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Diffuse Unilateral Subacute NeuroretinitisA Case ReportSony Siraj E DO, Reena A MS DO, Thomas George MS, DO Donald M Gass and his collegues recognized a “unilateral wipe out syndrome” in whichhealthy young individuals developed insidious usually severe loss of peripheral and centralvision, vitritis, diffuse and focal PED with relative sparing of macula, narrowing of retinalvessels, optic atrophy, increased retinal circulation time and subretinal electroretinographicfindings. Later it was called as Diffuse Unilateral Subacute Neuroretinitis. We report here aninteresting case of a 10 year old boy who was suspected to have DUSN and his conditioncompletely resolved after a course of antihelminthic therapy.
Key Words: Dusn, Ped, Mewds, Apmppe.
A 10 year old boy presented to us at Regional Instituteof Ophthalmology, OPD with complaints of defectivevision (RE) of 2 weeks duration. He was on treatmentfor hydronephrosis and protein energy malnutrition.
He had the habit of taking non-vegetarian dietfrequently from hotel and gave a history of dewormingevery 3 months. General examination revealed norelevant findings. Ocular examination showed a BCVA Fig. 1. Fundus pictures of left eye. Note the hyperemic disc, of 6/6 (RE) and 6/12 (LE). Anterior segment was with subretinal lobulated cystic swelling, macular star and in normal limits. Fundus of the LE showed a hyperemic disc with a lobulated cystic subretinal lesion of size Blood investigations showed a total count of 9600 per 2DD beneath the superotemporal arcade, 1DD away cumm and a differential count of P49 (polymorphs) from the superior border of the disc (Fig. 1).
L46 (Lymphocytes) E5 (Eosnophils). CRP (C-Reactive Superotemporal arcade vessels showed sheathing.
protein) value was raised (1.2mg %). B scan revealed Macular edema along with macular star was seen.
retinochoroidal complex thickening and oedema of the Multiple subretinal patches were there in the optic nerve. Patient was started on Tab Albendazole superotemporal quadrant, 1DD temporal to the cystic 400 mg od and after 24 hrs systemic steroids were lesion, suggestive of track lesion. A provisional diagnosis given. Patient showed dramatic improvement on day 3 of DUSN was made. Fundus of the RE was within of treatment. After 1month of treatment patient had a BCVA of 6/6 (BE). Fundus picture showed a complete Regional Institute of Ophthalmology, Thiruvananthapuram.
resolution of the subretinal lesion and macular star.
residual retinal changes. Occasionally the worm isidentified with fundus photography.
In the late stages, vision is typically 6/60 or less with adense central scotoma. Optic atrophy and vascularattenuation are prominent features. A subretinal massassociated with choroidal neovascularization has beendescribed in the macula and around the optic nerve.
ERG shows abnormal rod and cone function in theaffected eye with a reduction of b/a wave amplitude Fig. 2. Fundus pictures of left eye after treatment. Note the ratio suggestive of inner retinal injury. Eosinophilia is resolution of the disc and macular edema as well as rare in DUSN. Macular cyst has been reported to be associated with DUSN as an interesting and unusualfinding4. In patients with diffuse unilateral subacute Systemic steroids were tapered over 1 month and neuroretinitis (DUSN), the presence and, therefore, albendazole therapy was also stopped after 1 month.
clinical visualization of subretinal nematode makes thediagnosis obvious. However when located under the retinal pigment epithelium (RPE), diagnosis ispresumptive and challenging. The appearance of sub- DUSN, also called as the unilateral retinal wipe out syndrome typically affects children and young adults.
hypopigmentation and good clinical response to anti- Several species of nematodes, including Toxocara canis, helminthics support the diagnosis. Arundhati Anshu and Baylisascaris procyonis,3 and Ancylostoma caninum Soon Phaik Chee5 published a case report of presumed have been suggested as the potential etiologic agent of DUSN, where subretinal live worm was not seen and DUSN. The nematodes have been classified into the patient responded well to anti- helminthic therapy.
2 different sizes. The smaller nematode, measuring400 to 1000 μm in length, is endemic to the So it is important to have a high index of suspicion southeastern United States, the Caribbean islands, and when patients present with a combination of above Brazil. The larger nematode, measuring 1500 to findings. This will help in early control of ocular 2000 μm in length, has been described in the northern inflammation and also in salvaging vision. Other rare midwestern United States.2 Usually there are no presentations include a case report of diffuse unilateral associated systemic symptoms although cutaneous and subacute neuroretinitis (DUSN) that developed an acute neural larva migrans have been described in a few iridocyclitis with hypopyon after a year of follow-up patients. The proposed mechanism of vision loss include and resolved after treatment with systemic the host inflammatory reaction to the parasite, toxic corticosteroid. (Cristina Muccioli etal)6 .
effect of the worm’s secretary proteins, mechanical Differential diagnosis to be considered include damage produced by the movement of the worm or an intermediate uveitis, Pars planitis, MEWDS, APMPPE, autoimmune reaction somehow initiated by the toxoplasmosis, sarcoidosis, syphilis, Behcet’s disease, infection. The clinical features of DUSN manifest as early and late stages. In the early stages (vision 6/6 –6/60), the external and slit lamp examination is often Laser photocoagulation( Xenon or Argon) should be normal. Early features include retinal arteriolar considered as the first line of therapy in patients in narrowing, intraretinal perivascular exudates, pigment whom motile larva are identified provided the epithelial depigmentation and recurrent multifocal treatment will spare the macula. The role of a evanescent grey white lesion in the outer retina. The combination of laser treatment, systemic steroid, and retinitis is found typically in one sector of the fundus antihelminthics is also proposed10. For the 50 % of and can provide a clue to the worm location. The patients in whom a worm cannot be found, a month retinitis resolves in 7 to 10 days with minimal or no long course of albendazole (400 mg od) along with systemic steroids should be considered. Immobilization Vasumathy Vedantham, Mukesh Mohan Vats, Sathya JKakade, Kim Ramasamy. Diffuse unilateral subacute of the subretinal nematode has been observed following neuroretinitis with unusual findings. American journal systemic antihelminthic therapy, and so it has been of ophthalmology. 2006 Nov;142(5): 880-3.
recommended that patients with DUSN in whom worm Arundhati Anshu, Soon Phaik Chee. Diffuse unilateral cannot be initially identified receive a course of such subacute neuroretinitis. International Ophthalmology.
2008 April;28(2): 127-129.
therapy in order to maximize the chances of identifying Cristina Muccioli; Rubens Belfort J. Hypopyon in a and treating the offending organism.
patient with presumptive diffuse unilateral subacuteneuroretinitis. Ocular Immunology & inflammation 2000June; 8(2): 119–121.
Audo I, Webster AR, Bird AC et al: Progressive retinal Diffuse Unilateral Subacute Neuroretinitis in China.
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Gass JDM, Braunstein RA. Further observations Albert Jakobiec’s Principles and Practice of concerning the diffuse unilateral subacute neuroretinitis Ophthalmology. 3rd edition, Vol. 2, Pages: 2135-2140.
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American Academy of Ophthalmology- Intraocular Goldberg MA, Kazacos KR, Boyce WM, et al. Diffuse inflammation and uveitis : 2008- 2009, pages 266-268.
unilateral subacute neuroretinitis: morphometric, Myint K, Sahay R, Mon S, Saravanan VR, Narendran V, serologic, and epidemiologic support for Baylisascaris Dhillon B. “Worm in the eye” – the rationale for as a causative agent. Ophthalmology. 1993;100: treatment of DUSN in South India. Br J Ophthalmol

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