Miller Fisher's syndrome

Q: Which lab is diagnostic of Miller-Fisher syndrome (MFS)?

Answer:  Anti-GQ1b antibodies

Miller-Fisher syndrome (MFS) is a variant of GBS (Guillain–Barré syndrome), accounting for approximately 5% of cases. Clinically it is diagnosed by a descending paralysis, proceeding in the reverse order of the more common form of GBS. It affects the eye muscles first and presents with the triad of

• ophthalmoplegia
• ataxia
• areflexia

Also, Ataxia predominantly affects the gait and trunk, with the limbs relatively spared. Anti-GQ1b antibodies are present in 90% of cases.

#neurology

References: 

1. Teener JW. Miller Fisher's syndrome. Semin Neurol. 2012 Nov;32(5):512-6. doi: 10.1055/s-0033-1334470. Epub 2013 May 15. PMID: 23677659. 

2. Rocha Cabrero F, Morrison EH. Miller Fisher Syndrome. 2022 Jun 27. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 29939539.