Sickle cell anemia is a rare but important cause of stroke in children of African ancestry; acute hemiplegia is the most common manifestation but all types of focal cerebral disorders have been observed. The pathologic findings are those of infarction, large and small; their basis is assumed to be vascular obstruction associated with the sickling process. The association of sickle cell anemia with the moyamoya syndrome was mentioned earlier and surveillance for the development of supraclinoid stenosis may be undertaken by transcranial Doppler. Exchange transfusions have prevented or retarded the formation of moyamoya and the report by RJ Adams and colleagues indicates that the procedure may reduce the risk of stroke if the arteriopathy is detected. Intracranial bleeding (subdural, subarachnoid, and intracerebral) and cerebral venous thrombosis may also complicate sickle cell anemia, and—probably because of autosplenectomy—there is an increased incidence of pneumococcal meningitis. Treatment of the cerebral circulatory disorder, based presumably on sludging of red blood cells, is with intravenous hydration and transfusion. Cerebral venous sinus thrombosis in young children and neonates from various causes represents a special problem, difficult to diagnose, and with a poor prognosis (see deVeber et al).
Certain hereditary metabolic diseases (homocystinuria and Fabry angiokeratosis) and the mitochondrial disorder MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) may give rise to strokes in children or young adults; investigation of these causes is undertaken if the aforementioned clotting disorders have been excluded or if there is a family history. Figure 33-23 demonstrates an example of stroke related to MELAS.
Overall, in children and young adults with ischemic stroke, the main diagnoses to be considered are carotid and vertebral dissection, drug abuse (mainly cocaine), thrombosis induced by contraceptive estrogens (see below), antiphospholipid antibody syndrome, and cardiac disease including patent foramen ovale (PFO). Migraine might be added to this list, but it is a diagnosis by exclusion in these circumstances and CADASIL, albeit rare, should also be considered if migraine headaches and TIAs precede a stroke. Inherited prothrombotic states—such as those caused by the various clotting factor deficiencies discussed above, Fabry disease, moyamoya, and Takayasu arteritis—arise in the younger age group and require exploration if clinical circumstances suggest one of these processes on the basis of unusual TIAs (orthostatic, hyperventilation, or fever induced), Down syndrome, or strong family history of strokes in youth.
Oral Contraceptives, Estrogen, and Cerebral Infarction