Clinical Features and Management of Optic Neuritis in a Cohort of Patients with Combined Central and Peripheral Demyelination

Optic neuritis in combined central and peripheral demyelination (CCPD ON) is mainly reported from Eastern countries, with limited knowledge of its characteristics in Africa. Patients meeting both the EAN/PNS (European Academy of Neurology/Peripheral Nerve Society) criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) and clinical criteria for ON were described in this study which involved antibody screening (ganglioside, NF186, NF155), myelin co-culture screens, CSF analysis, nerve conduction studies, visual evoked potentials (VEPs), optical coherence tomography (OCT), MR imaging and treatment outcomes, based on international guidelines for ON, CIDP, and CCPD, with minor modifications. Twelve patients (12/122, 9.8%) were included in the study. Clinical examination, VEPs, OCT and visual fields were consistent with anterior visual pathway dysfunction and nerve conduction studies confirmed peripheral demyelination. None of the patients had clinical evidence of a retinitis or vitritis. Five (42%) had symmetrical white matter disease including the corpus callosum and retro lentiform limb of internal capsule and one had MS-like lesions. Five (42%) had asymmetrical optic nerve (orbital) enhancement, and 2 (16%) optic sheath enhancement. Two were positive for NF155 antibodies, one had serum and CSF IgG immunoreactivity against non-myelinating Schwann cells. Eleven (91%) were responsive to immunotherapy with good functional recovery as reflected by post treatment visual acuity and inflammatory neuropathy cause and treatment (INCAT) scores. Visual symptoms in CIDP should alert the clinician to underlying CCPD. Early escalation therapy, which may include B-cell depleting therapy, leads to significant recovery which highlights the importance of early diagnosis and prompt escalation therapy. Prospective studies, to identify novel shared peripheral and central myelin epitopes, will fill diagnostic gaps, perhaps even in idiopathic ON, ultimately resulting in bespoke therapies.