,

6 physical examination can be found in the jugular vein filling, Kussmaul (Kussmaul) sign, extra heart sounds during diastole, sometimes mistaken for pericardial snoring, some cases may have mitral regurgitation heart murmur, indicating valve infringement .

There are four types of clinically easy to invade the heart:

1. Primary systemic amyloidosis occurs in middle-aged and elderly people. The average age at diagnosis is divided into two groups of 55 years old and 62 years old. Men are prone to have a monoclonal immunization in the blood or urine. There are more globulin and myeloma plasma cells, and the clinical manifestations of the disease vary widely, but generally have the following symptoms:

1 idiopathic sensorimotor peripheral neuropathy with autonomic neuropathy;

2 restrictive myocardial lesions with low voltage and conduction disorder of ECG without other causes;

3 non-thrombocytopenic purpura with skin induration, squeezing purpura and rectum after purpura;

4 types of rheumatoid arthritis symptoms and significant large joint lesions (shoulder pad sign);

5 giant tongue disease; 6 bleeding tendency, secondary to the lack of isolated acquired factor X;

7 special nephrotic syndrome;

8 male patients with carpal tunnel syndrome, if the above clinical syndrome, should consider primary systemic amyloidosis.

2. Secondary systemic amyloidosis refers to lesions secondary to various chronic infectious, inflammatory or neoplastic diseases. The precise incidence of secondary systemic amyloidosis is difficult to count, rheumatoid joints. Inflammation is the most common predisposing factor, followed by chronic infection.

3. Multiple myeloma with amyloidosis multiple myeloma with amyloidosis age distribution, gender differences and clinical manifestations are very similar to primary systemic amyloidosis, 6% to 15% of patients with myeloma can develop starch Degeneration, most patients with amyloidosis have immunoglobulin paraprotein in their serum, and this week protein and proteinuria, a large number of free light chains in the blood, directly related to the formation and dissemination of starch-like deposits, The ratio of K and light chains is different from primary systemic amyloidosis, which is dominated by gamma light chain (this week protein).

4. Familial cardiac amyloidosis Skinnel reported in 1991 that five members of the siblings in Denmark have amyloidosis, myocardial lesions, symptoms of congestive heart failure after 40 years of age, and lesions develop through 2-6 Years of death, hemodynamic studies were consistent with restrictive cardiomyopathy, and 3 of the same relatives had persistent atrial arrest, clinical manifestations of bradycardia, lack of P waves, enlarged heart, and mild heart failure.

Amyloidosis cardiomyopathy

Endomysm myocardial histology is still the gold indicator for the diagnosis of amyloidosis cardiomyopathy. Any polarized microscope can be diagnosed by the characteristic green birefringence of Congo red staining tissue. If it is systemic amyloidosis, it is not suitable. For patients undergoing myocardial biopsy, histological examinations such as rectal, kidney and liver should be performed as appropriate.

1. Electrocardiogram almost all patients have abnormal electrocardiogram, low voltage, ST-T changes, sinus tachycardia, arrhythmia with atrioventricular block, and bundle branch block, premature beat, Atrial fibrillation, occasionally Q wave or myocardial infarction pattern.

2. X-ray chest radiographs often show normal heart size, when the pericardial effusion, the heart shape slightly increased.

3. The main performance of echocardiography:

1 except that the left ventricular internal diameter is normal or small, the ventricular chambers are enlarged;

2 compartments and ventricular wall thickening, and symmetry;

3 compartment flaps or papillary muscles may also be thickened or thickened due to lesion involvement;

4 about half of the pericardial effusion;

5 About 92% of patients thickened in the myocardium, there are scattered circular or irregular strong reflection small spots, which is a characteristic manifestation of this disease. In order to better recognize this spot, the sternum is generally taken. Long-axis view and short-axis view, instead of taking the apical four-chamber view, it is believed that this strong reflection small spot is caused by nodules formed by colloidal and amyloid tissue.

In addition, echocardiography was helpful in judging the severity of the disease. In a study of echocardiography in 27 patients with systemic starch disease, 14 patients had an increase in myocardial weight. These patients often had heart rhythms. Abnormal and progressive heart failure, and 13 patients with only a slight increase, the above clinical manifestations were not observed for 2 consecutive years. 132 patients with primary systemic amyloidosis confirmed by biopsy were divided into 4 under ultrasound. Group: Group I ventricular wall thickness 12mm; Group II > 12mm but 15mm; Group III > 15mm; Group IV with wall motion abnormalities, the study showed that the thicker the ventricular wall, the lower the systolic function.

4. When the cardiac catheter was examined for amyloidosis, the ventricular diastolic blood pressure increased, and the pressure curve decreased in the early stage of diastole, and then suddenly increased, and the plateau was square-shaped.

5. Magnetic resonance examination is very valuable for diagnosing amyloidosis in various tissues and organs of the whole body. The signal of affected organs is obviously increased, while the subcutaneous fat is obviously attenuated.

Diagnosis and differential diagnosis of amyloidosis

Patients over the age of 50, have clinical manifestations of primary systemic amyloidosis or other diseases are prone to amyloidosis, such as progressive refractory heart failure, X-ray chest shows that the heart does not expand, echocardiography Left ventricular cavity is small, left ventricular posterior wall and ventricular septal thickening, should be highly suspected as amyloidosis cardiomyopathy, the diagnosis depends on endocardial myocardial biopsy, unconditional endocardial myocardial biopsy patients, rectal mucosa and Kidney biopsy also helps to confirm the diagnosis.

Need to be identified are: constrictive pericarditis, idiopathic restrictive cardiomyopathy, idiopathic hypertrophic cardiomyopathy, coronary atherosclerotic heart disease, senile degenerative heart disease.

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