Keywords: subacute infective endocarditis

    Pathogenesis

    Oral surgery, abortion, childbirth or urinary tract surgery, heart surgery or respiratory infections, the bacteria can enter the bloodstream, the body’s defense mechanisms, multi-harmful. But when the bacteria attached to the existing heart valve lesions or endocardial, local platelets, fibrin deposition, enveloping the bacteria forming vegetation phagocytes phagocytosis of bacteria are difficult to play, when the vegetation rupture shedding the bacteria is released into the blood several times, the formation process of repeated chronic bacteremia.

    Certain predilection sites of infective endocarditis, occurred at the impact of blood flow or local eddy parts, such as atrial surface of mitral regurgitation, aortic regurgitation ventricular surface, right ventricular septal defect ventricular surface arterial ductus pulmonary artery intimal surface.

    Chronic course of subacute infective endocarditis Department of vegetation on bacteria difficult to wipe out, long-term survival, less migration infections occurred due to the low bacterial virulence.

    Clinical manifestations

    Most cases slow onset, fever, weakness, fatigue, and a small number of acute onset, chills, fever, or embolic phenomena have oral surgery, some patients before the onset of respiratory tract infection, a history of miscarriage or childbirth.

    Systemic infection fever is the most common, and often has unexplained persistent fever for more than a week, irregular fever, more than 37.5 ℃ -39 ℃ for intermittent fever or remittent fever, accompanied by fatigue, night sweats, conducted anemia, splenomegaly, late clubbing of the fingers.

    Second, the cardiac performance inherent in the signs of a heart attack, due to the growth of vegetation or off, changing valves, tendons destruction, noise, or a new murmur. The absence of noise can not be other than endocarditis exist, with advanced heart failure can occur. When the infection spread to the atrioventricular bundle or ventricular septal cause atrioventricular block and bundle branch block, rare arrhythmia may have premature beats or atrial fibrillation.

    Embolic phenomena and disease losses

    (A) of the skin and mucous membrane lesions caused by the toxin infection and bleeding capillaries make it brittle increase or microembolization. In the limbs to the skin and eyes alkaline conjunctival, oral mucosal petechiae batches, there may be slightly higher than the surface of purple or red Albright (Osler) nodules in the fingers, toes distal palm, also available in the palm of your hand or foot a small nodular bleeding the point (Janewey nodules), no tenderness.

    (B) cerebrovascular disease losses can have the following performance:

    ① meningoencephalitis like tubercular meningitis, cerebrospinal fluid pressure, protein and increased white blood cell count, normal chloride or sugar quantitative. (2) cerebral hemorrhage persistent headache or meningeal irritation caused by bacterial aneurysm rupture. ③ cerebral embolism patients with fever, sudden onset of paralysis or blindness. (4) central retinal embolism can cause sudden blindness.

    (C) renal embolism is the most common, accounting for about 1/2 of the cases, gross or microscopic hematuria, severe renal insufficiency often due to bacterial infection, the antigen – antibody complex deposition in the renal vessels ball, causing kidney glomerulonephritis results.

    (D) pulmonary embolism is common in congenital heart disease and infective endocarditis cases, more than in the right ventricle or pulmonary artery intimal surface vegetation, the incidence of acute chest pain, dyspnea, hemoptysis, cyanosis or shock. Infarct size is small, no obvious symptoms.

    Can also have coronary embolism, acute infarction, splenic embolization left upper abdominal pain or left hypochondrium pain, fever and local friction rub. Mesenteric artery embolization, manifested as acute abdomen, blood in the stool. Can embolism limbs pale chills limb arterial embolism, arterial pulse weakened or disappeared, limb ischemia and pain.

    Diagnostic tests

    “><Laboratory and other tests

    A positive blood culture can confirm the diagnosis and to provide a basis for the selection of antibiotics. Should pay attention to in order to provide a positive culture rate following: ① antibiotics before application, continuous culture 4-6 times. ② each blood volume 10ml, for aerobic and anaerobic culture. ③ longer incubation time, less than three weeks. ④ culture results positive for drug susceptibility testing.

    Blood have progressive anemia, white blood cell count is normal or increased.

    Third, the ESR

    Urine proteinuria and hematuria, about 1/3 of patients with advanced renal insufficiency.

    Echocardiography Figure heart valve or endocardial wall vegetation, and the inherent abnormalities of the heart disease.

     “><Diagnosis and differential diagnosis

    Early diagnosis depends mainly on the vigilance of the disease, where patients with structural heart disease, unexplained fever for more than a week, you need to consider the possibility of this disease. Blood culture and sensitivity test and should be immediately sent continuously. Blood culture positive diagnosis of the disease and its pathogen. Multiple blood culture negative, should pay attention to rheumatic fever recurrence or left atrial myxoma, non-bacterial endocarditis were identified. The only heart murmur, fever, blood culture negative, needs and long-term fever disease, such as tuberculosis, brucellosis tumor, lymphoma, liver abscess identify. If there is bleeding or embolism phenomenon, although helpful in the diagnosis of this disease, but the majority has entered the late stage of the disease.

    Treatment measures

    First, the application of antibiotics antibiotics according to pathogen culture results or sensitivity to antibiotics. Bacteria more than to be overshadowed by the fibrin, platelets, bacteria located in the deep of the vegetation, The antibiotics only by plasma penetration into the vegetation. The principles of the use of antibiotics: (1) selection of fungicides, such as penicillin, streptomycin, cephalosporin, vancomycin. The ② dose to be large. Vitro bactericidal concentration administered 4-8 times. For sterilization drops price determination, the product of serum dilution blood culture bacteria, such as 1:8 or higher drops price sterile growth and effective antibiotic dose is enough to. ③ treatment should be enough. It normally takes 4-6 weeks, extended to 8 weeks of antibiotic sensitivity of bacteria or complications stubborn cases. Treatment ④ soon as possible. 4-6 times and then began a trial treatment in the continuous blood culture, based on clinical features and possible routes of infection, pathogens can choose a combination of two different antimicrobial spectrum antibiotics.

    Second, the drug of choice

    (A) of the pathogen is not clear who-β-lactam ring antibiotics (penicillins, cephalosporins) and aminoglycoside antibiotics (streptomycin, kanamycin, gentamicin) combination of most bacteria killing effect, it can be the first choice, first G1000-2000 million units of penicillin intravenously, and intramuscular streptomycin daily 1.0g, effective, continuous application of about six weeks. If the treatment fails, switch to benzoyl isoxazole penicillin, 6-12g a day or two methicillin daily 6-12g, intravenous infusion of vancomycin, can also be used daily 2-3g points 4-6 intravenous injection or intravenous drip. Cephalosporins broader antimicrobial resistance can also use such antibiotics penicillin. The first-generation cephalosporins strong second and third-generation cephalosporins in addition to the aforementioned role of gram-negative bacilli also has a strong antibacterial effect against Gram-positive cocci role. Such as the ring ethylene amines cefotaxime (cephalosporin VI) complex reached new (cephalosporin it may be), daily 4-8g, 3-4 intravenous, Zinacef (cefuroxime) day 1.5 -4.5g, 3-4, intravenously. Blood culture positive antibiotic type and dose adjustment based on susceptibility circumstances.

    Pathogens were Gram-positive cocci (b), the choice of the aforementioned drug combination therapy, should pay attention to the application of large doses of penicillin G ① plus probenecid to slow penicillin penicillin concentration can be excreted by the kidneys, improve 4 times, no significant renal dysfunction, can be probenecid per 0.5g, orally, 3-4 times a day. ② penicillin G potassium salt per 100 million units of potassium ion 39.1mg, large doses should pay attention to hyperkalemia.

    (C) Gram-negative bacilli infections, refer to the table, or may choose to cefotaxime.

    (D) fungal infection available amphotericin liquid infusion 10mg joined for the first time, after each increase of 5-10mg / d until 0.5-1mg/kg/d, the total dose of 3.0g, a total of six weeks. The garlic liquid 5 – fluorocytosine, dense itraconazole or ketoconazole have some role, but the effects are not as good as amphotericin.

    * Synergistic the sulfa Department sulfamethoxazole 0.4g + the trimethoprim 0.08g mixture

    The general medication 3-5 days, if the temperature dropped, leukopenia, heart rate, effective treatment, there is still no effect as the full dose antibiotic treatment stopping a few days, you need to observe, sending blood culture.

    The excrescence exist antibiotics completely control the disease difficult, anticoagulant therapy can not inhibit the formation of vegetation, and the effects are certainly also difficult, and the risk of organ hemorrhage.

    Standard cure and relapse treatment, body temperature returned to normal, the spleen reduced symptoms disappeared in the course of antibiotics after the first, second and sixth weeks respectively for blood culture no recurrence, such as clinical blood culture negative, can be considered cured. Approximately 5-10% of the rate of recurrence of the disease, more than six weeks after stopping recurrence, relapse and more associated with the following situations: (1) before treatment longer duration the ② antibiotics are not sensitive dose or course of treatment, ③ serious lung, brain or heart the intima of damage. Antibiotic dose should be increased above situation by treatment, treatment should be extended treatment of recurrence, should be taken in combination, increase the dose and prolonged treatment.

    Surgical treatment of the following circumstances need to consider surgery: (1) valve perforation, rupture, chordal transection occurred refractory acute heart failure. The ② workers valve replacement surgery infection, medical treatment can not be controlled. The ③ concurrent bacterial aneurysm rupture or limbs, the main artery embolization. Of infective endocarditis, the ④ congenital heart disease treatment by the system, and still can not control, surgery should be carried out as soon as possible to strengthen the supportive therapy and antibiotics to control.

    “><Prognosis

    The prognosis and treatment of this disease sooner or later, the antibiotics of the pathogen’s ability to control the degree of heart valve damage and patients resistance. Postoperative prosthetic valve infections, particularly gram-negative bacilli and mildew infection with the worst prognosis. Multiple recurrent poor prognosis.

    “><Prevention

    Rheumatic heart disease or congenital heart disease, should pay attention to oral hygiene, timely processing of infected lesions should be given antibiotics to prevent surgical equipment inspection. Endocarditis tend to occur in about two weeks after surgery.