Idiopathic inflammation of optic nerve simulating optic nerve sheath meningioma: CT demonstration

Optic perineuritis

Optic perineuritis (OPN) is a rare inflammatory disorder in which the inflammation is confined to optic nerve sheath. It can be idiopathic or secondary to underlying systemic autoimmune disorder. It usually presents with unilateral progressive diminution of vision with pain on eye movements and optic disc oedema. Hence, clinically OPN mimics optic neuritis resulting in delayed diagnosis and suboptimal treatment. In contrast to optic neuritis, patients with OPN are usually of older age group and more likely show sparing of central vision. MRI is an important tool for diagnosis of OPN apart from optic nerve sheath biopsy. Perineural enhancement on MRI is diagnostic of OPN. Oral corticosteroid therapy gives dramatic and rapid improvement in signs and symptoms. Rapid tapering of steroids increases the risk of relapse. Overall, prognosis of OPN is generally good if adequate treatment is given timely.

The Role of Endonasal Endoscopic Optic Nerve Decompression as the Initial Management of Primary Optic Nerve Sheath Meningiomas

Background  The management of optic nerve sheath meningiomas (ONSMs) remains controversial. Surgical decompression through traditional resective techniques has been associated with significant morbidity. While radiation therapy, the current modality of choice is not exempt of risks. Transnasal endoscopic optic nerve decompression (EOND) offers a direct route to the orbit, optic canal, and orbital apex, providing a minimally invasive alternative. Objective  The main objective of this article is to assess EOND as the initial management of symptomatic patients with primary ONSM. Methods  Patients with ONSMs without a history of radiotherapy who underwent EOND were retrospectively reviewed. Postoperative imaging, duration of follow-up, and visual outcomes at the last ophthalmology visit were assessed. Results  Four women (age range 25-63 years) with primary ONSMs that underwent EOND were identified. All patients displayed subjective and objective baseline signs of vision loss. Additionally, baseline proptosis, diplopia, optic nerve atrophy, and ocular pain were identified. In none of the cases, the optic nerve sheath was breached. Following EOND, all patients deferred treatment with adjuvant radiotherapy. At a mean postoperative follow-up of 14 months, all patients were clinically stable without evidence of disease progression on imaging or physical examination. At last ophthalmologic evaluation, three out of four showed objective improvements from baseline visual acuity and visual field (remaining patient had baseline optic nerve atrophy). Conclusion  These results suggest that EOND could be a viable initial treatment modality of selected primary ONSM cases. Further studies are warranted to determine long-term efficacy and its role in a stepwise progression of management, preceding radiotherapy.

Optic Nerve Sheath Meningioma Masquerading as Optic Neuritis

Optic neuritis is a common presentation of demyelinating disorders such as multiple sclerosis. It typically presents with acute painful monocular vision loss, whereas chronic optic neuropathy can be caused by compressive lesions along the anterior visual pathway, genetic, toxic, or nutritional causes. We report an unusual presentation mimicking optic neuritis, which was subsequently diagnosed as optic nerve sheath meningioma (ONSM). Misinterpretation of white matter lesions on MRI of brain and the failure to image the optic nerves at the time of acute loss of vision led to the misdiagnosis of optic neuritis in this case. A comprehensive accurate history and ordering the appropriate imaging modality remain paramount in diagnosing progressive visual deterioration.

Idiopathic Inflammatory Neuroretinitis Simulating Optic Nerve Sheath Dural Ectasia

We report a case of a 32-year-old female patient who presented with decreased vision on both eyes and headache. In fundus examination, both eyes had elevation of the optic disc and star shaped hard exudates in the macula. Magnetic resonance imaging was completely normal except the saccular dilatation of bilateral optic nerve sheath. The patient was treated with oral steroids following high-dose intravenous methylprednisolone. She displayed good anatomical and functional results during the follow-up. This case raises the possibility that optic nerve sheath enlargement, probably induced by an idiopathic inflammatory optic neuritis, may simulate dural ectasia of the optic nerve sheath.

Bilateral disk edema with unilateral macular serous fluid secondary to neurocysticercosis

PURPOSE

The purpose of this article is to document a case of neurocysticercosis that manifested clinically with bilateral disk edema and serous fluid accumulation in the macula of the left eye. We also describe the recovery of visual-field loss (O.D.) and diminution of bilateral disk edema following anti-helminthic treatment.

CASE REPORT

A 41-year-old woman reporting headaches came to us with bilateral disk edema and co-existing serous macular fluid in the left eye.

RESULTS

Magnetic resonance imaging (MRI) revealed the presence of large multi-septated cysts that exhibited peripheral enhancement, with minimal surrounding edema at the posterior left temporal lobe. Scattered punctate lesions, suggesting areas of calcification, were also observed within both temporal lobes. The optic chiasm appeared compressed. This presentation was considered characteristic of neurocysticercosis and the patient was prescribed a regimen of 200mg albendazole b.i.d. The patient responded well to the treatment, with progressive resolution of the bilateral disk edema and macular fluid.

CONCLUSION

Although rare, cases of cysticercosis and neurocysticercosis may still be encountered in industrialized nations, where the parasite has been almost eradicated. Ocular signs of disk edema and macular serous fluid secondary to neurocysticercosis may correspond to optic nerve, parenchymal, or extraparenchymal disease.

Simultaneous occurrence of neuroretinitis and optic perineuritis in a single eye

A 52-year-old woman presented with pain, decreased visual acuity, decreased color vision, and visual field loss in the OD. Fundus examination revealed optic disc edema and later a macular star figure consistent with neuroretinitis. Magnetic resonance imaging showed enhancement of the orbital optic nerve sheath and perineural fat suggestive of optic perineuritis. The patient was not treated. At 11 months, visual function and fundus examination had returned to normal. This unusual simultaneous occurrence of neuroretinitis and optic perineuritis suggests that these two entities may have a similar pathogenesis.

Bilateral perineuritis of the optic nerves

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