Heart Attacks in Children? The Kawasaki Disease Epidemic

A recent study out of Australia published in the Journal of Pediatrics revealed that cases of the potentially deadly Kawasaki Disease are steadily increasing. Kawasaki Disease (KD) is a poorly understood condition known as vasculitis, which is the inflammation of small blood vessels. The disease is known for attacking the coronary arteries of children, the vital blood vessels supplying the heart muscle with oxygen and other nutrients. The child suffers from an acute fever and severe pain, essentially symptoms of both infection and a heart attack.

Doctors do not know the cause of KD, but they believe it may be infectious in origin because most cases occur between the winter and spring, and epidemics occur frequently.  KD most commonly affects Japanese children and those of Japanese ancestry: the incidence in Japan has been steadily increasing, from 102 per every 100,000 children <5 years old to 188 in 2006.  In the United States, it is 17.1 per 100,000 children <5 years old, but clinicians fear this number will continue to increase.

85% of children suffering from KD are <5 years old, and the median age is 2 years old. The symptoms begin with a high fever that lasts a minimum of 5 days and lasts as long as 4 weeks. The child typically experiences redness and swelling of his or her hands and feet and a morbilliform rash of the face and extremities. The lips and mouth will typically dry out, crack and blister.

Meanwhile, inside the coronary arteries, the body is attacking the vascular smooth muscle and causing inflammation that will lead to scarring and poor vessel integrity.  It is for this reason that coronary artery aneurysm (ballooning and tearing) occurs in 25% of cases, particularly if the child is less than 6 months or older than 6 years old. Other complications include myocardial infarction, cardiac arrest, heart failure, myocarditis and pericarditis. Two reports have noted children becoming insulin dependent diabetic within 4 months of the vasculitis.

When the pediatrician recognizes these harrowing symptoms, he or she will order an echocardiogram to visualize the heart.  When a blood test reveals high white blood cells (leukocytosis), high erythrocyte sedimentation rate (ESR) and high C-reactive protein (CRP), a diagnosis can be made.

The treatment for KD is intravenous immunoglobulin (IVIG), which is an injection of IgG (long-term) antibodies pooled from over 1,000 blood donors. High dose aspirin with or without corticosteroids is also administered to help reduce swelling and prevent a heart attack. The child should follow up with a cardiologist for repeated echocardiograms and long-term monitoring, since the highest risk for a heart attack is in the first year after diagnosis.

Until more is learned about KD and its origins, it will be added to a long list of autoimmune diseases that are poorly understood but well respected in the medical community.  

References

Saundankar J1, Yim D, Itotoh B, Payne R, Maslin K, Jape G, Ramsay J, Kothari D, Cheng A, Burgner D. The epidemiology and clinical features of Kawasaki disease in Australia. Pediatrics. 2014; 133(4):e1009-14.

Kawasaki Disease. Dynamed Database. Updated June 9, 2014. Accessed June 13, 2014.