Infective endocarditis

Introduction to Infective Endocarditis Infective endocarditis (infective endocarditis) refers to inflammation of the heart valve or ventricular wall by direct infection of bacteria, fungi and other microorganisms (such as viruses, rickettsia, chlamydia, spirochetes, etc.), which is different from rheumatoid arthritis. Non-infective endocarditis caused by heat, rheumatoid, systemic lupus erythematosus, etc. In the past, this disease was called bacterial endocarditis. It is not comprehensive enough and is not used now. The typical clinical manifestations of infective endocarditis include fever, murmur, anemia, embolism, skin lesions, and splenomegaly. Dahe blood culture is positive. basic knowledge The proportion of sickness: 0.0052% Susceptible population: more common in patients with heart disease Mode of infection: non-infectious Complications: congestive heart failure, arrhythmia

Causes of infective endocarditis

Bacterial infection (25%)

Acute infective endocarditis is often caused by the invasion of purulent bacteria into the endocardium, which is caused by infection of pathogens with strong virulence. S. aureus accounts for more than 50%. Subacute infective endocarditis Before the application of antibiotics to the clinic, 80% were caused by non-hemolytic streptococcus, mainly infection with Streptococcus viridans.

Drug factor (15%)

Due to the widespread use of broad-spectrum antibiotics, pathogenic strains have changed significantly, and almost all known pathogenic microorganisms can cause the disease. The same pathogen can produce an acute course of disease and a subacute course. And cases of rare drug-resistant microorganisms have increased in the past. The incidence of green staphylococcus in grass is decreasing, but it still dominates. The proportion of Staphylococcus aureus, Enterococcus, Staphylococcus epidermidis, Gram-negative bacteria or fungi is significantly increased. Anaerobic bacteria, actinomycetes, and Listeria are occasionally seen. A mixed infection of two bacteria was found.

Fungal infection (25%)

Fungi are particularly found in cardiac surgery and intravenous anesthetic addicts. Long-term use of antibiotics or hormones, immunosuppressive agents, intravenous catheters to high nutrient solutions can increase the chance of fungal infections. Among them, Candida, Aspergillus and Histoplasma are more common.

Infective endocarditis prevention

Patients with heart valve disease or cardiovascular malformation and artificial valve should enhance physical fitness, pay attention to hygiene, promptly remove infected lesions, perform dental or upper respiratory surgery or mechanical operation, lower gastrointestinal tract, gallbladder, urogenital surgery or operation, Antibiotics should be used prophylactically in other surgical procedures involving infectivity.

In dental and upper respiratory surgery and mechanical operation, penicillin G100-1.2 million u intravenous infusion and procaine penicillin 800,000 u intramuscular injection are usually given half an hour to one hour before surgery, and streptomycin 1g/d is added if necessary. After 2 to 3 days of surgery, for gastrointestinal, genitourinary surgery or mechanical operation, ampicillin and Qingda can be used before and after surgery.

Complications of infective endocarditis Complications congestive heart failure arrhythmia

(1) Congestive heart failure and arrhythmia Heart failure is the most common complication of this disease, which does not occur early, but after the valve is destroyed and perforated, and its supporting structures such as papillary muscles, chordae, etc. are damaged, the valve occurs. Insufficient function, or the original function is not fully aggravated, is the main cause of heart failure, severe mitral valve infection caused by papillary muscle septic abscess or mitral annulus damage caused by the sacral mitral valve, causing severe biceps Valve regurgitation, or lesions occur in the aortic valve, leading to severe aortic regurgitation, especially heart failure, 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 can cause heart failure caused by myocardial infarction. Other rare causes of heart failure are large left-to-right shunt, such as ruptured Vulgaris sinus tumor or ventricular septal perforation.

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. The mortality rate can be as high as 97. %.

When the infection involves the myocardium and invades the conductive tissue, it can cause arrhythmia, most of which are ventricular premature beats, a few cases of atrial fibrillation, endocarditis of the aortic valve or bacterial aneurysm with aortic sinus. Infection can invade the atrioventricular bundle or compress the ventricular septum causing atrioventricular block and bundle branch block.

(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 endothelial cells, so the embolism can be counted after the onset of fever. From the beginning of the day to the occurrence of several months, most of the early embolism is acute, the risk of the disease, embolism can occur in all parts of the body, the most common parts are brain, kidney, spleen and coronary artery, myocardial, kidney and spleen embolism is not easy to detect More than that found in autopsy, the manifestations of brain, lung and peripheral blood vessel embolism are more obvious.

Larger spleen embolism can suddenly occur in the left upper abdomen or left flank pain and splenomegaly, and there is fever and spleen area friction sound, even due to rupture of the spleen caused by intra-abdominal hemorrhage or peritonitis and underarm abscess, renal embolism may have Low back pain or abdominal pain, hematuria or bacteriuria, but smaller embolism does not necessarily cause symptoms, urine changes are not much, easy to be missed, the incidence of cerebrovascular embolization is about 30%, occurs in the middle cerebral artery and its branches, Hemiplegia is the most common symptom. Pulmonary embolism is more common in right heart endocarditis. If the neoplasm on the left heart valve is smaller than the patent foramen ovale, it can reach the lungs and cause pulmonary infarction. After pulmonary embolism, there may be Sudden chest pain, shortness of breath, cyanosis, cough, hemoptysis or shock, but small lung infarction may have no obvious symptoms, on the X-ray chest radiographs appear as irregular small shadows, can also be large leaf wedge shadow, to Attention to distinguish from other lung lesions, coronary embolism can cause sudden chest pain, shock, heart failure, severe arrhythmia and even sudden death. Extremity arterial embolism can cause limb pain, weakness, pale and cold, cyanosis, even To necrosis, central retinal artery embolization can cause sudden blindness. There is still the possibility of embolism within 1 to 2 years after the disease is cured. However, it is not necessarily a recurrence, so it should be closely observed.

(C) other complications of the heart Myocardial abscess is common in Staphylococcus aureus and Enterococcus infection, especially coagulase-positive Staphylococcus, can be multiple or single large abscess, direct dissemination of myocardial abscess or aortic aneurysm abscess Intracardiac can cause suppurative pericarditis, myocardial fistula or cardiac perforation, mitral abscess and ventricular septal abscess secondary to aortic valve infection, often located in the upper part of the septum, can affect the atrioventricular node and His bundle, causing the atrioventricular Conduction block or bundle branch block, surgical resection and repair should be timely, other myocardial ischemia due to coronary embolism, myocardial inflammation caused by bacterial toxin damage or immune complexes, etc. Non-suppurative pericarditis can also be caused by an immune response, congestive heart failure.

(4) fungal aneurysms are most common with fungal aneurysms. Bacterial aneurysms occur most often in the aortic sinus, followed by cerebral arteries, ligated arterial catheters, abdominal blood vessels, pulmonary arteries, coronary arteries, etc., without oppression The aneurysm of the tissue itself is asymptomatic and can present clinical symptoms after rupture. Localized headaches that cannot be relieved suggest that the cerebral artery has an aneurysm, local tenderness or pulsatile mass suggesting that there is an aneurysm there.

(5) Neuropsychiatric complications The incidence rate is about 10% to 15%. The clinical manifestations include headache, confusion, nausea, insomnia, dizziness and other symptoms of poisoning, a series of symptoms caused by vascular infective embolism in the brain, and Hemiplegia, paraplegia, aphasia, disorientation, ataxia, and other movements caused by nerve and spinal cord or peripheral nerve damage, sensory disturbances and peripheral neuropathy.

Other complications include interstitial nephritis and acute or chronic proliferative glomerulonephritis caused by immune complexes.

Infective endocarditis symptoms Common symptoms High fever Unexplained fever Fatigue muscle pain Systolic murmur Heart enlargement Tachycardia Anxiety Slow growth Heart murmur

First, symptoms and signs

(1) fever is the most common, the heat type is variable, the most irregular, can be intermittent or relaxation type, accompanied by chills and sweating, or only low fever, body temperature is mostly 37.5 ~ 39 ° C Between 3% and 15% of patients with normal or lower than normal temperature, more common in elderly patients with embolism or fungal aneurysm rupture caused by cerebral hemorrhage or subarachnoid hemorrhage and severe heart In the case of dysuria and uremia, antibiotics, antipyretics and hormones have not been used before the diagnosis of this disease.

(2) 70% to 90% of patients have progressive anemia, sometimes reach the severity, and even the most prominent symptoms, anemia causes general malaise, weakness and shortness of breath, patients with longer duration often have systemic pain, possibly due to toxicity Hypertension or embolism in various parts of the body, joint pain, low back pain and myalgia are more common at the onset, mainly involving the gastrocnemius and thigh muscles, tendons, wrists and other joints, but also multiple joint involvement, if the disease Serious bone pain should be considered due to periostitis, subperiosteal hemorrhage or embolism, embolization of aneurysms caused by bone or bone aneurysms.

(3) The clinical manifestations of elderly patients are more variable. Fever is often misdiagnosed as respiratory tract or other infections. Heart murmurs are often mistaken for senile degenerative valvular disease and neglected. Some may have no fever and heart murmur. , mental changes, heart failure or hypotension, prone to neurological complications and renal insufficiency.

(4) The main signs are that the original heart disease can be heard or the original normal heart is murmur. The change in the nature of the noise during the course of the disease is often caused by anemia, tachycardia or other hemodynamic changes. About 15% of patients started with no heart murmur, and there was murmur during treatment. A few patients did not have murmur until 2 to 3 months after treatment. Occasionally, there was no murmur after treatment for many years. In subacute infective endocardium In the inflammation, right heart valve damage is not common, 2/3 of the right heart endocarditis, especially those who invade the tricuspid valve, the neoplasms proliferate in the endocardium of the ventricular wall and aortic atherosclerotic plaque When you are on, you can also have no noise, but the latter is rare.

(5) The defects of skin and mucous membranes, linear bleeding under the nail bed, Osler knot, Janeway lesions and other skin lesions have decreased significantly in the past 30 years. The defect is that the toxin acts on the capillaries to increase the fragility and rupture. Or due to embolism, Changcheng group can also appear individually, the highest incidence, but has been reduced from 85% to 19% to 40% before the application of antibiotics, more common in the eyelid membrane, oral mucosa, chest and back of the hands and feet It lasts for several days, reappears after disappearing, and its center can be whitish. However, the microscopic embolism caused by cardiopulmonary bypass can also cause ocular sub-membrane hemorrhage. Therefore, some people think that the center is grayish and the sputum is more important than the yellow one. Systemic purpura can occur, the characteristics of the underlying nail bed is linear, the distal end does not reach the front edge of the nail bed, the pressure can be painful, the incidence of Osler knot has dropped from the past 50% to 10% to 20%, It is purple or red, slightly higher than the leather surface. The smuggling is about 1~2mm, and the larger one can reach 5~15mm. It occurs mostly on the palm of the finger or the end of the toe. The size of the fish or the sole of the foot may have tenderness and often last. 4 to 5 days to fade, Osler knot is not Unique to the disease, can also occur in systemic lupus erythematosus, typhoid, lymphoma, small painful hemorrhagic or erythematous lesions of 1 to 4 mm in diameter in the palm and sole of the foot, called Janeway damage, sickle Fingers (toes) are now rare. Retinopathy has the most bleeding, is fan-shaped or round, may have a white center, and sometimes only a round white spot on the fundus is called the Roth point.

(6) The spleen often has mild to moderate swelling, soft and tenderness, and the incidence of splenomegaly has been significantly reduced. For unexplained anemia, refractory heart failure, stroke, paralysis, peripheral arterial embolism, Progressive obstruction of the valve mouth and displacement of the valve, avulsion, etc. should pay attention to whether the disease exists, in patients with recurrent pneumonia, followed by liver, mild jaundice and finally patients with progressive renal failure, even Without heart murmur, the possibility of infective endocarditis on the right side should also be considered.

Second, the classification:

(1) Acute infective endocarditis often occurs in the normal heart, and endocarditis in the right heart of intravenous anesthetic addicts tends to be more acute, and the pathogen is usually a highly virulent bacteria. Such as Staphylococcus aureus or fungi, onset often sudden, accompanied by high fever, chills, systemic toxemia symptoms, often part of a serious systemic infection, the course of the disease is more acute and dangerous, easy to cover up the clinical symptoms of acute infective endocarditis Due to the sharp damage of the heart valve and the chordae, the high-pitched murmur or the original murmur property changes rapidly in a short period of time, and can often rapidly develop into acute congestive heart failure leading to death.

On the affected endocardium, especially the fungal infection, can attach large and brittle mites, and the shed embolism can cause multiple embolism and metastatic abscess, including myocardial abscess, brain abscess and purulent meningitis. If the embolus comes from the right heart chamber of the infection, pneumonia, pulmonary embolism and single or multiple lung abscesses may occur. The skin may have erythematous variegated and purpuric hemorrhagic lesions, and a small number of patients may have splenomegaly.

(B) subacute infective endocarditis most patients with slow onset, only non-specific insidious symptoms, such as general malaise, fatigue, low fever and weight loss, a small number of onset begins with the form of complications of the disease, such as Embolism, unexplained stroke, progressive exacerbation of valvular heart disease, refractory heart failure, glomerulonephritis, and heart valve murmur after surgery.

[Special type]

(I) Artificial valve infective endocarditis In the infective endocarditis complicated by cardiac surgery, the incidence of prosthetic valve endocarditis (PVE) accounts for about 2.1%, compared with other types of heart. The operation was 2 to 3 times higher. The PVE rate after double valve replacement was higher than that of single valve replacement. The PVE of the aortic valve was higher than that of the mitral valve. This may be due to the time of aortic valve replacement surgery. Long, transaortic aneurysm pressure gradient is large, local turbulence is related. For patients with natural valvular endocarditis before surgery, the chance of postoperative PVE is increased by 5 times, and the incidence of mechanical flap and artificial bioprosthetic PVE is the same. About 2.4%, the incidence of early PVE in mechanical flap is higher than that of artificial bioprosthesis, the mortality rate of PVE is higher, about 50%, and the mortality rate of early PVE (within 2 months after surgery) is higher than that of late PVE (2 after operation) After the month), the former pathogen is mainly staphylococcus, accounting for 40% to 50%, including Staphylococcus epidermidis, Staphylococcus aureus, diphtheria-like bacilli, other Gram-negative bacilli, mold is also more common, since the preoperative prophylactic antibiotics After treatment, the incidence rate is Lowering, late PVE is similar to natural endocarditis, mainly caused by various streptococcus (mainly by Streptococcus viridans), Enterococcus, Staphylococcus aureus, in which Staphylococcus epidermidis is more resistant than Staphylococcus epidermidis to early PVE. Sensitive, fungi (most commonly Candida albicans, followed by Aspergillus), Gram-negative bacilli, and diphtheria-like bacilli are not uncommon.

The clinical manifestations of artificial valve endocarditis are similar to those of natural valve endocarditis, but the sensitivity and specificity of the diagnosis are not high, because postoperative bacteremia, indwelling various intubations, thoracic surgery wounds, pericardium Incision syndrome, post-perfusion syndrome and anticoagulant therapy can cause fever, bleeding, hematuria, etc. More than 95% of patients have fever, white blood cell count is increased by about 50%, anemia is common, but skin disease in early PVE Loss occurs rarely, splenomegaly is mostly seen in late PVE, sometimes serum immune complex titer can be increased, rheumatoid factor can be positive, but serological test negative can not exclude the presence of PVE.

About 50% of patients have reflux murmurs. Artificial bioprosthetic endocarditis mainly causes destruction of the valve leaflets, resulting in incomplete murmurs, and rarely occurs in the annulus abscess. The infection of the mechanical valve is mainly at the attachment of the annulus. The sutures at the annulus and the valve are detached and split, forming a paravalvular leak and a new closed dysfunction and hemolysis, which makes the anemia worse, and the diffuse infection of the annulus even completely avoids the artificial valve. When the annulus is formed When the abscess is easily spread to the adjacent heart tissue, complications similar to those of the natural valve endocarditis occur. In the early stage of PVE, when the valve has no obvious damage, there is no noise, so the diagnosis cannot be delayed due to the absence of new noise. When sputum occludes the valve orifice, it can cause stenosis of the valve. Systemic embolism can occur in any part. In fungal PVE (especially caused by Aspergillus), embolization may be the only clinical finding, and skin flaky hemorrhage is early. PVE does not have diagnostic significance, because it can also be seen after the operation of artificial heart-lung machine, the other complications of PVE, like natural endocarditis, can also have heart function. Whole, embolism, myocardial abscess, bacterial aneurysm, etc., the artificial valve is weakened by the intensity of the closing sound, and the abnormal oscillation and displacement of the artificial valve are seen by X-ray fluoroscopy. The angle is greater than 7°-10° and the double ring caused by the annulus Stinsons sign, two-dimensional echocardiography found that the presence of neoplasms is helpful for diagnosis, blood culture is often positive, if multiple blood cultures are negative, be alert to fungal or rickettsia infection and slow-growing diphtheria The possibility of bacillary infection, PVE pathogens often come from hospitals, so it is easy to have drug resistance.

(2) Staphylococcal endocarditis is often acute, and the condition is sinister. Therefore, it is mostly acute, and only a few are subacute. Usually caused by penicillin G-resistant Staphylococcus aureus, it is more likely to invade the normal heart. Often causing severe and rapid valve damage, resulting in aortic and mitral regurgitation, multiple organ and tissue metastatic infections and abscesses, is important in the diagnosis.

(3) Enterococcal endocarditis is more common in patients with prostate and genitourinary tract infections. It is highly destructive to heart valves and has obvious murmurs, but it often appears in subacute forms.

(4) Fungal endocarditis due to the use of broad-spectrum antibiotics, hormones and immunosuppressive agents, long-term use of intravenous infusion, indwelling of blood vessels and intracardiac catheters, extensive development of open heart surgery and intravenous anesthetics in some countries The increase of addicts, the incidence of fungal endocarditis gradually increased, about 50% occurred after cardiac surgery, the pathogens are mostly Candida, tissue cytoplasm, Aspergillus or sputum, fungal heart Membrane onset is rapid, a few are more concealed, the incidence of embolism is very high, the neoplasm is large and brittle, easy to fall off, causing embolism of the larger arteries such as the femoral artery and radial artery, which occurs in right endocarditis can cause fungal Pulmonary embolism, if the giant sputum obstructs the valve orifice and forms a stenosis of the valve, severe blood flow disorder may occur. Fungal endocarditis may cause skin damage. For example, patients with histoplasmosis may have subcutaneous ulcers, oral cavity and Damage to the nasal mucosa, if histological examination, often has important diagnostic value, Aspergillus infection can still cause intravascular diffuse coagulation.

(5) Endocarditis involving the right heart is seen in left-to-right shunt congenital heart disease and artificial tricuspid valve replacement, urinary tract infection and infectious abortion, cardiac pacing, right heart catheterization and Normal childbirth can also be caused. In recent years, due to the increase of intravenous anesthetics addicts in some countries, the incidence of right heart endocarditis has increased significantly, about 5% to 10%. Most drug addicts have no heart disease, and may The drug is contaminated, does not follow the aseptic operation and the special substance in the intravenous material damages the tricuspid valve. The bacteria are mostly Staphylococcus aureus, followed by fungi, yeast, Pseudomonas aeruginosa, pneumococcal, etc. Gram-negative bacilli Can cause, the right heart infective endocarditis mostly involving the tricuspid valve, a few involving the pulmonary valve, the sputum is mostly located in the tricuspid valve, the right ventricular wall or pulmonary valve, the sputum biocracking causes lung inflammation, pulmonary artery branch sepsis Arteritis and bacterial pulmonary infarction, if caused by Staphylococcus aureus, the infarction site can be converted into lung abscess, because the clinical manifestations are mainly in the lungs, so splenomegaly, hematuria and skin lesions are rare, patients may have Cough, sputum, hemoptysis, pleural inflammatory chest pain and shortness of breath, there may be murmurs of tricuspid regurgitation, because the pressure gradient between the right atrium and the right ventricle is small (except in patients with organic heart disease and pulmonary hypertension) The tricuspid systolic murmur is short and very light, very soft, easy to mix with respiratory noise or mistaken for blood flow murmur, but the increase in murmur intensity during deep inhalation is highly suggestive of tricuspid regurgitation, involving the pulmonary artery The valve can hear the middle diastolic murmur caused by pulmonary valve regurgitation. The heart enlargement or right heart failure is not common. The chest X-ray shows nodules or fragmentary inflammatory infiltration in both lungs, which can cause pleural effusion and lung. Abscess or necrotizing pneumonia can also lead to pneumothorax, the most common cause of death of right heart endocarditis is pulmonary valve insufficiency and respiratory distress syndrome caused by recurrent septic pulmonary embolism, uncontrolled sepsis, severe right Heart failure and left valve involvement are rare causes of death. If diagnosed early, early antibiotic or surgical treatment, timely treatment of complications, simple right heart infection Endocarditis good prognosis.

(6) Recurrence and recurrence of infective endocarditis refers to infection signs or blood culture positive recurrence within 6 months after the end of antibiotic treatment, and the recurrence rate is about 5% to 8%, and early recurrence is more than 3 Within a month, it may be due to the fact that the bacteria hidden in the sputum are not easy to kill or have a long course before treatment or the previous antibiotic treatment is insufficient, thus increasing the resistance of the bacteria and serious complications. For example, embolism of the brain and lung may also cause double infection due to the application of broad-spectrum antibiotics.

After 6 months of initial onset, all cardiac manifestations and positive blood culture recurrence of infective endocarditis are called recurrences, usually caused by different bacteria or fungi, and the recurrence rate is higher than that of the first-time one.

Infective endocarditis

(1) Blood culture

About 75% to 85% of patients have positive blood cultures. Positive blood culture is the most direct evidence for the diagnosis of this disease, and it can also be followed up for the persistence of bacteremia. The pathogens are continuously spread from the neoplasm to the blood, and are continuous. Sexual, the number is not the same, acute patients should take 2 ~ 3 blood samples within 1 ~ 2h before the application of antibiotics, subacute patients collected 3 ~ 4 blood samples 24 hours before the application of antibiotics, patients who have previously applied antibiotics should At least 3 days of blood culture is taken every day to increase the positive rate of blood culture. The blood collection time is better when the chill or body temperature rises. The blood is removed every time to replace the venous puncture. The skin should be strictly disinfected. ~15ml, in patients who have been treated with antibiotics, the blood volume should not be too much, the ratio of culture fluid to blood is at least about 10:1, because excessive antibiotics in the blood can not be diluted by the medium, affecting the growth of bacteria, routine Should be used for aerobic and anaerobic culture, in artificial valve replacement, long-term indwelling intravenous cannula, catheter or drug addict, should be added for fungal culture, observation time of at least 2 weeks, when the culture results are negative Should be maintained until 3 weeks, the diagnosis must be more than 2 times blood culture positive, generally for venous blood culture, the positive rate of arterial blood culture is not higher than venous blood, in rare cases, blood culture negative patients, bone marrow culture can be positive, culture positive Drug sensitivity tests, either alone or in combination, should be performed to guide treatment.

(2) General laboratory inspection

Red blood cells and hemoglobin are reduced, the latter are mostly in the range of 6% to 10g%, and even hemolysis can occur. The white blood cell count can be normal or slightly increased in patients without complications, sometimes left shifting, and the erythrocyte sedimentation rate is mostly increased. More than half of patients may have proteinuria and microscopic hematuria. In patients with acute glomerulonephritis, interstitial nephritis or large renal infarction, gross hematuria, pyuria and blood urea nitrogen and creatinine may increase. Enterococcus heart Endometritis often leads to enterococci bacteriuria, as well as staphylococcal endocarditis, so urine culture can also help diagnose.

(three) ECG examination

Generally no specificity, in patients with embolic myocardial infarction, pericarditis can show characteristic changes, in patients with ventricular septal abscess or annulus abscess may occur incomplete or complete atrioventricular block, or bundle branch resistance Hysteresis and ventricular premature beats, intracranial aneurysm rupture, can appear "neurogenic" T wave changes.

(4) Radiographic examination

Chest X-ray examination is only helpful for the diagnosis of complications such as heart failure and pulmonary infarction. When patients with replacement artificial valves find that the valve is abnormally shaken or displaced, it may be associated with infective endocarditis.

Computerized tomography (CT) or spiral CT has a certain diagnostic effect on the suspected large aortic valve abscess, but the artifacts of the artificial valve and the pulsation of the heart affect its evaluation of the valve morphology. And depending on the contrast agent and limited cross-section, its clinical application is limited. Magnetic resonance imaging (MRI) is not affected by artificial valve artifacts. When two-dimensional echocardiography can not exclude aortic root abscess, it can Auxiliary, but more expensive.

(5) Echocardiography

The sputum on the valve can be detected by echocardiography, especially in the blood culture-positive infective endocarditis. It can detect the location, size, number and shape of the scorpion, two-dimensional through the chest wall. Echocardiography is very valuable for the early diagnosis of bioprosthetic valve PVE, but it is slightly worse for mechanical valve PVE, because it can show the shape of the former valve well, and it is easy to detect the neoplasms on the biological valve (especially the porcine). The scorpion creatures of the mechanical valve are difficult to determine because of their multiple echoes and multi-variable reflexes, and the scorpion organisms with a diameter less than 2 to 3 mm are detected in the Han dynasty, and sometimes the loose calcification or pseudo sputum on the valve is relatively rare. Difficult to identify.

Recently developed transesophage two-dimensional echocardiography is significantly superior to transthoracic two-dimensional echocardiography. In 90% of cases, neoplasms can be found, and smaller neoplasms with a diameter of 1 to 1.5 mm can be detected without mechanical The effect of the echo caused by the flap is more suitable for emphysema, obesity, thoracic deformity, greatly improving the diagnostic rate, and detecting the degree of valve destruction or perforation, rupture of the chordae, mitral or tricuspid valve Infectious aortic aneurysm and mitral valve disease caused by anterior mitral ventricular effusion injury caused by mitral regurgitation of the anterior mitral valve, as well as various suppurative intracardiac complications, aortic root or Annulus abscess, ventricular septal abscess, myocardial abscess, suppurative pericarditis, etc., and help to determine the original heart disease, assessment of the severity of valvular regurgitation and left ventricular function, can be used to judge the prognosis and determine whether surgery is needed Reference.

(6) Cardiac catheterization and cardiovascular angiography

For the diagnosis of the original heart disease, especially with coronary heart disease, it is possible to estimate the function of the valve. Some people take blood samples from the proximal and distal end of the valve through the cardiac catheter to determine the difference in bacterial count. The site of infection, but cardiac catheterization and cardiovascular angiography may cause embolism of the neoplasms, or cause severe arrhythmia, aggravate heart failure, must be carefully considered, and strictly control the indications.

(7) Radionuclide 67Ga (grain) heart scan

It is helpful for the diagnosis of inflammation and myocardial abscess in endocarditis, but it takes 72 hours to show positive, and the sensitivity is significantly worse than two-dimensional echocardiography, and there are more false negatives, so the clinical application value Not big.

(8) Serum immunological examination

Subacute infective endocarditis has a course of up to 6 weeks, and 50% of rheumatoid factor is positive. After antibiotic treatment, its titer can be rapidly decreased, and sometimes hypergammaglobulinemia or hypocomplementemia can occur. Common in patients with complicated glomerulonephritis, the level of decline is often consistent with renal dysfunction, about 90% of patients with circulating immune complex CIC positive, and often above 100g / ml, than patients with sepsis without endocarditis High, with the value of differential diagnosis, especially for blood culture negative, but pay attention to systemic lupus erythematosus, hepatitis C surface antigen positive patients and other immune diseases, CIC serum levels can also be greater than 100g / ml.

Other tests include the determination of the precipitated antibody in the case of fungal infection, the lectin reaction and the complement binding test, and the determination of the cell wall acid antibody of Staphylococcus aureus.

Diagnosis and differentiation of infective endocarditis

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

Due to the diverse clinical manifestations of this disease, it is often confused with other diseases, with fever as the main manifestation and mild cardiac signs must be identified with typhoid fever, tuberculosis, upper respiratory tract infection, tumor, collagen disease, etc., in the basis of rheumatic heart disease. The disease occurs, the heat is not retreated after adequate antibiotic treatment, heart failure is not improved, and the possibility of rheumatism should be suspected. At this time, attention should be paid to check the changes in the pericardium and myocardium, such as the progressive enlargement of the heart and the galloping. Pericardial rubbing or pericardial effusion, etc., but these two diseases can also exist at the same time, fever, heart murmur, embolization performance sometimes must be differentiated from atrial myxoma.

The disease is mainly manifested by neurological or psychiatric symptoms. In the elderly, attention should be paid to the differentiation of cerebral thrombosis, cerebral hemorrhage and mental changes caused by cerebral arteriosclerosis.

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