Morphological presentation of posttraumatic vasospasm.

Posttraumatic vasospasm is a well-recognized sequela of head injury. The risk factors associated with posttraumatic vasospasm have not been well defined. We studied 119 consecutive patients with head injury to determine the risk factors for posttraumatic vasospasm. Posttraumatic vasospasm was detected in 32 (35.6%) of 90 patients. Among these patients, 29 (90.6%) had severe head injury and 3 (9.4%) had moderate head injury. None of the patients with mild head injury suffered posttraumatic vasospasm. In most cases, the onset of posttraumatic vasospasm began on the fifth day and lasted 1 to 9 days. In 8 (25%) patients, posttraumatic vasospasm began within the first three days of the head injury. Clinical deterioration was documented in two (2.5%) patients. Morphologically, posttraumatic vasospasm resembled features of aneurysmal vasospasm. We found increased corrugation of the internal elastic lamina and increased amounts of connective tissue in the subendothelial layer. These findings showed that posttraumatic vasospasm, although clinically more mild, demonstrated the same morphological changes as did aneurysmal vasospasm.