A 25 year old male present with decrease in vision in both eyes following a viral illness. On examination he had mild decrease in visual acuity and paracentral scotomas. Examination of the fundus showed wedge-shaped parafoveal retinal lesions. What is he MOST likely suffering from?
**Core Concept**
The patient's presentation of decreased vision in both eyes following a viral illness, along with characteristic fundus findings, is suggestive of a post-viral retinal condition. This condition is associated with an inflammatory response in the retina, leading to damage and visual impairment.
**Why the Correct Answer is Right**
The patient's symptoms and examination findings are consistent with a diagnosis of Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE). APMPPE is a rare, bilateral, inflammatory condition of the retina, which typically occurs in young adults following a viral illness. The condition is characterized by the presence of wedge-shaped parafoveal retinal lesions, paracentral scotomas, and mild decrease in visual acuity. The pathophysiology of APMPPE involves an immune-mediated response, with the involvement of T-lymphocytes and the release of inflammatory cytokines.
**Why Each Wrong Option is Incorrect**
* **Option A:** While retinal vasculitis can present with similar symptoms, it typically involves the retinal vessels and does not characteristically present with wedge-shaped parafoveal lesions.
* **Option B:** Multiple evanescent white dot syndrome (MEWDS) is another retinal condition that can present with sudden vision loss, but it typically involves the peripheral retina and is not associated with wedge-shaped parafoveal lesions.
* **Option C:** Acute retinal necrosis is a more severe condition that typically presents in immunocompromised individuals and is associated with more severe visual impairment and retinal necrosis.
**Clinical Pearl / High-Yield Fact**
APMPPE is a rare but important condition to consider in the differential diagnosis of post-viral vision loss, particularly in young adults. It is essential to recognize the characteristic fundus findings and clinical presentation to avoid misdiagnosis and delay in treatment.
**Correct Answer:** D.