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History of stromal keratitis requires long-term oral antiviral
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ATLANTA – Many cases of Acanthamoeba keratitis are misdiagnosed as herpes, according to Zaina Al-Mohtaseb, MD, in a presentation on anterior segment infections here at SECO.
“Herpes epithelial keratitis that’s treated appropriately should resolve in 2 weeks,” she said. “In fact, herpes simplex virus is a self-limiting disease. Even if you don’t treat it, it should resolve on its own.
“If a patient you treated for herpes doesn’t resolve, it’s probably Acanthamoeba,” she continued. “You can get a co-infection, too, which may occur in 17% of cases according to one study.”
Al-Mohtaseb prefers oral treatment for HSV.
“I like Valtrex (valacyclovir, GlaxoSmithKline) because it’s administered the least amount of times a day and it’s generic,” she said.
“You either have a stromal keratitis component, or think about Acanthamoeba,” Al-Mohtaseb said. “Twenty-five percent of people who have had herpes before are likely to get a stromal keratitis component. If they have uveitis associated with it, I treat them with a full dose of acyclovir or Valtrex, or you could just do the prophylactic dose.”
Patients with a history of stromal keratitis should be on long-term treatment with acyclovir or Valtrex, she said.
“It’s well tolerated,” Al-Mohtaseb said, and can help prevent further scarring with re-infection.
“We’ve always been told that the inflammation is not active virus,” she said. “There’s great basic research to show that there’s an enzyme involved, and there may be treatment for the enzyme.”
The use of steroids, however, is controversial, Al-Mohtaseb said.
“The best time to use steroids is when you know what the pathogen is and you know the patient is starting to improve,” she said. “You put them on steroids to decrease the inflammation and risk of scarring.”
She said patients with Mycobacteria or fungal keratitis will feel better the first week they are on a steroid, then get worse and become dependent on the treatment. Those with Pseudomonas or gram-positive or gram-negative pathogens do great with steroids.
“Know what you’re dealing with,” she said. “Not everything in the cornea that looks like an infection is an infection. And sometimes steroids are the answer.” – by Nancy Hemphill, ELS, FAAO
Reference:
Al-Mohtaseb Z. Special session: Anterior segment solutions. Presented at: SECO; Feb. 28-March 4, 2018; Atlanta.
Disclosure: Al-Mohtaseb reports she is a consultant for Alcon, Bausch + Lomb, Kala and Shire.