Posttraumatic Hydrocephalus and Cerebral Atrophy

Ventriculomegaly is seen commonly after severe TBI in children (61). The enlargement of the ventricular system can be either from high-pressure hydrocepha­lus or from cerebral atrophy resulting in hydrocepha­lus ex vacuo.

Hydrocephalus ex vacuo describes enlargement of the ventricular system that results after cerebral atro­phy and loss of brain volume (Fig. 10.1). To distinguish between clinically significant hydrocephalus and the expected consequence of cerebral atrophy after severe TBI, one must consider the patient's clinical status as well as the amount of time that has passed since the injury. Overall, if the patient is continuing

Figure 10.1 Cerebral atrophy. (A) Normal computed tomography (CT) scan. (B) CT scan showing posttraumatic brain injury cerebral atrophy with ventriculomegaly and increased sulci.

to demonstrate ongoing and regular improvements in their clinical status, Ventriculomegaly is more likely to be due to cerebral atrophy. The patient who has hydrocephalus typically continues with poor clinical improvement or clinical deterioration. The CT scan findings will yield clues as well, with cerebral atrophy demonstrating areas of encephalomalacia or enlarge­ment of sulci, while hydrocephalus demonstrates more specific changes around the ventricular system out­lined in Table 10.2 (203).

Hydrocephalus should be suspected if clinical improvement is not noted in a patient status post-TBI or if the clinical picture includes functional decline, seizures, abnormal posturing, or increased tone. Consideration of hydrocephalus in these patients is paramount, as failure to identify hydrocephalus when it is present may delay recovery. CT scan of the brain allows for rapid detection of hydrocephalus. The treat­ing team may then choose to have a ventricular peri­toneal shunt placed, which may improve the clinical status of the patient when normal ventricular pres­sures are reestablished (204).