Myasthenia gravis (MG): miscellaneous tests

Ice pack test

• This is done when the Edrophonium test is contraindicated
• An ice pack is placed over the eye for 2-5 minutes
• This may lead to improvement of ptosis
• The test is falsely positive with botulism
• The diagnosis of MG should not rely on this test

Blood tests

Biopsy for thymoma

Video oculography (VOG)-based eye tracking

Emerging MG biomarkers

References

1. Thanvi BR, Lo TCN. Update on myasthenia gravis. Postgrad Med J 2004; 80:690–700.
2. Sethi KD, Rivner MH, Swift TR. Ice pack test for myasthenia gravis. Neurology 1987; 37:1383–1385.
3. Cosentino G, Alfonsi E, Lonati D, Locatelli CA, Valentino F, Brighini F. Positive ice pack test in a case of food-borne botulism: a clinical note. J Neurol 2012; 259:2486-2587.
4. Larner AJ, Thomas DJ. Can myasthenia gravis be diagnosed with the ‘ice pack test’? A cautionary note. Postgrad Med J 2000; 76:162-163.
5. Sussman J, Farrugia ME, Maddison P, Hill M, Leite MI, Hilton-Jones D. Myasthenia gravis: Association of British Neurologists' management guidelines. Pract Neurol 2015; 15:199-206.
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Related checklists

• Myasthenia gravis (MG) AChR antibodies
• Myasthenia gravis (MG): non-AChR antibodies
• Edrophonium test
• Myasthenia gravis (MG): neurophysiology
• Myasthenia gravis (MG): imaging tests