Excerpt from Mucocutaneous Lymph Node Syndrome (Kawasaki Disease)

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Diagnostic criteria have been set by the American Heart Association (see History). The hallmarks of KD are fever of unknown origin for more than 5 days, generalized erythema and desquamation, cervical nonsuppurative lymphadenopathy, and swelling of the hands and the feet.

Originally called mucocutaneous lymph node syndrome, KD was first recognized in Japan in 1967 by Dr Tomisaku Kawasaki. He reported 50 children over a 6-year period who manifested this constellation of distinctive findings. Since then, KD has been observed worldwide in children and adult patients of all races. However, Asians are most commonly affected; some 140,000 cases have been diagnosed in Japan since Kawasaki's original report.

Pathophysiology: The etiology of KD is unknown. Epidemiologic features and clinical manifestations imply an infectious etiology. To date, several infectious causes of KD have been theorized; these include Ebstein-Barr virus; retroviruses; Streptococcus pyogenes; Streptococcus viridans; Staphylococcus species; Chlamydia infections; and Staphylococcus, Propionibacterium, and Pseudomonas species. However, conventional bacterial and viral cultures and serologic studies have not confirmed an infectious cause. Other postulated etiologic agents are immunizations; medications; and environmental agents, such as exposure to rug shampooing agents or house dust mites. Whether genetic factors confer susceptibility to KD is not known. A current hypothesis is that KD is caused by a ubiquitous infectious agent in certain individuals who are genetically predisposed, especially Japanese and Korean children.

The finding of a skewed T-cell receptor response (VB2T) in the myocardium and coronary arteries led to a search for superantigens, such as toxic shock syndrome toxin-1 (TSST-1) produced by Staphylococcus aureus, as a possible cause of KD. However, others have been unable to confirm this hypothesis.

Immunohistochemical staining shows an inflammatory infiltrate of predominantly CD4⁺ (helper-induced) T lymphocytes and CD13 macrophages, but no CD20 B cells. An increased tumor necrosis factor a concentration is found in the epidermis and on blood vessel walls, whereas human leukocyte antigen DR (HLA-DR) (class II MHC molecules) are expressed by keratinocytes and endothelial cells. These immunohistochemical findings lend to the hypothesis of proinflammatory cell-mediated immune reactions possibly triggered by a superantigen or a conventional antigen.

Frequency:

• In the US: KD occurs worldwide in children of all races. It is most prevalent in Japan, with a 10 times higher incidence than those reported in Western countries. Although primarily an illness of young children, 38 reports in the English-language literature have documented KD in adults. Even though the initial reports of adult KD in the United States may have actually represented toxic shock syndrome, the occurrence of KD in adults should be acknowledged. A year-round disease occurrence exists, but a greater number of cases are seen in the winter and the spring.

• Internationally: The incidence in Japan increased from the late 1960s to the mid 1980s, with epidemiclike spread of cases occurring in 1979, 1982, and 1986. Data from Japan shows that th .....

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