Fisher syndrome

Miller Fisher syndrome: an updated narrative review

Introduction

Miller Fisher syndrome (MFS) is considered a rare variant of Guillain-Barré syndrome (GBS), a group of acute-onset immune-mediated neuropathies characterized by the classic triad of ataxia, areflexia, and ophthalmoparesis. The present review aimed to provide a detailed and updated profile of all aspects of the syndrome through a collection of published articles on the subject, ranging from the initial description to recent developments related to COVID-19.

Methods

We searched PubMed, Scopus, EMBASE, and Web of Science databases and gray literature, including references from the identified studies, review studies, and conference abstracts on this topic. We used all MeSH terms pertaining to "Miller Fisher syndrome," "Miller Fisher," "Fisher syndrome," and "anti-GQ1b antibody."

Results

An extensive bibliography was researched and summarized in the review from an initial profile of MFS since its description to the recent accounts of diagnosis in COVID-19 patients. MFS is an immune-mediated disease with onset most frequently following infection. Anti-ganglioside GQ1b antibodies, detected in ~85% of patients, play a role in the pathogenesis of the syndrome. There are usually no abnormalities in MFS through routine neuroimaging. In rare cases, neuroimaging shows nerve root enhancement and signs of the involvement of the central nervous system. The most consistent electrophysiological findings in MFS are reduced sensory nerve action potentials and absent H reflexes. Although MFS is generally self-limited and has excellent prognosis, rare recurrent forms have been documented.

Conclusion

This article gives an updated narrative review of MFS with special emphasis on clinical characteristics, neurophysiology, treatment, and prognosis of MFS patients.

Is Guillain-Barre syndrome following chickenpox a parainfectious disease? A case report and literature review

BACKGROUND

Polyradiculoneuropathy following infection with varicella zoster virus (VZV) is rare and most of the time, happens in the context of reactivation of latent VZV. We report a case of acute polyradiculoneuropathy following primary infection with VZV marked by atypical clinical features raising the hypothesis of a para-infectious disease.

CASE PRESENTATION

We describe a 43-years-old male who developed ataxia, dysphagia, dysphonia, and oculomotor disorders (vertical binocular diplopia and bilateral ptosis) followed by quadriplegia with areflexia which occurred 4 days later. The patient had a history of varicella that occurred 10 days before the onset of these symptoms. Nerve conduction study revealed features consistent with an acute motor-sensory axonal neuropathy (AMSAN). Anti-ganglioside antibodies were negative. Based on clinical presentation and ancillary examination, we retain the Miller Fisher/Guillain-Barré overlap syndrome diagnosis. The patient was treated with high doses of methylprednisolone but the evolution of the disease was nevertheless marked by a complete recovery six weeks after onset of symptoms.

CONCLUSION

GBS following varicella is a rare but severe disease occurring most often in adults and marked by greater involvement of the cranial nerves. Its clinical features suggest that it is a para-infectious disease. Antiviral therapy has no effect on the course of the disease but its administration within the first 24 h after the onset of chickenpox in adults can prevent its occurrence.

Pharyngo-Cervico-Brachial Variant of Guillain-Barré or Miller Fisher Syndromes? When the Overlap Is Misleading

Miller Fisher Syndrome (MFS) is a rare variant of Guillain-Barré Syndrome (GBS). It is largely a clinical diagnosis based on the classical features of ataxia, areflexia, and opthalmoplegia. Its clinical evolution is most often favorable. However, other neurological signs and symptoms may also be present. Supportive laboratory studies (positivity of antibodies, CSF albumin-cytological dissociation and nerve conduction studies) are useful especially in uncommon presentations. We report a case of a 74-year-old patient who exhibited dysphonia and difficulty to swallowing previously to the classic triad of ataxia, areflexia, and opthalmoplegia, characteristic of MFS. CSF analysis demonstrates an albumin-cytological dissociation. Anti-GTa1 antibodies were found but anti-GQ1b antibodies were negative. The patient has spontaneously and completely recovered after 6 weeks.

Autoantibodies in immune-mediated inflammatory neuropathies

Inflammatory neuropathies are a rare and heterogeneous group of diseases of the nervous system characterized by the dysfunction and damage of different structures of the peripheral nerves. This group includes Guillain-Barré syndrome, chronic demyelinating inflammatory polyradiculoneuropathy, multifocal motor neuropathy or neuropathies associated with monoclonal gammopathy. The aetiology of these diseases is unknown, but B cells and autoantibodies play a key role in their pathogenesis. Autoantibodies against peripheral nerve molecules such as gangliosides, proteins of the Ranvier node or myelin-associated glycoprotein have been described, allowing the identification of subgroups of patients with specific clinical phenotypes. For all these reasons, these antibodies are useful in clinical practice. This review focuses on the diagnostic and therapeutic relevance of autoantibodies in inflammatory neuropathies.

Immunotherapy of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS), the most common cause of acute neuromuscular weakness and paralysis worldwide, encompasses a group of acute immune-mediated disorders restricted to peripheral nerves and roots. Immune-mediated attack of peripheral nervous system myelin, axons or both is presumed to be triggered by molecular mimicry, with both cell- and humoral-dependent mechanisms implicated in disease pathogenesis. Good circumstantial evidence exists for a pathogenic role for molecular mimicry in GBS pathogenesis, especially with its axonal forms, providing insights that could guide future immunotherapy. Intravenous immunoglobulin (IVIg) and plasma exchange (PE) are the most commonly prescribed immunotherapies for GBS with variable efficacy dependent on GBS subtype, severity at initial presentation and other clinical and electrophysiologic prognostic factors. The mechanisms of action of IVIg and PE are not known definitely. Despite recent significant advances in molecular biology that provide insights into GBS pathogenesis, no advances in therapeutics or significant improvements in patient outcomes have occurred over the past three decades. We summarize the clinical aspects of GBS, its current pathogenesis and immunotherapy, and highlight the potential of leukocyte trafficking inhibitors as novel disease-specific immunotherapeutic drugs.

Acute Cerebellar Ataxia Associated with Anti-glutamic Acid Decarboxylase Antibodies Mimicking Miller Fisher Syndrome

We herein report the case of a 53-year-old man with cerebellar ataxia with anti-glutamic acid decarboxylase antibody (GAD-Ab) who mimicked Miller Fisher syndrome (MFS). He developed ophthalmoplegia, diplopia, and gait ataxia for one week. The serum and cerebrospinal fluid GAD-Ab titers were greatly increased, and the GAD-Ab index suggesting intrathecal antibody synthesis was elevated, while GQ1b-Ab was negative. After steroid pulse therapy and following prednisolone, his symptoms dramatically improved over the course of 11 months with the simultaneous decline of GAD-Ab titers. This case indicates that cerebellar ataxia with GAD-Ab can present with acute neurological findings mimicking MFS, and that steroid therapy has an excellent therapeutic effect.

Electrophysiology in Fisher syndrome

Fisher syndrome (FS), a variant of Guillain-Barré syndrome (GBS), is characterized by the clinical triad of ophthalmoplegia, ataxia, and areflexia. The lesion sites for these unique clinical features include the oculomotor nerves and group 1a neurons in the dorsal root ganglion, and the presence of FS is determined by the expression of ganglioside GQ1b in the human nervous system. Neurophysiological findings suggest that ataxia and areflexia are due to an impaired proprioceptive afferent system. Typically, the soleus H-reflex is absent and a body-sway analysis using posturography shows a 1-Hz peak, which indicates proprioception dysfunction. Sensory nerve action potentials and somatosensory-evoked potentials are abnormal in approximately 30% of FS patients, indicating the occasional involvement of cutaneous (group 2) afferents. During the disease course, approximately 15% of FS patients suffer an overlap of axonal GBS with nerve conduction abnormalities that reflect axonal dysfunction. This review summarizes electrophysiological abnormalities and their clinical significance in FS.

How often and when Fisher syndrome is overlapped by Guillain-Barré syndrome or Bickerstaff brainstem encephalitis?

BACKGROUND AND PURPOSE

Fisher syndrome (FS) may overlap with Guillain-Barré syndrome (GBS), in particular the pharyngeal-cervical-brachial variant form (PCB-GBS), or Bickerstaff brainstem encephalitis (BBE). Our aim was to elucidate the frequency of this overlap and the patterns of clinical progression in patients with FS.

METHODS

Sixty consecutive patients with FS were studied. FS/PCB-GBS was diagnosed when the patients developed pharyngeal, cervical and/or brachial weakness. Patients with flaccid tetraparesis were diagnosed as having FS/conventional GBS. FS/BBE was defined as the development of consciousness disturbances.

RESULTS

All 60 patients initially developed the FS clinical triad alone (pure FS). Of these, 30 (50%) patients had pure FS throughout their course, whereas the remaining 50% of patients showed an overlap: PCB-GBS in 14 (23%) patients, conventional GBS in nine (15%) patients and BBE in seven (12%) patients. The median (range) durations from FS onset to progression to FS/PCB-GBS, FS/GBS or FS/BBE were 5 (1-7), 3 (1-4) and 3 (1-5) days, respectively. Patients with overlap syndromes more frequently received immune-modulating treatment, and the outcomes were generally favourable. The frequencies of positivity for anti-GQ1b, GT1a, GD1a, GD1b, GalNAc-GD1a and GM1 antibodies were not significantly different amongst the four groups.

CONCLUSIONS

Of the patients with pure FS, 50% later developed an overlap with PCB-GBS, conventional GBS or BBE. The overlap occurred within 7 days of FS onset; thus, physicians should pay attention to the possible development of this overlap during the first week after FS onset.

Diagnosis, treatment and prognosis of Guillain-Barré syndrome (GBS)

Guillain-Barré syndrome (GBS) is an acute polyneuropathy with a variable degree of weakness that reaches its maximal severity within 4 weeks. The disease is mostly preceded by an infection and generally runs a monophasic course. Both intravenous immunoglobulin (IVIg) and plasma exchange (PE) are effective in GBS. Rather surprisingly, steroids alone are ineffective. Mainly for practical reasons, IVIg usually is the preferred treatment. GBS can be subdivided in the acute inflammatory demyelinating polyneuropathy (AIDP), the most frequent form in the western world; acute motor axonal neuropathy (AMAN), most frequent in Asia and Japan; and in Miller-Fisher syndrome (MFS). Additionally, overlap syndromes exist (GBS-MFS overlap). About 10% of GBS patients have a secondary deterioration within the first 8 weeks after start of IVIg. Such a treatment-related fluctuation (TRF) requires repeated IVIg treatment. About 5% of patients initially diagnosed with GBS turn out to have chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with acute onset (A-CIDP). It is yet unknown whether GBS patients who remain able to walk ('mildly affected GBS patients'), or patients with MFS, also benefit from IVIg. Despite current treatment, GBS remains a severe disease, as about 25% of patients require artificial ventilation during a period of days to months, about 20% of patients are still unable to walk after 6 months and 3-10% of patients die. Additionally, many patients have pain, fatigue or other residual complaints that may persist for months or years. Pain can also be very confusing in making the diagnosis, especially when it precedes the onset of weakness. Advances in prognostic modelling resulted in the development of a simple prognostic scale that predicts the chance for artificial ventilation, already at admission; and in an outcome scale that can be used to determine the chance to be able to walk unaided after 1, 3 or 6 months. GBS patients with a poor prognosis potentially might benefit from a more intensified treatment. A larger increase in serum IgG levels after standard IVIg treatment (0.4 g/kg/day for 5 consecutive days) seems to be related with an improved outcome after GBS. This was one of the reasons to start the second course IVIg trial (SID-GBS trial) in GBS patients with a poor prognosis. This study is currently going on. The international GBS outcome study (IGOS) is a new worldwide prognostic study that aims to get further insight in the (immune)pathophysiology and outcome of GBS, both in children and adults. Hopefully these and other studies will further help to improve the understanding and especially the outcome in patients with GBS.

Fisher syndrome: clinical features, immunopathogenesis and management

Since Miller Fisher's first report in 1956, evidence has accumulated about clinical and laboratory features, immunopathogenesis and treatment of Fisher syndrome (FS). Our literature review revealed the nature of FS. It has relatively uniform clinical and laboratory features. Ophthalmoplegia, ataxia and areflexia are essential prerequisites for an FS diagnosis, but there are several clinical variants with isolated ophthalmoplegia or ataxia. The discovery of serum anti-GQ1b antibody in FS has led to breakthroughs in FS research. The antibody is thought to be a key factor in the pathogenesis of FS, the understanding of which has progressed owing to the discovery of molecular mimicry between GQ1b and the lipo-oligosaccharides of Campylobacter jejuni and Haemophilus influenzae. The lesions responsible for the clinical symptoms have been debated but are close to clarification. Hence, the pathogenesis of FS has been made much clearer, although there are still some unanswered questions.