Endocarditis

• • Infection of any part of cardiac endothelium (usually bacterial)

  • Valves most frequently involved

  • -Vegetations may destroy leaflets or embolize

  • Abscess formation can cause heart block or persistent sepsis

  • Subacute: Symptoms for months, usually caused by hemolytic streptococci

  • Acute/fulminant: Days to weeks; typically caused by S aureus

  • Result in aortic regurgitation (AR), failure, sepsis, emboli

Epidemiology

• • Patients at risk for endocarditis include those with congenital or preexisting valvular defects, indwelling cardiac catheters, or prosthetic heart valves

  • Injection drug users and persons with prosthetic heart valves have highest incidence of gram-negative bacterial and fungal infections

  • Fourth leading cause of life-threatening infections in United States

Symptoms and Signs

• • Fever, bacteremia, peripheral emboli

  • Immunologic vascular phenomena:

  • -Glomerulonephritis

    -Osler's nodes (painful, erythematous nodules on pulp of fingers)

    -Roth spots (retinal hemorrhages)

  • Subungual splinter hemorrhages: Peripheral hemorrhages

  • Janeway lesions: Flat, painless red spots on palms and soles of feet

Laboratory Findings

• • 3 sets of blood cultures 1 hr apart: Positive

  • Culture-negative endocarditis occurs in < 5% of cases (due to antibiotics, fastidious organism, fungal infection)

  • ECG

  • -Nonspecific usually

    - PR prolongation may be seen in cases of annular abscess and is ominous

Imaging Findings

• • Chest film:

  • -Signs of heart failure including interstitial pulmonary edema and cardiomegaly

    -Parenchymal nodules (septic emboli) seen in right-sided heart involvement

  • Echocardiography: Document location and degree of valve involvement, vegetation size, presence of annular abscess

  • Catheterization: Contraindicated if aortic valve vegetations or annulus abscess

• • Evaluate for other sites of endovascular infection

  • Evaluate for secondary effects on cardiac muscle function

• • Vegetations > 1 cm (especially on mitral valve) have higher risk of embolization

• • IV antibiotics

  • Acute AR from endocarditis poorly tolerated

  • -Pulmonary edema, congestive heart failure rapid

  • AV replacement with allograft preferred due to high resistance to infection

  • Mitral valve repair with debridement of vegetation and pericardial patch reconstruction is possible in a small fraction of patients

Surgery

Indications

• • Severe valvular regurgitation with heart failure

  • Abscess of valve annulus

  • Persistent bacteremia > 7 days with adequate antibiotic therapy

  • Fungal or gram-negative bacterial infection

  • Recurrent emboli

  • Mobile vegetations > 1 cm

Prognosis

• • Untreated mortality is nearly 100%; parenteral antibiotics, 30-50% mortality

  • Overall mortality with antibiotics and surgery is 10%

  • Many injection drug users die of prosthetic valve infection or drug overdose after repair

References