Acute infective endocarditis

Introduction to acute infective endocarditis Acute infective endocarditis (AIE) is mostly part of a serious systemic infection. Pathogenic microorganisms are highly toxic, such as Staphylococcus aureus (most common, accounting for more than 50%), hemolytic streptococcus, meningococcal and Escherichia coli, etc., is clinically less common than subacute infective endocarditis, and patients have no history of heart disease. Acute infective endocarditis is mostly part of a serious systemic infection. The onset is urgent and progress is fast. 60% of patients have no heart disease, the pathogenic bacteria are more toxic, and Staphylococcus aureus accounts for more than 50%. Hemolytic streptococcus, pneumococcus, Gram-negative bacilli and fungi can also cause disease. Sepsis is the main clinical manifestations, high fever, chills, tachycardia, shortness of breath, muscle and joint pain, disturbance of consciousness, skin defects, embolism of various organs, heart murmurs vary greatly, white blood cells are significantly increased, progressive anemia, blood culture positive Due to the serious symptoms of systemic infection, the clinical manifestations of acute infective endocarditis can be masked. If effective antibiotics are not used in time, the mortality rate is high. basic knowledge The proportion of illness: the incidence rate is about 0.003% - 0.006% Susceptible people: no specific population Mode of infection: non-infectious Complications: heart failure

Causes of acute infective endocarditis

Bacterial infection (30%):

Almost all bacteria can cause this disease. Acute infective endocarditis is mostly caused by invasive endocardium by highly toxic bacteria, such as Staphylococcus aureus, pneumococcus, meningococcus, pyogenic streptococcus, influenza bacillus, Proteus, Escherichia coli, etc. These bacteria have strong virulence, acute onset, serious illness, and infections often secondary to other parts, such as meningitis, pneumonia, thrombophlebitis, etc. Metastatic suppurative lesions sometimes associated with other organs usually occur in normal hearts.

Active lesions (30%):

Acute infective endocarditis is different in pathogenesis from subacute infective endocarditis, with 50.0% to 60.0% occurring on normal heart valves. Pathogenic microorganisms usually come from skin, muscle, bone or lung. Active lesions, which are highly toxic, highly corrosive (such as Staphylococcus aureus, Group A Streptococcus, Streptococcus pneumoniae, Haemophilus influenzae, etc.) and adhesion, can directly invade the valve to cause infection.

Acute infective endocarditis prevention

1. Eliminate the cause and treatment of the cause: Actively prevent and treat various infectious diseases such as oral infections, skin infections, urinary tract infections and pneumonia, etc., timely treat various infections, and give antibiotics prevention before performing surgery or device examination, endocarditis It often occurs about two weeks after surgery.

2, health education: adhere to the main prevention, to publicize the dangers of the disease and advise people to stay away from drugs, for those who have intravenous drug addicts to encourage their active detoxification, reduce the important way of cardiac infective endocarditis.

3, preventive medication: first of all to prevent bacteremia, many scholars have found that temporary bacteremia often occurs after tooth extraction, especially in the case of periodontal disease or the simultaneous removal of many teeth, many Oral bacteria can enter the blood through wounds, but it is most common with Streptococcus viridans. Digestive tract and genitourinary system trauma and infection often cause enterococci and Gram-negative bacilli. Staphylococcal bacteremia is seen on the skin and away from the heart. Infection, therefore, it is necessary to use antibiotics to prevent this disease and to avoid abuse.

Complications of acute infective endocarditis Complications heart failure

Complications such as heart failure, embolism, metastatic abscess and infectious aneurysm often occur.

1, heart failure: acute infective endocarditis patients with mitral and aortic valve most susceptible, severe valve damage, resulting in acute valvular insufficiency, acute left ventricular dysfunction, pulmonary edema, lesions Involvement of the tricuspid valve and pulmonary valve, the appearance of right heart failure can occur, if the left and right heart valves are involved, it can produce signs of heart failure.

2, embolism: If the sputum organisms fall off, the emboli can cause multiple embolism, the most common parts of the brain, kidney, spleen and coronary artery can produce corresponding clinical manifestations.

3, metastatic abscess: acute infective endocarditis, the sputum is easy to fall off, these emboli can lead to the formation of abscess with the blood reaching various parts of the body.

4. Infectious aneurysms: Due to serious infections, pathogenic microorganisms erode the elastic tissue of the arterial wall, leading to local expansion of the arteries. The aortic aneurysms occurring in smaller arteries have a better prognosis. difference.

Acute infective endocarditis symptoms Common symptoms High tachycardia slow heart expansion chills debilitating chest pain right heart failure shortness of breath skin mucosal hemorrhage hemoptysis

The disease often has the following characteristics:

1, common manifestations of acute infective endocarditis

(1) There are often acute suppurative infections, recent surgery, trauma, calving fever or device examination history.

(2) rapid onset: mainly manifested as signs of sepsis, such as chills, high fever, sweating, weakness, skin mucosal hemorrhage, shock, vascular embolism and migratory abscess, and more can find the original infection.

(3) Heart: In the short term, there may be murmurs, and the nature is variable and rough. Because the valve damage is generally serious, it can produce signs of acute valvular insufficiency. Clinically, the mitral valve and/or aortic valve are the easiest. Affected, a small number of cases may involve the pulmonary valve and / or tricuspid valve, and produce corresponding signs of valvular insufficiency, in addition, often cause acute cardiac insufficiency, if the lesion mainly invades the mitral or aortic valve, it is acute Left ventricular dysfunction, pulmonary edema; if the lesion involves the tricuspid valve and pulmonary valve, it can be a sign of right heart failure; if left and right heart valves are involved, it can produce signs of heart failure.

(4) If the sputum is shed: the emboli can cause multiple embolism and metastatic abscess and cause corresponding clinical manifestations.

2. Special types of acute infective endocarditis

(1) prosthetic valve infective endocarditis (PVIE): one of the serious complications after heart valve replacement, the incidence rate is 1.4% to 3.1%, prosthetic valve after double valve replacement The incidence of infective endocarditis is higher than that after single-valve replacement. The aortic valve is more likely to occur than the mitral valve. The preoperative valve has more infective endocarditis, and the incidence of mechanical and bioprosthesis Similar, but the risk of mechanical valve infection is higher within 12 months after surgery.

Clinically, according to the occurrence time of prosthetic valve infective endocarditis, it is divided into early and late prosthetic valve infective endocarditis. Early refers to the symptoms within 60 days after surgery. The pathogenic microorganism is mainly staphylococcus. Including Staphylococcus epidermidis and Staphylococcus aureus, diphtheria bacilli, other Gram-negative bacilli, fungi are also more common, advanced refers to the incidence of 60 days after surgery, the pathogenic microorganisms are similar to natural valve infective endocarditis, staging The purpose was originally to distinguish between surgical complications (early) or social infection (late), but in fact, many patients who are infected 60 days to 1 year after surgery are likely to be acquired during hospitalization. However, the onset of the disease is delayed, and after more than one year after surgery, the infection may mainly come from the operation of the mouth, gastrointestinal tract and urinary tract, skin damage and infection.

The pathological damage of prosthetic valve infective endocarditis is different from the majority of infective endocarditis that is confined to the valve leaf. The infection of the mechanical valve is often the damage of the attachment of the annulus and is easily extended to the para-aortic tissue. Causes myocardial abscess, fistula, artificial valve cracking and paravalvular spasm, leading to severe hemodynamic abnormalities, while bioprosthetic infective endocarditis is mainly valve leaf destruction, perforation, followed by petals similar to mechanical valves Damage to the tissue around the ring.

The clinical manifestations of prosthetic valve infective endocarditis are similar to those of invasive endocarditis, but the early symptoms and signs of prosthetic valve infective endocarditis appearing shortly after valve replacement are easily treated by surgery or other concurrent Covered by the disease.

(2) Right heart infective endocarditis (RHIE): right heart infective endocarditis is mainly seen in intravenous drug addicts. Other rare causes are right heart catheterization, cardiac pacing and congenital Sexual heart disease, etc., with the increase of intravenous drug addicts, the incidence of prosthetic valve infective endocarditis has increased significantly. According to statistics, intravenous drug addicts have an annual risk of infective endocarditis. % to 5%, significantly higher than patients with rheumatic valvular heart disease or prosthetic valve replacement, the incidence of clinical right heart infective endocarditis is significantly lower than left heart infective endocarditis, may be related to the following factors related:

1 Rheumatic heart disease and congenital heart disease less affect the right heart valve.

2 The right heart pressure is lower than the left heart, and the valve endothelium is not easily damaged.

3 The right heart has low blood oxygen content, which is not conducive to bacterial growth. Most of the intravenous drug addicts have no heart disease, which may be related to drug contamination and lack of aseptic operation. The pathogenic microorganisms of prosthetic valve infective endocarditis are mostly golden yellow. Staphylococcus, followed by streptococcus, fungi and Gram-negative bacilli, etc., most of the mites are located in the tricuspid valve, right ventricular wall or pulmonary valve, most cases have a history of intravenous drug addiction before the onset, a few patients have right heart catheterization or Patients with congenital heart disease, such as fever, cough, cough, hemoptysis, chest pain and shortness of breath, can hear tricuspid and/or pulmonary regurgitation murmur, heart enlargement or right heart failure is not common, part Cases can be combined with left heart infective endocarditis, which can be accompanied by clinical manifestations of arterial embolism.

(3) Mycotic endocarditis (ME): In recent years, fungal endocarditis has an increasing trend. It is known that various fungi can cause fungal endocarditis, clinically with Candida (especially Is Candida albicans), histoplasma, cryptococci and aspergillus are common, fungal and bacterial endocarditis, most of which occur on the basis of organic heart disease, the clinical manifestations of bacterial endocarditis Both can be seen in fungal endocarditis, but fungal endocarditis can have the following characteristics:

More than 1 in the elderly, frail, long-term use of antibiotics, immunosuppressive drugs or hormones, after valve repair or replacement, long-term insertion of intravenous catheter or catheterization.

2 antibiotic treatment was ineffective or even worse, and multiple blood cultures were negative.

3 long course of disease, up to half a year or 1 year, often a large artery, especially lower extremity arterial embolism.

4 may be associated with uveitis or endophthalmitis.

5 evidence of systemic fungal infection, etc., for patients considering fungal endocarditis, in addition to SIE for related examinations, must be used for blood fungal culture, for culture-negative fungal endocarditis can be used for serological tests, Such as immunoprecipitation or agglutination test, in addition, in the absence of indwelling catheter, urine test found that Candida also has a certain diagnostic value.

Examination of acute infective endocarditis

1, blood culture

In blood culture, infections of pathogenic bacteria can be found, including Streptococcus, Staphylococcus aureus, Gram-negative bacilli, and the like.

2, echocardiography

Echocardiography can detect abnormal valves, such as severe regurgitation of the valve, sputum on the valve, aortic valve, mitral valve, tricuspid valve, pulmonary valve and other two or more damage at the same time.

3, ECG

Electrocardiogram examination can detect arrhythmia, such as sinus tachycardia, atrioventricular block, T wave changes.

In addition, immunological examinations are also helpful in the diagnosis of this disease.

4, blood routine

The white blood cells are obviously increased, the neutrophil nucleus is left-shifted, and there may be poisonous particles. In addition, progressive anemia may occur.

Diagnosis and identification of acute infective endocarditis

diagnosis

According to the above clinical manifestations, combined with echocardiography and blood culture results, more can make a diagnosis.

Differential diagnosis

Acute infective endocarditis, mainly the clinical manifestations of sepsis, especially in the absence of noise in the heart, the disease is often covered by the primary infection, easy to miss the diagnosis, for more than one week of fever, need to pay attention to cardiac auscultation changes, skin bleeding points And embolism, often need to be identified with cerebrovascular accidents, influenza, acute arthritis, acute suppurative meningitis, acute pyelonephritis, etc. In recent years, due to the progress of cardiac surgery and the widespread use of antibiotics, atypical or Special types of infective endocarditis are increasing, such as prosthetic valve replacement, hemodialysis or congenital heart disease correction, have increased the chance of endocardial infection, and patients with postoperative fever should be more vigilant.

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