cytomegalovirus (CMV) retinitis

Introduction

A sight-threatening disorder secondary to cytomegalovirus infection of the retina, generally in immunocompromised individuals.

Epidemiology

• most common ocular opportunistic infection
• occurs in 25-30% of patients with advanced HIV disease

Pathology

• untreated
  • inflammatory destruction of retina
  • retinal detachment

Clinical manifestations

• peripheral retinal lesions generally do not cause visual symptoms
• generally far advanced before recognition of symptoms
• lesions impinging on the macula or optic nerve head
  • floaters
  • scotomas
  • visual field defects
• blurred vision, painless vision loss
• yellow-white exudates, hemorrhages & vascular sheathing on ophthalmoscopic examination
• retinitis is generally unilateral, but may be bilateral in 20% of patients
• untreated, leads to visual loss

Laboratory

• dilated ophthalmoscopy required for diagnosis

Differential diagnosis

• Toxoplasma gondii chorioretinitis
  • fluffy white necrotizing retinitis adjacent to pigmented chorioretinal scar
  • vitreous inflammation

Management

• ganciclovir
  • induction therapy
    • 5 mg/kg every 12-24 hours IV for 14-21 days infused over 1 hour
  • maintenance therapy
    • intravenous infusion
      • 6 mg/kg/day for 5 days per week
      • 5 mg/kg/day
    • 1000 mg PO TID or 500 mg 6 times/day
  • intravitreous implant
    • may substantially increase disease-free interval
    • may be associated with post-operative visual changes
    • increased incidence of retinal detachment
    • no coverage for contralateral eye or systemic disease
• foscarnet
  • indications
    • patients with ganciclovir-resistant CMV
    • patients who cannot tolerate ganciclovir
  • induction therapy: 60 mg/kg every 8 hours for 2-3 weeks
  • maintenance therapy: 90-120 mg/kg/day
  • foscarnet is given IV as a 1-2 hour infusion
• cidofovir
• indefinite maintenance therapy is generally required to suppress CMV disease in patients with AIDS
• in some AIDS patients, CMV maintenance therapy can be discontinued when immune parameters improve
• median time to progression of disease is 2 months with IV treatment but may be longer with intravitreous implants

More general terms

• retinitis
• viral infection

Additional terms

• cytomegalovirus (CMV, human herpesvirus 5, HHV5)