1. Infective Endocarditis
October 11, 2005
Dr. Kanagala

2. 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

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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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)

13. 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

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

15. 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

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

17. 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

18. 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

19. 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)

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

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

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

31. 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

32. Answers
1) T
2) D
3) A