MOG Antibody Associated Disease

MOG antibody associated disease (MOGAD) is an inflammatory demyelinating disorder with antibodies against myelin oligodendrocyte glycoprotein.

• Affects children and adults equally; no strong sex bias. About 40 to 50% have a monophasic course, the rest relapse.

• Phenotypes: optic neuritis (often bilateral with optic disc swelling), transverse myelitis (conus involvement), ADEM, cortical encephalitis with seizures, brainstem syndromes.

• Better recovery than NMOSD. Persistent high titres predict relapse.

• Painful optic neuritis with marked disc oedema and perineural enhancement, severe at onset but recovering well.

• Myelitis with bladder, bowel and erectile dysfunction, conus lesions.

• ADEM in children with encephalopathy, fever, headache. FLAIR hyperintense cortical lesions, seizures.

• Relapse in 40 to 50%, more often optic neuritis.

• MOG IgG by live cell based assay in serum; titre interpretation depends on clinical context, and low titres need confirmation.

• MRI orbits (long optic nerve lesion anterior sparing the chiasm), spine (longitudinally extensive, H sign), brain (fluffy lesions, deep grey matter).

• CSF: pleocytosis; oligoclonal bands uncommon (under 15%), differentiating from MS.

• Exclude MS, AQP4 NMOSD, infection, vasculitis, neoplasm.

• Acute attack: methylprednisolone 1 g IV daily for 3 to 5 days, then oral prednisolone taper over 4 to 12 weeks (prolonged taper reduces early relapse); plasma exchange or IVIG 2 g/kg for severe attacks.

• Monophasic disease: no long term therapy; monitor titres and MRI.

• Relapsing disease: IVIG 1 to 2 g/kg every 4 weeks (effective), rituximab 1 g every 6 months (variable), mycophenolate mofetil 1 to 1.5 g twice daily, azathioprine 2 to 3 mg/kg, tocilizumab 8 mg/kg monthly, satralizumab (trials).

• Avoid disease modifying therapies for MS (interferon, glatiramer, fingolimod are ineffective).

• Symptomatic management of spasticity and bladder dysfunction, neurorehabilitation.

• Seizures: levetiracetam 500 to 1000 mg twice daily.