A case of injury to right brow due to a fall from scooter presents with sudden loss of vision in the right eye. The pupil shows absent direct reflex but a normal consensual pupillary reflex is present. The fundus is normal. The treatment or choice is:
**Core Concept**
The case described is likely suffering from a third cranial nerve (oculomotor nerve) palsy, characterized by impaired pupillary constriction due to damage to the parasympathetic fibers responsible for controlling pupil size. This condition can result from direct trauma to the nerve, which in this scenario is suggested by the injury to the right brow.
**Why the Correct Answer is Right**
The absent direct pupillary reflex indicates impaired pupillary constriction on the affected side, while the normal consensual pupillary reflex suggests that the afferent pupillary pathway (sensory input) remains intact. This differential response is a hallmark of third nerve palsy, as the efferent (motor) pathway is affected. The normal fundus examination rules out other causes of sudden vision loss, such as retinal detachment or ischemic optic neuropathy.
**Why Each Wrong Option is Incorrect**
* **Option A:** This choice might be a medication or surgical intervention, but without more information, it's difficult to assess its relevance to the case.
* **Option B:** This option could be a diagnostic test, but it's not directly related to the management of third nerve palsy.
* **Option C:** This option might be a treatment for a different condition, such as glaucoma or angle-closure attack. It's not the correct choice for a case of third nerve palsy.
* **Option D:** This option could be a surgical intervention, but without more information, it's difficult to assess its relevance to the case.
**Clinical Pearl / High-Yield Fact**
In cases of third nerve palsy, it's essential to consider the possibility of an aneurysm of the posterior communicating artery, which can compress the oculomotor nerve and cause the symptoms. This is a classic "red flag" that requires urgent evaluation with imaging studies, such as CT or MRI.
**Correct Answer:** C.