Introduction
The main diseases of concern are a couple viruses apart of the herpes family:
- Cytomegalovirus (CMV) HHV-5
- Herpes Simplex Virus (HSV) HHV-1 and 2
- Varicella Zoster Virus (VZV) HHV-3
Dead Giveaways
PORN and ARN
Covered in anterior segment disease, progressive outer retinal necrosis and acute retinal necrosis are caused by the herpes virus.
Peripheral and rapidly progressing and destructive retinitis
Herpes invades retinal cells causing retinitis and inflammation, leading to lysis and occlusion of arterioles and choriocapillaris, leading to ischaemia and is followed by necrosis or death of the cells. This sloths off into the vitreous chamber
Retinal breaks can thus also occur, which causes RRD affecting 75%
Cytomegalovirus Retinitis (CMV)
Dormant CMV
Asymptomatic in immunocompetent host (virus latent)
Low CD4+ count --> impaired T-cell response
75-85% of AIDS patients with CD4+ counts under 50 cells/micron
Causes encephalitis, hepatitis, colitis, uveitis, retinitis
Shows a classic "pizza pie retinopathy", composed of retinal haemorrhages and vasculitis
diagnostic features
Primary Risk Factor:
Immunosuppression with HIV/AIDS
Patients who are undergoing immunosuppression therapy for medical reasons
PORN and ARN:
PORN typically affects immunocompromised individuals
ARN typically affects immunocompetent individuals
Is classified as a sight threatening disease
CMV Retinitis:
Initially unilateral, but progresses to bilateral in 20% of cases
Asymptomatic early on in 50% of cases
Mild anterior segment inflammation (KP, A/C cells, vitritis)
Characteristic full thickness yellow-white necrotising retinitis in peripheral retina with perivascular distribution.