Two weeks after an injury to his right eye, a boy presents with bilateral pain and redness, most probable diagnosis is –
**Core Concept**
Posterior segment injury to one eye can lead to sympathetic ophthalmia, a rare but potentially sight-threatening condition. This is an autoimmune response to the injury, where the immune system mistakenly attacks the healthy eye. The condition is characterized by pain, redness, and vision loss in both eyes.
**Why the Correct Answer is Right**
Sympathetic ophthalmia occurs when the immune system recognizes the injured eye as foreign and mounts an immune response against it. This response can then cross over to the healthy eye, causing inflammation and tissue damage. The condition typically presents 1-4 weeks after the initial injury, with symptoms including bilateral eye pain, redness, and vision loss. In severe cases, sympathetic ophthalmia can lead to complete vision loss in both eyes.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is not a relevant condition, as sympathetic ophthalmia is a specific autoimmune response to eye injury, not a general term for eye inflammation.
* **Option B:** This is a viral infection that causes eye inflammation, but it is not related to the autoimmune response seen in sympathetic ophthalmia.
* **Option C:** This is a type of eye inflammation caused by a bacterial infection, but it is not associated with sympathetic ophthalmia.
**Clinical Pearl / High-Yield Fact**
Sympathetic ophthalmia is a rare but potentially devastating condition that requires prompt recognition and treatment. It is essential to consider this diagnosis in any patient who presents with bilateral eye pain and redness after an eye injury.
**Correct Answer: C. Endophthalmitis.**