May 2008

 

OPHTHALMOLOGY NEWS

 

Signs of chikungunya fever


by Vanessa Caceres EyeWorld Contributing Editor

   

Viral infection spreading through Africa and Asia, showing ocular features

Unilateral iridocyclitis

Unilateral Chikungunya retinitis Source: Padmamalini Mahendradas, D.O., D.N.B.

Bilateral viral retinitis Source: Padmamalini Mahendradas, D.O., D.N.B.

An oddly named viral infection is reemerging in parts of Africa and Asia, and some patients are showing ocular manifestations, according to a study published in the February 2008 issue of Ophthalmology.

Chikungunya fever—its name comes from a Swahili word that means “that which bends up”—is transmitted by infected mosquitoes and is a member of the genus Alphavirus. “[The] infection can cause a debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain,” reports a fact sheet on chikungunya from the Centers for Disease Control and Prevention (CDC).

“The disease resembles dengue fever and is characterized by severe, sometimes persistent arthritis, fever, and skin rash,” wrote lead study investigator Padmamalini Mahendradas, D.O., D.N.B., head of Uveitis and Ocular Immunology, Narayana Nethralaya Super Specialty Eye Hospital and Postgraduate Institute of Ophthalmology, Bangalore, India.

The incubation period for chikungunya can be two to 12 days and usually lasts a few days to a couple of weeks, the CDC reports. Still, patients can have fatigue that lasts several weeks and joint pain that lasts weeks or months.

Chikungunya was first described in Africa in the 1950s. Since then, outbreaks have occurred in parts of Africa and Asia, including Tanzania, India, Vietnam, and Indonesia. The last outbreak in India was in 1971, although outbreaks have occurred recently, bringing renewed attention to the infection.

“Recent reports of large-scale outbreaks of fever caused by chikungunya virus infection have confirmed the reemergence of this virus in various parts of the world, including India,” wrote Dr. Mahendradas. The CDC reports there is no vaccine or specific antiviral treatment for chikungunya fever. Most patients are treated with rest, fluids, and ibuprofen or similar medicine.

The recent epidemic led Dr. Mahendradas and co-investigators to analyze ophthalmic manifestations in nine patients with clinical features of chikungunya as verified by serology.

Ocular features

The nine patients were seen in 2006 at a tertiary eye-care center in Bangalore, India. Chikungunya was confirmed with demonstration of a chikungunya immunoglobulin M (IgM) antibody that was captured by a chromatographic immunoassay method in a serum sample from the patients. Patients had a variety of other ocular evaluations and lab tests. All nine patients had the typical clinical features of chikungunya fever, including sudden onset of fever, headache, nausea, vomiting, chills, joint pains, and swelling.

The patients presented to the investigators at varying intervals after onset of fever, ranging from four to 12 weeks later, with a median of six weeks.

Five of the nine patients presented with clinical features of iridocyclitis. “Two of the patients had biliateral iridocyclitis with increased IOP that varied from 27 mm Hg to 42 mm Hg,” the investigators wrote.

Slitlamp biomicroscopic examination showed circum corneal injection in two cases and diffuse fine keratic precipitates, flare 2+, cells 2+, and vitreous cells 1+ in all five cases with iridocyclitis, and confocal microscopy of Keratic precipitates showed a dendritic pattern.

“Patients responded well to topical 1% prednisolone acetate ophthalmic suspension, 2% homatropine hydrobromide eyedrops, and 0.1% diclofenac sodium ophthalmic solution,” the investigators wrote. After three weeks, the inflammation had improved in all patients; they also had normal IOPs.

Three patients had viral retinitis (one bilateral and two unilateral). These patients received systemic acyclovir of varying doses and prednisolone (40 mg daily, orally, for a week). This was tapered over a six-week period along with topical 0.1% diclofenac sodium four times a day. “At six weeks of follow up, visual acuity improved with resolving retinitis,” the investigators wrote.

Overall, the ocular features seen were conjunctivitis, iridocyclitis, episcleritis, scleritis, retinitis, optic neuritis, and secondary glaucoma, Dr. Mahendradas said. The ocular symptoms were redness, blurred vision, floaters, pain, watering, photophobia, and diplopia.

Taking a broader look

Recognizing the features of chikungunya may not seem very relevant outside of Asia and Africa. However, if you see patients with these kinds of symptoms, it could be helpful to ask if they’ve recently traveled to those parts of the world, said Christopher J. Rapuano, M.D., professor of ophthalmology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, and co-director, Cornea Service, Wills Eye Institute, Philadelphia.

This is especially important considering that patients were seen at the eye-care center four to 12 weeks after the onset of fever, Dr. Rapuano added.

An awareness of chikungunya may also help physicians who will travel to affected areas—and the number of affected areas is growing. Just in February, the CDC reported an outbreak of the infection in Singapore.

Those traveling to the affected areas should use an insect repellent containing DEET, wear long sleeves and pants, and take all measures to limit their exposure to mosquito bites, the CDC recommends. Travelers can also keep track of outbreaks via the CDC’s Travelers’ Health Website (www.cdc.gov/travel).

Practitioners should also be aware of chikungunya if they treat patients with Dengue fever, as the two are clinically difficult to differentiate, the investigators wrote. “Correlation with parameters such as serology (IgM antibody) and platelet count can differentiate the same,” they wrote.

Furthermore, “although chikungunya retinitis may morphologically mimic the herpetic viral retinitis, the history of fever, joint pains, and skin rash prior to the onset of the visual symptoms are helpful in the clinical diagnosis, particularly in endemic regions,” Dr. Mahendradas said.

Editors’ note: Dr. Mahendradas and Dr. Rapuano have no financial interests related to their comments.

Contact Information

Mahendradas: +91-80-66121349, m.padmamalini@gmail.com

Rapuano: 215-928-3180, cjrapuano@willseye.org

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