What are the approach considerations in the workup of Kawasaki disease?

Updated: Jul 29, 2018
  • Author: Tina K Sosa, MD; Chief Editor: Russell W Steele, MD  more...
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Complete KD is a clinical diagnosis; no laboratory or imaging evaluations are required aside from echocardiography once the diagnosis is made. Pre-diagnosis laboratory and imaging evaluations are of greater utility for cases of incomplete KD, when the diagnosis is suspected but the patient does not meet criteria for complete KD. Normal results on some studies can help narrow the differential diagnosis; however, it should be noted that KD can occur concurrently with other diseases that mimic its findings, including respiratory viruses.

A typical initial laboratory evaluation may include a complete blood count (CBC), electrolyte panel, renal function testing, liver enzymes, albumin, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and urinalysis. Certain laboratory abnormalities coincide with various stages. On complete blood counts, mild-to-moderate normochromic anemia is often observed in the acute stage. During the subacute stage, thrombocytosis is common. The platelet count begins to rise in the second week and continues to rise during the third week. Platelet counts average 700,000/μL, but levels as high as 2 million have been observed. Thrombocytopenia is associated with severe coronary artery disease and MI; rarely, it may be associated with disseminated intravascular coagulation. Hypoalbuminemia may be present and is often associated with more severe and prolonged illness. Acute-phase reactants are almost universally elevated at presentation. Sterile pyuria is also sometimes present due to urethral inflammation. In the convalescent stage, the levels of platelets and other markers begin to return to values within the reference range. Laboratory values may require 6-8 weeks to normalize.

Research is ongoing to attempt to identify specific biomarkers to aid in the diagnosis of KD. Recently, 2 urine proteins have been identified as potential biomarkers of KD: meprin A and filamin C. Meprin A is an immune regulator, and filamin C is associated with endothelial and myocardial cell injury. [60, 61]

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