**Question:** In optic neuritis in children, all symptoms are present EXCEPT:

- A. Decreased visual acuity
- B. Altered colour vision
- C. Pupillary abnormalities
- D. Loss of peripheral vision

**Core Concept:** Optic neuritis is an inflammation of the optic nerve, typically caused by an immune-mediated demyelination process. In children, optic neuritis presents with a constellation of symptoms related to visual dysfunction.

**Why the Correct Answer is Right:** In children, optic neuritis usually presents with symptoms related to vision loss or visual disturbances. The correct answer (C) refers to pupillary abnormalities, which are not typically part of the initial presentation in pediatric optic neuritis. Instead, children usually present with symptoms such as:

1. **Decreased visual acuity (A):** This refers to a reduction in the ability to see distant objects clearly.
2. **Altered colour vision (B):** This may include difficulties distinguishing between different colours, often seen in demyelinating disorders like multiple sclerosis.
3. **Loss of peripheral vision (D):** This refers to the inability to see objects at the side of the visual field, which could be present in optic neuritis.

**Why Each Wrong Option is Incorrect:**

A. Pupillary abnormalities (C) are less common in pediatric optic neuritis compared to adults. In contrast, other symptoms are more likely to be present.
B. Altered colour vision (B) is less specific and not exclusive to optic neuritis, as it can be seen in other conditions like color vision defects, which are not directly related to optic neuritis.
D. Loss of peripheral vision (D) is also less specific, as it could be present in optic neuritis, but may also be seen in other conditions like optic disc edema or papilledema.

**Clinical Pearl:** Optic neuritis in children should prompt a thorough neurological evaluation to identify potential underlying causes, such as multiple sclerosis. While the correct answer options (A, B, and D) are commonly observed in pediatric optic neuritis, pupillary abnormalities are less common and not specific to optic neuritis.

For a comprehensive differential diagnosis and management of optic neuritis in children, refer to the following link: [Optic Neuritis in Children](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7267198/)

**Correct Answer:** C (Pupillary abnormalities)

**Why This is the Correct Answer:** Pupillary abnormalities are less common in pediatric optic neuritis compared to adults. Although optic neuritis in children should prompt a thorough neurological evaluation, pupillary abnormalities are not specific to optic neuritis and can be seen in other conditions like optic disc edema or papilledema. Therefore, this answer is selected as it is less likely but still relevant in the differential diagnosis process.