Pediatric infective endocarditis
Introduction
Introduction to Infectious Endocarditis in Children Infective endocarditis in children refers to endocardial inflammatory lesions caused by various causes, often involving heart valves, but also involving ventricular septal defect, intracardiac intima or aortic catheter, arteriovenous fistula, etc., according to reasons Can be divided into two major categories of infectious and non-infective, non-infectious endocarditis includes: rheumatic endocarditis, rheumatoid endocarditis, systemic lupus erythematosus endocarditis, neonatal acute Symptomatic endocarditis, etc., here mainly describes infective endocarditis. Infective endocarditis (infective endocarditis) has been divided into acute and subacute types in the past. Acute cases occur mostly in children with no heart disease. Invasive bacteria have strong virulence, rapid onset, rapid progress, and the course of disease is Within 6 weeks. Subacute patients mostly infected with weaker virulence bacteria on the basis of the original heart disease, the onset of disease is late, the progress is relatively slow, and the course of disease is more than 6 weeks. basic knowledge The proportion of illness: 0.002% Susceptible people: young children Mode of infection: non-infectious Complications: sepsis, sputum bacillus pneumonia, pericarditis, meningitis, peritonitis, osteomyelitis
Cause
Causes of infective endocarditis in children
(1) Causes of the disease
1. The primary lesion of the heart 92% of patients with infective endocarditis have primary heart disease, of which congenital heart disease is the most common, accounting for 78%, ventricular septal defect is most likely to be associated with infective endocardium Inflammation, followed by tetralogy of Fallot, patent ductus arteriosus, pulmonary stenosis, aortic stenosis, aortic valve bilobal malformation, atrial septal defect, etc.; acquired heart disease such as rheumatic valvular disease, mitral valve Prolapsed endocarditis can also be complicated by prolapse syndrome. With the development of pediatric cardiac surgery technology, more and more pediatric heart disease can be corrected and cured, but the devices or materials that are left in the heart chamber (such as Intracardiac patches, artificial heart valves, etc.) are common predisposing factors for infective endocarditis in recent years.
2. Pathogens Almost all kinds of bacteria can cause infective endocarditis. Streptococcus viridans is still the most common pathogen, but the proportion has decreased significantly. In recent years, Staphylococcus aureus, Staphylococcus aureus, Infective endocarditis caused by Gram-negative bacilli such as enterococci and aerogens is significantly increased, fungal endocarditis is rare, and endocarditis caused by rickettsia and viral infection is rare, a few Infective endocarditis is caused by more than one pathogen, common in prosthetic valve surgery, and other pathogenic factors such as long-term use of antibiotics, corticosteroids or immunosuppressive drugs.
3. Inducing factors can be found in about 1/3 of the children in the medical history. Common predisposing factors are orthodontic treatment and tonsillectomy. In recent years, cardiac catheterization and interventional therapy, prosthetic valve replacement, open heart surgery The extensive development of surgery is also one of the important predisposing factors of infective endocarditis. Other predisposing factors include long-term use of antibiotics, adrenocortical hormones, and immunosuppressive drugs.
(two) pathogenesis
1. The pathogenesis of hemodynamic changes caused by endothelial damage and bacteremia, is the most important mechanism for the formation of infective endocarditis, under normal circumstances, such as a small number of pathogens from the mouth, nose, throat and skin When the site enters the bloodstream, it is quickly eliminated. When there is an organic cardiovascular disease, the pathogen can inhabit the damaged heart valve, endocardium or endothelium, surrounded by platelet thrombosis and red blood cells and white blood cells. And is surrounded by cellulose to form neoplasms, forming endocardial inflammation, hemodynamic changes caused by abnormal cardiac structure (such as stenosis or regurgitation, intracardiac shunt) is the basis of endothelial injury, the mechanism is: high speed Jet blood flow impacts the intima; valvular stenosis creates a pressure gradient. In most cases, endothelial injury occurs on the low pressure side of the pressure gradient. The occurrence of bacteremia is often caused by invasive medical procedures, such as periodontal disease surgery. The incidence of bacteremia is as high as 88%. After endothelial injury, platelets and fibrin accumulate in the lesion, forming aseptic neoplasms. If bacteremia occurs, it will form infectious sputum. Was vegetation once formed, blood flow in the continuous impact will result in disruption and thrombosis neoplasm internal organs.
2. Pathological changes
(1) Heart and blood vessels: The basic pathological changes of this disease are heart valve, endocardial and large blood vessel intimal surface with scorpion-like infectious neoplasms. During active period, the sputum is divided into 3 layers: the innermost layer is mainly composed of platelets and fibers. Element, red blood cell, collagen fiber, necrotic tissue and bacteria; the middle layer is composed of bacteria; the outer layer is composed of cellulose and bacteria. The outermost layer of the healing period is covered by cellulose, and the middle and inner layers are glassy and calcified. The sputum of the valve can cause ulceration and perforation of the valve, and can also affect the chordae and papillary muscles, shortening or breaking the chordae, an aneurysm, huge sputum can block the valve orifice, leading to acute circulatory disorders, and blood flow to the sputum. The impact often has fine embolism. Due to the size of the embolism and the embolization site, different organ embolism symptoms can occur and cause different consequences. The embolism of the left heart causes kidney, brain, spleen, limb and mesenteric artery embolization. The right ventricular embolism causes pulmonary embolism, in which the incidence of pulmonary embolism is the highest, small embolism embolizes capillaries to produce skin defects, endothelial cell proliferation and perivascular circumference in small arteries Peri-inflammatory reaction, the formation of Oslers nodes of the skin, the following changes can occur after embolic embolization:
1 The ischemic infarction occurs in the distal tissue of the embolization site;
2 inflammation spread near the embolization site;
3 Endarteritis at the embolization site destroys the elastic layer of the artery and the muscular layer or tiny embolism embolizes the nutrient vessels of the aortic wall, causing necrosis of the aortic wall to form an infectious aneurysm. It is believed that the Euclidean knot may be The tissue is directed against the manifestations of immune vasculitis produced by the infection. Janeways lesion is an embolism caused by infectious emboli containing bacteria and neutrophils, and secondary to subcutaneous hemorrhage and necrosis. The pale Roths spots are often accompanied by hemorrhagic foci.
(2) Kidney: The kidney is the most common organ of systemic embolism, and its pathological changes are:
1 renal artery embolization caused infarct lesions;
2 focal glomerulonephritis;
3 diffuse glomerulonephritis, the latter two may be caused by microembolism or glomerular immune injury.
(3) Central nervous system: lesions can be extensively involved in cerebral arteries, meninges, ventricles, brain parenchyma, cranial nerves and spinal cord. The main pathological changes are vascular injuries. Microvascular embolism can cause mental disorders or diffuse meningoencephalitis. , edema, brain softening and brain abscess, cerebral hemorrhage after rupture of cerebral arterial aneurysm, intraventricular or arachnoid hemorrhage.
(4) Immune mechanism: During the pathogenesis, cell-mediated immunity and humoral immune system activity are enhanced, activation of polyclonal B cells and antigen-specific B cells leads to high gamma globulinemia, and renal pathology is immune complex Focal and diffuse glomerulonephritis, rheumatoid factor and circulating immune complexes are found in infective endocarditis, which lowers plasma levels when administered effectively. In addition, anti-endocardial antibodies, anti-endometrium (Antisarcolemmal) antibodies, anti-muscle membrane (Antimyolemmal) antibodies and anti-nuclear antibodies and other autoantibody levels are also increased.
Prevention
Pediatric infective endocarditis prevention
Prevention of infective endocarditis is extremely important. Children with congenital or rheumatic heart disease should pay attention to oral hygiene, prevent gingivitis, dental caries, prevent infection; perform oral surgery, tonsillectomy, cardiac catheterization and cardiac surgery. At the time of surgery, 1 to 2 hours before surgery and 48 hours after surgery, intramuscular injection of penicillin 800,000 U / d, or long-acting penicillin 1.2 million U a dose, penicillin allergic, optional cephalosporin or vancomycin intravenous injection Then, oral erythromycin 30mg / (kg · d) was changed and taken in 4 times for 2 consecutive days.
Complication
Complications of infective endocarditis in children Complications septic type sputum bacillus pneumonia pericarditis meningitis peritonitis osteomyelitis
Pathogens with strong virulence such as Staphylococcus aureus infection, rapid onset, chills, high fever, night sweats and weakness and other systemic symptoms, mainly sepsis sepsis, liver, kidney, spleen, deep brain soft tissue can occur abscess, Or complicated by pneumonia, pericarditis, meningitis, peritonitis and osteomyelitis, embolism is more common, the disease progresses sharply, can be life-threatening in days or weeks, such as early rescue, can recover health within a few weeks, heart valve In severe cases, chronic valvular heart disease can be left behind after recovery.
Symptom
Infectious endocardial symptoms in children Common symptoms Unexplained fever Heart murmur Cardiopulmonary embolism Splenomegaly Neonatal anemia
Infectious endocarditis in children can be caused by bacteria, mold, rickettsia and viruses. There are three main types of symptoms in the clinic, namely systemic infection symptoms, cardiac symptoms, embolism and vascular symptoms.
Infective endocarditis in children can not only see fever, but also fever is the most common and most important systemic symptoms. Young children, especially those under 2 years of age, often have symptoms such as fever and other symptoms of infection, and even mask the symptoms of endocarditis. In addition to fever, children are often accompanied by pneumonia, enteritis, empyema, skin infections, osteomyelitis and so on. The heart's performance is mainly due to changes in the nature of the heart auscultation and the generation of new murmurs. Other symptoms include chest pain, hemoptysis, headache, hemiplegia, etc. due to different embolization and organ involvement.
Another prominent feature of infective endocarditis in children is that most of the children with this disease have primary heart disease, of which congenital heart disease is the most common, and the disease rarely occurs in the normal heart. Therefore, if there is a heart disease in the clinic, and there is fever of unknown cause for more than 1 week, the disease should be highly vigilant. Blood culture specimens should be taken as early as possible to confirm the diagnosis.
The fever of pediatric infective endocarditis is caused by infection, so to effectively control body temperature, you must first control the infection. This is also the key to the treatment of this disease. Usually treat this disease, advocate a large number of early antibiotics, and should choose a combination of strong bactericidal drugs, in addition to strengthen care, pay attention to rest, pay attention to diet and nutrition, if necessary, blood transfusion and other treatment.
Examine
Examination of infective endocarditis in children
1. Blood examination common blood picture is progressive anemia, mostly positive cell anemia and leukocytosis, neutrophils increased, erythrocyte sedimentation rate increased, C-reactive protein positive, when combined with immune complex-mediated glomerulonephritis When severe heart failure or hypoxia causes polycythemia, serum globulin often increases, even albumin, globulin ratio is reversed, immunoglobulin is elevated, gamma globulin is elevated, circulating immune complexes are increased, and rheumatoid factor is increased. Positive,
2. Blood culture blood culture positive is an important basis for the diagnosis of infective endocarditis. For those whose causes are unexplained fever, the body temperature lasts for more than 1 week, and the original heart disease should actively and repeatedly carry out blood culture. In order to increase the positive rate, if the blood culture is positive, the drug sensitivity test should be done.
3. Urine examination has red blood cells in the urine, proteinuria can occur during fever.
4. Electrocardiogram Because the myocardium can have multiple pathological changes at the same time, there may be fatal ventricular arrhythmia, atrial fibrillation suggesting atrioventricular valve regurgitation, complete atrioventricular block, right bundle branch block, left anterior or posterior branch Blocking has been reported, suggesting that myocardial suppuration or inflammatory response is aggravated.
5. Echocardiography Echocardiography can detect sputum organisms larger than 2mm in diameter, so it is helpful for the diagnosis of infective endocarditis. In addition, echocardiography can dynamically observe the size and shape of sputum during treatment. , activity and valve function status, to understand the degree of valve damage, has a reference value for deciding whether to do the valve replacement surgery, the examination can also find the original heart disease,
6. CT examination should be done in time for patients with suspected intracranial lesions to understand the extent of the lesion.
Diagnosis
Diagnosis and diagnosis of infective endocarditis in children
Differential diagnosis
1. Febrile diseases such as fever as the main manifestation, need to be differentiated from typhoid, sepsis, tuberculosis, rheumatic fever and systemic lupus erythematosus.
2. Heart failure with heart failure as the main manifestation with low fever or no fever, should be differentiated from heart disease complicated with heart failure.
3. Rheumatic myocarditis Active rheumatic myocarditis is more difficult to distinguish from this disease, because both can have fever, anemia, increased erythrocyte sedimentation rate and heart damage, but if there is embolism, splenomegaly, hematuria, clubbing and blood Positive culture, especially two-dimensional echocardiography found that there are larger neoplasms, support the diagnosis of infective endocarditis.
4. Left atrial myxoma Sometimes this disease and left atrial myxoma are not easy to identify, but the presence of neoplasms in infective endocarditis is rare in the left atrium.
5. Postoperative endocarditis needs to be differentiated from the following two diseases:
(1) Pericardial incision syndrome: occurs several days to several weeks after heart surgery with a happy bag, showing fever, chest pain, pericardial cavity and/or pleural effusion, leukocytosis, increased erythrocyte sedimentation rate, and sometimes pericardium Filling, need pericardial puncture to drain the effusion, this disease is a self-limiting disease, oral aspirin or hormone is effective.
(2) Postoperative perfusion syndrome: more than 3 to 6 weeks after cardiopulmonary bypass, clinical manifestations of fever, anorexia, hepatosplenomegaly, pleural effusion and atypical lymphocytosis, etc. When the giant cell inclusion body virus is contaminated, it is also a self-limiting disease, and the treatment method is the same as the pericardial incision syndrome.
