A man with weight loss, ataxia, and confusion for 3 months

Advances in Therapies of Cerebellar Disorders: Immune-mediated Ataxias

The identification of an increasing number of immune mediated ataxias suggests that the cerebellum is often a target organ for autoimmune insults. The diagnosis of immune mediated ataxias is challenging as there is significant clinical overlap between immune mediated and other forms of ataxia. Furthermore the classification of immune mediated ataxias requires further clarification particularly for those ataxias where no specific antigenic trigger and associated antibodies have been identified. Recognition of immune mediated ataxias remains imperative as therapeutic interventions can be effective, although given the relative rarity of this entity, large-scale treatment trials may not be feasible. This review will discuss advances in therapies for immune mediated ataxias based on what is currently available in the literature.

Gluten-related disorders: gluten ataxia

The term gluten-related disorders (GRD) refers to a spectrum of diverse clinical manifestations triggered by the ingestion of gluten in genetically susceptible individuals. They include both intestinal and extraintestinal manifestations. Gluten ataxia (GA) is one of the commonest neurological manifestations of GRD. It was originally defined as otherwise idiopathic sporadic ataxia in the presence of circulating antigliadin antibodies of IgA and/or IgG type. Newer more specific serological markers have been identified but are not as yet readily available. GA has a prevalence of 15% amongst all ataxias and 40% of all idiopathic sporadic ataxias. It usually presents with gait and lower limb ataxia. It is of insidious onset with a mean age at onset of 53 years. Up to 40% of patients have evidence of enteropathy on duodenal biopsy. Gastrointestinal symptoms are seldom prominent and are not a reliable indicator for the presence of enteropathy. Furthermore, the presence of enteropathy does not influence the response to a gluten-free diet. Most patients will stabilise or improve with strict adherence to gluten-free diet depending on the duration of the ataxia prior to the treatment. Up to 60% of patients with GA have evidence of cerebellar atrophy on MR imaging, but all patients have spectroscopic abnormalities primarily affecting the vermis. Recent evidence suggests that patients with newly diagnosed coeliac disease presenting to the gastroenterologists have abnormal MR spectroscopy at presentation associated with clinical evidence of subtle cerebellar dysfunction. The advantage of early diagnosis and treatment (mean age 42 years in patients presenting with gastrointestinal symptoms vs. 53 years in patients presenting with ataxia) may protect the first group from the development and/or progression of neurological dysfunction.

Gluten-related neurologic dysfunction

The term gluten-related disorders (GRD) encompasses a spectrum of systemic autoimmune diseases with diverse manifestations. GRD are characterized by abnormal immunological responsiveness to ingested gluten in genetically susceptible individuals. Celiac disease (CD) or gluten-sensitive enteropathy is only one of a number of GRD. Extraintestinal manifestations include dermatitis herpetiformis (DH) and neurologic dysfunction. Furthermore it is only recently that the concept of extraintestinal manifestations without enteropathy has become accepted. In this chapter we review the spectrum of neurologic manifestations in GRD, discuss recent advances in their diagnosis, and look at their possible pathophysiologic mechanisms.

Regional cerebral hypoperfusion in patients with celiac disease

BACKGROUND

Neurological and psychiatric disorders occur in approximately 10% of patients with celiac disease. Although some of these alterations respond to a gluten-free diet, the etiology of these abnormalities is uncertain. Because of a case report that cerebral hypoperfusion in a celiac patient resolved after a gluten-free diet, we studied brain perfusion changes in untreated celiac patients, treated celiac patients, and healthy controls.

METHODS

A total of 15 untreated celiac patients without conditions affecting brain perfusion were enrolled; none had neurological or psychiatric disorders other than anxiety or depression. We also studied 15 celiac patients who were on a gluten-free diet for almost 1 year, and 24 healthy volunteers of similar sex and age. All subjects underwent cerebral single photon emission computed tomography examination.

RESULTS

Of the 15 untreated celiac patients, 11 (73%) had at least one hypoperfused brain region, compared with only 1 (7%) of the 15 celiac patients on a gluten-free diet and none of the controls (P = 0.01). Cerebral perfusion was significantly lower (P <0.05) in untreated celiac patients, compared with healthy controls, in 7 of 26 brain regions. No significant differences in cerebral perfusion were found between celiac patients on a gluten-free diet and healthy controls.

CONCLUSION

There is evidence of regional cerebral blood flow alteration in untreated celiac patients.

Neurological complications of coeliac disease

A variety of neurological disorders have been reported in association with coeliac disease including epilepsy, ataxia, neuropathy, and myelopathy. The nature of this association is unclear and whether a specific neurological complication occurs in coeliac disease remains unproved. Malabsorption may lead to vitamin and trace element deficiencies. Therefore, patients who develop neurological dysfunction should be carefully screened for these. However, malabsorption does not satisfactorily explain the pathophysiology and clinical course of many of the associated neurological disorders. Other mechanisms proposed include altered autoimmunity, heredity, and gluten toxicity. This review attempts to summarise the literature and suggests directions for future research.

Clinical, radiological, neurophysiological, and neuropathological characteristics of gluten ataxia

BACKGROUND

Ataxia is the commonest neurological manifestation of coeliac disease. Some individuals with genetic susceptibility to the disease have serological evidence of gluten sensitivity without overt gastrointestinal symptoms or evidence of small-bowel inflammation. The sole manifestation of disease in such patients may be ataxia. We describe the clinical, radiological, and neurophysiological features of this disorder.

METHODS

Patients with ataxia attending the neurology outpatient clinics at the Royal Hallamshire Hospital, Sheffield, UK, were screened for gluten sensitivity as shown by the titre of antibody to gliadin. Those with other causes of ataxia were excluded. We carried out clinical, neurophysiological, neuroradiological, and, in two cases, neuropathological examinations.

FINDINGS

28 patients with gluten ataxia were identified. All had gait ataxia and most had limb ataxia. Those with more severe gait ataxia had longer disease duration. No patient had tremor or other extrapyramidal features. 19 patients showed some form of peripheral neuropathy on neurophysiological examination. 16 patients had no gastrointestinal symptoms. Distal duodenal biopsy showed lymphocytic infiltration in two patients, and changes compatible with coeliac disease in 11. Six patients had evidence of cerebellar atrophy on magnetic-resonance imaging. Necropsy was done on two patients who died; there was lymphocytic infiltration of the cerebellum, damage to the posterior columns of the spinal cord, and sparse infiltration of the peripheral nerves.

INTERPRETATION

Gluten sensitivity is an important cause of apparently idiopathic ataxia and may be progressive. The ataxia is a result of immunological damage to the cerebellum, to the posterior columns of the spinal cord, and to peripheral nerves. We propose the term gluten ataxia to describe this disorder.