Management of Bilateral Uveitis Secondary to Intraocular Filariasis

Management of uveitis secondary to filariasis has been inadequately described as these cases are rare. We report a case of bilateral uveitis due to intraocular filariasis and discuss its medical and surgical treatment. We also document the use of doxycycline hydrochloride, which sterilizes adult worms by eliminating their symbiotic bacteria and may prevent recurrences of uveitis.

A 49-year-old Asian Indian man had decreased vision in both eyes for 3 months, with pain and redness in the right eye for 1 month. Both eyes had a best-corrected visual acuity of counting fingers at 1 m with nongranulomatous anterior uveitis, posterior synechiae, cataracts, and dense vitritis. In addition, the right eye had an iris bombe configuration with an intraocular pressure of 44 mm Hg. Systemic history and examination results were unremarkable. Antiglaucoma medication, topical steroids, and cycloplegics were started. A motile worm (approximately 200 μm long) was subsequently observed on the anterior capsule of the left eye. Peripheral blood smear showed microfilariae of Wuchereria bancrofti. Stool examination was negative for cysts or ova of parasites.

Oral prednisone (1 mg/kg/d) was started, and antifilarial treatment (diethylcarbamazine, 6 mg/kg/d for 3 weeks, and albendazole, 400 mg once daily for 1 week) was initiated 3 days later. Treatment with oral doxycycline hydrochloride, 100 mg twice daily, was given for 4 weeks to eradicate Wolbachia. Glaucoma was unresponsive to medical management. Therefore, a trabeculectomy with phacoemulsification and intraocular lens implantation was performed on the right eye within 1 week of commencing treatment with steroids. The postoperative period was uneventful. Six months later, phacoemulsification with intraocular lens implantation was performed on the left eye. Steroids were gradually tapered and stopped. Both eyes have been quiet for 6 months, with a visual acuity of 6/12 J2 due to an epiretinal membrane over the macula. Peripheral blood smear 1 year after doxycycline treatment did not show any microfilaria.

Quiz Ref IDUveitis secondary to intraocular filariasis in the Indian subcontinent is mainly due to W bancrofti and Brugia malayi.¹Quiz Ref IDIntraocular filariasis is caused more commonly by microfilariae than by adult worms.² This is an unusual case of microfilariae causing bilateral uveitis, which to our knowledge has been reported in only 1 other article.³

Quiz Ref IDThe role of antifilarial drugs is controversial because of the possibility of increased uveitis due to the killing of microfilaria as seen in the Mazzotti reaction. However, several reports have used these successfully under steroid cover without untoward effects.^2-4Quiz Ref IDDiethylcarbamazine and ivermectin clear the microfilaria from the blood but do not act on the adult worm, which lives in the lymphatic system for 10 to 15 years.^2,5 Therefore, repeated treatments may be necessary to prevent recurrent episodes of uveitis.^2,3 Albendazole can reduce the microfilaria possibly due to its embryotoxic effect on the adult worms.⁵ Recently, an endobacterium of the Wolbachia species that belongs to the family Rickettsiaceae was found in some of these nematodes.⁶ These are mutualistic symbionts. Quiz Ref IDTreatment with tetracyclines clears the Wolbachia from the worm, affecting embryogenesis and resulting in worm sterility.⁶ This may prevent future episodes of uveitis. Doxycycline treatment showed no effect on Loa loa infections in humans because they do not possess Wolbachia.⁶ Therefore, accurate identification of the nematode is essential when planning treatment.

In conclusion, we report a case of bilateral uveitis due to intraocular filariasis treated with corticosteroids and antifilarial drugs (diethylcarbamazine, albendazole, and doxycycline) to prevent recurrences. Also, cataract extraction with intraocular lens implantation performed under steroid cover did not increase the postoperative uveitis in this patient and resulted in quicker visual rehabilitation.

Correspondence: Dr Pradhan, Department of Ophthalmology, Christian Medical College, Schell Eye Hospital, Arni Road, Vellore 632001, Tamil Nadu, India (zedpradhan@gmail.com).