Overview
Definition:
Infective endocarditis (IE) is a serious infection of the endocardial surface of the heart, including heart valves and intracardiac devices
In children, it often occurs in those with underlying structural heart defects or medical devices.
Epidemiology:
IE is rare in children, with an incidence estimated at 0.03-0.07 cases per 1000 patient-years in developed countries
The incidence is higher in neonates and immunocompromised children
Congenital heart disease (especially ventricular septal defects, patent ductus arteriosus, and complex cyanotic heart disease) and indwelling central venous catheters are major risk factors.
Clinical Significance:
Prompt diagnosis and management of IE are crucial to prevent severe complications such as heart valve destruction, systemic embolization (stroke, splenic infarcts, renal infarcts), development of abscesses, and death
Understanding the Duke criteria is vital for accurate diagnosis and guiding management strategies in pediatric patients.
Clinical Presentation
Symptoms:
Fever, often persistent and unexplained
Malaise and fatigue
Arthralgias or myalgias
New or worsening heart murmur
Shortness of breath
Chest pain
Abdominal pain
Splenomegaly
Petechiae, splinter hemorrhages, Janeway lesions, Osler's nodes
Embolic phenomena (stroke, organ infarction).
Signs:
Fever
Tachycardia
New or changed heart murmur (most common finding)
Splenomegaly
Signs of peripheral emboli (petechiae, splinter hemorrhages in nail beds, Janeway lesions on palms/soles, Osler's nodes on fingertips/toes)
Signs of heart failure (dyspnea, edema, hepatomegaly).
Diagnostic Criteria:
The modified Duke criteria, adapted for children, are used for diagnosis
They rely on clinical findings, microbiological evidence, and echocardiographic findings
A definitive diagnosis is made with pathological evidence of IE or two positive blood cultures and a positive echocardiogram, or one positive blood culture plus echocardiographic findings, or clinical evidence of definite IE with at least one of the modified Duke criteria met.
Diagnostic Approach
History Taking:
Detailed history of fever duration and characteristics
Presence of known congenital heart disease or acquired valvular disease
History of indwelling central venous catheters, recent surgery, or dental procedures
Recent antibiotic use
Symptoms suggestive of embolization (neurological deficits, abdominal pain, flank pain).
Physical Examination:
Thorough cardiovascular examination to detect murmurs, gallops, or rubs
Examination of skin for petechiae, splinter hemorrhages, Osler's nodes, and Janeway lesions
Palpation for splenomegaly
Neurological assessment for signs of stroke or embolic events
Examination of extremities and abdomen.
Investigations:
Blood cultures: At least three sets from different sites, ideally before antibiotic therapy
Positive blood cultures with typical organisms are crucial
Echocardiography: Transthoracic echocardiogram (TTE) is the initial imaging modality
transesophageal echocardiogram (TEE) may be needed for better visualization, especially in older children
Echocardiographic findings include vegetations, valve leaflet perforation, abscess, or prosthetic valve dehiscence
Laboratory tests: Complete blood count (CBC) with differential (leukocytosis, anemia), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) (elevated inflammatory markers)
Urinalysis (hematuria may suggest renal involvement).
Differential Diagnosis:
Other causes of fever in children: Viral infections (influenza, adenovirus), acute rheumatic fever, Kawasaki disease, systemic lupus erythematosus, post-pericardiotomy syndrome, bacteremia without endocarditis, non-infective endocarditis (e.g., Libman-Sacks endocarditis in SLE), myocardiitis.
Management
Initial Management:
Prompt empiric antibiotic therapy should be initiated after obtaining blood cultures, especially in critically ill patients
Consultation with pediatric infectious disease and pediatric cardiology is essential.
Medical Management:
Antibiotic therapy is guided by blood culture results and local susceptibility patterns
Duration is typically 4-6 weeks
For native valve endocarditis, common empiric regimens include a beta-lactam (e.g., penicillin, ampicillin, or ceftriaxone) plus an aminoglycoside (e.g., gentamicin)
For prosthetic valve endocarditis, regimens often include vancomycin, gentamicin, and ceftriaxone or cefotaxime
Specific antibiotic choices and doses must be tailored based on organism sensitivity and patient factors
Careful monitoring for therapeutic response and drug toxicity is critical.
Surgical Management:
Indications for surgery include: severe valve dysfunction leading to heart failure, uncontrolled infection (persistent fever despite antibiotics, large vegetations), recurrent emboli, prosthetic valve dehiscence, or abscess formation
Surgery may involve valve repair or replacement
Early surgical intervention can significantly improve outcomes.
Supportive Care:
Intravenous fluid management
Antipyretics for fever control
Pain management
Monitoring for complications such as heart failure, emboli, and arrhythmias
Nutritional support and psychological support for the child and family.
Complications
Early Complications:
Heart failure due to severe valvular damage or regurgitation
Systemic embolization to the brain (stroke), spleen, kidneys, or limbs
Abscess formation in the myocardium, pericardium, or other organs
Rupture of chordae tendineae.
Late Complications:
Chronic valve damage requiring valve replacement
Residual cardiac dysfunction
Recurrence of endocarditis
Renal failure
Neurological sequelae from embolic events
Osteomyelitis or septic arthritis from spread of infection.
Prevention Strategies:
Prophylaxis against IE is recommended for children at high risk before certain dental or invasive procedures
High-risk patients typically include those with prosthetic cardiac valves, previous IE, unrepaired congenital heart disease, or repaired congenital heart disease with residual defects
Recommended antibiotics include amoxicillin (oral) or ampicillin/ceftriaxone/cefazolin (intravenous)
Regular dental and medical follow-up for children with cardiac conditions is crucial.
Prognosis
Factors Affecting Prognosis:
The presence of congenital heart disease, the specific organism involved (e.g., Staphylococcus aureus has a worse prognosis than viridans streptococci), the extent of valve damage, the development of heart failure, and the occurrence of embolic events significantly impact prognosis
Prompt diagnosis and appropriate treatment are paramount.
Outcomes:
With modern management, the mortality rate for IE in children has decreased significantly but remains substantial, especially in neonates and those with complex conditions
Survivors may experience long-term morbidity related to valvular damage and embolic sequelae.
Follow Up:
Children who have recovered from IE require long-term follow-up by pediatric cardiology and potentially infectious disease specialists
This includes regular echocardiographic monitoring to assess valve function and rule out recurrence, monitoring for embolic complications, and ongoing dental prophylaxis.
Key Points
Exam Focus:
Remember the major and minor Duke criteria for diagnosing IE in children
Understand the high-risk patient populations and the importance of blood cultures and echocardiography
Know the indications for surgical intervention and antibiotic prophylaxis guidelines for dental procedures.
Clinical Pearls:
Consider IE in any child with unexplained fever and a new murmur, or known congenital heart disease
Early echocardiography is key
Prompt antibiotic therapy after blood draws is critical
Think about embolization to any organ system.
Common Mistakes:
Delaying blood cultures before starting antibiotics
Underestimating the role of echocardiography in diagnosis
Failing to consider IE in children with central venous lines
Inadequate duration or inappropriate choice of antibiotic therapy
Not considering prophylaxis in high-risk patients.