Neurological episodes after minor head injury and trigeminovascular activation.

Children appear particularly susceptible to severe but reversible neurological symptoms and/or signs after minor head injury; these include headache, confusion, drowsiness, vomiting, hemiparesis, cortical blindness, or seizures. Significantly, these neurological episodes are not associated with any identifiable structural brain abnormality on neuro-imaging. We propose that the cause of this condition is a reactive hyperaemia, a 'benign hyperaemic encephalopathy' mediated via activation of the trigeminovascular system.