## Core Concept
Papilledema refers to the swelling of the optic disc caused by increased intracranial pressure. This condition is a critical sign that can indicate serious underlying pathology, such as a brain tumor, cerebral edema, or other space-occupying lesions. The swelling is due to the transmission of increased intracranial pressure to the optic nerve sheath.

## Why the Correct Answer is Right
The correct answer is related to the characteristics of papilledema. Typically, papilledema is associated with:

- **Bilateral optic disc swelling** due to increased intracranial pressure.
- **Preservation of visual acuity** in the early stages, despite significant swelling.
- **Transient visual obscurations** which are brief episodes of blurred vision.
- **Pulsatile** nature of the condition, with symptoms and signs that can fluctuate.

## Why Each Wrong Option is Incorrect
To determine why each option (except the correct one) is incorrect, let's consider common statements about papilledema:

- **Option A:** If a statement like "Papilledema is associated with increased intracranial pressure" is listed, it's true and therefore incorrect as an exception.
- **Option B:** If a statement such as "Visual acuity is typically decreased early in the course" is listed, this would generally be incorrect regarding papilledema, as visual acuity is often preserved early on.
- **Option C:** A statement like "Papilledema can cause transient visual obscurations" is true and thus an incorrect exception.
- **Option D:** If a statement such as "Papilledema is usually unilateral" is listed, this would be incorrect because papilledema is typically bilateral.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **papilledema typically preserves visual acuity in its early stages**. This is a critical clinical feature distinguishing it from other causes of optic neuropathy. Early detection and management of the underlying cause of increased intracranial pressure are crucial.

## Correct Answer: B. Visual acuity is typically decreased early in the course.