As indicated in Table 33-2 in an earlier section, ischemic necrosis of cerebral tissue can occur in utero. The resulting stroke is usually referred to as congenital hemiplegia but there are heterogeneous causes and in most instances, the underlying vascular disease cannot be discerned. The adjacent ventricular region tends to expand into the stroke cavity and may cause a porencephalic cyst.
Acute hemiplegia in infants and children is a rare but well-recognized phenomenon. In a series of 555 consecutive postmortem examinations at the Children’s Medical Center in Boston (now Boston Children’s Hospital), there were 48 cases (8.7 percent) of occlusive vascular disease of the brain (Banker). The occlusions, studied neuropathologically, were both embolic (mainly associated with congenital heart disease) and thrombotic, and the latter were actually more common in veins than in arteries.
Similarly, stroke is not an uncommon event in young adults (ages 15 to 45 years), accounting for an estimated 3 percent of cerebral infarctions in typical series. In terms of causation, this group is also remarkably heterogeneous. Among 144 such patients, more than 40 possible etiologies were identified by H.P. Adams and colleagues. Nevertheless, most of the strokes could be accounted for by three categories, more or less equal in size: (1) atherosclerotic thrombotic infarction (usually with a recognized risk factor); (2) cardiogenic embolism (particularly in the past association with rheumatic heart disease, infective and noninfective endocarditis, paradoxic embolism through patent foramen ovale and other cardiac defects, and prosthetic heart valves); and (3) one of several nonatherosclerotic vasculopathies (arterial trauma, dissection of the carotid artery, moyamoya, lupus erythematosus, drug-induced vasculitis). Hematologically related disorders—use of oral contraceptives (discussed further on), the postpartum state, and other hypercoagulable states—were the probable causes in 15 percent patients. The presence of antiphospholipid or anticardiolipin antibodies (lupus anticoagulant) explains some of these cases and is discussed further in the section on “Stroke as a Complication of Hematologic Disease”; the majority of these patients are women in their thirties without manifest systemic lupus erythematosus.
Despite the attention they have received recently as a cause of strokes in the juvenile and young adult period, the frequency of inherited deficiencies of naturally occurring anticoagulant factors as a cause of stroke is low.