Infective Endocarditis October 11, 2005 Dr. Kanagala

Microbiology: Organisms Responsible Bacteria are the predominant cause Fungi Rickettsia Chlamydia Microorganisms vary dependent on risk factors predisposing patient to IE Staph Aureus= single most common cause

Native Valve Endocarditis Streptococcus responsible for more than 50% of cases Staphylococci Enterococci Infection occurs most frequently in those with preexisting valvular abnormality

Staphylococci Causes endocarditis in those with normal and abnormal valves Most are coagulase positive S.Aureus Causes destruction of valves, multiple distal abscesses, myocardial abscesses, conduction defects, and pericarditis

Enterococci Patients generally have underlying valvular disease May occur following manipulation of genitourinary or lower gastrointestinal tract Remainder of cases caused by Haemphilus Actinobacillus, Cardiobacterium, Eikenella, Kingella, Bartonella, or Coxiella Burnetti

Diagnosis Negative culture can occur in 5% of patients. 1/3 to ½ are negative due to prior antibiotic use In patients with culture negative IE, advise lab to allow specialized testing to recover the causative organism which is needed to adequately treat

IDU associated IE Skin flora and contaminated injection devices are the most frequent sources involved in IDU-associated IE S. Aureus – Most common (50% of cases) Streptococcal species Gram negative Bacilli Pseudomonas Serratia species Fungi Candida

Prosthetic Valve Endocarditis Most commonly occur during the perioperative period S. epidermidis Most frequently isolated organism Early PVE (w/i 60 days of surgery) Assoc. with valve dysfunction and fulminant clinical course Late PVE (beyond 60 days postop) Disease course is less fulminant Mycotic PVE (Aspergillus and Candida) Larger vegetations

Clinical Features Acute IE – Rapid onset of high fevers and rigors with hemodynamic deterioration and death within days to weeks if not treated Assoc. with highly virulent organisms such as Staph Aureus Subacute IE – Indolent course with progressive constitutional signs and symptoms and gradual deterioration Assoc. with avirulent organisms such as viridans streptococci

Clinical Features Bacteremia can produce signs and symptoms that are often nonspecific usually within 2 weeks of infection Most common course of disease (fevers, chills, nausea, vomiting, fatigue and malaise) Fever is the most common symptom Fever can be absent in pts with antibiotic use, antipyretic use, severe CHF, or renal failure Prosthetic valve patient with a fever requires IE work up

Cardiac Clinical Features Heart murmurs are present in up to 85% of cases of IE. Most commonly regurgitant lesions secondary to valvular destruction Acute or progressive CHF is the leading cause of death in patients with IE (70% of patients) Distortion or perforation of valvular leaflets Rupture of the chordae tendinae or papillary muscles Perforation of the cardiac chambers (rare) Valvular abscesses and Pericarditis Heart blocks and Arrhythmias

Embolic Clinical Features Extracardiac manifestations are the result of arterial embolization of fragments of the friable vegetation CNS complications occur in 20-40% of cases (embolic stroke with MCA affected most frequently) Retinal artery emboli may cause monocular blindness Mycotic aneurysm may cause a SAH IVDU can cause right sided lesions (tricuspid valve) – Pulmonary complications Pulmonary complications ( pulmonary infarction, pneumonia, empyema, or pleural effusion) Coronary artery emboli (Acute MI or myocarditis with arrhythmias) Splenic infarction (LUQ abdominal pain) Renal emboli (flank pain or hematuria)

Clinical Features Persistent bacteremia can stimulate the humoral and cellular immune systems resulting in circulating immune complexes Petechiae – Red, nonblanching lesions that become brown after several days (20-40%) Conjunctivae, buccal mucosa, and extremities Splinter hemorrhages – Linear dark streaks under the fingernails (15%) Osler’s nodes – Small tender subcutaneous nodules that develop on the pads of the fingers or toes (25%) Janeway lesions – Small hemorrhagic painless plaques located on the palms or soles Roth spots – Oval retinal hemorrhages with pale centers located near the optic disc

Diagnosis Diagnosis of IE requires hospitalization Cultures Echocardiogram Clinical observation Duke Criteria – 90% sensitive Major Criteria Minor Criteria

Major Criteria Positive blood culture for: Strep bovis, Strep viridans, or HACEK group Staph aureus or Enterococci Microorganisms c/w IE from persistent positive blood cultures 2 positive blood cultures drawn >12 hrs apart All of 3 or a majority of 4 or more positive blood cultures

Major Criteria Echocardiographic involvement: Mass on valve Abscess Dehiscence of prosthetic valve New valvular regurgitation

Minor Criteria Predisposition: Heart condition or injection drug use Fever > 38 degrees C Vascular: Emboli, conjunctival hemorrhages, janeway lesions Immunological: Glomerulonephritis, osler’s nodes, roth spots, and rheumatoid fever Positive blood cultures Echocardiographic findings c/w IE

Duke Criteria Definite infective endocarditis Microorganisms demonstrated by culture or histologic examination of vegetation or emboli Abscess with active endocarditis Two major criteria One major and three minor criteria Five minor criteria Possible endocarditis Findings c/w IE that fall short of definite, but not rejected Rejected Firm alternate diagnosis Resolution of manifestations of IE with abx for < 4 days No pathologic evidence of IE at surgery or autopsy after 4 days of abx

DDx and Consideration of IE IE should be considered in: All febrile IDUs Pts with a cardiac prosthesis and fever (or malaise, vasculitis or new murmur) Pts with new murmur or change in murmur with evidence of vasculitis or embolization Any cardiac risk factor with unexplained fever Any patient with a prolonged fever (>2 weeks)

Evaluation of Bacteremia All patients with suspected bacteremia should have blood cultures drawn in the ED prior to abx Blood cultures should be drawn in 3 different sites Minimum of 10 ml blood in each bottle Minimum of one hour between first and last bottle

Diagnostic Tests ECG should be done in all pts with suspected IE Nonspecific usually Conduction abnormalities ( new LBBB, Prolonged PR interval, new RBBB, complete heart block) Junctional tachycardia Chest Xray Pulmonic emboli or CHF Nonspecific lab tests Anemia (70-90% of cases) Elevated ESR (>90% of cases) Hematuria

Echocardiography Mandatory in all pts with possible IE Transthoracic Echo(TTE) should be done first. Specificity for vegetations is 98% Sensitivity varies but it is the highest with IDUs because they more often have larger vegetations, right sided valvular lesions and favorable precordial windows. Transesophageal Echo(TEE) has a higher sensitivity and specificity than TTE Recommended for the following: Prosthetic valves Pts with obesity, chest wall deformities, COPD Intermediate or high probability of IE

Treatment Initial Stabilization Rapid airway stabilization secondary to possible respiratory or hemodynamic compromise( acidosis, altered mental status, sepsis) Cardiac decompensation may occur secondary to left sided valvular rupture Intraaortic balloon counterpulsation may be indicated Neurologic complications such as stroke Standard stroke protocol

Empiric Treatment Therapy of suspected Bacterial Endocarditis Uncomplicated history Ceftriaxone or nafcillin plus gentamycin IVDU, Congenital heart disease, MRSA, current abx use Nafcillin plus gentamycin plus vancomycin Prosthetic heart valve Vancomycin plus gentamycin plus rifampin Most patients will require 4 to 6 weeks of antibiotic therapy

Surgical Treatment Indications for surgical management: Severe valvular dysfunction: Acute CHF or impaired hemodynamic status Relapsing prosthetic valve endocarditis Major embolic complications Fungal endocarditis New conduction defects or arrhythmias Persistent bacteremia

Anticoagulation Anticoagulation for native valve endocarditis has not been shown to be beneficial Increase the risk of intracranial hemorrhage Pts with prosthetic valves who are treated with anticoagulation can be maintained on their regimen with proper caution for CNS complications

IE Prophylaxis Prophylaxis is indicated for: Prosthetic heart valves Congenital cardiac manifestations Acquired valvular dysfunction Hypertrophic cardiomyopathy Mitral valve prolapse with documented regurgitation History of endocarditis Not indicated for the following: MVP without regurgitation Pacemakers Physiologic murmurs Prior CABG, angioplasty, ASD repair, VSD, or PDA

IE Prophylaxis Dental, oral, respiratory or esophageal procedures Amoxicillin or Ampicillin or Clindamycin Genitourinary, gastrointestinal procedures Ampicillin plus Gentamycin plus Ampicillin (post) or Amoxicillin Alternate regimen: Vancomycin plus Gentamycin

Question 1: T/F Streptococcus is responsible for more than 50% of Native Valve Endocarditis.

Question 2: Embolic clinical features of infective endocarditis include: A) CNS complications B) Pulmonary complications C) Coronary Artery Emboli D) All of the above

Question 3: Small hemorrhagic painless plaques located on palms or soles are called? A) Janeway lesions B) Osler’s nodes C) Roth Spots D) Splinter hemorrhages

Answers 1) T 2) D 3) A