Microcephaly and craniostenosis

Abstract

The radiological features likely to be of assistance in making the distinction between microcephaly and craniostenosis have been reviewed and the following conclusions were reached. 1. Premature fusion of sutures.—This should always occur in craniostenosis, but appears to occur also in some cases of microcephaly, where in many cases the sutures tend to be narrower than normal. 2. Evidence of increased intracranial pressure.—This should not occur in microcephaly; it is by no means universal in craniostenosis, but is relatively common in the most severely affected cases. It is, however, a late sign and may indicate that irreparable brain damage has already occurred. 3. Skull size.—By definition the cranial vault is small in microcephaly, but in craniostenosis a considerable degree of compensation for the effects of the sutural fusion can occur by growth in a direction parallel to the fused suture, provided other sutures remain open. This is reflected in the results of capacity estimations. A small skull was, however, more frequently present in those cases with multiple sutural fusions. 4. Skull shape.—Abnormalities in shape, while frequent in craniostenosis, also occur in microcephaly. Moreover, the shape tends to be less frequently abnormal in cases with multiple sutural fusions. It is evident therefore that no single radiological feature will afford an absolute distinction between the two conditions, but when taken together they will do so in most cases. In a few, the distinction may be difficult or impossible, and evidence is adduced to suggest that this may be due to the fact that both conditions can co-exist in the same patient.