Endocarditis Flashcards
What is endocarditis?
Infection of the heart valves and other endocardial tissue (membrane that lines the chambers of the heart and covers the valves)
What patient groups are more likely to develop endocarditis?
Hospitalized patients (0.1%)
Patients over 50
Patients who inject drugs
Review slides 5 to 7 for illustration of endocarditis
What is the pathophysiology of endocarditis?
- Altered endocardial surface produces a suitable site for bacterial attachment and colonization
- Formation of platelet-fibrin thrombus on the altered surface
- Endocarditis most commonly happens from hematogenous spread (results in bacterial adhesions and colonization)
- Formation of vegetation of fibrin, platelets, and bacteria (protective cover for the bacteria so it can grow)
What are some characteristics of acute endocarditis?
- Severe and rapid clinical course
- History of bacteremia
- Normal valves are involved (require early treatment as valve may be destroyed in only a few days)
- Often Staph. aureus
What are some subacute characteristis of acute endocarditis?
- Illness often lasts months before diagnosed
- Usually some form of prior valve disease
- History of dental work or procedures
- Usually Streptococcal or Enterococcal
What is early onset prosthetic valve endocarditis?
Usually occurs within 1 year of surgery (usually Staphylococcal. can be gram - bacilli or fungal)
What is late onset prosthetic valve endocarditis?
Usually occurs after 1 year of surgery (same organisms as native valve endocarditis, ex. Strep)
How is prosthetic valve endocarditis treated?
Very hard to sterilize prosthetic valves, so treatment usually involves surgery
What are some risk factors for endocarditis?
- Age over 60
- Male sex
- Structural heart disease (valvular heart disease, congenital heart disease)
- Prosthetic valve
- Prior infective endocarditis
- Intravenous drug use
- Oral hygiene or dental pathology
- See more on slide 13
What is the organismal etiology of endocarditis?
Staphylocci (30-70%)
- Coagulase positive: 20-68%
- Coagulase negative: 3-26%
Streptococci (9-38%)
- Viridans group Strep: 10-28%
Enterococci (5-18%)
How do the organisms responsible for Streptococci associated endocarditis enter the bloodstream?
- Mostly coming from oral and respiratory flora (dental or respiratory tract procedures may introduce bacteria into bloodstream)
- Group D Strep is also found in GI tract
How do the organisms responsible for Staph aureus associated endocarditis enter the blood stream?
Usually seen in patients with history of IV drug use and early prosthetic valve endocarditis
How do the organisms responsible for Enterococci associated endocarditis enter the blood stream?
Found in gut or genitourinary tract (any GI/GU procedure may introduce into blood)
What are some signs and symptoms associated with endocarditis?
- Fever (86-96% of cases), can be low-grade
- Heart murmur (new or worsening of old murmur)
- Fatigue, weakness, weight loss, arthragias, myalgias (non-specific symptoms)
- Osler nodes (3%) and Janeway lesions (5%) (specific signs of endocarditis, see slide 17)
- Splinter hemorrhages, petechiae, vascular embolic events (see slide 18)
What are Osler nodes?
- Purplish SC nodules on tips of fingers and toes
- Painful or tender
- Caused by immune complex deposition
What are Janeway lesions?
Erythematous, non-painful macules on palms and soles
What are splinter hemorrhages?
They are thin, linear hemorrhages under nailbeds
What are petechiae?
- Small, red, painless hemorrhagic lesions
- Frequently on trunk, buccal mucosa, palate and conjunctivae
How do vascular embolic events occur?
- Pieces of vegetation in the heart can break off and can block blood supply in capillary beds (kidneys, lungs, brain, etc.)
What are the characteristics of IV drug use associated endocarditis?
- More often leads to right sided endocarditis
- Often presents as a pulmonary syndrome (fever, cough, hemoptysis(coughing up blood), pleuritic chest pain)
What are some blood lab changes for patients with endocarditis?
- Usually normocytic, normochromic anemia
- Increased WBC
- Increased ESR or CRP (indicate inflammation)
- RF may be increased (in 50% of cases)
What are some other lab tests performed on patients supected of having endocarditis?
Blood cultures and sensitivity:
- Get shedding of bacteria from vegetation
- Obtain 3 samples at different times or sites
- May be negative due to previous antibiotic therapy or difficult
ECG
- Visualize vegetation and see cardiac function and abnormalities
What are some major diagnostic criteria for endocarditis?
- Positive blood cultures (need 3 blood cultures)
- Evidence of endocardial involvement
What are some minor diagnostic criteria for endocarditis?
- Predisposition for infective endocarditis. fever, vascular phenomenon(hemorrhage or emboli), immunologic phenomenon (ex. Osler’s nodes, RF), positive blood culture
What is the minimum requirement for definite endocarditis diagnosis based on diagnostic criteria?
2 major; 1 major and 3 minor; or 5 minor
What is the minimum requirement for possible endocarditis diagnosis based on diagnostic criteria?
1 major and 1 minor; or 3 minor
What is the mortality rate for endocarditis?
In hospital: 15-20%
1 year after infection: approaching 40%
Up to 90% for fungal endocarditis
What damage caused by endocarditis results in relatively high rates of mortality?
- Destruction of valve tissue, fibrosis, abscess
- HF
- Cardiomyopathy
- Septic emboli
- Glomerulonephritis
- Stroke
What is the impact of vegetation on the treatment of endocarditis?
Vegetation protects bacteria from antibodies, macrophages, and antibiotics
What are some characteristics of bacteria encased in vegetation?
Bacteria are in high density with a slow rate of growth within biofilms and low microorganism metabolic activity
- Dense bacteria will produce beta-lactamase at higher concentrations
- Slow growth means fewer active penicillin-binding proteins
- Efficacy of drug varied depending on the degree of penetration into the vegetation, pattern of distribution within, and the size of vegetation