A 36-year-old man with HIV infection presents with progressive painless visual loss. His CD4 count is 30 cells/mm3. Fundoscopy shows fluffy white granular retinal necrosis with haemorrhage along the borders of the lesions, following the vascular arcades, with minimal overlying inflammatory reaction. Which organism is responsible?
- A Toxoplasma gondii
- B Cytomegalovirus ✓
- C Herpes simplex virus type 1
- D Mycobacterium tuberculosis
Correct answer: B. Cytomegalovirus
Explanation
CMV retinitis is the leading ocular opportunistic infection in AIDS and classically develops when CD4 counts fall below 50 cells/mm3. The described pizza pie appearance, granular white necrosis with bordering haemorrhage along vessels, is pathognomonic. Toxoplasmosis produces a dense focal chorioretinal lesion with heavy overlying vitritis rather than a broad granular band, and HSV causes acute retinal necrosis with prominent pain and anterior chamber inflammation, features absent here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.