Pediatric Keshan disease
Introduction
Introduction to Pediatric Keshan Disease Keshandise (Keshandisease) is an endemic cardiomyopathy in China with unclear etiology. It was first discovered in Keshan County, Heilongjiang Province in 1935, so it is called Keshan disease. It is popular in Northeast China, Southwest China, Central South and other parts of China. The main clinical manifestations are acute or chronic heart failure accompanied by various arrhythmias. basic knowledge The proportion of illness: 0.02% Susceptible people: children Mode of infection: non-infectious Complications: A-S syndrome Syndrome shock Arrhythmia
Cause
The cause of pediatric Keshan disease
Soil and water diet (30%):
A large amount of data confirm that the incidence of Keshan disease is related to biogeochemical factors. Selenium deficiency may be the basic pathogenic factor of Keshan disease, but it is not the only factor. The lack of nutrients in diet is a more important cause of Keshan disease. One of them; other factors such as carbon monoxide poisoning can also be used as an inducing condition for the disease.
(1) Selenium deficiency: Selenium deficiency in water and soil in high-incidence areas and imbalance between selenium and molybdenum, magnesium, manganese and other trace elements are related to the pathogenesis of Keshan disease. The main basis is: low-concentration zone in high-incidence zone, low-selenium in foreign countries There are similar case reports; the selenium content in the water and soil and crop staple foods in the high-incidence area is significantly lower than that in the non-incidence area; the urine selenium, selenium and blood selenium in the high-incidence area are lower than the non-infected area; the incidence rate after selenium supplementation is significantly reduced It can prevent the occurrence of acute and subacute forms; there is no incidence of Keshan disease in the high selenium area, but it is also found that there is no Keshan disease in some low selenium areas; the selenium level of new cases has no significant difference with those who have not. In the high incidence season, there is no corresponding decrease in selenium levels in the ward; even in low selenium areas, the annual incidence rate is different; patients with different selenium levels have no significant differences in myocardial ultrastructural lesions, but all have mitochondrial intrinsic lesions, The facts show that low selenium is not the starting factor of Keshan disease.
(2) Lack of nutrients in the diet: Selenium supplementation can not prevent the occurrence of potential Keshan disease, and there are other chemical elements in the crops in high-incidence areas, except for the lack of selenium; The above facts indicate that in addition to selenium deficiency, the lack of certain amino acids and vitamins in nutrients may be involved in the pathogenesis of Keshan disease. The high vitamin E content in the high-incidence population is low, and the antioxidant capacity is decreased, which may be related to the pathogenesis of Keshan disease. Large-scale census found that the key to the incidence of high-risk population is diet structure and eating habits. The incidence of partial eclipse and irrational diet is high. At the same time, animal experiments show that the rats with high-incidence area feed the rats with myocardial parenchymal lesions. The rate of exit is high.
(3) Carbon monoxide poisoning: In the northern region, burning in winter and heating, easy to cause carbon monoxide poisoning, can cause myocardial hypoxia, aggravate myocardial damage, may also be related to the incidence of Keshan disease.
Biological cause (20%):
Keshan disease is a natural epidemic disease with a trend of infection, which is consistent with the characteristics of viral infection, but lacks evidence. The results of the virus isolation from the stool of Keshan disease patients, blood and autopsy specimens are very inconsistent, and even if the virus is isolated The positive rate was not high (16.3%). In 1997, Yang Yingzhen used PCR to detect enterovirus RNA in the endocardial biopsy or autopsy myocardial specimens of Keshan disease. The positive rate was 82.2%. Mountain disease is associated with certain cardiomyopathy infections. At present, most scholars believe that viral infection plays a role in compound pathogenic factors in the pathogenesis of Keshan disease.
Immune injury (20%):
The study found that there were IgG deposition in myocardial biopsy and autopsy specimens of Keshan disease. Anti-myocardial antibodies and anti-nuclear antibodies were detected in Keshan disease serum, and the titer of immune complexes was significantly increased, suggesting that immune damage may be related to Keshan disease. The incidence is related, but the consequences of immune damage is the causative factor or Keshan disease is not clear.
Membrane oxidative damage (10%):
Selenium deficiency and nutrient deficiency cause abnormal or insufficient enzymes, including oxygen radical scavengers such as superoxide dismutase. The increase of oxygen free radicals in the body leads to membrane oxidative damage, which reduces the antioxidant capacity of the membrane and causes myocardial mitochondria. disease.
Prevention
Pediatric Keshan disease prevention
Group prevention should be carried out, environmental sanitation should be improved, water quality and crops should be improved, dietary and living conditions should be improved, and the causes of the disease should be prevented, including prevention of intestinal and respiratory infections, avoiding overheating, excessive cold or overwork, and prevention of overeating and mental health. Stimulation, etc. In recent years, some wards have tried oral sodium selenite to prevent and treat this disease, which can reduce the acute attack and reduce the mortality rate of the disease. The usage is 0.5mg every 1~5 years old, 1mg, 6~9 years old, 10 2mg above the age, once a week, starting before the onset season, continuous taking 3 to 6 months, generally no adverse reactions, selenium poisoning reaction increased alanine aminotransferase, hematopoietic and coagulopathy, hair loss, dislocation, etc. The preventive effect of sodium selenite on this disease is unknown. It seems that selenium is an important component of glutathione oxidase and coenzyme Q10, which may be related to the tolerance of myocardial to hypoxia. Some areas use molybdic acid. Ammonium, selenium salt, and zinc salt fertilization can be used to prevent the disease and increase the yield of crops, which is worth exploring.
Complication
Pediatric Keshan disease complications Complications A-S syndrome Cardiogenic shock arrhythmia
Often complicated by heart failure, A-S syndrome, cardiogenic shock, arrhythmia, autonomic dysfunction, pleural and abdominal effusion, pulmonary infarction, cerebral infarction. Cerebral infarction is also called ischemic stroke, which is called stroke or stroke in Chinese medicine. The disease is caused by various causes of blood supply disorders in the local brain tissue region, leading to necrosis of hypoxic lesions in the brain tissue, which in turn produces clinically corresponding neurological deficits.
Symptom
Pediatric Keshan disease symptoms common symptoms pale pale irritability, arrhythmia, loss of appetite, abdominal pain, compression, small hair, abdominal cavity, effusion, chest pain, tachycardia
General symptoms and signs
The clinical manifestations of Keshan disease can be divided into 4 types according to the urgency and cardiac function status: acute type, sub-acute type, slow type, and latent type.
(1) Emergency type:
More common in children over 7 years old, due to extensive degeneration of the heart muscle, necrosis, cardiac output decreased sharply, mainly for acute cardiogenic shock, according to the condition is divided into mild, severe, often under a certain cause of sudden onset, severe A few hours to several days before the onset of the disease, the patient often has dizziness, headache, chest tightness, "heart discomfort", general weakness, and then nausea, vomiting, abdominal pain, polydipsia, cold sweat, cold limbs, irritability, dark face and other shocks Performance, after the symptoms of acute left heart failure such as dry cough, heart palpitations, shortness of breath, etc., some patients began to develop with paroxysmal abdominal pain, and some patients suddenly began to develop with repeated attacks of A-S syndrome, and some of the gastrocnemius pain was very obvious. In the early stage, the body temperature is reduced (about 35 °C). Only a few patients have a slight heat of more than 37 °C. The physical examination shows that the pulse is too fast or too slow, the hair is weak or unclear, the blood pressure drops, the pulse compression is small, or the pulse is completely undetectable. The heart is enlarged, the heart sound is blunt, the heart sound is weakened, especially the first heart sound is obvious, and there are many systolic murmurs within the level II, arrhythmia, variable heart rhythm and variability are its characteristics. You can hear galloping, the liver is enlarged, such as acute left heart failure, there are breathing difficulties, cyanosis, lung snoring, etc. In addition, the nervous system examination may have hyperreflexia of the knee, slow or disappear, and the abdominal wall reflection disappears. There may be manifestations of autonomic nervous disorder such as Pap smear and bilateral pupils with poor light reflection, high total number of white blood cells and neutrophils, rapid erythrocyte sedimentation rate, and myocardial damage manifested by electrocardiogram. If improper treatment may die soon, emergency The clinical manifestations of mild cases were only milder and less variable, and the cardiogenic shock was not obvious. The systolic blood pressure was above 12.0 kPa (90 mmHg).
(2) Sub-quick type:
It is the main type of Keshan disease in children. It is more common in children aged 2-6 years. The incidence is slightly slower than the acute type. The clinical manifestations are more acute congestive heart failure, and may be accompanied by different degrees of cardiogenic shock. Like feeling, lack of energy, fatigue, weakness, not love to play, irritability, easy to cry, loss of appetite, coughing later, increased shortness of breath, difficulty breathing, often accompanied by abdominal pain, nausea, vomiting, cold limbs, gray face, mouth Pale, red cheeks, eyelid edema, oliguria and other manifestations of increased heart failure, physical examination showed cyanosis, jugular vein engorgement, enlarged heart, arrhythmia, increased heart rate, gallop, liver enlargement, blood pressure Reduced, small pulse compression, both lungs often have a voice, severe cases may have chest, abdominal effusion, lower extremity edema.
(3) Slow type ( type):
This type has no seasonality, but it is more common in winter and spring. It has a slow onset and has a history of acute onset. It is mainly characterized by chronic heart failure. The child has chronic disease, poor growth and development, pale or slightly sputum, and apathetic Excessive fatigue, often dizziness, headache, cough, cough, difficulty breathing, abdominal distension, edema and oliguria, etc., often in the late stage, limbs are cold and cyanosis, physical examination shows enlarged heart, fast heart rate, irregular rhythm, The first heart sound is weakened and the systemic blood stasis, liver enlargement, edema, etc., the heart disease can cause heart failure due to cold, overwork, mental stimulation and other factors, when there is an acute clinical change, it is called slow acute attack, the above Type III patients sometimes cause pulmonary infarction due to thrombus detachment in the heart chamber, chest pain, hemoptysis, or cerebral infarction, convulsions and hemiplegia.
(4) Potential type:
This type exists all year round, and some of them are transformed from other types of patients. Some of them are ill without getting consciously. The symptoms are not obvious or very mild. The heart function is well compensated, but the heart test can be found to have weak heart sounds and arrhythmia. Heart enlargement, hypotension, etc. Some scholars believe that patients with Keshan disease can hear the level II systolic murmur in the sixth auscultation area of the heart (near the midpoint of the line connecting the pulmonary valve area and the mitral auscultation area). The diagnosis has certain value. The above 4 types of clinical manifestations can be transformed under certain conditions. The acute type can be converted into a slow type, while the slow type can be an acute or sub-acute type. Keshan disease is about children. 30% coexisted with digestive tract, respiratory infections and intestinal ascariasis.
Examine
Pediatric Keshan disease examination
Patients with acute or subacute seizures have increased serum myocardial enzyme activity, such as creatine phosphokinase, lactate dehydrogenase, lactate dehydrogenase isoenzyme (LDH1), aspartate aminotransferase and alanine aminotransferase, especially in the former. Reflecting myocardial cell damage, some children with serum anti-myocardial antibodies and circulating immune complexes are positive, suggesting autoimmune phenomena.
Electrocardiogram
The electrocardiogram changes of Keshan disease are complex and changeable, including myocardial damage, conduction block and ectopic heart rhythm.
(1) Myocardial damage: mainly ST-T changes, QT interval prolongation and low voltage, etc., acute and subacute V3, V4 lead ST segment horizontal depression can reach 0.3 ~ 0.4mV, severe ST segment can A single-phase curve or a pathological Q wave appears. If the ST-T changes in a potential type of child, the QT interval prolongs and the low voltage coexist, suggesting that the condition is unstable and there is a progression of fresh lesions.
(2) Conduction block: It is the most prominent electrocardiogram manifestation of Keshan disease, including atrioventricular block and bundle branch block. Right bundle branch block is the most common. 30%~38% of potential type can be found right bundle. Branch conduction block, acute right bundle branch block can be transient, can disappear with the improvement of the disease; while other types of right bundle branch block are mostly permanent, left bundle branch block is rare, once more It is a double bundle branch block.
(3) ectopic pulsation: premature ventricular contraction is most common, mostly frequent, two-law, triple-law or multi-source, common in acute early and other types, can improve with the condition and heart failure Disappeared, acute type may have paroxysmal ventricular tachycardia or supraventricular tachycardia, a few may die due to ventricular fibrillation, atrial fibrillation is rare.
2. Chest X-ray
It can be seen that different degrees of heart enlargement, mainly left ventricle, the left atrium also has different degrees of increase, the heart beat is weakened, sometimes the localized beat is weakened, the lungs may have different degrees of pulmonary congestion or pulmonary edema, acute children The heart chain is moderately increased, but the heart beats weakly; the lung field can be seen with interstitial edema or with alveolar edema. The subacute type of child has a large heart, the left ventricle is light, moderately enlarged, and the right ventricle is normal or slightly increased. Large, heart beats are obviously weakened, a few localized beats are weakened or disappeared; pulmonary congestion or interstitial edema can be seen in the lung field, and the heart of the chronic type is spherical, the heart beats weakly or irregularly, and a few of the visible beats disappear or abnormal. The arterial node is shrunk, the pulmonary artery segment is slightly bulged, and the superior vena cava is dilated; the interstitial edema and congestion are seen in the lung field, and the heart shadow of the underlying type is slightly enlarged, with the transverse diameter increasing and the superior vena cava not expanding; There is no congestion in the lungs.
3. Echocardiography
Mainly manifested as atrial, ventricular cavity enlargement and wall motion weakened, chronic left ventricular diameter increased significantly, left ventricular posterior wall and ventricular septal activity weakened, the wall often did not thicken, potential type and a few chronic type may have ventricular septal hypertrophy The ratio of the interventricular septum to the thickness of the posterior wall of the left ventricle is greater than 1.3:1, but as the heart failure progresses, the left ventricular diameter increases progressively, while the thickness of the chamber wall and interventricular septum gradually becomes thinner, and the characteristic change of Keshan disease is near. The apical wall of the apex is more pronounced, the pulsation is weakened, and the amplitude of the anterior mitral valve is reduced, but the change of the left ventricle is not obvious. The cardiac function measurement shows that the left ventricular ejection fraction is decreased.
4. Mechanical mechanical examination
Prolonged ejection of the pre-ejection period (PEP), shortened left ventricular ejection time (LVET), increased PEP/LVET, significant decrease in cardiac output and cardiac index in both chronic and latent types, PEP/LVET 0.42, A Wave rate 15%, suggesting cardiac insufficiency.
5. Cardiac catheter
The hemodynamics of the potential patients were basically normal. The chronic right ventricle, pulmonary artery and pulmonary artery wedge pressure were mild, moderately elevated, and the heart index decreased. Acute type patients should not be examined by cardiac catheterization.
6. Myocardial biopsy light microscopy, electron microscopy
There are varying degrees of changes, mainly in the increase of myocardial mitochondria number, degeneration and shape strange, dense electronic inclusions and myeloid bodies; followed by myofibril loss, sarcoplasmic reticulum, cell serosal changes.
Diagnosis
Diagnosis and diagnosis of pediatric Keshan disease
diagnosis
At present, there is no specific method for the diagnosis of Keshan disease. It is mainly based on epidemiological characteristics, clinical manifestations, electrocardiogram changes and X-ray examinations. The second national diagnosis and treatment of Keshan disease in 1977 The Research Collaboration Conference proposes the following diagnostic indicators for reference.
1. Characteristics of Keshan disease Keshan disease occurs in certain areas, seasons and certain populations (farmers' children from 1 year old to preschool children and women in reproductive period), and the migrant population lives in the ward and local farmers for 3 months. Above, can only occur.
2. Diagnostic indicators
(1) acute, chronic heart failure;
(2) heart enlargement;
(3) galloping horses;
(4) Arrhythmia:
1 multiple ventricular premature contraction (more than 5 times per minute);
2 atrial fibrillation;
3 paroxysmal ventricular or supraventricular tachycardia.
(5) embolization (such as brain, lung, kidney, etc.);
(6) ECG changes:
1 atrioventricular block;
2 bundle branch block (left and right bundle branches, double bundle branch and three bundle branch block);
3ST-T change;
4Q-T interval extension;
5 multiple, polymorphic ventricular premature contractions (including parallel heart rhythm);
6 paroxysmal ventricular or supraventricular tachycardia (including crossover);
7 atrial fibrillation or flutter;
8 low voltage plus sinus tachycardia (at rest);
9I, aVL, and Vl-6 are QRS waves.
(7) X-ray inspection changes:
1 heart enlargement;
2 heart beats weakened, irregular and limited beats disappeared and abnormal beats;
3 pulmonary vein hypertension (or mixed high pressure), with the characteristics of Keshan disease, and one of the diagnostic indicators or one of them, can rule out the heart disease caused by other diseases, can be diagnosed as Keshan disease, for the diagnosis can not be diagnosed In suspected patients, the necessary treatment should be given first, and the diagnosis should be confirmed in time during the treatment.
Differential diagnosis
Chronic Keshan disease should be differentiated from rheumatic heart disease, congenital heart disease, myocarditis, endocardial fibroelastosis and heart-type beriberi. Acute type requires acute gastritis, biliary or intestinal ascariasis, nephritis. Pneumonia and infection toxic shock and other identification.
1. Viral myocarditis This disease generally has a history of pre-infection, but there is no epidemiological characteristics of Keshan disease, no endemic trend, no obvious seasonality; electrocardiogram is more common with ectopic rhythm, acute heart expansion is not obvious The effect on heart function is not as serious as Keshan disease, more curable, and the prognosis is relatively good.
2. Dilated cardiomyopathy This disease is very similar to the clinical manifestations of chronic Keshan disease. It is difficult to identify. Chronic Keshan disease has a whole heart enlargement, no room wall hypertrophy, thin interventricular septum, and lower left ventricle (near The function of the apex is obviously weakened; while the dilated cardiomyopathy is mainly caused by left ventricular enlargement, and the upper and lower parts of the left ventricle are diffusely weakened, which can be distinguished by epidemiology. Mountain disease.
3. Pericarditis The physical examination of this disease has a strange pulse, X-ray examination of the heart shadow to the bilateral symmetry expansion, the heart of each bow boundary is unclear, echocardiography shows that there is effusion in the pericardial cavity, combined with epidemiological characteristics is not difficult Keshan disease identification.
4. Endocardial cardiomyopathy This disease is more common in infants and young children, with heart enlargement and urgency, chronic heart failure as the main performance, but no epidemiological characteristics, heart enlargement and endocardial thickening, autopsy or biopsy It can be seen that the inner part of the heart is grayish-white thickened in the endocardium. The ultrasound image shows enhanced endocardial reflex, and the electrocardiogram is more common with left ventricular hypertrophy and strain.
