NEW YORK — Don't feel guilty about overdiagnosing and overtreating Kawasaki disease, Dr. Jeffrey R. Starke said at a meeting sponsored by the American College of Emergency Physicians.
“If you look at the risk-benefit ratio of treatment versus the complications if we don't treat, it's clear we should err on the side of overtreatment, especially in children younger than 12 months who are at high risk for developing severe coronary artery abnormalities,” Dr. Starke said.
These youngest patients also are more likely to present with incomplete Kawasaki disease. This diagnosis should be considered in infants under 6 months with fever for longer than 6 days and unexplained systemic inflammation. An incomplete Kawasaki diseasediagnosis also should be considered in children with fever for over 5 days and two or three, rather than four, of the features of Kawasaki disease (see box).
In such a patient, if the C-reactive protein is 3 mg/dL or greater and/or the erythrocyte sedimentation rate is 40 mm/hour or more, supplemental laboratory criteria should be obtained. If three or more are present, the child should have an echocardiogram and treatment should begin.
If there are fewer than three of the laboratory criteria, an echocardiogram is needed. If the echo shows cardiac abnormalities, treat. If it is negative and the fever abates, disease is unlikely. If fever persists, repeat the echo, said Dr. Starke, vice chairman of pediatrics at Baylor College of Medicine, Houston.
Standard treatment with intravenous immunoglobulin (IVIG), 2 g/kg as a single infusion is quite safe, though expensive, which is another reason to err on the side of treatment. On occasion, treatment can begin before an echocardiogram. Aspirin is routinely given, though a recent review found insufficient evidence supporting this practice (Cochrane Database Syst. Rev. 2006;doi:10.1002/14651858.CD004175.pub2). High doses of 80–100 mg/kg per day should be given initially.
Some continue the high dose for 14 days and then reduce the dose to 3–5 mg/kg per day, while others maintain the high dose only until 24–48 hours after the patient defervesces, and then switch to the low dose for 2 months for antiplatelet effects.
“I don't know of a single infectious disease expert or rheumatologist who doesn't still use aspirin in addition to IVIG in the treatment of Kawasaki disease,” Dr. Starke said.
Some data suggest some benefit of adding corticosteroids to treatment. In a recent prospective randomized trial of 178 Kawasaki patients, children on prednisolone with IVIG had a shorter duration of fever and a faster fall in C-reactive protein, but no difference in coronary artery dilation at 1 month (J. Pediatr. 2006;149:336–41).
If the fever persists or returns more than 36 hours after completion of the IVIG infusion, a second dose can be given.
“But be patient. It's very common for kids to continue to run a fever the day after you give the IVIG dose, even as other symptoms are improving,” he said.
Clinical Diagnostic Features of Kawasaki Disease
Diagnostic Criteria
Fever greater than 39 degrees C for 5 days, plus four of the following:
Conjunctivitis, usually bulbar and bilateral
Mucus membrane changes such as redness and cracking
Rash, either generalized or local
Enlarged cervical lymph nodes, usually unilateral and nontender
Peripheral changes such as swelling or peeling
Incomplete Kawasaki Supplemental Laboratory Criteria
Albumin 3 g/dL or less
Anemia for age
Elevation of alanine aminotransferase
Platelets 450,000/mm
While blood cell count 15,000/mm
Urine white blood cell count 10/HPF or more
Sources: Dr. Starke; Circulation 2004;110:2747–71.