A number of infectious diseases cause uveitis (see table Infectious Causes of Uveitis Infectious Causes of Uveitis A number of infectious diseases cause uveitis (see table Infectious Causes of Uveitis). The most common are toxoplasmosis, herpes simplex virus, and varicella-zoster virus. Different organisms... read more ). The most common are toxoplasmosis Toxoplasmosis Toxoplasmosis is infection with Toxoplasma gondii. Symptoms range from none to benign lymphadenopathy, a mononucleosis-like illness, to life-threatening central nervous system (CNS) disease... read more , herpes simplex virus Herpes Simplex Virus (HSV) Infections Herpes simplex viruses (human herpesviruses types 1 and 2) commonly cause recurrent infection affecting the skin, mouth, lips, eyes, and genitals. Common severe infections include encephalitis... read more , and varicella-zoster virus Herpes Zoster Herpes zoster is infection that results when varicella-zoster virus reactivates from its latent state in a posterior dorsal root ganglion. Symptoms usually begin with pain along the affected... read more . Different organisms affect different parts of the uveal tract.
(See also Overview of Uveitis Overview of Uveitis Uveitis is defined as inflammation of the uveal tract—the iris, ciliary body, and choroid. However, the retina and fluid within the anterior chamber and vitreous are often involved as well.... read more .)
Toxoplasmosis Toxoplasmosis Toxoplasmosis is infection with Toxoplasma gondii. Symptoms range from none to benign lymphadenopathy, a mononucleosis-like illness, to life-threatening central nervous system (CNS) disease... read more is the most common cause of retinitis in immunocompetent patients. Most cases are acquired postnatally; however, congenital cases occur as well, particularly in countries where infection is endemic. Symptoms of floaters Floaters Floaters are opacities that move across the visual field and do not correspond to external visual objects. With aging, the vitreous humor can contract and separate from the retina. The age at... read more and decreased vision may be due to cells in the vitreous humor or to retinal lesions or scars. Concurrent anterior segment involvement can occur and may cause ocular ache, redness, and photophobia. Laboratory testing should include serum anti-Toxoplasma gondii antibody titers.
Treatment is recommended for patients with posterior lesions that threaten vital visual structures, such as the optic disk or macula, and for immunocompromised patients. Multidrug therapy is commonly prescribed; it includes pyrimethamine, sulfonamides, clindamycin, and, in select cases, systemic corticosteroids. Corticosteroids should not, however, be used without concurrent antimicrobial coverage. Toxoplasmosis can recur, and patients with vision-threatening lesions may require long-term prophylaxis with trimethoprim-sulfamethoxazole. Long-acting periocular and intraocular corticosteroids (eg, triamcinolone acetonide) should be avoided.
Patients with small peripheral lesions that do not directly threaten vital visual structures may be observed without treatment and should begin to show slow improvement in 1 to 2 months.
Herpesviruses: HSV and VZV
Herpes simplex virus Herpes Simplex Virus (HSV) Infections Herpes simplex viruses (human herpesviruses types 1 and 2) commonly cause recurrent infection affecting the skin, mouth, lips, eyes, and genitals. Common severe infections include encephalitis... read more (HSV) causes anterior uveitis. Varicella-zoster virus Chickenpox Chickenpox is an acute, systemic, usually childhood infection caused by the varicella-zoster virus (human herpesvirus type 3). It usually begins with mild constitutional symptoms that are followed... read more (VZV) does so less commonly, although the prevalence of zoster-associated anterior uveitis increases with age. Both HSV and VZV can also result in posterior uveitis, although this is less common.
Symptoms of anterior uveitis include
Conjunctival injection and anterior chamber inflammation (cells and flare), often accompanied by corneal inflammation (keratitis Herpes Simplex Keratitis Herpes simplex keratitis is corneal infection with herpes simplex virus. It may involve the iris. Symptoms and signs include foreign body sensation, lacrimation, photophobia, and conjunctival... read more )
Decreased corneal sensation
Patchy or sectorial iris atrophy
Intraocular pressure may be elevated as well, in contrast to the low intraocular pressure typically associated with most forms of uveitis; elevation can be detected by using applanation tonometry Tonometry The eye can be examined with routine equipment, including a standard ophthalmoscope; thorough examination requires special equipment and evaluation by an ophthalmologist. History includes location... read more with, for example, a Goldmann tonometer, a pneumotonometer, an electronic indentation tonometer, or, if these are not available, a Schiotz tonometer.
Treatment should generally be initiated by an ophthalmologist and should include a topical corticosteroid and a cycloplegic-mydriatic drug. Acyclovir (400 mg orally 5 times/day for HSV and 800 mg orally 5 times/day for herpes zoster virus [HZV]) or valacyclovir (1 g orally 2 times/day for HSV and 1 g orally 3 times/day for HZV) may also be given. Drops to lower intraocular pressure may be required in patients with ocular hypertension Overview of Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage in which an important part is a relative increase in intraocular pressure (IOP) that can lead to irreversible... read more .
Acute retinal necrosis (ARN) is a rapidly progressing form of retinitis that is a much less common manifestation of VZV and HSV infection. ARN typically manifests as confluent retinitis, occlusive retinal vasculitis, and moderate to severe vitreous inflammation. One third of ARN cases become bilateral, and in three fourths of eyes, retinal detachment Retinal Detachment Retinal detachment is separation of the neurosensory retina from the underlying retinal pigment epithelium. The most common cause is a retinal break (a tear or, less commonly, a hole) (rhegmatogenous... read more occurs. ARN may also occur in patients with HIV/AIDS, but severely immunocompromised patients can have less prominent vitreous inflammation. Vitreous biopsy for culture and polymerase chain reaction analysis may be useful in diagnosing ARN. Treatment options include IV acyclovir, IV ganciclovir or foscarnet, intravitreal ganciclovir or foscarnet, and oral valacyclovir or valganciclovir.
Cytomegalovirus Cytomegalovirus (CMV) Infection Cytomegalovirus (CMV, human herpesvirus type 5) can cause infections that have a wide range of severity. A syndrome of infectious mononucleosis that lacks severe pharyngitis is common. Severe... read more (CMV) is the most common cause of retinitis in immunocompromised patients, but prevalence has decreased among patients with HIV/AIDS receiving antiretroviral therapy (ART). Currently, ≤ 5% of these patients are affected. Most affected patients have a CD4+ count < 100 cells/mcL. CMV retinitis may also occur in neonates and in pharmacologically immunosuppressed patients but is uncommon. CMV can rarely cause anterior uveitis in the immunocompetent person.
Symptoms of CMV retinitis include blurry vision, blind spots, floaters, flashing lights, and vision loss. However, infection is often asymptomatic.
The diagnosis is largely clinical based on direct or indirect ophthalmoscopic examination; serologic tests are of limited use, although analysis of aqueous fluid can be confirmatory if the diagnosis is in question.
Treatment in patients with HIV/AIDS is with systemic or intravitreal ganciclovir, systemic or intravitreal foscarnet, or systemic valganciclovir. Therapy is typically continued indefinitely, unless immune reconstitution is achieved with combination antiretroviral therapy (typically a CD4+ count > 100 cells/mcL for at least 3 months). Patients with CD4+ counts < 50 cells/mcL, even if asymptomatic, should be monitored every 3 months for CMV retinitis.