**Question:** Important feature of sympathetic ophthalmitis: March 2013 (e)

**Core Concept:** Sympathetic ophthalmitis is a rare complication of uveitis, where inflammation occurs in one eye after a previous ocular surgery or infection in the other eye. It is a severe inflammatory condition affecting the eye's structures, including the retina, optic nerve, and choroid.

**Why the Correct Answer is Right:** In sympathetic ophthalmitis, the inflammation is caused by the release of inflammatory mediators from the inflamed eye, which cross the blood-aqueous barrier and enter the circulation. These mediators then stimulate the sympathetic ganglia, leading to the activation of the sympathetic nervous system and the release of catecholamines (epinephrine, norepinephrine, and dopamine). The catecholamines then cross the blood-retinal barrier and cause inflammation in the fellow eye, leading to symptoms and signs like pain, vision loss, and optic neuropathy.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because sympathetic ophthalmitis is a result of the release of inflammatory mediators from the inflamed eye, not a direct action of sympathetic ganglia.

B. This option is incorrect because sympathetic ophthalmitis occurs after a previous ocular surgery or infection, not directly due to a heart attack.

C. This option is incorrect because sympathetic ophthalmitis is a consequence of inflammation in one eye, not a condition related to the functioning of the pituitary gland.

D. This option is incorrect because sympathetic ophthalmitis develops due to the release of inflammatory mediators from the inflamed eye, not due to the action of the sympathetic nervous system on the choroid.

**Clinical Pearl:** Sympathetic ophthalmitis is a rare but severe complication of uveitis, and it is essential for clinicians to consider this in the differential diagnosis of patients with bilateral eye inflammation, particularly following ocular surgery or infection. Prompt diagnosis and treatment are crucial to prevent significant vision loss and optic nerve damage.