Herpes simplex uveitis

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Disease Entity[edit | edit source]

Herpes simplex infection is one of the common reasons for anterior uveitis.

Etiology[edit | edit source]

Herpes simplex iritis is due to the Herpes simplex virus.

Epidemiology[edit | edit source]

Additional information may be found on the Wiki pages for Herpes Simplex virus and HSV ocular disease.

Risk Factors[edit | edit source]

No specific risk factors have been demonstrated for HSV manifesting as iritis. Risk factors for HSV infection or HSV ocular disease may be found on other Wiki pages.

General Pathology[edit | edit source]

Additional information can be found on the Wiki page for Herpes Simplex virus.

Pathophysiology[edit | edit source]

Additional information can be found on the Wiki page for Herpes Simplex virus.

Primary prevention[edit | edit source]

There is no evidence of primary prevention strategies for HSV iritis or ocular HSV. There is no evidence of prevention of recurrent HSV iritis. The HEDS study evaluated prophylaxis of recurrence of HSV ocular disease and more information can be found on the associated Wiki pages.

Clinical Findings / Signs[edit | edit source]

Keratouveitis and iritis are uncommon manifestations of primary HSV ocular infection. In a study of a large population in the Northern California region of Kaiser Permanente, iritis was the presenting sign in 1% of patients with an initial episode of HSV eye disease.[ref.]

Most commonly, in patients with iritis due to HSV, a keratouveitis is present. Findings in those cases may include a combination of these findins: (from anterior to posterior) corneal epithelial and/or stromal edema, stromal keratitis, keratic precipitates, endothelitis, and anterior chamber cells and flare. Although less common, iritis alone, without evidence of keratitis, may be present during some episodes. Traditionally, the iritis is thought to be secondary to the keratitis when keratouveitis is present. However, in the absence of stromal leukocyte infiltration, assigning a primary and secondary site of inflammation may not be obvious nor correct.

Keratic precipitates (KP) may take several forms. They can be granulomatous, nongranulomatous, or stellate. Often they may be present in a patch on the endothelial surface, underlying a localized patch of corneal edema. They can be regional, in the inferior one-third of the cornea or (less commonly) diffuse. When stellate KP are present, they are typically diffuse. [BCSC] High intraocular pressure is a common complication of HSV iritis and can serve as a diagnostic hallmark. [Table of acute iritis and high IOP] The IOP can be very high, in the range of 50-60 mm Hg during an episode of acute iritis. High IOP is due to trabeculitis, as well as inflammatory cells clogging the trabecular meshwork. Although antiglaucoma therapy may be required in the acute setting, once the inflammation is controlled, typically the intraocular pressure will normalize and the patient will not require ongoing antiglaucoma treatment.

Spontaneous hyphema can occur in HSV iritis, as well as layers of hyphema mixed with hypopyon, known as a “candy-cane hypopyon”.

Although patchy iris atrophy may be present following an episode of HSV keratouveitis or iritis, inflammatory iris lesions are not typically seen.

Symptoms[edit | edit source]

Typical symptoms of iritis with photophobia and pain are seen in HSV iritis. If there is an accompanying high IOP, headache, deeper pain, and decreased vision due to corneal edema may be present. In patients with keratouveitis, pain and decreased vision may be present because of the keratitis and edema. If there is significant damage to CN 5, from prior episodes of HSV, the patient may not have significant pain.

Clinical diagnosis[edit | edit source]

The diagnosis of HSV iritis is suggested by a unilateral anterior uveitis, accompanied by high intraocular pressure. The presence of patchy iris transillumination defects further suggests HSV iritis, but the absence of transillumination defects does not rule it out. A prior history of HSV ocular disease is also strongly suggestive of the role of HSV in ipsilateral iritis.

Diagnostic procedures / Laboratory Testing[edit | edit source]

Because of the high prevalence of positive HSV antibodies in most populations, serology is only helpful in the diagnosis in that a negative HSV antibody titer will rule out the possibility that iritis is due to HSV. Polymerase chain reaction for HSV DNA from an anterior chamber tap may be helpful in diagnosis.

Management[edit | edit source]

Medical therapy[edit | edit source]

Topical corticosteroids are the mainstay of treatment for HSV iritis. Cycloplegic agents may be helpful to decrease symptoms of photophobia and decrease or lyse posterior synechiae.

Topical antiviral agents may help to prevent dendritic keratitis during treatment with corticosteroids, in patients with keratouveitis. In general topical antivirals are of little use in the treatment of HSV iritis, since these agents do not penetrate well into the anterior chamber. In fact, topical antiviral agents may be detrimental due to their topical toxicity. Systemic antiviral agents, such as acyclovir, famcyclovir, or valacyclovir, attain excellent anterior chamber drug levels and may be beneficial in cases of iritis. The HEDS study’s [link to HEDS page] trial of acyclovir in the treatment of HSV iritis was stopped prior to meeting the number of subjects needed according to the sample size estimates. This was done because of problems with recruitment. In the findings that were published, there was a statistically suggestive trend for more rapid resolution of iritis with the use of systemic acyclovir, 400 mg five times per day.

Appropriate doses of systemic antiviral agents for treating active ocular disease are: acyclovir, 400 mg five times per day; valacyclovir, 1000 mg twice per day; famciclovir 250 mg three times per day.

Local injections or systemic corticosteroids are not typically required for control of inflammation.

Some patients may require very slow tapering of topical corticosteroids and may require long term, low dose topical corticosteroid therapy to control inflammation.

Long term, low dose, systemic antiviral therapy may be beneficial for some patients, in order to decrease the frequency of recurrences of iritis. At present, controlled studies to show this are lacking. One might expect the HEDS study’s findings on prophylaxis may be generalizable to iritis, but this cannot be certain. Oral doses for prophylaxis for ocular herpes simplex disease are acyclovir, 400 mg twice per day or valacyclovir, 500 mg daily.

Surgery[edit | edit source]

There are no surgical treatments for HSV iritis. If adequate medical management of high intraocular pressure is not possible, glaucoma surgery may be occasionally needed. One should keep in mind, however, that in most patients, the intraocular pressure will significantly improve once inflammation is controlled.