Case of the Month #14 - Miller Fisher syndrome

Published 02/02/2022

What is the likely diagnosis?

The likely diagnosis in this case is Miller Fisher syndrome, a variant of Guillain-Barré syndrome, characterised classically by a triad of ataxia, areflexia and ophthalmoplegia.

Guillain-Barré syndrome, and its variants such as Miller Fisher, are the result of an autoimmune response, causing an acute inflammatory polyneuropathy. This autoimmune response is in reaction to a stimulus to the immune system. In this case, it is likely the result of a Campylobacter Jejuni enteritis (accounting for 25-50% of causes).  Other causes include viral illnesses such as Influenza, CMV and EBV; Mycoplasma infection; and vaccinations.

Clinical features of Guillain-Barré syndrome include:

  • Bilateral ascending motor weakness
  • Areflexia
  • Paraesthesia
  • Miller Fisher variant – cranial nerve involvement and bulbar symptoms
  • Respiratory failure from muscle weakness
  • Autonomic dysfunction – including dysrhythmias, diarrhoea and vomiting, decreased sweating, labile blood pressure