The main, long-term side effects are cardiac problems, such as aortic aneurysms (a bulge in the blood vessel leading away from the heart that is dangerous, because it may burst, spilling blood and potentially causing hemorrhaging), cardiac arrythmias (irregular heartbeats), inflammatory disease of the heart and abnormalities in the heart valves. Twenty to 25 percent of patients develop a coronary artery aneurysm afterwards. The mean age at presentation for cardiac damage is 24, plus or minus 8 years. It's recommended that Kawasaki patients be followed for 10 or 20 years.
Seizures are very uncommon. Maybe during the acute episode during a high fever; fevers themselves can cause seizures sometimes. But Kawasaki syndrome is rarely a cause of encephalitis (swelling of the brain) or residual brain problems. I'm sure there are exceptions to the rule, but I can't speak to that.
Kawasaki syndrome is not believed to be one of the etiologies of autism. Autism is a congenital, neuro-developmental disorder, which means you are born with it. It emerges between ages one and three. Because it starts during early infancy and because these children can look normal initially, a whole host of things have been attributed to causing autism: vaccines, infections, lead and other toxins. And because we can't point to a cause of autism, there's an impression that these temporally related issues must have caused it.
What happened in this case is that, unfortunately, this child probably had an episode of Kawasaki disease and, because it occurs between ages one and three, that was a time they noted neuro-developmental disorders, and seizures are more common in autistic children. I never heard of Kawasaki syndrome as a cause of autism till I read about Jett Travolta [allegedly having the disorder].
What is the treatment for Kawasaki?
The main treatments are to prevent cardiac disease. Patients are usually put on IV gamma globulin, a mixture of antibody proteins that fights inflammation and help fight infection by boosting the immune system, for a week to 10 days, and usually put on aspirin, to prevent inflammation, for years.
While aspirin has been linked to Reyes syndrome (a potentially fatal condition that can cause brain and liver damage) in young children, there's a risk-benefit ratio. If you have a reason, that would outweigh any potential risks. Aspirin has a specific inflammatory effect that's different from ibuprofen. It has anti-platelet function and is used for stroke prevention, as well. Ibuprofen doesn’t have those properties.
Most children recover, are put on aspirin and are followed for years to make sure they're stable. And that's it. The main problem is follow-up for cardiac disease.
How often is it fatal?
Rarely. Most children tend to recover. Death may occur if the cardiac complication is unrecognized.