UC San Diego departments collaborate in Kawasaki study

A graphic explaining the symptoms of Kawasaki disease.

Highlighted by the fact that San Diego County has seen a three-fold increase in Kawasaki disease diagnoses in children so far this year, two UC San Diego departments are collaborating to study the disease, the recent spike and a possible trigger. Their findings were published in Scientific Reports.

According to the Centers for Disease Control, the non-contagious Kawasaki disease is “an acute febrile illness of unknown etiology that primarily affects children younger than 5 years of age,” can damage the hearts of children, and is reported as a leading cause of acquired heart disease in the United States. Serious complications include coronary artery dilatations and aneurysms.

Jane Burns, M.D., professor and director of the UCSD Kawasaki Disease Research Center said an average of 80 to 100 patients are treated at Rady Children’s Hospital for Kawasaki disease each year, but this past winter was “particularly dramatic” in that there have been 54 cases since Jan. 1. “That is at least three times higher than our normal rate,” she said.

The disease is a complex combination of a genetic predisposition activated by a (likely) man-made trigger, the latter of which may have become more present during the most recent winter storms, and is being studied at UCSD.

“The way we think this disease operates is that children are born with a complicated genetic predisposition,” Burns explained. “It’s not like a single mutation like cystic fibrosis, where if you are born with those mutations, you will get the disease. This is a number of different genes that all have to be present in a certain form. In most cases, neither parent had it when they were children, but they carry a part of the pattern. ... In children who get the disease, each parent contributed a portion of the pattern so the whole pattern exists. That makes these children susceptible.”

If the child is exposed to the mysterious trigger, Kawasaki can manifest.

But what it is?

UCSD School of Global Policy & Strategy associate professor Jennifer Burney said the working hypothesis is that the trigger is an inhaled particle.

“But the question is, what is it?” she posed. “An environmental science approach, which is what we bring to this, is to take the statistics of where and when and really how the disease presents, and use that to generate some hypotheses of where this agent might be coming from.”

Burney added: “It could be that the disease is transported over long distances and that allows the agent to accumulate and trap it here. Or it could be that these agents allow a local source to proliferate. The goal is to use these statistics to sort this out.”

She said there is a seasonality to the disease that varies around the world. In San Diego, the “peak” builds up into March then falls off with a second smaller peak in the summer, reaches a low point in October, and then picks back up.

“We get bursts of lots of cases and then little or none,” Burney said. “But these aren’t happening in one neighborhood, we might get one in Temecula and one in San Diego, so there is an environmental scale here. We look at what’s happening on those days in those high density periods versus regular or low Kawasaki, and we see strong climate differences. In San Diego, these high density clusters of Kawasaki tend to be associated with warmer than normal conditions and reduced circulation of on-shore winds.”

Earlier Kawasaki studies used a weather model to determine where the air now over San Diego was five days ago. However, Burney notes that most children come in a few days after symptoms manifest, so a “sophisticated” system would need to be in place to look at circulation patterns from a few days prior and beyond.

And while the findings are “hopeful,” an answer is not quite “in front of our noses,” Burney said.

The good news?

While there has been an increase in diagnoses this year, the good news is Kawasaki is still considered rare, and can be easily spotted.

“It is very visual,” Burns said. “I want to empower parents to the concept that they can make the diagnosis themselves. The visuals are fever and everything turning red: a rash, red lips that may crack, red tongue, both eyes become bloodshot and the hands and feet can become swollen and palms and soles bright red. The fever will be consistent, but the others are not going to be there all the time.”

Should these symptoms appears, parents should take their children to their healthcare provider.

“The most useful thing a parent can say is ‘Could this be Kawasaki disease?’ because just saying those words may elevate the possibility in the consciousness of the healthcare provider, who honestly, in the peak of virus season, may see 20 kids in a day who all have a rash and fever. So it can be a needle in the haystack problem,” Burns said.

Further, the disease is treatable.

“We have a really effective therapy that can reduce the chances of permanent heart damage in these children,” she said. “That’s why making the diagnoses is so important. Without treatment, the changes of irreversible — and later in life potentially fatal — heart damage is 25 percent. With treatment within 10 days, that number goes down to 5 percent.”