Following is a feature of papilloedema –
**Core Concept**
Papilloedema is a condition characterized by swelling of the optic disc due to increased intracranial pressure. The underlying pathophysiology involves the transmission of pressure from the cranial vault to the optic nerve head, leading to venous congestion and subsequent edema.
**Why the Correct Answer is Right**
Papilloedema typically presents with a swollen optic disc, which is a result of the accumulation of fluid within the optic nerve head. This is often accompanied by a loss of the normal cup-disc ratio, as the swollen disc pushes the cup (the central depression in the optic disc) upward and outward. The optic disc may also become hyperemic, with a characteristic "cotton-wool" appearance due to the presence of axonal swelling and leakage of fluid from the retinal vessels.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because papilloedema is not typically associated with a decrease in visual acuity, as the condition primarily affects the optic disc and not the retina or the visual pathway.
**Option B:** This option is incorrect because optic neuritis is a distinct clinical entity characterized by inflammation of the optic nerve, which can cause pain on eye movement and loss of vision, but it does not typically cause swelling of the optic disc.
**Option C:** This option is incorrect because glaucoma is a group of conditions that can cause damage to the optic nerve, but it is not typically associated with increased intracranial pressure or swelling of the optic disc.
**Clinical Pearl / High-Yield Fact**
It's essential to distinguish papilloedema from other conditions that can cause optic disc swelling, such as optic neuritis or glaucoma. A thorough clinical examination, including assessment of visual acuity, pupillary reactions, and fundoscopic examination, is crucial in making an accurate diagnosis.
**Correct Answer: D. Swelling of the optic disc**