I33.0
DESCRIPTION
Infection of the endothelial surface of the heart.
Suspect infective endocarditis in all children with fever and underlying heart disease.
Antibiotic therapy in these children is highly dependent on the results of microbiology.
DIAGNOSTIC CRITERIA
Clinical
- An underlying heart defect and a persistent low grade fever without an obvious underlying cause.
- Associated other findings include: fatigue, joint pain, new murmurs, clubbing, splenomegaly and haematuria.
- Must be differentiated from acute carditis due to rheumatic fever.
- The Duke criteria have been suggested as a guide to diagnosis, but have definite limitations as they were developed for use in adult patients.
Table 1: Major and minor clinical criteria used in the modified Duke criteria for diagnosis of infective endocarditis (IE)
| MAJOR CRITERIA | MINOR CRITERIA |
|---|---|
|
Positive blood culture: > typical micro-organisms from two separate blood cultures: S. viridans , including nutritional variant strains, S. bovis , *HACEK group, S. aureus , or > Enterococci, in the absence of a primary focus, or > persistently positive blood culture with a micro-organism consistent with IE from blood cultures drawn > 12 hours apart, or > all 3 or a majority of 4 or more separate blood cultures, with the first and last drawn at least one hour apart, or > positive serology for Q fever, > single positive blood culture for Coxiella burnetti or anti-phase 1 IgG antibody titre > 1:800. Evidence of endocardial involvement: > positive echocardiogram for IE (transoesophageal echocardiography is recommended for patients with prosthetic valves): oscillating intracardiac mass, on valve or supporting structures, or in the path of regurgitant jets, or on implanted materials, in the absence of an alternative anatomic explanation, or > abscess, or > new partial dehiscence of prosthetic valve, or, > new valvular regurgitation. |
Predisposing heart condition or IV drug use Fever ≥ 38ºC. Vascular phenomena: > major arterial emboli, > septic pulmonary infarcts, > mycotic aneurysm, > intracranial haemorrhage, > conjunctival haemorrhages, > Janeway lesions. Immunologic phenomena: > Osler’s nodes, > Roth spots, > glomerulonephritis, > rheumatoid factor. Microbiologic evidence: > positive blood culture but not meeting major criterion, or > serologic evidence of active infection with organism consistent with IE. |
*A group of fastidious gram negative organisms originating in the mouth.
Table 2: Modified Duke criteria for diagnosis of infective endocarditis (IE)
| DEFINITE IE | POSSIBLE IE | REJECTED |
|---|---|---|
|
Pathological criteria » Micro-organisms -by culture or histology in a vegetation, or - in a vegetation that has embolised, or -in an intracardiac abscess, or Lesions » Vegetation or intracardiac abscess present – confirmed by histology showing active IE. Clinical criteria » 2 major criteria, » 1 major and 3 minor, or » 5 minor. |
At least one major and one minor criterion, or 3 minor. |
Alternative diagnosis for manifestation of endocarditis, or resolution of manifestations, with antibiotic therapy ≤ 4 days, or no pathologic evidence of IE at surgery or autopsy, after antibiotic therapy for ≤ 4 days. |
Limitations of the Duke Criteria in children
The clinical criteria rely heavily on relatively rare clinical features.
In contrast, common clinical features like splenomegaly, clubbing and haematuria have not been included.
Investigations like CRP or ESR, which may be of value, have also not been included.
Investigations
- Blood cultures:
- Sterile blood culture technique is essential.
- Take three blood cultures (venous) from different sites within 2 hours if very ill, otherwise within 24 hours. There is little benefit of doing more than five blood cultures.
- Child need not necessarily have a fever as patients are mostly constantly bacteraemic.
- Urine test strips – haematuria.
- CRP/ESR may be helpful.
GENERAL AND SUPPORTIVE MEASURES
- Bed rest/limit physical activity.
- Ensure adequate nutrition.
- Maintain haemoglobin > 10 g/dL.
- Measures to reduce fever.
MEDICINE TREATMENT
For heart failure see section 4.9:Heart failure .
For fever:
- Paracetamol, oral, 15 mg/kg/dose, 6 hourly as required.
Antibiotic therapy
Antibiotics are seldom indicated as part of emergency treatment.
It is important to obtain adequate blood culture specimens prior to initiation of antibiotics.
Antibiotics are always given IV.
Empiric treatment
If culture is not yet available or remains negative:
- Benzylpenicillin (Penicillin G), IV, 50 000 units/kg/dose, 6 hourly for 4-6* weeks.
PLUS
- Cloxacillin, IV, 50 mg/kg/dose 6 hourly for 4-6* weeks .
PLUS
- Gentamicin, IV, 3 mg/kg/day for 2 weeks.
*The longer duration of therapy is used for patients with complications or prosthetic valves.
If positive culture available: Consult paediatric cardiologist, infectious disease specialist or clinical microbiologist.
Prophylaxis
The use of prophylaxis is controversial but still recommended.
For children with the following cardiac conditions:
- rheumatic heart disease;
- prosthetic cardiac valve or prosthetic material used in valve repair;
- previous infective endocarditis;
- unrepaired cyanotic heart disease, including palliative shunts;
- during the first 6 months after complete repair of congenital heart defect with prosthetic material or device (complete endothelialisation of prosthesis after 6 months);
- repaired cyanotic heart disease with residual defect at or adjacent to prosthetic patch or device; or
- cardiac transplant recipients who develop cardiac valvulopathy.
Children with the above cardiac conditions should receive prophylaxis when undergoing the following procedures:
- All dental procedures that involve manipulation of gingival tissues or periapical region of teeth or trauma to oral mucosa.
- Prophylaxis is not recommended for procedures involving the GIT, GUT, respiratory tract, skin or soft tissue in the absence of existing infections. (If infections of GIT/GUT are present include cover for enterococcus e.g. amoxicillin or ampicillin, and for infections of respiratory tract, soft tissue and skin include cover for staphylococcus aureus e.g. cloxacillin or cephalexin).
Regimens for dental procedures
- Amoxicillin, oral, 50 mg/kg (maximum 2 g) 1 hour before the procedure.
Patients unable to take oral medication:
- Ampicillin, IV, 50 mg/kg (maximum 2 g) ½ hour before the procedure.
REFERRAL
- All patients with suspected (for echocardiography) and confirmed (for antibiotic and possible surgical management) infective endocarditis as soon as possible.