## **Core Concept**
Papilloedema is the swelling of the optic disc caused by increased intracranial pressure. The initial bed-side investigation aims to directly visualize the optic disc for signs of swelling. Ophthalmoscopy is a crucial tool for this purpose.

## **Why the Correct Answer is Right**
The correct answer, **Fundoscopy (or Ophthalmoscopy)**, is the most appropriate initial bed-side investigation for papilloedema. This method allows for direct visualization of the optic disc, enabling the detection of signs such as blurred disc margins, disc elevation, and obliteration of the physiological cup. These signs are indicative of increased intracranial pressure.

## **Why Each Wrong Option is Incorrect**
- **Option A: Ultrasound**: While ultrasound can be used in various medical assessments, it is not the primary bed-side method for directly visualizing the optic disc for papilloedema.
- **Option B: CT Scan**: A CT scan is a more advanced imaging technique that can help identify causes of increased intracranial pressure but is not a bed-side investigation.
- **Option C: MRI**: Like CT scans, MRI provides detailed images and is used to investigate the causes of papilloedema but is not suitable for bed-side assessment.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that papilloedema is often associated with **normal visual acuity** in the early stages. Therefore, the absence of visual symptoms does not rule out papilloedema. Early detection through ophthalmoscopy is critical.

## **Correct Answer:** . Fundoscopy