Endocarditis in the elderly

Introduction to endocarditis in the elderly Endocarditis in the elderly is also divided into two categories: infectious and non-infective. The former is more common, so this article only focuses on infective endocarditis (IE). In streptococcal-infected endocarditis, it has been observed that the type of Streptococcus strains varies with age. For example, people aged 35-55 years are often Staphylococcus aureus, while those aged >55 are Streptococcus bovis and intestines. Cocci are common. Endocarditis caused by Streptococcus bovis bacteremia is associated with lower gastrointestinal damage such as polyps and colon cancer in the elderly; endocarditis caused by enterococci and urinary tract infection of prostate disease in elderly male patients related. Staphylococcus has become a common pathogen of infective endocarditis. According to statistics, infective endocarditis in the elderly accounts for 20% to 30%. Golden, epidermis and Staphylococcus aureus can cause disease, mainly after heart valve replacement and cardiac catheterization. The incidence of Gram-negative bacilli endocarditis in the elderly is not low. The main strains are Escherichia coli, Klebsiella enterica, Pseudomonas and Serratia, caused by Escherichia coli. Heart valve infections often come from abdominal infections. In addition, some intestine Gram-negative bacilli that are difficult to grow and require special nutrition, that is, the infectious heart caused by Haemophilus, Actinobacter, H. solanium, and Gibberella are collectively called "HACEK" group. Endometritis has also been reported. In addition, there are fungi, anaerobic bacteria, rickettsia, chlamydia, spirochetes and viruses. Cardiac basal lesions induce endocardial injury: the underlying lesions that induce endocardial injury in the elderly are common with degeneration, mainly degenerative calcification lesions, such as aortic valve calcification or mitral annulus calcification, mitral valve prolapse, There are also rheumatic diseases, congenital anomalies or intraoperative cardiac injuries, blood regurgitation due to valvular lesions or deformities, disparity in pressure gradients, and disordered blood flow due to stenosis of the valve orifice or abnormal passages. Injury, it has also been reported that the intimal injury is caused by the direct deposition of immune complexes on the endocardium during infection. Autopsy has shown that 30% to 50% of the elderly have not confirmed the underlying lesions, some of which are extremely mild degenerative lesions. It is difficult to find even at autopsy, but it can become a lesion of the endocardium. basic knowledge The proportion of illness: 0.002%-0.005% Susceptible people: the elderly Mode of infection: non-infectious Complications: congestive heart failure, arterial embolism, arrhythmia, myocarditis, aneurysm

The cause of endocarditis in the elderly

Causes

1. Pathogens: The main pathogens infected by elderly patients are streptococcus and staphylococcus.

In streptococcal-infected endocarditis, it has been observed that the type of Streptococcus strains varies with age. For example, people aged 35-55 years are often Staphylococcus aureus, while those aged >55 are Streptococcus bovis and intestines. Cocci are common. Endocarditis caused by Streptococcus bovis bacteremia is associated with lower gastrointestinal damage such as polyps and colon cancer in the elderly; endocarditis caused by enterococci and urinary tract infection of prostate disease in elderly male patients related.

Staphylococcus has become a common pathogen of infective endocarditis. According to statistics, infective endocarditis in the elderly accounts for 20% to 30%. Golden, epidermis and Staphylococcus aureus can cause disease, mainly after heart valve replacement and cardiac catheterization.

The incidence of Gram-negative bacilli endocarditis in the elderly is not low. The main strains are Escherichia coli, Klebsiella enterica, Pseudomonas and Serratia, caused by Escherichia coli. Heart valve infections often come from abdominal infections. In addition, some intestine Gram-negative bacilli that are difficult to grow and require special nutrition, that is, the infectious heart caused by Haemophilus, Actinobacter, H. solanium, and Gibberella are collectively called "HACEK" group. Endometritis has also been reported.

In addition, there are fungi, anaerobic bacteria, rickettsia, chlamydia, spirochetes and viruses.

2. Invasion pathway: With the development of modern medicine, dental, genitourinary, gastrointestinal and respiratory or device examinations are widely carried out, and bacteremia is correspondingly increased. Some treatments such as long-term hemodialysis, cardiac surgery, increasing venous catheter operation and infusion, prosthetic valve replacement, and intravenous anesthesia addiction can all become endocarditis infection pathways. Bacteremia caused by acne, systemic infection, and decreased host defense ability is also susceptible to infective endocarditis.

3. Susceptibility factors: In organic heart disease, the proportion of rheumatic heart disease and congenital heart disease decreased, and mitral valve prolapse, senile degenerative valvular disease, artificial valve, artificial cardiac pacemaker There is a tendency for concurrent infective endocarditis to increase. It has been reported that in native valvular infective endocarditis, aged degenerative heart disease accounts for 21%. Prosthetic heart valves, aortic valve disease, mitral regurgitation, and various congenital heart diseases are risk factors for infective endocarditis, mitral stenosis, pulmonary valve disease, idiopathic hypertrophic aorta Subvalvular stenosis and calcific aortic sclerosis are risk factors for infective endocarditis. In recent years, mitral valve prolapse has been emphasized, especially in patients with reflux, which is more likely to develop infective endocarditis.

The incidence of degenerative valvular disease and calcific aortic atherosclerosis in the elderly is high. The increase in the number of valve replacement surgery in the elderly and the increase in the pace of artificial heart pacemaker implantation may be related to the increased incidence of the elderly.

Pathogenesis

Various studies have shown that the pathogenesis of infective endocarditis often forms tiny thrombi on the basis of endocardial injury induced by basal lesions, and then adheres to it by bacteria, further activating the coagulation mechanism to produce infectious neoplasms and increasing Diffusion, described as follows:

1. Cardiac basal lesion-induced endocardial injury: The underlying lesions induced by the elderly in endocardial injury are common with degeneration, mainly degenerative calcification lesions, such as aortic valve calcification or mitral annulus calcification, mitral valve prolapse In addition, there are rheumatic diseases, congenital anomalies or intraoperative cardiac injuries, blood regurgitation due to valvular lesions or deformities, disparity in pressure gradients, and disordered blood flow due to stenosis of the valve orifice or abnormal passages. Intimal injury has also been reported to cause endometrial damage due to direct deposition of immune complexes on the endocardium during infection. Autopsy has shown that 30% to 50% of the elderly have not confirmed the underlying lesions, some of which are extremely mild. Degenerative lesions, even at autopsy, are difficult to detect, but can become lesions of the endocardium.

2. Microthrombus formation: When the endocardial cells are damaged, the underlying matrix is exposed and activates the coagulation mechanism, triggering platelet and fibrin deposition to form a tiny thrombus, which is the birthplace of infection. The autopsy is found in the mitral valve and aorta. The closed line of the valve is often the site of microthrombus formation, and this is precisely the site of endocervitis.

3. Bacterial adhesion: It is known that bacteria must adhere to the surface of the endocardium to cause infection. It has been found that the glucan synthesized by bacteria plays an important role in bacterial adhesion. The test tube test demonstrates the ability of bacteria to adhere to the platelet-fibrin matrix. It is proportional to the amount of glucan produced. Studies have also shown that the adhesion of bacteria is also affected by the strain. For example, actinomycetes, diphtheria or enterobacteria have been detected in blood culture, but rarely occur. Endocarditis; on the contrary, such as Streptococcus viridans and Staphylococcus aureus are very easy to adhere, it is the main pathogen of endocarditis.

4. Formation and expansion of neoplasms: Studies have shown that except for Staphylococcus aureus, which directly promotes coagulation by its own staphylococcal coagulase, most other bacteria stimulate the valve tissue to release tissue by means of bacteria that have adhered to the surface of the valve. Thrombinogenase, which activates the coagulation mechanism, forms infectious nervons through a series of complex chain-locking processes.

Experiments have shown that bacteria adhere to the intimal thrombus often accompanied by mononuclear and multinucleated cell infiltration. After 3 to 6 hours, bacterial colonies appear and are embedded in the thrombus. After 24 hours, the neoplasms increase and begin to be mechanized. When cells phagocytose Staphylococcus epidermidis or Streptococcus sanguis, tissue thromboplastin is produced, so it plays an important role in the formation and expansion of neoplasms.

In summary, the mechanism of infective endocarditis can be:

1 formation of non-bacterial thrombotic neoplasms, damage to endothelial cells, fibrin and platelet deposition;

2 The human body releases the pathogenic bacteria into the blood circulation;

3 pathogenic bacteria are attached to the mites, followed by fibrin and platelet aggregation, covering the pathogen colonies and becoming the basis of sputum;

4 The bacteria can grow and breed here. The process of these processes forms an infection. After that, the infection continues to evolve: the local rupture of the sputum, releasing the pathogen into the blood circulation, producing transient bacteremia; Local invasion of the organism leads to abnormal intracardiac conduction system, annulus abscess and pericarditis, aortic sinus aneurysm and valve perforation; infected sputum fragments are detached, causing peripheral circulation embolism; existing antibodies in blood form immune with infectious bacteria antigen Complex.

Elderly endocarditis prevention

Infective endocarditis in the elderly is a disease with high treatment difficulty and mortality. Therefore, prevention of this disease is more important than active treatment. It is mainly for the elderly to take precautionary measures for the cause of this disease. Better results.

For example, the elderly often suffer from dental caries, periodontal disease, etc., and are prone to streptococcal bacteremia during dental treatment. Therefore, intramuscular injection of procaine penicillin 1.2 million U and streptomycin 1 g for urinary administration 1 h before treatment. Gram-negative bacilli or enterococci bacteremia may also occur in the department, gynecological or gastrointestinal examination or surgery. Therefore, antibiotics should be given 1 hour before surgery and once every 12 hours.

Especially in the elderly patients undergoing prosthetic valve replacement, antibiotics should be given prophylactic treatment before and after surgery, because the risk of infection and the possibility of bacteremia are great in valve replacement, in addition to the heart In elderly patients with valvular surgery or nasopharyngeal surgery, antibiotics should be given orally or intramuscularly 1 hour before surgery to prevent infective endocarditis.

However, Vander Meer et al. objected to the use of antibiotics to prevent autologous valve endocarditis, and their clinical observations showed that the preventive effect was only 6%.

Elderly endocarditis complications Complications Congestive heart failure Arterial embolism Arrhythmia Myocarditis Aneurysms

Heart failure

Congestive heart failure is the most common complication of patients with infective endocarditis and can occur at any stage. Compared with other complications, heart failure can seriously affect the prognosis and efficacy of infective endocarditis. Causes of death, severe valve damage, myocardial abscess and embolic myocardial infarction are the main causes of heart failure.

2. Embolization

About 2/3 acute endocarditis complicated with arterial embolism, and subacute patients account for about 1/3, according to the order of incidence of brain, lung, heart, spleen and limb arteries, because the elderly often have atheroma It is also prone to arterial embolism. The consequences of embolization depend on the size of the embolus and the embolization site.

3. Other

In addition, there are myocardial infarction, conduction disorders, arrhythmia, myocarditis and myocardial abscess, and rare complications include bacterial aneurysms, renal dysfunction and metastatic infections.

Myocardial abscess is a rare complication of inflammatory endocarditis after valve replacement. According to reports in the literature, this complication accounts for only 0.5% to 2.0% of mitral valve replacement, and the mortality rate is 75%. It is rarer and gradually spreads to the ventricular wall. In severe cases, it can penetrate the ventricular wall. The infection of myocardial abscess is common with Staphylococcus aureus, followed by Pneumococci and Streptococcus.

Elderly endocardial inflammation symptoms Common symptoms Loss of appetite, fatigue, sorrow, back pain, slow muscle pain, coma, heart failure, renal failure, arrhythmia

Due to the changes in the underlying heart disease and pathogenic microorganisms of infective endocarditis and the significant changes in therapeutics, the typical clinical manifestations that have been considered in the past have also changed, fever, heart enlargement, loss of appetite, fatigue, ESR and anemia are still the main clinical manifestations, while splenomegaly, skin blemishes, clubbed toes, Osler nodules, Janeway knots are rare, and heart murmurs and new murmurs are rare.

When the elderly suffer from illness, the clinical manifestations are often atypical. The course of the disease is slow and gradually deteriorates. It often begins with non-characteristic symptoms such as weakness, discomfort, anorexia, weight loss, joint pain or myalgia.

Fever

Most patients have fever, the heat type is irregular, or it can be intermittent or relaxation type. The body temperature is generally lower than 39.5 °C, but about 1/3 of the elderly patients have no fever, may have used antibiotics before fever or Hormone, unresponsive to infection, old age, extremely weak or accompanied by severe heart failure or kidney function

Failure, even if confirmed to have bacteremia, can also be expressed as athermal bacteremia.

Anemia

This is one of the more common symptoms, mainly due to the inhibition of bone marrow caused by infection, mostly mild, moderate anemia, severe anemia can occur in advanced patients, and red blood cells and hemoglobin are progressively decreased.

3. Heart

Patients often suffer from heart failure due to perforation of the valve or chordae, myocardial abscess and embolic myocardial infarction, mostly congestive heart failure. Heart failure is the most serious complication of this disease, and the most common cause of death. Once heart failure occurs, The patient's prognosis is extremely poor.

Physical and cardiac murmurs may be caused by damage to the underlying heart disease and/or endocarditis. When new fever is present, a new heart murmur is present, which strongly suggests the diagnosis of infective endocarditis. According to statistics, the disease Aortic valve involvement is 42%, mitral valve is 48%, tricuspid valve is rare, most patients can hear heart murmur, but the murmur is light, soft mid-tone early contraction murmur, often explained as Fever, anemia and other non-cardiac causes, 25% to 33% of elderly patients can not hear murmurs, only congestive heart failure or extracardiac symptoms of unknown cause, arrhythmia and death can occur when the lesions involve the conduction system Sexual block, coronary embolism can occur with or without symptoms of acute myocardial infarction.

4. The nervous system

Cerebral embolism can cause sudden onset of various transient or persistent neurological syndromes. About one-third of elderly patients may have neurological symptoms and signs, such as delirium, confusion, language disorder, hemiplegia or coma. These symptoms mainly come from Thrombosis, embolism, cerebral hemorrhage, subarachnoid hemorrhage, fungal aneurysm or brain abscess, etc., the occurrence of symptoms depends on the location of vascular lesions, the hemiplegia caused by middle cerebral artery embolization is as high as 15%, can also be expressed For other forms of cerebrovascular disease such as brain abscess, encephalitis and meningitis, the mortality rate of cases with neurological damage is as high as 55%.

5. Kidney

Renal damage is also the main clinical manifestation of elderly patients. Renal embolism can be characterized by renal pain, hematuria and proteinuria. Leukocytes and casts can be seen in urine sediment. Occasionally, renal artery embolism can lead to ischemic necrosis and acute renal failure. .

6. Other

About 20% of elderly patients may have peripheral vascular damage, common defects, linear hemorrhage, Roth nodules, Janeway knots, Osler's nodules and clubbing, splenic embolism may have left upper abdominal pain, spleen area can be heard Friction sound, splenomegaly is rare, only 15%, skeletal muscle system symptoms such as joint pain, back pain, diffuse myalgia of the lower extremities are more common in elderly patients, often mistaken for rheumatism, but also due to lung, intestine The corresponding clinical symptoms appear in the extremity arterial embolism.

Examination of endocarditis in the elderly

Blood culture: blood culture has a definite value in the treatment of infective endocarditis, and provides a basis for treatment. Domestically, the positive rate of blood culture is 25% to 44%, and that of foreign countries is 63% to 92%. Take 3 to 5 times of blood in the first 24 to 48 hours, each time 10ml, blood can increase the positive rate when fever, the blood sample has been diluted with the antibiotics 20 times with the medium, if used penicillin plus penicillin enzyme, used cephalosporin The high-permeability medium should be routinely used for aerobic and anaerobic cultures. If necessary, special culture can be carried out for certain special microorganisms. The medium should not be discarded before the end of treatment, as a reference for the selection of antibiotics.

Echocardiography

This has become one of the main means of diagnosing infective endocarditis. It can detect infective endocarditis by detecting neoplasms. It can also provide information about valvular damage, hemodynamic changes and complex complications. Information, transesophageal echocardiography has emerged in recent years, and the value in infective endocarditis is significantly better than M-mode echocardiography and transthoracic echocardiography. The advantage of transesophageal echocardiography by using the esophagus close to the anatomy of the heart To make the structure of the heart clearer, it is to place the echocardiographic sensor in the endoscope, showing the structure of the heart from the esophagus, avoiding the interference of the chest wall and the lung through the chest wall. Shapiro et al reported that 44 cases have typical valves. The patient's examination results of sputum, the transesophageal echocardiography detection rate was 33/44, and the transthoracic echocardiography was 23/44, there was a significant difference between the two, and transesophageal echocardiography to detect smaller neoplasms Better, but ultrasound has its limitations:

1 may be calcified, thickened, valve leaf or chordae rupture as a neoplasm.

2 It is not easy to determine whether the lesion is an active infection, especially in relapse.

3 and aseptic thrombotic endocarditis is difficult to identify.

4 ultrasound results can not rule out infective endocarditis.

2. Nuclide check

For example, 67Ga scan can show infection. Recently, 99mTc-labeled anti-NCA-95 anti-granulocyte antibody has been reported to be concentrated in infective endocarditis infection, which can be used as an auxiliary diagnostic tool for echocardiography to improve infectivity. The rate of diagnosis of endocarditis.

3. Other

Direct measurement of specific pathogen antigens and antibodies, such as immunoprecipitation experiments and complement-binding assays, cardiac catheterization, rarely used for the diagnosis of infective endocarditis, because of the risk of paralysis, sometimes only used to understand Valve severity and hemodynamic changes.

Diagnosis and identification of endocarditis in the elderly

Diagnostic criteria

The diagnosis of infective endocarditis is mainly based on bacteremia or fungalemia, evidence of active valvular disease, peripheral vascular embolism and immune vascular phenomenon. It is mainly used for the diagnosis of infective endocarditis. The standard has two diagnostic criteria, BETH ISRAEL and DUKE. Currently, the revised DUKE diagnostic standard is common.

Revised DUKE diagnostic criteria:

Main standard

(1) Positive blood culture:

1 From the two different blood, there are microorganisms with typical infective endocarditis such as Streptococcus pyogenes and Streptococcus bovis HACEK.

2 Staphylococcus aureus or Enterococcus in the absence of a previous lesion.

3 Sustained blood culture positive was determined as re-ignition of microorganisms causing infective endocarditis.

4 blood culture blood samples are separated by 12h; or 5 in 3 parts, or the first and fourth parts of the majority of 4 parts are at least 1h apart.

(2) Evidence involving the endocardium:

1 a positive finding of echocardiography, such as on the valve or its supporting structure, or on a reflux pathway, or on a heart implant, or lack of anatomically well-argued drifting intracardiac mass; myocardial abscess; Partial cracking of the newly repaired valve.

2 A new valve regurgitation occurs (new murmurs or changes in existing murmurs occur).

2. Secondary criteria

(1) Susceptible: susceptible to heart conditions or intravenous drug use.

(2) Body temperature: 38 °C.

(3) vascular phenomenon: major arterial embolism, septic pulmonary embolism, fungal aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway knot.

(4) Immune phenomenon: glomerulonephritis, Osler nodules, Roth spots, rheumatoid factor.

(5) Echocardiography: the performance of infective endocarditis, but lack of the above main diagnostic conditions.

(6) Microbiological evidence: Serological basis for microbial active infection consistent with the main diagnostic conditions and infective endocarditis.

Differential diagnosis

1. Identification with febrile diseases: such as typhoid fever, malaria, upper respiratory tract infections and certain malignant tumors.

2. Identification of active rheumatism: Most patients with rheumatism are young people. Sodium salicylate can often alleviate symptoms; blood culture is positive, embolism, sputum and spleen enlargement are seen in infective endocarditis, sometimes two If the disease exists at the same time, anti-rheumatic treatment should be tried.

3. Embolization of infective endocarditis: Sometimes the symptoms of embolized organs can be clearly misdiagnosed as independent diseases, such as misdiagnosed as encephalitis, kidney stones, anemia, etc., elderly patients should also be associated with atherosclerosis Plaque aorta is distinguished by embolization of plaque aorta.

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