[An infantile case of cerebral infarction associated with thrombocytosis].

Cerebral infarction in children is often caused by intracranial vascular disorder, cardiac disease, head injury, or infection, and is rarely induced by blood disease. In this paper, we describe an infantile case of cerebral infarction associated with thrombocytosis. A female infant of eight months of age developed left hemiparesis after a slight head injury. Her CT and MRI demonstrated a cerebral infarction located from the right internal capsule to the right corona radiata. Laboratory findings revealed iron-deficiency anemia and thrombocytosis with a platelet count 107.5 x 10(4)/mm3. Although she had no disorder that had caused iron deficiency, serum Fe value of the patient was low with a count of 18 micrograms/dl. Her bone marrow was normal except for a slight increase in the number of megakaryocytes. One month later, her anemia was improved by means of oral iron replacement. However, her platelet count remained at more than 100 x 10(4)/mm3 as it had been before. Her condition of left-sided hemiparesis gradually improved by a program of rehabilitation, and did not recur after aspirin administration. Although the main cause of her thrombocytosis that led to a transient cerebrovascular accident is obscure, it is postulated that her iron deficiency anemia induced secondary thrombocytosis, or else the patient had essential thrombocytosis.