Kawasaki disease (mucocutaneous lymph node syndrome) is a febrile, multisystem disorder that occurs almost exclusively in children before the age of puberty. The peak incidence is in boys under 4 years of age. The incidence is higher in late winder and spring. Vasculitis (inflammation of blood vessels) is the principal (and life-threatening) finding because it can lead to formation of aneurysm and myocardial infarction.
The cause of Kawasaki disease is unknown, but it apparently develops in genetically predisposed individuals after exposure to an as-yet-unidentified infection agent. After the infection (perhaps an upper respiratory infection), altered immune function occurs. An increase in antibody production creates circulating immune (antibody-antigen) complexes that bind to the vascular endothelium and cause inflammation. The inflammation of blood vessels lead to aneurysms, platelet accumulation, and the formation of thrombi or obstruction in the heart and blood vessels.
ASSESSMENT
Kawasaki disease begins with an acute phase (stage 1) of high fever (102 to 104 degrees Fahrenheit [39 to 40 degree celcius]) that does not respond to antipyretics. The child acts lethargic or irritable and may have reddened and swollen hands and feet. Soon the bulbar mucous membranes of the eyes become inflamed (conjunctivitis) and the child develops a “strawberry” tongue and red, cracked lips. A variety of rashes occur, often confined to the diaper area. Cervical lymph nodes become enlarged. As internal lymph nodes swell, children may develop abdominal pain, anorexia, and diarrhea. Joints may swell and redden, simulating an arthritic process. White blood cell count and the ESR are both elevated.
About 10 days after the onset, a subacute phase begins. The skin desquamates, particularly on the palms and soles. The platelet count rises; this increases the possibility of clotting, which could result in necrosis of distant body cells, particularly the fingertips, if they no longer receive adequate blood. Aneurysms may form in coronary arteries, compromising heart activity. Sudden death from accumulating thrombi or rupture of an aneurysm may occur, making this the most dangerous phase.
The convalescent phase (stage II) begins at about the 25th day and lasts until 40 days. Stage III lasts from 40 days until the ESR returns to normal. To be diagnosed with Kawasaki disease, a child must manifest fever and four of the typical symptoms: [(1) Fever of 5 or more days duration (2) Bilateral congestion of ocular conjunctivae (3) Changes of the mucous membrane of the upper respiratory tract, such as reddened pharynx; red, dry, fissured lips; or protuberance of tongue papillae (“strawberry” tongue) (4) Changes of the peripheral extremities, such as peripheral edema, peripheral erythema, desquamation of palms and soles (5) Rash, primarily truncal and polymorphous (6) Cervical lymph node swelling. ] plus echocardiographic confirmation of artery disease. Children are followed by sequential echocardiograms to monitor for development of aneurysms.