Endocarditis_CMC_2010

Endocarditis_CMC_2010 - Infective Endocarditis Shehla...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Infective Endocarditis Shehla P.Islam, M.D. Division of Infectious Diseases University of Florida Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Case s s s At midnight on July 2, your first night on call as an intern, you've just admitted 5 patients and are crosscovering for your co-intern. You got a call from the micro lab. One of the patients your colleague admitted earlier that day, one set of the blood cultures is positive, growing gram positive cocci. The patient is a 40 y.o. female with a history of asthma. One day PTA, she was seen in the ER with several days of low grade fevers, and the initial work up was unrevealing. Blood cultures were drawn and she was sent home. She came back with persistent low grade fevers, and now has pleuritic chest pain and some shortness of breath. Her admission WBC was 10.2 with a left shift, CXR showed small left pleural effusion s What would you do at this time? 1. This is bacterial endocarditis; I'd start her on vancomycin STAT 2. draw one more set of blood cultures to be sure, and start her on vancomycin 3. draw 2 more sets of blood cultures, and start her on vancomycin 4. could be a contaminant; I'd draw 2 more sets of blood cultures and hold off on abx 5. it's probably a contaminant (coag negative staph); hold off on abx, order tylenol STAT, and go back to bed Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Epidemiology s s s >50% of case over age 50 male:female 1.7:1 Aortic valve and Mitral valve most common (age dependent) Tricuspid rarer (iv drug abusers) Pulmonary valve exceedingly rare Outline s s s s s s Epidemiology Pathogenesis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Pathogenesis s s Host factors Nonbacterial thrombotic endocarditis (NBTE) Venturi effect Bacterial factors Bacterial adherence Transient bacteremia "Vegetation" s Nonbacterial Thrombotic Endocarditis (NBTE) s s s Damage to the endocardium results in the deposition of platelets, and fibrin Causes of endocardial damage include: 1. Rheumatic heart disease (age 10-35) 2. Bicuspid Valve (age 50-60) (Most common) 3. Calcific Aortic Stenosis (age 60-70) 4. Mitral Valve Prolapse (murmur present) 5. Marfan's Syndrome No risk factor in 38% (J.Infect. 38:87-93, 1999) Pathogenesis Venturi effect s s s Pressure gradient required producing a highvelocity jet stream. The high flow results in a Venturi effect (a low pressure area adjacent to the area of high flow) Bacteria to settle in this area of low pressure. s In mitral regurgitation on atrial side, in aortic regurgitation on aortic side Venturi Bacterial Adherence s s Accounts for the preponderance of certain organisms Adherence of oral streptococci to NBTE may depend on the production of a complex extracellular polysaccharide, dextran. S. aureus: ability to destroy normal valves s Transient Bacteremia s s s Procedure or action Dental Dental extraction Periodontal surgery Chewing gum Tooth brushing Oral irrigation device Upper airway Bronchoscopy Intubation s s % + Blood Cultures 18-85 32-88 15-51 0-26 27-50 s 15 16 Transient Bacteremia (cont) s s Gastrointestinal Upper GI endosc. Sigmoidoscopy Barium Enema Liver Bx percutan. Urologic Urethral dilatation Urethral Catheter Cystoscopy Transurethral prostatectomy s 8-12 0-9.5 11 3-13 s 18-33 8 0-17 12-46 The Vegetation s s s Platelet fibrin complex provides a protective environment. Phagocytes incapable of entering, eliminating an important host defense Pathogenic bacteria often induce platelet aggregation Colony counts in vegetations 10 9-10 11 bacteria/g of tissue Is Prophylaxis Useful? s s s s Efficacy of prophylaxis has never been proven s Risk of one dental procedure causing endocarditis = 1/400 s To prove efficacy would need a huge study. Who would agree to be in the placebo group? No relationship between bleeding during dental procedure and bacteremia Amoxacillin po 1 hr. before the procedure only for high risk patients prosthetic material prior endocarditis congenital heart disease Use bacteriocidal abtibiotics time it so that peak serum level is at the time of the procedure Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Case (back to the patient) s s s 40 yo female with low grade fevers and GPC in blood You decided that you want to get more hx She tells you that 2 week prior to admission, she had removed a splinter from her foot. Over the past week, she has low grade fevers, malaise, and generalized weakness, but no pulmonary/GI/GU Sx Clinical Manifestations s s s s Incubation period usually < 2 wks Time of onset of symptoms until Rx 4-5 wks Hx: Fever 80% Fatigue History in Infective Endocarditis s Fever Chills Weakness Sweats Anorexia Weight loss Malaise Cough Arthralgia/Myalgia Back pain s 80% 40% 40% 25% 25% 25% 25% 25% 15% 10% Physical Findings in IE s Fever Heart murmur Embolic phenomenon Skin manifestations Oslers nodes Splinters Petechiae Janeway lesion Splenomegally Clubbing Retinal lesion s 90% 85% >50% 18-50% 10-23% 15% 20-40% <10% 20-57% 12-52% 2-10% Case s s You decided to review her admission lab values WBC 9.0 Hct 30 (MCV 90) Cr 1.2 ESR 95 Q: WBC count is normal, this can't be endocarditis 1. True 2. False Laboratory Findings in IE s s s s s s Normochromic, Normocytic anemia (90%) WBC usually normal, can be increased High ESR (90-100%) Positive Rheumatoid factor (50%) Hypergammaglobulinemia (20-30%) (false positive lyme or VDRL serology) Proteinuria (50-65%), hematuria (30-50%) Case s s The next day right before rounds, you got another call from the micro lab. Both sets of initial BCx turned out to be S. aureus, and the BCx you drew overnight (12 hours later from the initial BCx) are also postive, and is growing gram positive cocci You presented the case to your medical attending, and you're asked: What do you think the patient has? (i.e. what is your diagnosis?) s s s s s 1. this is obviously S. aureus endocarditis 2. she has S. aureus bacteremia, and possibly has endocarditis 3. she has S. aureus bacteremia, but no evidence of endocarditis 4. hmmm, let me look up the Duke criteria, and get back to you in an hour 5. I'll call ID consult and they'll tell us the diagnosis Quantitation of Bacteremia in IE Abscess Endocarditis Time (hrs) Blood Cultures in IE s s s s s Blood Cultures (15 min intervals) Yield 85-95% on 1st BC 95-100% on the 2nd Recommend 3 BC in the 1st 24 hrs. Low level bacteremia, 100 bacteria/ml Draw at least 10 ml/BC If HACEK group suspected hold 4 wks. Prior antibiotics within 2 wks lower sensitivity "Why are blood cultures so often falsenegative, making it necessary that three be drawn?" s s Only falsely negative if the patient has received antibiotics before blood cultures What is your next step to confirm the diagnosis of endocarditis? s s s s s s s 1. order EKG 2. draw more blood cultures 3. order TTE (transthoracic echo) 4. order TEE (transesophageal echo) 5. order both TTE and TEE 6. call infectious disease consult 7. call cardiology consult Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Cardiac Echo in IE s s Transthoracic(TTE): sensitivity 65% If negative order a transesophageal echo Transesophageal(TEE): sensitivity 95-100% Can detect vegetations < 10 mm Helpful in assessing the need for surgery Detects perivalvular extension Use in the initial evaluation for suspected IE (if prior probability 4-60%) (useful in S. aureus line sepsis 2 vs 4 wk abx) Modified Duke Criteria for Diagnosis of IE (Clin. Inf. Dis. 30:633, 2000) s Definite Infective Endocarditis - 2 major - 1 major & 3 minor - 5 minor s Possible Infective Endocarditis - 1 major & 1 minor - 3 minor Major Criteria s s s + Blood cultures for endocarditis - 2 separate + B.C. with typical organisms including S. aureus associated with line sepsis (OR) - Persistent (2 + 12 h apart or 3 + over 1 h) Evidence of endocardial involvement + echo (patients with Possible IE a TEE is recommended) (OR) - new regurgitant murmur Positive Q fever serology or single +BCx for Coxiella burnetii Minor Criteria s s s s s Predisposing heart condition or IVDU Fever > 38C Vascular phenomenon Immunologic phenomenon Single positive BC with typical organism Etiologic Agent in IE Etiologic Agent in IE s s s s s Streptococci Viridans Streptococci Enterococci Other Streptococci Staphylococci Coagulase + Coagulase Gram Negative aeorobic Fungi Culture Negative 60-80% 30-40% 5-18% 15-25% 20-35% 10-27% 1-3% 1.5-13% 2- 4% <5-24% HACEK s s Fastidious organisms, slow growing Hold blood cultures x 4 wks, Subculture on chocolate agar, 5%CO2 s Haemophilus aphrophilus s Actinobaccillus actinomycetemcomitans s Cardiobacterium hominus s Eikenella s Kingella An Additional cause of Culture Neg Tropheryma whippelii Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) Cardiac Complications of IE s s s s Congestive Heart Failure Myocardial abscess/pericarditis Conduction defects can progress to complete heart block (which valve most commonly is associated with this complication?) Myocardial Infarction Other Complications of IE s s s Emboli - CNS, Splenic, Lung (Rt sided IE) Immune-complex glomerulonephritis Mycotic aneurysms Occur at bifurcations -Middle cerebral artery -Adominal aorta -Mesenteric arteries Case s s s 1. 2. 3. 4. 5. 6. TTE showed a small vegetation on the tricuspid valve, there is no abscess BCx ultimately grew MSSA She is currently on vancomycin, what would you do? Penicillin 20 million units per day x 6 weeks Oxacillin 10 gms per day x 4 weeks Doxycycline 100 mg iv twice per day x 4 weeks Penicillin 20 million units per day combined with gentamicin 80 mg 3 x per day x 2 weeks Chloramphenicol 400 mg four times per day x 4 weeks Ceftriaxone 1 gm per day x 6 weeks "I found the antibiotic therapy for infective endocarditis section difficult and slightly overwhelming." Outline s s s s s s Epidemiology Pathogenesis & Antibiotic prophylaxis Clinical Manifestations Diagnosis (TEE & Modified Duke Criteria) Complications Treatment (emphasis on early surgery) s IV antibiotics s consider surgery evaluation Antibiotic Treatment s Prolonged parenteral therapy required Privileged environment of vegetation High number of organisms some dormant s s Avoid Bacteriostatic agents Serum bacteriocidal level of possible value (1:64 peak, 1:34 trough = 100% cure) s Important to follow up blood cultures to document sterilization Antibiotic Treatment (Continued) s s s Penicillin susceptible Streptococci (MBC 0.1-1 ug/ml) PCN x 4 wks or PCN + gentamicin x 2 wk Enterococci (High risk of relapse, MBC to PCN high) PCN (ampicillin) and Gentamicin x 4-6 wks Staphylococcus aureus (coagulase +) Oxacillin or Nafcillin x 4-6 wks Surgery for IE s s s Threshold has lowered Delay to often results in a fatal outcome due to irreversible L. ventricular dysfunction Indications: (1) Refractory CHF, (2) more than one systemic embolus, (3) uncontrolled infection, (4) resistant organisms, (5) perivalvular/myocardial abscess Focal neurological deficit is not a contraindication for surgery Conclusions: Infective Endocarditis s s s s s s s Usually requires an NBTE except S. aureus Organisms that cause IE increased adherence Clinical symptoms usually nonspecific Always look for embolic lesions Duke criterion, importance of timed Blood Cultures, use of TEE Privileged environment of vegetation requires prolonged cidal antibiotics Low threshold for surgery This 51 yo WF presented with a C.C. of: Fever, myalgias, nausea, vomiting and diarrhea Mrs S. had a long history of asthma requiring corticosteroids. Otherwise she was healthy until 2 days PTA when she experienced the sudden onset of fever . Fever was associated with nausea, vomiting and watery diarrhea, as well as a generalized HA. 1 day PTA she noted the acute onset of sharp pleuritic chest pain along the lateral aspect of her left chest wall. She had no weight loss. She noted 1 week prior to admission she had removed a splinter from her foot. PE: Temp 38.4, HR. 112, BP 127/69, RR 28, GENERAL: Small female lying in bed, complaining of chest pain. SKIN: No rashes or evidence of microemboli Fundi: no hemorrhages. . HEART: Normal S1., S2 No murmurs, rubs or gallops. All pulses intact. LUNGS: Decreased breath sounds at the left base, broncho-vesicular BS, e to a changes ABDOMEN: Nontender, no organomegally EXTREMITIES: No edema. NEUROLOGICAL EXAM: No focal deficits LAB: WBC 17,000 (80% PMN, 10 Bands) Hct 27 ESR 140 CXR: moderate sized left pleural effusion, several "cannon ball-like" iniflitrates BC pending, cardiac echo pending s s Host factors usually involves formation of a predisposing cardiac lesion. Endocardial damage that has occurred previously leads to accumulation of fibrin and platelets, leading to the formation of a NBTE. This lesion now can serve as an ideal site to trap bacteria. I would have expected that they would infect the right side of the heartor get "stuck" in the lung capillaries before they made it to the left side of the heart. s American Heart Prophylaxis s s Penicillin does not reduce the level of bacteremia Cumulative exposure is often hundreds of times greater than a single procedure "I don't understand why prophylaxis has not been proven... if you provided consistent antibiotic therapy, should it be able to overcome and even prevent the "cumulative exposure" s This 51 yo WF presented with a C.C. of: Fever, myalgias, nausea, vomiting and diarrhea Mrs S. had a long history of asthma requiring corticosteroids. Otherwise she was healthy until 2 days PTA when she experienced the sudden onset of fever . Fever was associated with nausea, vomiting and watery diarrhea, as well as a generalized HA. 1 day PTA she noted the acute onset of sharp pleuritic chest pain along the lateral aspect of her left chest wall. She had no weight loss. She noted 1 week prior to admission she had removed a splinter from her foot. PE: Temp 38.4, HR. 112, BP 127/69, RR 28, GENERAL: Small female lying in bed, complaining of chest pain. SKIN: No rashes or evidence of microemboli Fundi: no hemorrhages. . HEART: Normal S1., S2 No murmurs, rubs or gallops. All pulses intact. LUNGS: Decreased breath sounds at the left base, broncho-vesicular BS, e to a changes ABDOMEN: Nontender, no organomegally EXTREMITIES: No edema. NEUROLOGICAL EXAM: No focal deficits LAB: WBC 17,000 (80% PMN, 10 Bands) Hct 27 ESR 140 CXR: moderate sized left pleural effusion , several "cannon ball-like" infiltrates BC pending, cardiac echo pending s ...
View Full Document

Ask a homework question - tutors are online