What are the precursor signs of brain herniation?

The first signs of brain herniation may include increased intracranial pressure, such as severe headache, frequent projectile vomiting unrelated to eating, agitation, and pupillary changes. In addition, some patients may have dyskinesia, which may be characterized by decreased muscle strength or paralysis of the contralateral limb. Pathologic signs may be positive on physical examination, and some patients may have altered consciousness and disturbed vital signs.