Behçet's disease of the optic nerve

Optic nerve involvement in Behçet's disease is rare. However, progressive optic atrophy and visual loss associated with Behçet's does occur. Acute optic neuropathy and more specifically, Anterior ischemic optic neuropathy (AION) have been reported in Behçet's disease.

Background

Behçet's disease is a systemic immune-mediated vasculitis with major symptoms including oral and genital ulcers, skin lesions and ocular inflammation. Ocular Behçet's occurs in 60-80% of patients with Behçet's disease and can affect both the anterior and posterior chambers of the eye. Common ocular manifestations include anterior and/or posterior uveitis, retinal vasculitis and occlusion, macular edema, optic disk hyperemia, iridocyclitis, hypopyon and vitreitis.

Behçet's disease may result in primary or secondary optic nerve involvement. Optic nerve atrophy has been identified as the most common cause of visual impairment in ocular Behçet's disease. Papilledema as a result of dural sinus thrombosis and atrophy resulting from retinal disease, have been characterized as secondary causes of optic nerve atrophy in Behçet's disease.

Acute primary optic neuropathy in Behçet's disease has also been reported.[5-6] In cases of acute optic neuropathy, symptoms were often associated with exacerbations or relapse of systemic disease. Moreover, visual symptoms may herald the onset of CNS manifestations of the disease. Acute optic neuropathy may be unilateral or bilateral at its onset and may recur or come to involve the contralateral eye.[5-6]

Epidemiology

In an epidemiologic study by Krause et al., 56% of patient’s with Behçet's disease developed ocular involvement at a mean age of 30. Ocular involvement was the first manifestation of Behçet's disease in 8.6% of patients.[7] Ocular Behçet's with involvement of the optic nerve is rarely reported. Among patients with ocular Behçet's disease funduscopic findings of optic atrophy, and optic disc paleness have been identified with a frequency of 17.9% and 7.4%, respectively. Other fundoscopic findings include vascular sheathing(23.7%), retinal hemorrhage(9%), macular edema(11.3%), branch retinal vein occlusion(5.8%), and retinal edema(6.6%). However, optic atrophy was the most significant cause of visual impairment identified in 54% of patients with ocular Behçet's disease and permanent visual impairment.

Pathophysiology

Vasculitis resulting in occlusion of the vessels supplying the optic nerve may be the cause of acute optic neuropathy and progressive optic atrophy in Behçet's disease. Histological evaluation in a reported case of acute optic neuropathy demonstrated substitution of the axonal portion of the optic nerve with fibrous astrocytes without retinal changes. CNS involvement in Behçet's may lead to intracranial hypertension most commonly due to dural venous sinus thrombosis [8-10] and subsequent secondary optic atrophy.

Signs and Symptoms

File:Eye dilate.gif

Pupillary light reflex.

Signs and symptoms of acute optic neuropathy include painless loss of vision which may affect either one or both eyes, reduced visual acuity, reduced color vision, Relative Afferent Pupillary Defect, central scotoma, swollen optic disc, macular edema, or retrobulbar pain. When these symptoms occur with concurrent mucocutaneous ulcerations, they raise suspicion of acute optic neuropathy in Behçet's Disease. Progressive optic atrophy may result in decreased visual acuity or color vision. Intracranial hypertension with papilledema may be present.

File:Eyevessels 001.jpg

Funduscopic photo left eye centered on the optic disc.

Diagnosis

Visual acuity, or color vision loss with concurrent mucocutaneous lesions and/or systemic Behçet's symptoms should raise suspicion of optic nerve involvement in Behçet's disease and prompt a work-up for Behçet's disease if not previously diagnosed in addition to an ocular work-up. Diagnosis of Behçet's disease is based on clinical findings including oral and genital ulcers, skin lesions such as erythema nodosum, acne, or folliculitis, ocular inflammatory findings and a pathergy reaction. Inflammatory markers such ESR, and CRP may be elevated. A complete ophthalmic examination may include a slit lamp examination, optical coherence tomography to detect nerve loss, visual field examinations, fundoscopic examination to assess optic disc atrophy and retinal disease, fundoscopic angiography, and visual evoked potentials, which may demonstrate increased latency. Optic nerve enhancement may be identified on Magnetic Resonance Imaging (MRI) in some patients with acute optic neuropathy. However, a normal study does not rule out optic neuropathy. Cerebrospinal fluid (CSF) analysis may demonstrate elevated protein level with or without pleocytosis. Imaging including angiography may be indicated to identify dural venous sinus thrombosis as a cause of intracranial hypertension and optic atrophy.

Differential Diagnosis

Leber's hereditary optic neuropathy

Multiple Sclerosis-Optic Neuritis

Anterior Ischemic Optic Neuropathy (AION)

Temporal Arteritis (Non-arteritic AION)

Posterior Ischemic Optic Neuropathy

Cerebral venous sinus thrombosis

Treatment/Prognosis

Given its rarity, the optimal treatment for acute optic neuropathy in Behçet's disease has not been established. Early identification and treatment is essential. Response to cyclosporin, periocular triamcinolone, and IV methylprednisone followed by oral prednisone has been reported although relapses leading to irreversible visual loss may occur even with treatment.[5] Immunosuppressants such as interferon alpha and tumour necrosis factor antagonists may improve though not completely reverse symptoms of ocular Behçet's, which may progress over time despite treatment. When symptoms are limited to the anterior chamber of the eye prognosis is improved. Posterior involvement, particularly optic nerve involvement is a poor prognostic indicator. Secondary optic nerve atrophy is frequently irreversible. Lumbar puncture or surgical treatment may be required to prevent optic atrophy in cases of intracranial hypertension refractory to treatment with immunomodulators and steroids.

External links

• http://www.behcet.org.il/ohnotalkE.htm

References

5. Voros, G.M., S.S. Sandhu, and R. Pandit, Acute optic neuropathy in patients with Behcet's disease. Report of two cases. Ophthalmologica, 2006. 220(6): p. 400-5.

6. Yamauchi, Y., et al., Suspected simultaneous bilateral anterior ischemic optic neuropathy in a patient with Behcet's disease. Ocul Immunol Inflamm, 2005. 13(4): p. 317-25.

7. Krause, L., et al., Ocular involvement in Adamantiades-Behcet's disease in Berlin, Germany. Graefes Arch Clin Exp Ophthalmol, 2009. 247(5): p. 661-6.

8. Brissaud, P., et al., Digital angiography for the diagnosis of dural sinus thrombosis in Behcet's disease. Arthritis Rheum, 1985. 28(3): p. 359-60.

9. el-Ramahi, K.M. and M.Z. al-Kawi, Papilloedema in Behcet's disease: value of MRI in diagnosis of dural sinus thrombosis. J Neurol Neurosurg Psychiatry, 1991. 54(9): p. 826-9.

10. Fujikado, T. and K. Imagawa, Dural sinus thrombosis in Behcet's disease—a case report. Jpn J Ophthalmol, 1994. 38(4): p. 411-6.

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