During the examination of a 22-year-old woman who sustained a head injury from an automobile accident 4 hours earlier, the nurse notices the following changes: pupils were equal, but now the right pupil is fully dilated and nonreactive, and the left pupil is 4 mm and reacts to light. What do these findings suggest?

Choice A reason: Herniated brainstem causes bilateral pupil changes and severe neurological signs, not unilateral dilation. Unilateral pupil dilation suggests increased intracranial pressure, so this is incorrect for these findings. Choice B reason: Unilateral pupil dilation and nonreactivity, as seen in the right pupil, indicate increased intracranial pressure, often from mass effect compressing the oculomotor nerve. This is critical, making it the correct finding. Choice C reason: Subdural hemorrhage may cause pressure but isn’t specific to these pupil changes. Unilateral dilation points to increased intracranial pressure as the immediate concern, so this is less precise. Choice D reason: Cerebral edema contributes to pressure but is a broader term. Unilateral pupil dilation specifically suggests increased intracranial pressure, a more immediate and precise diagnosis, so this is incorrect.