Certified Medical-Surgical Registered Nurse Practice Exam

Which cranial nerve irritation could lead to photophobia in a patient with meningitis?

1. Cranial Nerve III

2. Cranial Nerve IV

3. Cranial Nerve V

4. Cranial Nerve VI

The correct answer is: Cranial Nerve V

Photophobia, or sensitivity to light, can often be associated with irritation of certain cranial nerves, particularly when meningitis is present. The correct choice refers to the trigeminal nerve, which is responsible for sensation in the face and motor functions such as biting and chewing. In the context of meningitis, inflammation can affect the trigeminal nerve's pathways, leading to increased sensitivity to sensory stimuli, which includes light. The trigeminal nerve has sensory components that innervate not only the face but also provide input from the meninges and other structures. When it becomes irritated due to the inflammatory process seen in meningitis, it can lead to symptoms like photophobia. Understanding the role of the other cranial nerves clarifies why they are not the correct answer in this scenario. Cranial Nerve III primarily controls eye movements and parasympathetic functions such as pupil constriction, while Cranial Nerve IV focuses on the superior oblique muscle of the eye. Cranial Nerve VI controls lateral eye movements. While these nerves play essential roles in eye function, they do not directly mediate the sensory input related to light sensitivity as actively as the trigeminal nerve does in this case. Therefore, irritation of the trigeminal