Author: Hala El Belidi (Morocco)
Co-authors: Yahya Saoiabi, Lalla Ouafae Cherkaoui
Purpose
Toxocariasis is a parasitic disease involving infection by Toxocara canis or Toxocara cati. The Toxocara species are clinically classified into visceral larva migrans , ocular larva migrans , and neurological larva migrans . Previous studies from Western countries have reported that ingestion of embryonated eggs or larvae through contact with infected puppies or contaminated soil was the main route of infection. However, recent studies from Asia have reported a higher prevalence than expected in uveitis patients, whose infection may have involved ingestion of infected raw cow liver or meat. Ocular toxocariasis (OT) occurs when Toxocara larvae migrate into the eye through blood circulation ; it usually induces inflammation in uveal and retinal tissues, and results in diverse sequelae such as simple retinal pigmentation, epiretinal membrane , retinal nerve fiber layer defect, or macular scar. OT is clinically diagnosed based on its typical clinical ocular presentation, positive serologic test results, and exclusion of other possible causes . we report a case of ocular toxocarosis revealed by neglected contusive ocular trauma .
Setting/Venue
HOPITAL DES SPECIALITES . RABAT . MOROCCO
Methods
we report a case of a 14-year-old male , having as a medical history neglected contusive trauma of the left eye by stone throw 1 month ago. He presented to our hospital with a 15-day history blurry vision in the left eye. The patient had contact with neighborhood dogs . The ophthalmologic examination revealed visual acuity which allowed detection of hand movement in the left eye and 20/20 with correction in the right eye. Examination of the anterior segment was normal bilaterally. Examination of the posterior segment of the left eye had a white-yellow subretinal lesions in supero-nasal and inferior quadrant compatible with granulomas , a fibrotic band and an epiretinal membrane causing an inferior retinal detachment and vitritis .The right eye exam was normal . No serological or radiologic evidence of toxoplasma, rubella, cytomegalovirus, herpes simplex virus, syphilis or rheumatologic disease was observed. The only major finding was a positive enzyme-linked immunosorbent assay result for Toxocara canis immunoglobulin G antibody.This case was diagnosed with OT. He was treated with albendazole, and methylprednisolone . The best corrected visual acuity of the affected eye improved to 20 / 63 after treatment . Then the patient underwent a pars plana vitrectomy .
Results
OT is reported in the literature to occur more frequently in boys, with a mean age between 5 and 9 years . Recent studies demonstrate higher risk for Toxocara seropositivity in rural regions . OT can manifest in three distinct clinical forms: focal granuloma of the posterior pole ( 25–50%); peripheral granuloma (as seen in our case ) (in 50%); and diffuse endophthalmitis (less than 25%).The level of visual impairment is suspected to be dependent on the extent and location of intraocular inflammation and the fibrotic response involved in the development of a retinal detachment. Positive serology may be suggestive of infection. Because of the highly invasive natureofocular sample collection for testing, diagnosis remains largely based on clinical and ophthalmologic findings. Prompt referral to experienced ophthalmologists is essential in the context of suspected OT because of the compromise of vision. Studies have shown the efficacy of albendazole and corticosteroid therapy in improving intraocular inflammation, but current recommendations do not support the use of antihelminthic therapy in quiescent disease. Pars plana vitrectomy indications include tractional retinal detachment involving the macula, severe persistent vitreous opacities despite systemic corticosteroid treatment, rhegmatogenous retinal detachment, and dense macular epiretinal membranes .
Conlusions
ocular toxocariasis is a frequent cause of uveitis in the pediatric age . The visual sequelae of a Toxocara infection are important. it is crucial to detect the disease early, educating ophthalmologists, pediatricians, general practitioners, and parents. Prevention via de-worming of dogs and cats plus an appropriate disposal of their excretions are one of the best control strategies for limiting infection.In eyes with no retinal detachment oral corticosteroids appear to be beneficial. In eyes with retinal detachment, the visual prognosis is poor despite surgical intervention.
Financial Disclosure
We have no financial interest to disclose
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