Kawasaki disease (KD), also known as Kawasaki syndrome, lymph node syndrome and mucocutaneous lymph node syndrome is an acute febrile illness of unknown etiology that primarily affects children younger than 5 years of age. KS was first described in Japan by Tomisaku Kawasaki in 1967, and the first cases outside of Japan were reported in Hawaii in 1976. It affects many organ systems, mainly those including the blood vessels, skin, mucous membranes, and lymph nodes; however its rare but most serious effect is on the heart where it can cause fatal coronary artery aneurysms in untreated children.
Signs and symptoms
The usual symptoms and signs of Kawasaki's disease include
reddening of the eyes without pus,
cracked and inflamed lips and mucous membranes of the mouth with an inflamed "strawberry" tongue,
ulcerative gum disease (gingivitis),
swollen lymph nodes in the neck (cervical lymphadenopathy),
joint pain often on both sides of the body,
cough and runny nose, and a rash that is raised and bright red, especially on the palms and soles.
The rash appears in a glove-and-sock fashion over the skin of the hands and feet. The rash becomes hard, swollen (edematous), and then peels off.
Like all autoimmune diseases, the cause of Kawasaki disease is presumably the interaction of genetic and environmental factors, possibly including an infection. The specific cause is unknown, but current theories center primarily on immunological causes for the disease. Evidence increasingly points to an infectious etiology,but debate continues on whether the cause is a conventional antigenic substance or a superantigen. Children's Hospital Boston reported that "some studies have found associations between the occurrence of Kawasaki disease and recent exposure to carpet cleaning or residence near a body of stagnant water; however, cause and effect have not been established."Other data show a clear correlation between KD and tropospheric wind patterns; winds blowing from central Asia correlate with KD cases in Japan, Hawaii and San Diego and indicate a wind-borne pathogen. Efforts are under way to identify the suspected pathogen in air-filters flown at altitude above Japan.
An association has been identified with a SNP in the ITPKC gene, which codes an enzyme that negatively regulates T-cell activation. An additional factor that suggests genetic susceptibility is the fact that regardless of where they are living, Japanese children are more likely than other children to contract the disease. The HLA-B51 serotype has been found to be associated with endemic instances of the disease.
Children with Kawasaki disease should be hospitalized and cared for by a physician who has experience with this disease. When in an academic medical center, care is often shared between pediatric cardiology, pediatric rheumatology and pediatric infectious disease specialists (although no specific infectious agent has been identified as yet). It is imperative that treatment be started as soon as the diagnosis is made to prevent damage to the coronary arteries.
Intravenous immunoglobulin (IVIG) is the standard treatment for Kawasaki disease and is administered in high doses with marked improvement usually noted within 24 hours. If the fever does not respond, an additional dose may have to be considered. In rare cases, a third dose may be given to the child. IVIG by itself is most useful within the first seven days of onset of fever, in terms of preventing coronary artery aneurysm.
Salicylate therapy, particularly aspirin, remains an important part of the treatment (though questioned by some) but salicylates alone are not as effective as IVIG. Aspirin therapy is started at high doses until the fever subsides, and then is continued at a low dose when the patient returns home, usually for two months to prevent blood clots from forming. Except for Kawasaki disease and a few other indications, aspirin is otherwise normally not recommended for children due to its association with Reye's syndrome. Because children with Kawasaki disease will be taking aspirin for up to several months, vaccination against varicella and influenza is required, as these infections are most likely to cause Reye's syndrome.
Corticosteroids have also been used, especially when other treatments fail or symptoms recur, but in a randomized controlled trial, the addition of corticosteroid to immune globulin and aspirin did not improve outcome.
Additionally, corticosteroid use in the setting of Kawasaki disease is associated with increased risk of coronary artery aneurysm, and so its use is generally contraindicated in this setting. In cases of Kawasaki disease refractory to IVIG, cyclophosphamide and plasma exchange have been investigated as possible treatments, with variable outcomes.
There are also treatments for iritis and other eye symptoms. Another treatment may include the use of Infliximab (Remicade). Infliximab works by binding tumour necrosis factor alpha.