Prehospital Trauma Life Support (PHTLS) Practice Test

In the event of a traumatic brain injury, which sign is most indicative of increased intracranial pressure?

1. Confusion or disorientation

2. Unequal pupil size

3. Persistent vomiting

4. Lateralizing motor weakness

The correct answer is: Unequal pupil size

Unequal pupil size is a significant indicator of increased intracranial pressure (ICP) following a traumatic brain injury. This condition, known as anisocoria, suggests that there may be pressure on the optic nerve or other structures within the cranial cavity. When ICP rises, it can lead to brain swelling or hemorrhage, impacting the surrounding nerves, including those that control pupil reaction and size. Changes in pupil size reflect underlying issues within the brain. For instance, if one pupil is dilated (mydriasis) and the other is constricted (miosis), this can indicate a hematoma, brain herniation, or other forms of injury that influence ICP. Monitoring these signs is crucial in the management of traumatic brain injuries, as they can lead to rapid deterioration if not addressed promptly. While confusion or disorientation, persistent vomiting, and lateralizing motor weakness can all suggest brain injury or other neurological impairments, they are not as specific to increased ICP as unequal pupil size. Unequal pupils are a more direct reflection of pressure dynamics within the cranial cavity, making them a critical component in initial assessments and interventions for patients with head trauma.