When assessing a patient with head trauma, what does unequal pupil size suggest?

Unequal pupil size, a condition known as anisocoria, can be a significant indicator of potential brain injury. This physiological response often suggests that one side of the brain is affected, which may be due to several underlying issues such as increased intracranial pressure, bleeding in the brain, or a direct injury to the brain itself.

In the context of head trauma, the brain controls many autonomic functions, including pupil dilation and contraction. Therefore, when there is an imbalance in neural control, it can reflect disturbances in brain function or structural damage. For instance, if one pupil is dilated and the other is constricted, it may indicate that the third cranial nerve is compromised or that there is a mass effect on one side of the brain.

Recognizing unequal pupil size is crucial for medical personnel, as it can help quickly identify the severity of a brain injury and guide treatment decisions.