commonly, children may have cardiac disease (pericarditis, cardiomegaly, EKG changes, myocardial infarction) or pulmonary involvement (diffuse infiltrates, pulmonary hemorrhage, or hemothorax) Clinical Assessment The patient should be examined carefully for signs of end-organ involvement, including blood pressure elevation, abdominal tenderness, arthritis, CNS disease (e.g., hemiparesis), cardiac disease (e.g., pericarditis, myocardial infarction), and pulmonary involvement Urinalysis is a useful marker for renal involvement Laboratory findings in polyarteritis are nonspecific but suggest both acute and chronic inflammation Most children have white blood cell counts higher than 15,000/mm3, hemoglobin