Recurrent optic neuritis as early presentation of idiopathic hypertrophic cranial pachymeningitis

Abstract

A 44-year-old Malay lady presented with drooping of the right eyelid and worsening of left eye vision for one week duration. There was associated headache, periorbital discomfort and diplopia on left gaze. She previously had a history of recurrent optic neuritis affecting both eyes over a period of 12 years. On examination, there was right-sided partial ptosis and left exotropia. The adduction, abduction, elevation and depression of the right eye was limited. Left eye extraocular movements were full. The right eye visual acuity was 6/9, while the left eye visual acuity was perception to light, with a positive relative afferent papillary defect and a pale optic disc. The right optic disc was normal. There was reduced sensation in the trigeminal nerve distribution over the right side of the face. Neurological examination was otherwise normal. Magnetic resonance imaging of the brain and orbit revealed meningeal thickening with involvement of the right orbital apex and cavernous sinus. Blood investigations for infectious and autoimmune causes were unremarkable. She was diagnosed to have idiopathic hypertrophic cranial pachymeningitis and treated with systemic corticosteroids. The right eye extraocular motility improved, while the left eye visual acuity improved to counting finger. This case demonstrates that idiopathic hypertrophic cranial pachymeningitis may present as recurrent optic neuritis in the early phase, before radiological evidence of the disease is present. A high index of suspicion for the underlying cause is essential to prevent irreversible optic nerve damage due to recurrent optic neuritis.