2020–2021 BCSC Basic and Clinical Science Course™
8 External Disease and Cornea
Chapter 9: Infectious Diseases of the External Eye: Basic Concepts and Viral Infections
DNA Viruses: Herpesviruses
Epstein-Barr Virus Dacryoadenitis, Conjunctivitis, and Keratitis
Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that infects most humans by early adulthood. Spread of EBV occurs by the sharing of saliva, and the virus results in subclinical infection in the first decade of life; if acquired later in life, it causes infectious mononucleosis. The virus remains latent in B lymphocytes and pharyngeal mucosal epithelial cells throughout life. Ocular disease is uncommon.
Epstein-Barr virus is the most common cause of acute dacryoadenitis, characterized by inflammatory enlargement of 1 or both lacrimal glands. Acute follicular conjunctivitis, Parinaud oculoglandular syndrome, and bulbar conjunctival nodules have been reported in patients with acute infectious mononucleosis and may be the result of EBV infection. There are 3 principal forms of EBV stromal keratitis; the diagnosis is made on the basis of a history of recent infectious mononucleosis and/or persistently high EBV serologic titers:
Type 1: multifocal subepithelial infiltrates that resemble adenoviral keratitis
Type 2: multifocal, blotchy, pleomorphic infiltrates with active inflammation (Fig 9-16) or granular ring-shaped opacities (inactive form) in anterior to midstroma
Type 3: multifocal deep or full-thickness peripheral infiltrates, with or without vascularization, that resemble interstitial keratitis due to syphilis
EBV-associated keratitis may be unilateral or bilateral and may, in select cases, appear similar to the interstitial keratitis induced by HSV, VZV, Lyme disease, adenovirus, or syphilis. As EBV is rare, clinical suspicion for it is usually low; EBV should be considered in patients with disease refractory to conventional antiviral treatment.
Figure 9-16 Interstitial keratitis caused by Epstein-Barr virus.
(Reprinted with permission from Chodosh J. Viral keratitis. In: Parrish RK, ed. The University of Miami Bascom Palmer Eye Institute Atlas of Ophthalmology. Boston: Current Medicine; 1999.)
DIAGNOSIS AND MANAGEMENT
Because it is difficult to isolate the virus, the diagnosis of EBV infection depends on the detection of antibodies to various viral components. During acute infection, first immunoglobulin (Ig) M and then IgG antibodies to viral capsid antigens (VCAs) appear. Anti-VCA IgG may persist for the life of the patient. There is an increase in the level of antibodies to early antigens during the acute phases of the disease and a subsequent decrease to low or undetectable levels in most individuals. Antibodies to EBV nuclear antigens appear weeks to months later, providing serologic evidence of past infection. Acyclovir is not an effective treatment for the clinical signs and symptoms of infectious mononucleosis, but the impact of antiviral therapy on the corneal manifestations of EBV infection remains unknown. Corticosteroids may be effective in patients with reduced vision due to apparent EBV stromal keratitis, but they should not be administered without a prophylactic antiviral if HSV infection is a possibility.
Chodosh J. Epstein-Barr virus stromal keratitis. Ophthalmol Clin North Am. 1994;7(4): 549–556.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.