Evaluation of Kawasaki Disease
CBC with differential
A CBC with differential will help evaluate for possible infection or inflammatory response. It is also
useful to evaluate for possible anemia, thrombocytopenia or thrombocytosis, any of which could be
present in this patient. Typical CBC findings in a patient with Kawasaki disease:
WBC: The white blood count is usually elevated, with a predominance of neutrophils.
Hbg/Hct: A normochromic, normocytic anemia is common.
MCV: The MCV is usually normal.
Platelets: The markedly elevated platelet count associated with Kawasaki disease is usually
not seen until the second week of the illness.
Blood culture
Although the clinical course is long for a bacteremic illnesses, the height of the fever and the
clinical appearance of the patient justify obtaining a culture.
Liver enzymes
Liver enzymes can be elevated in a number of conditions on the differential, including both
Kawasaki disease and Stevens-Johnson syndrome. Although this is an important test to obtain, it
is of little benefit in narrowing your diagnosis in this case. Serum albumin level is frequently low in
Kawasaki disease.
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Acute phase reactants
There is great debate in the role of acute phase reactants (erythrocyte sedimentation rate [ESR] or
C-reactive protein [CRP]). Their lack of specificity limits their utility for diagnostic purposes, though
they can lend support for and against some diagnoses. They frequently play a more useful role in
following a disease process.
In this case, a negative ESR would argue strongly against Kawasaki disease. The persistence of
an elevated ESR after the fever has subsided can help to distinguish Kawasaki disease from other
infectious rash/fever illnesses.
Urinalysis
A sterile pyuria, secondary to a sterile urethritis, is associated with Kawasaki disease. A cleancatch
urine is likely to show white cells, whereas a catheterized urine may not (because the white
cells come from the urethra).