bacterial endocarditis
Introduction
Introduction to bacterial endocarditis Bacterial endocarditis, including the heart's valve and atrial and ventricular walls. When the bacteria enter the bloodstream, they travel around the body with the blood. When flowing through the heart, it is impossible to stop because the atrium and ventricular wall are smooth. But when the valve is inflammatory or damaged, the bacteria can stay, grow and multiply, and cause inflammation of the valve. In addition, when there is atrial septal defect or ventricular septal defect, the blood flow forms a vortex through the defect, and the bacteria can also stay in the defect to cause inflammation. Therefore, bacterial endocarditis is more common in children with congenital heart disease or acquired heart disease. Bacterial endocarditis is characterized by long-term fever, mostly irregular heat, moderate or high fever. If a child with heart disease has fever for more than half a month and there are no more other systemic symptoms, the possibility of bacterial endocarditis should be considered. The general symptoms are still lack of energy, headache, chest tightness, shortness of breath, loss of appetite and so on. The performance of the heart is aggravated on the basis of the original, and symptoms of cardiac insufficiency appear. basic knowledge The proportion of illness: 0.001% Susceptible people: more common in children with congenital heart disease or acquired heart disease Mode of infection: non-infectious Complications: arrhythmia heart failure
Cause
Causes of bacterial endocarditis
Cause: In most cases, the cause is from a bacterial infection. In acute cases, the cord-like tendon or valve matrix is rapidly destroyed and necrotic, leading to valve dysfunction and heart failure. Earthworms contain fibrous layers, platelets, red blood cells and white blood cells and bacteria. Often caused by bacteria with strong pathogenicity, Staphylococcus aureus, hemolytic streptococcus, pneumococcus, influenza bacillus, Proteus and Escherichia coli are common. These bacteria have strong virulence, acute onset, serious illness, and infections often occurring in other parts, which are part of systemic infections, such as meningitis, pneumonia, thrombophlebitis, etc., sometimes accompanied by metastatic suppuration of other organs. Lesion. Usually occurs in normal heart.
Prevention
Bacterial endocarditis prevention
Prevention: Care should be taken in the treatment of subacute bacterial endocarditis. The bactericidal antibiotic should be administered at a dose above the minimum inhibitory concentration for at least 4 to 6 weeks (7 days parenteral administration followed by oral administration).
The choice of antibiotics should be based on the results of blood culture. Animals that are negative during culture or cultured should be administered in combination with ampicillin and gentamicin for at least 5 to 7 days (monitoring renal function). Then use amoxicillin and quinolones such as enflurane. Oral for 3 to 5 weeks.
In addition, appropriate treatment should be given for arrhythmia and congestive heart failure.
Complication
Bacterial endocarditis complications Complications arrhythmia heart failure
1, congestive heart failure and arrhythmia: heart failure is the most common complication of this disease. It does not occur in the early stage, but after the valve is destroyed and perforated, and its supporting structures such as papillary muscles, chordae, etc. are damaged, valve insufficiency occurs, or the original function is not fully aggravated, which is the main cause of heart failure. Severe mitral valve infection causes a septic episode of the papillary muscle or destruction of the mitral annulus resulting in a sacral mitral valve, causing severe mitral regurgitation, or lesions occurring in the aortic valve, resulting in severe aortic regurgitation Sometimes heart failure occurs. In addition, infection can also affect the heart muscle, inflammation, myocardial abscess or a large number of microemboli into the myocardial blood vessels; or a large embolus into the coronary artery caused by myocardial infarction can cause heart failure. Other rare causes of heart failure are large left-to-right shunts, such as an infected ruptured Vascular sinus or a ventricular septum that is pierced by an abscess.
Heart failure is the leading cause of death in this disease. Heart failure caused by aortic regurgitation can be exacerbated by severe mitral regurgitation caused by lesions involving the mitral valve, and even evolve into refractory heart failure, with a mortality rate as high as 97%.
2, embolism: is a common complication after heart failure. The incidence rate is 15% to 35%. It takes 6 months for the sputum on the damaged valve to be completely covered by the endothelial cells, so the embolism can occur from several days to several months after the onset of fever. Most of the early embolism is acute and the disease is at risk. Embolization can occur throughout the body, and the most common sites are the brain, kidney, spleen, and coronary arteries. Myocardium, kidney and spleen embolism are not easy to detect, more than found in autopsy, and the performance of brain, lung and peripheral blood vessel embolization is more obvious.
Symptom
Bacterial endocarditis symptoms Common symptoms Infectious fever Heart murmur
Most cases have slow onset, low fever, fatigue, fatigue, a few onset, chills, high fever or embolism. Some patients have a history of oral surgery, respiratory infection, abortion or childbirth before onset.
First, systemic infection: fever is the most common, often unexplained continuous fever for more than a week, irregular low fever, mostly between 37.5 ° C -39 ° C, can also be intermittent heat or relaxation heat, accompanied by fatigue, night sweats, Progressive anemia splenomegaly, in the late stage may have clubbing.
Second, the heart performance: the inherent signs of heart disease, due to the growth or loss of neoplasms, the destruction of valves, chordae, variability, or new noise. If there is no noise, the endocarditis cannot be excluded, and heart failure can occur in the late stage. When the infection affects the atrioventricular bundle or interventricular septum, it can cause atrioventricular block and bundle branch block. Arrhythmia is rare, and there may be premature beats or atrial fibrillation.
Third, embolism phenomenon and vascular lesions:
1. Skin and mucous membrane lesions: caused by the infection of toxins acting on capillaries to increase the fragility and rupture, or microembolism. In the limbs, the skin and the eyelids may be combined with the membrane and the oral mucosa in a batch, and the purple or red Osler nodules slightly above the surface may appear on the palm and toe of the palm of the toe, or in the palm of the hand. Or a small nodular hemorrhage (Janewey nodule) in the foot, no tenderness.
2, cerebrovascular lesions: can have the following performance: 1 meningoencephalitis: similar to tuberculous meningitis, increased cerebrospinal fluid pressure, increased protein and white blood cell count, chloride or sugar quantitative normal. 2 cerebral hemorrhage: persistent headache or meningeal irritation caused by rupture of bacterial aneurysm. 3 cerebral embolism: the patient has fever, sudden paralysis or blindness. 4 central retinal embolism can cause sudden blindness.
3, renal embolism: the most common, accounting for 1/2 cases, with gross or microscopic hematuria, severe renal insufficiency often due to bacterial infection, antigen-antibody complex deposition in the renal glomerulus, causing renal glomerulonephritis the result of.
4, pulmonary embolism: common in congenital heart disease and infective endocarditis cases, sputum organisms are located in the right ventricle or pulmonary intima surface, acute onset, chest pain, difficulty breathing, hemoptysis, cyanosis or shock. If the infarct size is small, there are no obvious symptoms. In addition, there may be coronary embolism, which is characterized by acute infarction, spleen embolism with left upper abdominal pain or left rib pain, fever and local friction. Mesenteric artery embolism, manifested as acute abdomen, bloody stools and so on. Arterial embolization of the extremities may have pale and chilly embolization limbs, weakened or disappeared arterial pulsations, and ischemic pain in the limbs.
Examine
Examination of bacterial endocarditis
First, blood culture: positive can determine the diagnosis, and provide a basis for the selection of antibiotics. In order to provide a positive rate of culture, the following points should be noted:
1. Continuously culture 4-6 times before antibiotic application.
2, each time the blood volume is 10ml, while aerobic and anaerobic culture.
3. The training time should be long, not less than three weeks.
4, the culture results are positive, should be used for drug sensitivity test.
Second, blood: there is progressive anemia, white blood cell count is normal or increased.
Third, the blood sedimentation increased.
Fourth, urine routine: proteinuria and hematuria, about 1/3 of patients with advanced renal insufficiency.
5. Echocardiography: There are neoplasms in the heart valve or endocardial wall, and abnormal manifestations of inherent heart disease.
Diagnosis
Diagnosis and identification of bacterial endocarditis
Differential diagnosis of bacterial endocarditis:
1, subacute bacterial endocarditis: often occurs in the original heart disease (such as heart valve disease congenital heart disease) combined with bacterial infection. The pathogens are mostly Staphylococcus aureus, and a few are Escherichia coli. It belongs to the category of "warm disease" of Chinese medicine.
2, acute bacterial endocarditis: 50-60% occurs in normal heart valves, valves and chordae may have ulcer perforation, chordae rupture and large and brittle mites, sputum organisms fall off into bacterial emboli, leading to embolism And a migratory abscess.
