Miller Fisher Syndrome

Miller-Fisher syndrome (MFS) is a rare cranial nerve variant of Guillain-Barré syndrome (GBS; see this term).

Epidemiology

Annual incidence is estimated at 1/1,000,000.

Clinical description

MFS is characterized by the clinical triad of acute onset of gait ataxia, areflexia, and ophthalmoplegia. Acute onset of external ophthalmoplegia is a cardinal feature of MFS. Facial and bulbar nerve palsies have also been reported.

Etiology

In the majority of cases, MFS occurs following Campylobacter jejuni infection. Although the exact pathological mechanism is not fully understood, MFS is associated with the presence of antiganglioside antibodies (primarily, anti-GQ1b).

Differential diagnosis

The clinical picture in MFS shows clinical overlap with Bickerstaff brainstem encephalitis (BBE; see this term), which is also associated with raised titers of anti-GQ1b antibodies, leading to the suggestion that BBE and MFS represent variable manifestations of the same clinical spectrum. However, patients with BBE also have central nervous system involvement leading to disturbed consciousness and in some cases tetraparalysis with involvement of cranial nerves (including the intraocular nerves leading to fixed pupils).

Prognosis

MFS is generally self-limiting and patients recover within a few months, however, cases of progression to respiratory failure have been reported in MFS patients with features of both MFS and other forms of GBS (MFS/GBS overlap syndrome).