Medium-Vessel Vasculitis

Kawasaki Disease (mucocutaneous lymph node syndrome)

Kawasaki disease is a pediatric disease and a medium-vessel vasculitis. It's common in children less than 5 years old, especially children of Asian descent. Although the exact cause is unknown, it's believed to be a result of anti-endothelial or anti-smooth muscle antibodies. Thus, Kawasaki disease is an autoimmune disease. Although Kawasaki disease is a vasculitis, the most pressing issue are coronary artery aneurysms. Aside from coronary artery aneurysms, Kawasaki disease can also result in coronary artery thrombosis, thromboembolism, occlusion, and rupture, which can lead to myocardial infraction and/or sudden death.

The clinical presentation of Kawasaki disease includes conjunctivitis, desquamative rash, cervical lymphadenopathy, strawberry tongue, edema and erythema, and fever.

The mnemonic for the clinical presentation is CRASH & Burn:

Conjunctivitis

Desquamative Rash

Adenopathy

Strawberry tongue

Hands (edema and erythema )

Burn = fever

Treatment includes IVIg and high dose aspirin. This is one of the only times aspirin is given to children (aspirin use in children can lead to Reye's syndrome).

Why does IVIg help treat Kawasaki disease?

Although the exact mechanism of action of IVIg's anti-inflammatory effect in treating Kawasaki disease is unknown, there are some proposed mechanisms that we list here (1):

1. IVIg increases clearance of autoantibodies through competitive binding of neonatal Fc receptors (FcRn)
2. IVIg activates inhibitory Fc receptor (FcyRIIB) on macrophages
3. IVIg leads to the blockade of adhesion molecules that are important for inflammatory cell trafficking to the vascular endothelium
4. IVIg preparations contain antibodies that can neutralize cytokines, chemokines, and activated complement proteins