Infective endocarditis remains a serious illness in children. Causative bacteria include:

Less often, endocarditis can be caused by enterococci, pneumococci, Pseudomonas spp., and a variety of other less common organisms, including those of the HACEK group (Haemophilus parainfluenzae, Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella species, and Kingella spp.). In addition to bacteria, a variety of fungi can cause infective endocarditis (Candida spp. and Aspergillus), especially in patients treated with broad-spectrum antibiotics and steroids, premature infants, and patients with indwelling catheters.

Pertinent historical features in the patient with infective endocarditis include an underlying heart defect, a recent dental procedure or disease, and a previous episode of
endocarditis. The illness is generally indolent, with an insidious onset that develops over weeks to months. Anorexia, lethargy, fever, weight loss, and night sweats are prominent historical features. Common clinical manifestations include:

Classic findings, such as Janeway lesions (painless lesions on the palms and soles), Osler nodes (painful lesions on the pads of the fingers and toes), and Roth spots (retinal hemorrhages), are seen less often. The key to the diagnosis of endocarditis is a blood culture positive for the causative organism. At least three blood cultures should be obtained and need not be timed to fever spikes. The first blood culture is positive in >90% of the patients with subacute endocarditis. Supporting laboratory findings include anemia, leukocytosis with a left shift, elevated acute phase reactants, and microscopic hematuria.

For a select group of patients the American Heart Association recommends prophylactic antibiotics to prevent the development of bacterial endocarditis. Endocarditis prophylaxis is indicated for patients undergoing dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa, tonsillectomy or adenoidectomy, a surgical procedure, or biopsy involving the respiratory mucosa. In a significant change from prior guidelines, patients undergoing genitourinary and gastrointestinal procedures no longer require endocarditis prophylaxis.

According to the current guidelines, patients with the following conditions should receive prophylactic antibiotics:

Except for the conditions listed in the preceding, antibiotic prophylaxis is no longer recommended for any other form of CHD. A heart murmur alone is not an indication for antibiotic prophylaxis. Specifically, patients with innocent heart murmurs do not require pretreatment.

According to the current recommendations, standard general prophylaxis for dental, oral, respiratory tract, or esophageal procedures includes amoxicillin (50 mg/kg orally 1 hour before the procedure; maximum dose, 2.0 g), clindamycin (20 mg/kg orally 1 hour before the procedure; maximum dose, 600 mg), or cephalexin (50 mg/kg orally 1 hour before the procedure; maximum dose, 2.0 g). For patients unable to take oral medications, intramuscular or intravenous ampicillin, intravenous clindamycin, or intravenous or intramuscular cefazolin or ceftriaxone are acceptable.

Acute rheumatic fever is an immunologic disease, the delayed sequela of group A streptococcal infection of the pharynx. Streptococcal skin infections or infections at other sites do not cause the subsequent development of acute rheumatic fever. The causative Streptococcus organism belongs to the mucoid group A type 18 (M-18). Acute rheumatic fever generally develops 1 to 5 weeks following streptococcal pharyngitis; however, a history of clinical infection may not be obtained. The latent period between the streptococcal infection and the development of isolated chorea may be as long as 2 to 6 months.

The diagnosis of acute rheumatic fever is made according to the revised Jones criteria (Table 26.1). The diagnosis requires evidence of a recent streptococcal infection (elevated antistreptolysin O [ASO] titer or a throat culture positive for group A streptococcus) in addition to the presence of either two major criteria or one major criterion and two minor criteria. Remember that arthralgia cannot be used as a minor criterion when polyarthritis is a major finding, and a prolonged PR interval cannot be used when carditis is a major finding.

The treatment of acute rheumatic fever includes the administration of 0.6 to 1.2 million units of benzathine penicillin G intramuscularly. Anti-inflammatory medications can be given but should be withheld until a definitive diagnosis is established. Bed rest is generally advised during the inflammatory process. For severe carditis or resistant symptoms, steroids can be administered. The prevention of subsequent acute rheumatic fever is highly desirable, and a regimen of 1.2 million units of benzathine penicillin G given intramuscularly every 21 to 28 days is recommended. Less effective alternatives include 250 mg of oral penicillin twice a day or 250 mg of oral erythromycin twice
a day. Prophylactic antibiotics are generally continued through childhood. Lifetime prophylaxis is recommended for patients with valvular involvement or in high-risk occupations, such as teaching.

Kawasaki disease is an immunologically mediated disease of unknown cause. It most commonly affects children between the ages of 6 months and 2 years and presents as total body inflammation.

Because the etiologic agent in Kawasaki disease has not been identified, the diagnosis is based on specific criteria (Table 26.2). For a diagnosis of Kawasaki disease, the presence of fever for 5 days or more must be documented, in addition to at least four of the other five features. Skin changes include papular and maculopapular rashes and erythema multiforme. Conjunctivitis is usually bilateral. Oral pharyngeal changes generally include erythematous involvement of the anterior oral pharynx, cracking of the lips, and reddening of the tongue (strawberry tongue). In addition to the diagnostic criteria, frequently associated clinical findings include severe irritability, abdominal pain, and diarrhea. Other associated findings include:

Typical laboratory findings include leukocytosis, anemia, elevation of acute phase reactants (e.g., erythrocyte sedimentation rate and C-reactive protein), and thrombocytosis. Mild to moderate elevations in serum transaminases occur in 40% of patients, sterile pyuria in 33%, and cerebrospinal fluid (CSF) pleocytosis in 50% of those who undergo lumbar puncture.

The most serious clinical complication of Kawasaki disease is the development of coronary artery aneurysms, seen in approximately 20% of untreated children. Coronary artery aneurysms are diagnosed by echocardiography. Congestive heart failure or arrhythmias can also develop in children with Kawasaki disease. An echocardiogram is required when the diagnosis of Kawasaki disease is considered.

Patients with Kawasaki disease are treated with intravenous immune globulin 2 g/kg as a continuous infusion. In addition, aspirin 80 to 100 mg/kg per day in four divided doses should be administered as soon as Kawasaki disease is suspected. Once the patient is afebrile or when signs of acute inflammation resolve, the aspirin dose is reduced to 3 to 5 mg/kg per day and continued for 6 to 8 weeks. If coronary artery aneurysms develop, aspirin is continued indefinitely. Corticosteroids are not currently recommended for the treatment of Kawasaki disease. However, in cases of resistant or recurrent disease, steroids can be administered.

Pericarditis is an acute inflammation of the pericardium. It is usually idiopathic or secondary to viral infection. Other causes include acute rheumatic fever, bacterial infection (purulent pericarditis), tuberculosis, collagen-vascular disease, and uremia. Pericarditis can also follow cardiac surgery or treatment of malignancy.

The patient may have a history of a preceding upper respiratory illness or a predisposing feature. The hallmarks of the illness include fever and chest pain. The pain is generally precordial, with radiation to the shoulder or neck. It tends to be constant but may be worse when the patient is in the supine position and exacerbated by swallowing or breathing. Clinical examination may reveal a pericardial friction rub. The signs of cardiac tamponade including tachycardia, pulsus paradoxus, jugular venous distension, and hepatomegaly. Distant heart tones may develop if a large pericardial effusion is present. In most cases, pericarditis produces only a small effusion. The electrocardiogram (Fig. 26.1) characteristically shows global ST elevation with flattened or inverted T waves. In addition, a depressed PR segment may be present. Echocardiography may demonstrate a pericardial effusion, but the absence of pericardial effusion indicated on the echocardiogram does not exclude the diagnosis of pericarditis, and echocardiography is not routinely required.