Cytomegalovirus retinitis is a late complication of cytomegalovirus (CMV) infection, usually occurring in immunosuppressed patients. It is an acquired immune deficiency syndrome (AIDS) defining illness.
The reported incidence and prevalence of CMV retinitis varies with geographical location. The prevalence in patients with AIDS in Africa and China is reported at 0-8.5% 1 and 7.5% respectively. However, the prevalence in Singapore is reported at 0.125% 3. A possible explanation for these findings include the availability of active screening in patients with AIDS.
CMV retinitis tends to occur in patients that cannot generate a T cell response against CMV. The highest incidence is observed in patients with AIDS and immunosuppression for organ transplantation (including bone marrow transplantation).
Interestingly, the initiation of antiretroviral therapy in patients with CMV retinitis can cause a paradoxical increase in symptoms of up to 40% of patients due to T cell response against dead CMV virus 4.
CMV retinitis tends to manifest with CD4+ counts of <50 cells/mm3. Approximately 50% of patients have bi-ocular involvement 5.
The symptoms may include:
- presence of floaters in the vision
- decreased vision
Ocular findings may include:
- retinal vessel vasculitis
- retinal (including macular) inflammation to varying degrees
The diagnosis of CMV retinitis is made with ophthalmic examination and the presence of CMV IgG. The diagnosis is made with fundus photographs and optical coherence tomography.
Although the diagnosis is generally clinical, bedside ultrasound may be helpful in cases where retinal detachment is suspected 6.
Additionally, MRI and CT brain may show the presence of concurrent CMV encephalitis.
Treatment and prognosis
The treatment for CMV retinitis involves administration of antiviral medications (e.g. valganciclovir, ganciclovir, foscarnet, or cidofovir). In one study, it was found that the mortality rate for patients with CMV retinitis was 28% 7.
- in immunosuppressed or immunocompromised patients suspect CMV as a cause of retinitis if patients complain of new onset visual disturbances
- bedside ultrasound may serve as a good initial test to screen for possible retinal detachment
- further follow-up with ophthalmic imaging will be required
- 1. Kestelyn P. The epidemiology of CMV retinitis in Africa. (1999) Ocular immunology and inflammation. 7 (3-4): 173-7. Pubmed
- 2. Ying Shi, Hongzhou Lu, Taiwen He, Yalin Yang, Li Liu, Renfang Zhang, Yufang Zheng, Yinzhong Shen, Yunzhi Zhang, Zhiyong Zhang. Prevalence and clinical management of cytomegalovirus retinitis in AIDS patients in shanghai, china. (2011) BMC Infectious Diseases. 11 (1): 326. doi:10.1186/1471-2334-11-326 - Pubmed
- 3. Teoh SC, Wang PX, Wong EP. The epidemiology and incidence of cytomegalovirus retinitis in the HIV population in Singapore over 6 years. (2012) Investigative ophthalmology & visual science. 53 (12): 7546-52. doi:10.1167/iovs.12-10349 - Pubmed
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- 6. Westafer, Lauren, Nickels, L. Connor, Flach, Eike, De Portu, Giuliano, Stead, Latha Ganti. Role of Bedside Ultrasound in CMV Retinitis: A Case Report. (2018) Case Reports in Emergency Medicine. 2012: 690598. doi:10.1155/2012/690598 - Pubmed
- 7. Tun, NiNi, Smithuis, Frank M., London, Nikolas, Drew, W. Lawrence, Heiden, David. Mortality in Patients With AIDS-Related Cytomegalovirus Retinitis in Myanmar. (2014) Clinical Infectious Diseases. 59 (11): 1650. doi:10.1093/cid/ciu648 - Pubmed