Three case reports of optic perineuritis complicated by ocular scleritis and hypertrophic pachymeningitis

Optic perineuritis (OPN) is an uncommon form of the orbital inflammatory disease targeting the optic nerve sheath, which is distinct from optic neuritis. It causes reduced visual acuity and ocular pain and is linked to infection or autoimmunity, including myelin oligodendrocyte glycoprotein-associated disease, but 30-50% are idiopathic. We report three cases of OPN with ocular scleritis and hypertrophic pachymeningitis occurring together or sequentially; in one, pachymeningitis extended from the optic sheath, in two, it was separate. Case 1: 54-year-old man with a history of ocular scleritis developed left ocular pain, diplopia, and visual loss. MRI showed left optic sheath hyperintensity and dural enhancement. Serology and CSF were unremarkable. Intravenous methylprednisolone (IVMP) followed by prednisolone (PSL) improved visual accuracy to 20/13, with no relapse at 10 months on tapering PSL. Case 2: 76-year-old man developed ocular scleritis, OPN, and hypertrophic pachymeningitis presenting as orbital apex syndrome. Blood examination showed pancytopenia. After the treatment of concomitant pneumonia, IVMP partially improved symptoms. Later, he was also diagnosed as myelodysplastic syndrome. He did not relapse without further immunotherapy. Case 3: 63-year-old woman with previous history of ocular scleritis developed acute right visual loss. MRI showed optic sheath and connected dural enhancement. IVMP followed by PSL treatment improved vision from no light perception to 20/125, without relapse at 7 months. These cases suggested possible shared connective-tissue autoimmunity, and warrant attention to the overlap of the three diseases.