What is a late sign of head injury in children?

Delayed or impaired pupillary responses serve as a late sign of head injury in children because they indicate significant neurological impairment. When there is an injury to the brain or skull, it can affect the functioning of cranial nerves, particularly the third cranial nerve responsible for pupillary reactions. As the injury progresses, the ability of the pupils to respond to light may diminish or become uneven, reflecting increased intracranial pressure or brainstem involvement.

Identifying pupillary changes is crucial in assessing the severity of a head injury. Late signs, such as those involving pupillary responses, often suggest a more serious level of brain injury, necessitating immediate medical intervention. In contrast, the other options listed are generally considered earlier signs of head injury or symptoms that may occur with various conditions rather than specifically indicating late-stage complications related to head trauma.