Specific Pediatric Diseases

Kawasaki's Disease

Kawasaki's disease, also known as mucocutaneous lymph node syndrome, was first described in 1967. This disease is a panvasculitis whose victims are primarily children (>80% <4 years of age). Kawasaki's disease is divided into three stages: the acute febrile stage (1 to 2 weeks), the subacute phase, and finally, the convalescent stage (usually 6 weeks after onset). The cause is uncertain but presumed to be infectious. The diagnosis is made when patients fulfill five of six criteria: (1) cervical lymphadenopathy with one node larger than 1.5 cm; (2) mucosal changes, usually the oropharynx, with red, cracked lips; (3) more than 5 days of fever with temperatures of 101°F to 105°F; (4) conjunctival edema and injection; (5) erythema of the palms and soles, often with desquamation after 2 weeks; and (6) an erythematous rash.

Although the disease affects many organ systems, cardiovascular involvement is the usual cause for ICU admission. Forty percent of patients have cardiac involvement with myocarditis, effusion, and arrhythmias. Coronary aneurysms with and without thrombosis develop in 20%. Acute myocardial infarction causes death in 3% to 4% of patients.

Laboratory tests reveal an elevated leukocyte count with a left shift, increased acute-phase reactants, and after the first few weeks, a platelet count that is often grossly elevated. An echocardiogram must be performed in any child with this presumed diagnosis for assessment of the coronary arteries.

Treatment at present is high-dose aspirin (20 to 25 mg/kg every 6 hours) and intravenous gamma globulin, 2 g/kg administered as a 10- to 12-hour infusion. Some patients require inotropic support, and there is much controversy regarding the use of anticoagulation in the face of thrombosis in coronary aneurysms. Survivors of this disease often have resolution of their aneurysms, although some require coronary artery bypass surgery to maintain adequate myocardial perfusion. ^{[79] [80]}

Anomalous Origin of Coronary Arteries

Vascular causes of myocardial ischemia are extremely uncommon in pediatric patients. Anomalous origin of the left coronary artery is one rare exception (incidence of 1:300,000). In this congenital disease, the coronary artery originates from the pulmonary artery. During the first weeks to months of life, when PVR is elevated, coronary perfusion may be adequate. As PVR decreases, however, coronary perfusion falls and, in fact, can become retrograde. These infants usually present with overwhelming myocardial failure at the age of 2 to 6 months. In the presence of large collateral vessels, these patients can survive into adulthood. Treatment is surgical.^[81]