Chronic phase This stage is only of clinical importance in patients who have developed cardiac complications. Its duration is of lifetime significance since the aneurysm formed in childhood may rupture in adulthood. In some cases of aneurysms rupturing in adult life, careful reviews of past medical histories have revealed febrile childhood illnesses of unknown etiology. There are multiple theories, including an infectious etiology, an immunological abnormality and even the possibility of a link with carpet shampoo. Clinical and epidemiologic features support an infectious etiology, but many authorities believe that there is also an autoimmune component.
Cultures are all negative.
A baseline echocardiogram is important. The echo should be repeated in the second or third wk and again 1 mo after all other lab results have normalized. If abnormal at any point, the child should have a complete cardiac work up and follow up with a pediatric cardiologist. An ultrasound of the gall bladder may be necessary if there is any suggestion of liver or gall bladder dysfunction. During the subacute stage, platelet count elevation is the outstanding marker.