NEW ORLEANS - One hospital reported an increase in the diagnosis of Kawasaki disease (KD) in children who do not meet American Heart Association (AHA) criteria. In addition, these atypical cases seemed to develop more coronary artery abnormalities, said Paul C. Young, MD, at the Pediatric Academic Societies meeting here.
However, the time to treatment with intravenous immunoglobulin (IVIG) was the same whether or not the patient met the criteria set by the AHA, added Young, of the department of pediatrics, University of Utah, School of Medicine, Salt Lake City.
Kawasaki disease is an acute febrile illness. The cause is unknown, but early treatment with IVIG reduces the risk of developing coronary abnormalities.
There is no diagnostic test. Diagnosis depends on signs and symptoms: fever lasting for five days or more, nonpurulent conjunctivitis; erythematous mouth and pharynx, strawberry tongue and red, cracked lips; a polymorphous erythematous rash; changes in peripheral extremities and at least one cervical lymph node larger than 1.5 cm.
A patient should have the prolonged fever and four of the other five findings. "Diagnosis is not straightforward, however," said Young, "because fever, rash, conjunctivitis and adenopathy are common features of many childhood illnesses and because of reports of atypical cases." Atypical cases are children with fewer clinical criteria but who have coronary artery abnormalities characteristic of KD.
Researchers reviewed the medical records of all patients diagnosed with KD from 1991 to 1997 at Primary Children's Hospital in Salt Lake City. "We determined the duration of fever and the presence of the other AHA criteria, the time from earliest recorded symptoms to treatment with IVIG, the presence of coronary artery abnormalities as determined by echocardiography, and the results of laboratory tests," he said.
There were 127 children diagnosed with KD during the study period; most were younger than 15 months. Eighty-one met the AHA criteria. During the latter half of the study, there was an increase of those diagnosed with KD who did not meet the criteria (45% in the second half of the vs. 27% in the first). However, the groups did not differ with respect to the interval when they received IVIG - between eight and nine days.
"In addition, 20% of the patients who did not meet the criteria did develop coronary artery abnormalities whereas only 7% of those who met them did," he said.
Of the 46 patients who did not meet the criteria, 30 had prolonged fever. Only 16 had fever lasting less than five days. Three of these patients had all five other findings; 13 had four findings.
"The designation, atypical Kawasaki disease was first used to describe children who were found to have coronary artery abnormalities typical of KD but who did not have the full clinical picture. In our series, only 20% of the 46 children who did not meet the criteria had such abnormalities, while 80% did not. We suggest that these latter children should be labeled partial or incomplete and that it's appropriate to reserve the term atypical in its original intended sense for those who actually had coronary artery abnormalities," he said.
The origin of the fever in these children is unknown. "Maybe they had Kawasaki disease and didn't develop coronary artery abnormalities because of IVIG treatment or, perhaps, they had some other condition. What we do know is that no other diagnosis was made while they were hospitalized and that none of them were later found to develop coronary artery abnormalities," he said.
Pediatricians encountering a child without all the criteria face difficult decisions. Should they treat with IVIG and aspirin and commit the child to a year of cardiac follow-up and several echocardiograms? Should they order an echocardiogram to determine if there are abnormalities, which might signal atypical disease, or should they observe the child and see whether a full clinical picture develops?
At Young's hospital, the first strategy appears to be the path most taken. "We think our pediatricians who adopt this strategy are acting on the belief that doing so improves the chances of a good outcome for their patients, and they may be correct, although we cannot support this hypothesis from our data," he explained.
"Diagnosing a child with KD initiates an expensive cascade of events including hospitalization, consultation with specialists, echocardiography, IVIG, aspirin, and extended follow-up with a pediatric a cardiologist," he said. What is needed, Young said, is a better understanding of the condition and better diagnostic tools.
For your information:
- Witt MT, Minich LL, Bohnsack JF, et. al. Kawasaki disease: Does diagnosis without meeting AHA criteria change management or outcome? Abstract 216. Presented at the Pediatric Academic Societies meeting. May 1-5. New Orleans.
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