Endocarditis, Infective

Key Features

Essentials of Diagnosis

• Positive blood culture

• Intracardiac oscillating mass, abscess, or new valve regurgitation on echocardiogram

• Fever

• Elevated erythrocyte sedimentation rate or C-reactive protein

General Considerations

• Bacterial or fungal infection of the endocardium

  • Rare

  • Usually occurs in the setting of a preexisting abnormality of the heart or great arteries

  • May occur in a normal heart during septicemia or as a consequence of infected indwelling central catheters

• The frequency of infective endocarditis (IE) appears to be increasing for following reasons

  • Increased survival in children with congenital heart disease (CHD)

  • Greater use of central venous catheters

  • Increased use of prosthetic material and valves

• Children without preexisting heart disease are also at increased risk for IE because of

  • Increased survival rates for children with immune deficiencies

  • Long-term use of indwelling lines in ill newborns and patients with chronic diseases

  • Increased injection drug use

• Children at greatest risk

  • Those with unrepaired or palliated cyanotic heart disease (especially in the presence of an aorta to pulmonary shunt)

  • Those with implanted prosthetic material

  • Those who have had a prior episode of IE

• Common causative organisms

  • Viridans streptococci (30–40% of cases)

  • Staphylococcus aureus (25–30%)

  • Fungal agents (about 5%)

Clinical Findings

• Fever, malaise, and weight loss

• Joint pain and vomiting are less common

• New or changing murmur

• Splenomegaly

• Hepatomegaly

Diagnosis

• Laboratory findings

  • Multiple positive blood cultures

  • Elevated erythrocyte sedimentation rate or C-reactive protein

  • Hematuria

• Transthoracic echocardiography can identify large vegetations in some patients

• However, transesophageal imaging has better sensitivity

Treatment

• Appropriate antibiotic therapy should be initiated as soon as IE is suspected

• Therapy can be tailored once the pathogen and sensitivities are defined

• Vancomycin or a β-lactam antibiotic, with or without gentamicin, for a 6-week course is most common regimen

• Surgical excision of the infected area and prosthetic valve replacement must be considered if heart failure occurs and progresses despite adequate antibiotic therapy

Outcome

Prevention

• Conditions requiring antibiotic prophylaxis

  • Prosthetic cardiac valves

  • Prior episode of IE

  • CHD

  • Cardiac transplant with valvulopathy

• IE prophylaxis is not recommended for

  • Gastrointestinal or genitourinary procedures

  • Body piercing

  • Tattooing

• Recommended prophylaxis

  • 50 mg/kg of oral amoxicillin for patients < 40 kg

  • 2000 mg of oral amoxicillin for those > 40 kg

  • Dose is to be given 1 hour prior to procedure

Prognosis

• Factors associated with a poor outcome

  • Delayed diagnosis

  • Presence of prosthetic material

  • Perioperative associated IE

  • S aureus infection

• Mortality for bacterial endocarditis in children ranges from 10% to 25%, with fungal infections having a much greater mortality (50% or more)

Reference