neurology

MGFA Clinical Classification for Myasthenia Gravis

Myasthenia Gravis Foundation of America (MGFA) clinical classification for myasthenia gravis. Guides prognosis and treatment intensity. Distinguishes ocular from generalised MG.

Clinical class*

Score interpretation

Class I — Ocular MG 1

MGFA Class I — ocular myasthenia gravis only

→ Pyridostigmine; corticosteroids if refractory; patch/prism for diplopia; discuss thymectomy if <60y with generalised MG; low risk of crisis

Class II — Mild Generalised 2–2.5

MGFA Class IIa/IIb — mild generalised MG

→ Cholinesterase inhibitors; corticosteroids; azathioprine/mycophenolate if steroid-sparing needed; thymectomy if appropriate; IVIg/PE for acute worsening

Class III — Moderate 3–3.5

MGFA Class IIIa/IIIb — moderate generalised MG

→ Optimise immunosuppression; regular neurological review; respiratory monitoring; consider rituximab or eculizumab for refractory disease; PE or IVIg for exacerbations

Class IV/V — Severe / Crisis 4–5

MGFA Class IV/V — severe generalised MG or myasthenic crisis

→ ICU admission for Class V; mechanical ventilation if needed; plasma exchange (preferred) or IVIg; IV methylprednisolone; hold or reduce pyridostigmine if cholinergic crisis suspected; urgent neurology review

Interpretation bands for the MGFA Classification. Apply clinical judgement and local guidance.

References

Jaretzki A et al. Myasthenia gravis: recommendations for clinical research standards. Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America. Neurology. 2000;55(1):16–23.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Myasthenia Gravis Activities of Daily Living (MG-ADL) Scale · Neuromuscular

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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