Sarcoid-like disorder of the intracranial optic nerve

Chronic Relapsing Inflammatory Optic Neuropathy (CRION)

Purpose of review

This review highlights the epidemiology, clinical and radiologic characteristics of chronic relapsing inflammatory optic neuropathy (CRION) and treatment modalities.

Recent findings

Summary

CRION is an inflammatory optic neuropathy that is characterized by a chronic and relapsing course, that is characterized by pain associated with subacute vision loss. It is favorably responsive but highly dependent on corticosteroids with frequent relapses in the setting of steroid tapering. Additional diagnostic biomarkers and further studies are required to better diagnose and treat this rare but potentially debilitating condition.

Current options for the treatment of optic neuritis

Optic neuritis can be defined as typical (associated with multiple sclerosis, improving independent of steroid treatment), or atypical (not associated with multiple sclerosis, steroid-dependent improvement). Causes of atypical optic neuritis include connective tissue diseases (eg, lupus), vasculitis, sarcoidosis, or neuromyelitis optica. In this manuscript, updated treatment options for both typical and atypical optic neuritis are reviewed. Conventional treatments, such as corticosteroids, therapeutic plasma exchange, and intravenous immunoglobulin therapy are all discussed with commentary regarding evidence-based outcomes. Less commonly used treatments and novel purported therapies for optic neuritis are also reviewed. Special scenarios in the treatment of optic neuritis – pediatric optic neuritis, acute demyelinating encephalomyelitis, and optic neuritis occurring during pregnancy – are specifically examined.

Neurosarcoïdose : état des connaissances

The origins of neurosarcoidosis, a multisystemic granulomatous disease, remain unknown. Nervous system localizations remain rare, but severe. Lymphocytic meningitis, psychiatric disorders, diabetes insipidus and cranial nerve palsy are the most frequent signs. Cerebral fluid test and cervical medullar and cerebral MRI with gadolinium have to be performed first. In some cases, histological evidence of granuloma have to be obtained with neuromuscular, meningeal or cerebral biopsies. Functional impairment and life-threatening conditions require early corticosteroid therapy. In worsening cases or in the event of no therapeutic response or poor tolerance to corticosteroids, other immunosuppressive agents should be associated. Maintenance therapy and most often life long maintenance therapy allow a continuous success while avoiding relapse.

Retinal cotton-wool spots as the first sign of systemic sarcoidosis

Isolated retinal cotton-spots have not yet been reported as the sign of ocular sarcoidosis. We describe three patients with retinal cotton-wool spots of initially unknown etiology in whom systemic sarcoidosis was diagnosed 6-16 months later. The diagnosis was confirmed by conjunctival biopsy. These observations indicate that sarcoidosis should be included in the differential diagnosis of retinal cotton-wool spots and patients with these lesions should be followed for the development of this disease.

Sarcoid masquerading as optic nerve sheath meningioma

Sarcoid manifesting as an optic nerve tumor without evidence of systemic disease is uncommon. Throughout a 2-year period, a 22-year-old white woman had progressive monocular loss of vision to the level of no light perception. Optic atrophy but no uveitis was noted in the affected eye. Magnetic resonance imaging revealed thickening and enhancement of the apical optic nerve, with "tram-tracking." The presumptive diagnosis was optic nerve sheath meningioma; however, a biopsy specimen from the optic nerve revealed sarcoid. Extensive postoperative investigations revealed no systemic sarcoidosis. To our knowledge, 17 cases similar to ours, with the diagnosis proved by optic nerve biopsy, have been previously reported in the English-language literature. Most of these were mistaken preoperatively for optic nerve sheath meningioma. None of the patients had evidence of systemic sarcoidosis on initial postoperative testing. Neuroimaging, serum level of angiotensin-converting enzyme, and clinical characteristics such as age, race, sex, and optochoroidal collaterals do not distinguish optic nerve sheath meningioma from sarcoid of the optic nerve. In the absence of uveitis or systemic involvement, optic nerve sarcoid manifesting as an orbital tumor is virtually impossible to diagnose without results of biopsy.

Optic nerve enlargement and chronic visual loss

We present four patients with sarcoidosis of the anterior visual pathways. The first patient presented with unilateral visual loss, a mass lesion at the optic nerve head, and an enlarged orbital optic nerve. The second patient presented with bilateral progressive painless visual loss, associated with optic nerve pallor and visual field loss. In these two patients, optic nerve biopsy was diagnostic of sarcoidosis. The third patient developed optic nerve and chiasmal involvement after sarcoidosis was established by lacrimal gland biopsy. The fourth patient had optic nerve, pulmonary, and lymph node involvement with sarcoidosis. A conjunctival and lung biopsy were diagnostic. Computed tomography and magnetic resonance imaging have greatly facilitated diagnosis of sarcoidosis of the anterior visual pathways. Sarcoidosis of the anterior visual pathways may occur alone or in association with other ocular or systemic manifestations. A conjunctival or lacrimal gland biopsy may be preferable as the initial diagnostic approach. Treatment of patients with this condition may require systemic immunosuppression, in addition to corticosteroids, to prevent permanent visual loss.

Meningeal sarcoidosis, pseudo-meningioma, and pachymeningitis of the convexity

Two cases of meningeal sarcoidosis with unusual and misleading presentations are reported. In the first case, CT scan, angiographic, and MRI findings were indistinguishable from those of meningioma. CSF pleiocytosis may help in diagnosing sarcoid pseudo-meningioma. The second patient had transient focal deficits and pachymeningitis of the convexity. The transient deficits were probably of epileptic origin based on their response to antiepileptic treatment. The diagnosis of neurosarcoidosis was made only after meningeal biopsy, despite thorough investigations.

Sarcoidosis of the anterior visual pathway: successes and failures

Four patients with progressive visual deterioration were found to have sarcoidosis involving the anterior visual pathway. They all developed chiasmal dysfunction and bilateral optic neuropathy, which responded to megadose corticosteroid therapy. When an attempt was made to withdraw the corticosteroids, the patients experienced a recrudescence of visual dysfunction and were subsequently unable to tolerate the corticosteroid dose levels necessary to maximise their visual potential. Each patient was treated with high-voltage radiation therapy, totalling up to 4500 rads. The beneficial response obtained was temporary, and immunosuppressive therapy with azathioprine or chlorambucil was instituted, preventing further deterioration.

Course and outcome of ocular sarcoidosis

In a series of 281 patients with histologically confirmed sarcoidosis, 79 initially had ophthalmic sarcoid manifestations. Of 22 patients with uveitis, 21 were seen regularly as long as the inflammation was active, and 71 of the 79 patients (90%) underwent a follow-up study five to 16 years (mean, nine years) later and using the same protocol. In the 21 patients with uveitis, the disease exhibited either a monophasic course (eight patients) with favorable visual outcome or a relapsing course (13 patients) with severe visual loss in five eyes. Thirty-three patients showed chronic ophthalmic changes at the follow-up examination, including conjunctival granulomas (13 patients), lacrimal gland involvement (22 patients), uveitis (four patients), and involvement of lacrimal passages (three patients). In 15 of these 33 patients, the general physical examination and the chest x-ray showed no evidence of systemic sarcoidosis. However, the serum angiotensin converting enzyme level was increased in a significantly greater proportion of these 15 patients than in the patients assessed as totally recovered from sarcoidosis.

Optic neuropathy in sarcoidosis

Five patients with isolated optic neuropathy and sarcoidosis are discussed. The spectrum of clinical disease was variable but two groups could be identified: patients with chronic progressive visual loss which was associated with thickening of the optic nerve and was refractory to steroid treatment, and patients with acute or subacute optic neuropathy in which the visual loss responded rapidly to steroids. In the latter group steroid dependence developed in all three of the patients. In none did the clinical picture resemble that of the optic neuritis associated with multiple sclerosis.

Rare multiple orbital localizations of sarcoidosis. A case report

We report a case of bilateral orbital sarcoidosis without other systemic lesions. Steroid therapy did not improve the clinical status of the patient.

Eleven cases of sarcoidosis of the optic nerve

Of 11 patients (eight women and three men, ranging in age from 16 to 48 years) who had sarcoidosis of the optic nerve that caused decreased visual acuity and visual field abnormalities, only two were known to have sarcoidosis at the time the visual impairment developed. Four patients had granulomas involving the optic nerve head, four had granulomatous inflammation of the orbital or intracranial optic nerve or chiasm, and three had retrobulbar neuritis. All 11 patients had histologically confirmed idiopathic noncaseating granulomatous inflammation and eight of the 11 had abnormalities compatible with sarcoidosis in chest roentgenograms. In the three patients in whom the serum level of angiotensin-converting enzyme was determined, it was increased in one and normal in the other two. Computed tomography of the anterior visual pathways was the single most useful neurodiagnostic study. Treatment with corticosteroids was beneficial in six of the 11 cases. These cases demonstrated that sarcoidosis should be included in the differential diagnosis of any inflammatory or compressive lesion involving the anterior visual pathways.