Sensory ganglionopathy due to gluten sensitivity

Antibodies in immune-mediated peripheral neuropathies. Where are we in 2024?

Over the past 30 years, about 20 antibodies have been identified in immune-mediated neuropathies, recognizing membrane or intracellular proteins or glycolipids of neuron and Schwann cells. This article reviews the different methods used for their detection, what we know about their pathogenic role, how they have helped identify several disorders, and how they are essential for diagnosis. Despite sustained efforts, some immune-mediated disorders still lack identified autoantibodies, notably the classical form of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. The reasons for this are discussed. The article also tries to determine potential future developments in antibody research, particularly the use of omic approaches and the search for other types of biomarkers beyond diagnostic ones, such as those that can identify patients who will respond to a given treatment.

Sensory Symptoms without Structural Pathology in Patients with Gluten Sensitivity

We report on a group of patients with gluten sensitivity with and without coeliac disease presenting with unexplained sensory symptoms in the absence of structural pathology.

METHODS

The patients were selected from the gluten neurology clinic based at the Royal Hallamshire Hospital, Sheffield, UK, on the basis of sensory symptoms but normal neuroaxis imaging and peripheral nerve evaluation.

RESULTS

A total of 30 patients were identified with a mean age at presentation of 47 years. The prevalence of enteropathy was 78%. The sensory disturbance was characterised by tingling at 50%, numbness at 27%, pain at 20%, burning at 13% and "buzzing" feeling at 7%. The distribution of the sensory symptoms included hands and feet in 27% of the patients, torso in 27%, legs only in 23%, face in 17% and arms only in 10%. For five patients, the sensory disturbance was migratory and affected different parts of the body at any given time. After the introduction of a gluten-free diet, 77% of patients noted significant improvement in their sensory symptoms. In one-third of the patients, there was a complete resolution of the sensory symptoms.

CONCLUSION

Unexplained sensory symptoms can be seen in patients with gluten sensitivity and respond to strict adherence to a gluten-free diet.

Inflammatory sensory neuronopathies

Inflammatory sensory neuronopathies are rare disorders mediated by dysimmune mechanisms targeting sensory neurons in the dorsal root ganglia. They constitute a heterogeneous group of disorders with acute, subacute, or chronic courses, and occur with cancer, systemic autoimmune diseases, notably Sjögren syndrome, and viral infections but a noticeable proportion of them remains isolated. Identifying inflammatory sensory neuronopathies is crucial because they have the potential to be stabilized or even to improve with immunomodulatory or immunosuppressant treatments provided that the treatment is applied at an early stage of the disease, before a definitive degeneration of neurons. Biomarkers, and notably antibodies, are crucial for this early identification, which is the first step to develop therapeutic trials.

Cerebellar degeneration in gluten ataxia is linked to microglial activation

Gluten sensitivity has long been recognized exclusively for its gastrointestinal involvement; however, more recent research provides evidence for the existence of neurological manifestations that can appear in combination with or independent of the small bowel manifestations. Amongst all neurological manifestations of gluten sensitivity, gluten ataxia is the most commonly occurring one, accounting for up to 40% of cases of idiopathic sporadic ataxia. However, despite its prevalence, its neuropathological basis is still poorly defined. Here, we provide a neuropathological characterization of gluten ataxia and compare the presence of neuroinflammatory markers glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, major histocompatibility complex II and cluster of differentiation 68 in the central nervous system of four gluten ataxia cases to five ataxia controls and seven neurologically healthy controls. Our results demonstrate that severe cerebellar atrophy, cluster of differentiation 20+ and cluster of differentiation 8+ lymphocytic infiltration in the cerebellar grey and white matter and a significant upregulation of microglial immune activation in the cerebellar granular layer, molecular layer and cerebellar white matter are features of gluten ataxia, providing evidence for the involvement of both cellular and humoral immune-mediated processes in gluten ataxia pathogenesis.

Sensory neuronopathies, diagnostic criteria and causes

PURPOSE OF REVIEW

To stress on the diagnostic strategy of sensory neuronopathies (SNN), including new genes and antibodies.

RECENT FINDING

SNN involve paraneoplastic, dysimmune, toxic, viral and genetic mechanisms. About one-third remains idiopathic. Recently, new antibodies and genes have reduced this proportion. Anti-FGFR3 and anti-AGO antibodies are not specific of SNN, although SNN is predominant and may occur with systemic autoimmune diseases. These antibodies are the only marker of an underlying dysimmune context in two-thirds (anti-FGFR3 antibodies) and one-third of the cases (anti-AGO antibodies), respectively. Patients with anti-AGO antibodies may improve with treatment, which is less clear with anti-FGFR3 antibodies. A biallelic expansion in the RFC1 gene is responsible for the cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) in which SNN is a predominant manifestation. Most of the patients have an adult onset and are sporadic. The RFC1 mutation may represent one-third of idiopathic sensory neuropathies. Finally, the criteria for the diagnosis of paraneoplastic SNN have recently been updated.

SUMMARY

The diagnostic of SNN relies on criteria distinguishing SNN from other neuropathies. The strategy in search of their cause now needs to include these recent findings.

Acrodystrophic axonal polyneuropathy with celiac disease: a case report

Background

Patients with celiac disease present with not only gastrointestinal symptoms but also extraintestinal manifestations such as anemia, osteopathy, dermatitis herpetiformis, and celiac neuropathy. Despite a fairly wide range of celiac neuropathies, we report a case of the acrodystrophic variant of celiac polyneuropathy, which has not been previously described.

Case presentation

A 41-year-old Ukrainian male suffered from symmetric, sensorimotor axonal polyneuropathy and encephalopathy associated with celiac disease, which is characterized by severe trophic disorders in the lower extremities (trophic ulcers, hyperkeratosis, and anhidrosis). Acrodystrophic changes in the lower extremities were due to both neurogenic and direct immunoinflammatory damaging effects. Clinical–electrophysiological dissociation was also noted, which was represented by a gross axonal lesion with the preservation of muscle strength. The absence of enteropathic manifestations was accompanied by the pronounced histological changes in the duodenal mucosa by IIIb stage of Marsh. A gluten-free diet in combination with membrane plasma exchange and intravenous pulse methylprednisolone was prescribed to reduce the severity of sensory disorders and regression of encephalopathy within 7 months.

Conclusion

Celiac disease may be a potential cause of neuropathy and encephalopathy in adult patients. Further immunosuppressive treatment protocols for both intestinal and extraintestinal manifestations of celiac disease are required.

Sudomotor dysfunction in patients with gluten neuropathy

BACKGROUND AND AIM

Gluten neuropathy (GN) is a common neurological manifestation of gluten sensitivity (GS), characterized by serological evidence of GS, while other risk factors for developing neuropathy are absent. The degree of small fiber dysfunction in GN has not been studied in depth to date. Small fiber involvement may lead to pain, thermal perception abnormalities, and sweat gland dysfunction. Sudomotor innervation refers to the cholinergic innervation of the sympathetic nervous system through small fibers in the sweat glands. The aim of our study was to assess the sudomotor function of GN patients.

METHODS

Patients with GN were recruited. Clinical and neurophysiological data were obtained. HLA-DQ genotyping was performed. The skin electrochemical conductance (ESC) was measured with SUDOSCAN^TM.

RESULTS

Thirty-two patients (25 males, mean age 69.5±10.2 years) were recruited. Thirteen patients (40.6%) had abnormal sudomotor function of the hands. Sixteen patients (50%) had abnormal sudomotor function of the feet. Twenty-one patients (65.6%) had abnormal sudomotor function of either the hands or feet. Sudomotor dysfunction did not correlate with the type of neuropathy (length-dependent neuropathy or sensory ganglionopathy), gluten-free diet adherence, severity of neuropathy, and duration of disease or HLA-DQ genotype. No differences in the ESC were found between patients with painful and patients with painless GN.

CONCLUSION

Sudomotor dysfunction affects two-thirds of patients with GN. The lack of correlation between pain and sudomotor dysfunction suggests different patterns of small fiber involvement in patients with GN.

Non-length-dependent small fiber neuropathy: Not a matter of stockings and gloves

The clinical spectrum of small fiber neuropathy (SFN) encompasses manifestations related to the involvement of thinly myelinated A-delta and unmyelinated C fibers, including not only the classical distal phenotype, but also a non-length-dependent (NLD) presentation that can be patchy, asymmetrical, upper limb-predominant, or diffuse. This narrative review is focused on NLD-SFN. The diagnosis of NLD-SFN can be problematic, due to its varied and often atypical presentation, and diagnostic criteria developed for distal SFN are not suitable for NLD-SFN. The topographic pattern of NLD-SFN is likely related to ganglionopathy restricted to the small neurons of dorsal root ganglia. It is often associated with systemic diseases, but about half the time is idiopathic. In comparison with distal SFN, immune-mediated diseases are more common than dysmetabolic conditions. Treatment is usually based on the management of neuropathic pain. Disease-modifying therapy, including immunotherapy, may be effective in patients with identified causes. Future research on NLD-SFN is expected to further clarify the interconnected aspects of phenotypic characterization, diagnostic criteria, and pathophysiology.

The Intersection Between Cerebellar Ataxia and Neuropathy: a Proposed Classification and a Diagnostic Approach

Neuropathy is a common associated feature of different types of genetic or sporadic cerebellar ataxias. The pattern of peripheral nerve involvement and its associated clinical features can be an invaluable aspect for narrowing the etiologic diagnosis in the investigation of cerebellar ataxias. In this review, we discuss the differential diagnosis of the intersection between peripheral nerve and cerebellar involvement, and classify them in accordance with the predominant features. Genetics, clinical features, neuroimaging, and neurophysiologic characteristics are discussed. Furthermore, a diagnostic approach for cerebellar ataxia with neuropathy is proposed according to the different clinical characteristics. This is an Educational and Descriptive review with the aim of medical education for the approach to the patients with cerebellar ataxia and neuropathy. The diagnostic approach to the patient with cerebellar ataxia with neuropathy requires a detailed medical history, phenotyping, characterization of disease progression and family history. Neuroimaging features and the neurophysiological findings play pivotal roles in defining the diagnosis. Establishing an organized classification method for the disorders based on the clinical features may be very helpful, and could be divided as those with predominant cerebellar features, predominant neuropathic feature, or conditions with both cerebellar ataxia and neuropathy. Second, determining the mode of inheritance is critical on cerebellar ataxias: autosomal dominant and recessive cerebellar ataxias, mitochondrial or sporadic types. Third, one must carefully assess neurophysiologic findings in order to better characterize the predominant pattern of involvement: damage location, mechanism of lesion (axonal or demyelinating), motor, sensory or sensory motor compromise, large or small fibers, and autonomic system abnormalities.

Sensory neuronopathies: A case series and literature review

Sensory neuronopathies are heterogeneous disorders of dorsal root ganglia. The clinical and laboratory features in a single-centre series, including response to treatment and outcome have been described. They retrospectively included 54 patients meeting Camdessanché et al (2009) criteria for sensory neuronopathy. The patients were classified according to their likely aetiology and analysed their demographic, clinical, neurophysiological, histological and spinal MRI features. The outcome with the modified Rankin Scale (mRS) was evaluated, and the response to treatment was assessed. About 54 patients were included (18 male; median age 54.5 years). The most common initial symptoms were hypoaesthesia, paraesthesia, ataxia and pain. Half of patients had a slow onset, greater than 12 months before seeing a neurologist. The aetiology as possibly inflammatory (meaning nonspecific laboratory evidence of immune abnormality) in 18 patients (33%), paraneoplastic 8 (15%), autoimmune 7 (13%) and idiopathic 6 (11%) was classified. About 31 patients received immune therapy of which 11 (35%) improved or stabilised. Corticosteroids were the most used treatment (24 patients) and cyclophosphamide had the highest response rate (3/6, 50%). At the final follow up (median 24 months) 67% had mRS ≥3 and 46% mRS ≥4, including 15% who died. Worse outcome was associated with generalised areflexia and pseudoathetosis by logistic regression, and with motor involvement and raised CSF protein by univariate analysis. Sensory neuronopathies caused severe disability, especially in patients with generalised areflexia and pseudoathetosis. Of those without an obvious cause, most had some evidence of dysimmunity. Some patients had a positive response to immunotherapy, but rarely enough to improve disability much.

The Neuropathology of Gluten-Related Neurological Disorders: A Systematic Review

Gluten-related neurological disorders (GRND) represent a spectrum of neurological manifestations that are triggered by gluten. In coeliac disease, a T-cell mediated enteropathy is triggered by gluten in genetically predisposed individuals. The underlying pathological mechanism of the neurological dysfunction is not yet clear. The aim of this review is to collate existing neuropathological findings in GRND as a means of aiding the understanding of the pathophysiology. A systematic search of the Pubmed Database yielded 188 articles, of which 32 were included, containing 98 eligible cases with a description of pathological findings in GRND. In gluten ataxia, loss of Purkinje cells, atrophy, gliosis and astrocytosis were apparent, as well as diffuse lymphocytic infiltration and perivascular cuffing with lymphocytes. In patients with large-fiber neuropathy, nerve biopsies revealed axonopathy, loss of myelinated fibers and focal and perivascular infiltration by inflammatory cells. Inflammatory infiltrate was also observed in muscle in myopathy and in cerebrum of patients with encephalopathy and patients with epilepsy. Such changes were not seen in skin biopsies from patients with small fiber neuropathies. The findings from this systematic review suggest an immune mediated pathogenesis for GRND. Future research should focus on the characterization of the inflammatory cell infiltrates and identifying target epitopes.

Causes of chronic neuropathies: a single-center experience

OBJECTIVES

Chronic neuropathies are a common cause of neurological disability worldwide. However, few reports have evaluated, in real life, the prevalence of the several conditions which can cause it.

PATIENTS AND METHODS

The authors reviewed informatic database for outpatient office to confirm identification of chronic neuropathy in a 3-year interval period.

RESULTS

Among the 100 selected patients with chronic neuropathies, almost one fifth (19%) remained idiopathic. The most common etiologies were diabetes (17%), dysimmune neuropathies (38%), and vitamin B12 deficiency (9%). In the "dysimmune neuropathies" group, we distinguished various etiologies, including dysimmune neuropathies associated or not with systemic autoimmune diseases (7 and 3%, respectively), chronic inflammatory polyneuropathy (CIDP) (8%), multifocal motor neuropathy (MMN) (3%), paraproteinemic (8%), celiac disease-related (6%), and paraneoplastic (3%) neuropathies.

CONCLUSIONS

In this report from a single neurological center, treatable causes of chronic neuropathies, such as dysimmune neuropathies, including CIDP, and celiac disease-associated neuropathy, were common. These findings suggest the utility of routine screening with blood testing for dysimmune neuropathy and celiac disease for all patients presenting with idiopathic chronic polyneuropathy in whom primary diagnostic testings had failed to identify an etiology for the disease.

SIGNIFICANCE

Our results indicate that patients with peripheral neuropathy could receive a benefit from being evaluated routinely in a specialized neurological center, as many of the conditions that were discovered represented potentially treatable causes of neuropathy.

Treatment of Neurological Manifestations of Gluten Sensitivity and Coeliac Disease

PURPOSE OF REVIEW

The aim of this paper was to overview the current literature in order to establish the available treatment options for the neurological manifestations of gluten-related disorders (serologically confirmed gluten sensitivity and coeliac disease).

RECENT FINDINGS

A range of debilitating neurological manifestations is increasingly being recognized in patients with gluten sensitivity with and without enteropathy even in the absence of gastrointestinal symptoms. Ataxia is the commonest neurological manifestation, followed by peripheral neuropathy. Epilepsy, headache, encephalopathy, various movement disorders, cognitive impairment, and muscle disorders have also been linked to gluten sensitivity and coeliac disease and are discussed in this review. Strict gluten-free diet is an effective first-line treatment of the neurological manifestations of gluten-related disorders. Very few patients will require additional immunosuppressive treatment usually in the form of mycophenolate.

Gluten-free diet in non-celiac patients: beliefs, truths, advantages and disadvantages

A gluten-free diet is the safest treatment for the treatment of patient with celiac disease (CD) and other gluten-related disorders. However, in the last years, gluten-free diet is one of the most popular diet followed by the general population and by patients affected from others clinical conditions, such as non-celiac gluten sensitivity (NCGS), irritable bowel syndrome (IBS), autism, neurological, psychiatric and rheumatologic diseases and for improving sports practice. This review highlights some questions about the appropriateness of following this trend answering to some questions such as how safe are the current gluten-free products, what are the benefits and side effects of gluten-free diet and what are clinical conditions that might benefit from gluten avoidance.

Gluten neuropathy: prevalence of neuropathic pain and the role of gluten-free diet

BACKGROUND AND AIM

Peripheral neuropathy is a common extraintestinal manifestation of gluten sensitivity (gluten neuropathy). We aimed to establish the prevalence of neuropathic pain in patients with otherwise idiopathic PN and gluten sensitivity (positive antigliadin, endomysial, and/or transglutaminase antibodies, with or without enteropathy) and to describe any contributory factors.

METHODS

All consecutive patients with gluten neuropathy (GN) attending a specialist gluten/neurology clinic were invited to participate. Pain was assessed via the DN4 questionnaire and the visual analog scale. Overall Neuropathy Limitations Scale was used to assess the severity of neuropathy. The Mental Health Index (MHI-5) was used to measure participants' general mental health status.

RESULTS

In total, 60 patients (76.7% males, mean age 69.9 ± 10.1 years) with GN were recruited. Neuropathic pain was present in 33 patients (55.0%). Comparison between groups of painful and not painful GN did not show significant differences regarding age, gender, neuropathy severity and neuropathy type. Patients with painless GN were more likely to be on a strict gluten-free diet (55.6 versus 21.2%, p = 0.006). Patients with painful GN presented with significantly worse MHI-5 score (75.9 ± 13.8 versus 87.4 ± 8.1, p < 0.001). Multivariate analysis showed that, after adjusting for age, gender and MHI-5, strict gluten-free diet was associated with lowering the odds of peripheral neuropathic pain by 88.7% (95% CI 47.2-97.6%, p = 0.006).

CONCLUSION

Neuropathic pain is very prevalent in GN and is associated with poorer mental health status. Strict gluten-free diet might be protective as it is associated with a significant reduction of the odds of peripheral neuropathic pain associated to GN.

Quality of Life in Patients with Gluten Neuropathy: A Case-Controlled Study

Background: Gluten neuropathy (GN) is defined as an otherwise idiopathic peripheral neuropathy in the presence of serological evidence of gluten sensitivity (positive native gliadin antibodies and/or transglutaminase or endomysium antibodies). We aimed to compare the quality of life (QoL) of GN patients with that of control subjects and to investigate the effects of a gluten-free diet (GFD) on the QoL. Methods: All consecutive patients with GN attending a specialist neuropathy clinic were invited to participate. The Overall Neuropathy Limitations Scale (ONLS) was used to assess the severity of the neuropathy. The 36-Item Short Form Survey (SF-36) questionnaire was used to measure participants’ QoL. A strict GFD was defined as effectively being able to eliminate all circulating gluten sensitivity-related antibodies. Results: Fifty-three patients with GN and 53 age- and gender-matched controls were recruited. Compared to controls, GN patients showed significantly worse scores in the physical functioning, role limitations due to physical health, energy/fatigue, and general health subdomains of the SF-36. After adjusting for age, gender, and disease severity, being on a strict GFD correlated with better SF-36 scores in the pain domain of the SF-36 (beta 0.317, p = 0.019) and in the overall health change domain of the SF-36 (beta 0.306, p = 0.017). Conclusion: In GN patients, physical dysfunctioning is the major determinant of poor QoL compared to controls. Routine checking of the elimination of gluten sensitivity-related antibodies that results from a strict GFD should be encouraged, as such elimination ameliorates the overall pain and health scores, indicating a better QoL.

IVIg for apparently autoimmune small-fiber polyneuropathy: first analysis of efficacy and safety

OBJECTIVES

Small-fiber polyneuropathy (SFPN) has various underlying causes, including associations with systemic autoimmune conditions. We have proposed a new cause; small-fiber-targeting autoimmune diseases akin to Guillain-Barré and chronic inflammatory demyelinating polyneuropathy (CIDP). There are no treatment studies yet for this 'apparently autoimmune SFPN' (aaSFPN), but intravenous immunoglobulin (IVIg), first-line for Guillain-Barré and CIDP, is prescribed off-label for aaSFPN despite very high cost. This project aimed to conduct the first systematic evaluation of IVIg's effectiveness for aaSFPN.

METHODS

With IRB approval, we extracted all available paper and electronic medical records of qualifying patients. Inclusion required having objectively confirmed SFPN, autoimmune attribution and other potential causes excluded. IVIg needed to have been dosed at ⩾1 g/kg/4 weeks for ⩾3 months. We chose two primary outcomes - changes in composite autonomic function testing (AFT) reports of SFPN and in ratings of pain severity - to capture objective as well as patient-prioritized outcomes.

RESULTS

Among all 55 eligible patients, SFPN had been confirmed by 3/3 nerve biopsies, 62% of skin biopsies, and 89% of composite AFT. Evidence of autoimmunity included 27% of patients having systemic autoimmune disorders, 20% having prior organ-specific autoimmune illnesses and 80% having ⩾1/5 abnormal blood-test markers associated with autoimmunity. A total of 73% had apparent small-fiber-restricted autoimmunity. IVIg treatment duration averaged 28 ± 25 months. The proportion of AFTs interpreted as indicating SFPN dropped from 89% at baseline to 55% (p ⩽ 0.001). Sweat production normalized (p = 0.039) and the other four domains all trended toward improvement. Among patients with pre-treatment pain ⩾3/10, severity averaging 6.3 ± 1.7 dropped to 5.2 ± 2.1 (p = 0.007). Overall, 74% of patients rated themselves 'improved' and their neurologists labeled 77% as 'IVIg responders'; 16% entered remissions that were sustained after IVIg withdrawal. All adverse events were expected; most were typical infusion reactions. The two moderate complications (3.6%) were vein thromboses not requiring discontinuation. The one severe event (1.8%), hemolytic anemia, remitted after IVIg discontinuation.

CONCLUSION

These results provide Class IV, real-world, proof-of-concept evidence suggesting that IVIg is safe and effective for rigorously selected SFPN patients with apparent autoimmune causality. They provide rationale for prospective trials, inform trial design and indirectly support the discovery of small-fiber-targeting autoimmune/inflammatory illnesses.

Rapid neurophysiological screening for sensory ganglionopathy: A novel approach

BACKGROUND AND AIM

Pure sensory neuropathies involving the dorsal root ganglia are commonly referred to as sensory ganglionopathies (SG). Causes of SG can be inherited (as seen in Friedreich's ataxia) or acquired (e.g. immune-mediated or paraneoplastic). Diagnostic criteria for confirming SG have been published and consist of a combination of clinical and neurophysiological parameters. The aim of our study was to develop a neurophysiological method for rapid screening for diagnosis of SG.

METHODS

For each subject we obtained the sensory nerve action potentials (SNAPs) of five nerves (median, ulnar, radial, sural and superficial peroneal) bilaterally. In the presence of an entrapment neuropathy we obtained the SNAP of the medial antebrachial cutaneous nerves bilaterally. We estimated the number of pairs of nerves showing a SNAP asymmetry of >50% (difference of SNAPs/ lower SNAP).

RESULTS

Sixty-eight subjects, 34 patients with SG and 34 age and sex-matched controls, participated in the study. Among all subjects using a receiver operating characteristic (ROC) curve analysis, the area under the curve was 0.984 (95% CI, 0.960-1.000; SE, 0.012; p < .001). In order to detect SG, presence of SNAP asymmetry of >50% in 2 pairs of nerves, not explained by an entrapment neuropathy, shows a sensitivity of 97.1%, a specificity of 94.1%, a positive predictive value of 94.3% and a negative predictive value of 97.0.

CONCLUSION

The number of pairs of nerves showing a SNAP asymmetry of >50% may be used as a novel rapid screening tool of patients with SG.

Transglutaminase 6 antibodies in gluten neuropathy

BACKGROUND

TG6 antibodies have been shown to be a marker of gluten ataxia but their presence in the context of other neurological manifestations of gluten sensitivity has not been explored. We investigated the presence of TG6 antibodies in gluten neuropathy (GN), defined as as an otherwise idiopathic peripheral neuropathy associated with serological markers of gluten sensitivity (one or more of antigliadin IgG and/or IgA, endomysial and transglutaminase-2 antibodies).

METHODS

This was a cross-sectional study conducted at the Sheffield Institute of Gluten Related Diseases, Royal Hallamshire Hospital, Sheffield, UK. Blood samples were collected whilst the patients were on a gluten containing diet. Duodenal biopsies were performed to establish the presence of enteropathy.

RESULTS

Twenty-eight patients were recruited (mean age 62.5±13.7 years). Fifteen (53.6%) had sensory ganglionopathy, 12 (42.9%) had symmetrical axonal neuropathy and 1 had mononeuritis multiplex. The prevalence of TG6 antibodies was 14 of 28 (50%) compared to 4% in the healthy population. TG6 antibodies were found in 5/15 (33.3%) patients with sensory ganglionopathy and in 8/12 (66.7%) with symmetrical axonal neuropathy. Twenty-four patients underwent duodenal biopsy 11 (45.8%) of which had enteropathy. The prevalence of TG6 was not significantly different when comparing those with or without enteropathy.

CONCLUSIONS

We found a high prevalence of antibodies against TG6 in patients with GN. This suggests that TG6 involvement is not confined to the central nervous system. The role of transglutaminase 6 in peripheral nerve function remains to be determined but TG6 antibodies may be helpful in the diagnosis of GN.

Sensory Neuronopathies

PURPOSE OF REVIEW

The sensory neuronopathies are sensory-predominant polyneuropathies that result from damage to the dorsal root and trigeminal sensory ganglia. This review explores the various causes of acquired sensory neuronopathies, the approach to diagnosis, and treatment.

RECENT FINDINGS

Diagnostic criteria have recently been published and validated to allow differentiation of sensory neuronopathies from other polyneuropathies. On the basis of serial electrodiagnostic studies, the treatment window for the acquired sensory neuronopathies has been identified as approximately 8 months. If treatment is initiated within 2 months of symptom onset, there is a better opportunity for improvement of the patient's condition. Even though sensory neuronopathies are rare, significant progress has been made regarding characterization of their clinical, electrophysiologic, and imaging features. This does not hold true, however, for treatment. There have been no randomized controlled clinical trials to guide management of these diseases, and a standard treatment approach remains undetermined.

Sensory Ganglionopathy and the Blink Reflex: Electrophysiological Features

Background: Sensory ganglionopathy (SG) is characterised by asymmetrical sensory fibre degeneration, with the primary pathology occurring at the level of the dorsal root ganglion. It is seen in the context of autoimmune, paraneoplastic, and degenerative disorders. There is limited literature examining the electrophysiological correlate of the trigeminal ganglion and associated pathways, the blink reflex (BR), in cases of SG. Previous work has suggested that the BR is preserved in cases of SG associated with paraneoplasia. Methods: The local clinical neurophysiology database was searched for patients diagnosed with SG from peripheral nerve conduction studies in whom the BR was performed. Twenty-six patients were included in the final analysis. Results: Sjögren’s syndrome constituted the most common SG aetiology (8/26), followed by idiopathic cases (7/26) and paraneoplasia (5/26). BR abnormalities were seen in 9 of the 26 patients (34.6%) across all aetiologies. No patients reported sensory disturbance in the distribution of the trigeminal nerve, indicating that the changes noted are subclinical. Three patients showed abnormality of the R1 response; in the remaining six patients, only R2 responses were affected. Conclusions: Subclinical abnormalities of both R1 and R2 can be seen in the context of SG of varying aetiologies, including paraneoplasia. Performing the BR in patients with suspected of having SG may be helpful in providing additional evidence of patchy sensory fibre involvement that is characteristic of the disease.

Immunotherapy Prospects for Painful Small-fiber Sensory Neuropathies and Ganglionopathies

The best-known peripheral neuropathies are those affecting the large, myelinated motor and sensory fibers. These have well-established immunological causes and therapies. Far less is known about the somatic and autonomic "small fibers"; the unmyelinated C-fibers, thinly myelinated A-deltas, and postganglionic sympathetics. The small fibers sense pain and itch, innervate internal organs and tissues, and modulate the inflammatory and immune responses. Symptoms of small-fiber neuropathy include chronic pain and itch, sensory impairment, edema, and skin color, temperature, and sweating changes. Small-fiber polyneuropathy (SFPN) also causes cardiovascular, gastrointestinal, and urological symptoms, the neurologic origin of which often remains unrecognized. Routine electrodiagnostic study does not detect SFPN, so skin biopsies immunolabeled to reveal axons are recommended for diagnostic confirmation. Preliminary evidence suggests that dysimmunity causes some cases of small-fiber neuropathy. Several autoimmune diseases, including Sjögren and celiac, are associated with painful small-fiber ganglionopathy and distal axonopathy, and some patients with "idiopathic" SFPN have evidence of organ-specific dysimmunity, including serological markers. Dysimmune SFPN first came into focus in children and teenagers as they lack other risk factors, for example diabetes or toxic exposures. In them, the rudimentary evidence suggests humoral rather than cellular mechanisms and complement consumption. Preliminary evidence supports efficacy of corticosteroids and immunoglobulins in carefully selected children and adult patients. This paper reviews the evidence of immune causality and the limited data regarding immunotherapy for small-fiber-predominant ganglionitis, regional neuropathy (complex regional pain syndrome), and distal SFPN. These demonstrate the need to develop case definitions and outcome metrics to improve diagnosis, enable prospective trials, and dissect the mechanisms of small-fiber neuropathy.

Movement and Other Neurodegenerative Syndromes in Patients with Systemic Rheumatic Diseases: A Case Series of 8 Patients and Review of the Literature

Patients with rheumatic diseases can present with movement and other neurodegenerative disorders. It may be underappreciated that movement and other neurodegenerative disorders can encompass a wide variety of disease entities. Such disorders are strikingly heterogeneous and lead to a wider spectrum of clinical injury than seen in Parkinson's disease. Therefore, we sought to stringently phenotype movement and other neurodegenerative disorders presenting in a case series of rheumatic disease patients. We integrated our findings with a review of the literature to understand mechanisms which may account for such a ubiquitous pattern of clinical injury.Seven rheumatic disease patients (5 Sjögren's syndrome patients, 2 undifferentiated connective tissue disease patients) were referred and could be misdiagnosed as having Parkinson's disease. However, all of these patients were ultimately diagnosed as having other movement or neurodegenerative disorders. Findings inconsistent with and more expansive than Parkinson's disease included cerebellar degeneration, dystonia with an alien-limb phenomenon, and nonfluent aphasias.A notable finding was that individual patients could be affected by cooccurring movement and other neurodegenerative disorders, each of which could be exceptionally rare (ie, prevalence of ∼1:1000), and therefore with the collective probability that such disorders were merely coincidental and causally unrelated being as low as ∼1-per-billion. Whereas our review of the literature revealed that ubiquitous patterns of clinical injury were frequently associated with magnetic resonance imaging (MRI) findings suggestive of a widespread vasculopathy, our patients did not have such neuroimaging findings. Instead, our patients could have syndromes which phenotypically resembled paraneoplastic and other inflammatory disorders which are known to be associated with antineuronal antibodies. We similarly identified immune-mediated and inflammatory markers of injury in a psoriatic arthritis patient who developed an amyotrophic lateral sclerosis (ALS)-plus syndrome after tumor necrosis factor (TNF)-inhibitor therapy.We have described a diverse spectrum of movement and other neurodegenerative disorders in our rheumatic disease patients. The widespread pattern of clinical injury, the propensity of our patients to present with co-occurring movement disorders, and the lack of MRI neuroimaging findings suggestive of a vasculopathy collectively suggest unique patterns of immune-mediated injury.

Immune-Mediated Neurological Disorders

Autoimmune disorders are increasingly recognized causes of several neurological disorders leading to significant clinical disability. This article reviews recent developments in our understanding on the pathophysiology, clinical presentations, and diagnoses of selected immune-mediated neurological disorders. It also provides a brief summary of current theories on autoimmunity and the role that certain environmental factors play in the development of immune-mediated neurological disorders. Recently recognized biomarkers might play a pathogenetic role or simply serve as a diagnostic tool.

Neurologic manifestations of gastrointestinal and liver diseases

Hepatic and gastrointestinal disorders can produce a wide spectrum of neurologic complications both affecting the central nervous system (CNS) and the peripheral nervous system. These manifestations range in severity from coma in acute liver failure and acute pancreatitis, to minor cognitive changes in chronic portosystemic encephalopathy and hepatitis C. Cerebrovascular diseases can complicate hepatitis C infection and inflammatory bowel disease. Demyelinating disorders may co-exist with inflammatory bowel disease. Anti-tumor necrosis factor alpha drugs may induce demyelination. Ataxia may occur in malabsorption syndromes and in gluten related disorders. Characteristic movement disorders are key features of acquired hepatocerebral degeneration and of Whipple disease. Multiple types of neuropathy can be found in association with hepatitis, inflammatory bowel disease and gluten related disorders.

The neurologic significance of celiac disease biomarkers

OBJECTIVE

To report neurologic phenotypes and their etiologies determined among 68 patients with either (1) celiac disease (CD) or (2) no CD, but gliadin antibody positivity (2002-2012).

METHODS

Neurologic patients included both those with the CD-prerequisite major histocompatibility complex class II human leukocyte antigen (HLA)-DQ2/DQ8 haplotype, and those without. The 3 groups were as follows: group 1 (n = 44), CD or transglutaminase (Tg)-2/deamidated gliadin immunoglobulin (Ig)A/IgG detected; group 2 (n = 15), HLA-DQ2/DQ8 noncarriers, and gliadin IgA/IgG detected; and group 3 (n = 9), HLA-DQ2/DQ8 carriers, and gliadin IgA/IgG detected. Neurologic patients and 21 nonneurologic CD patients were evaluated for neural and Tg6 antibodies.

RESULTS

In group 1, 42 of 44 patients had CD. Neurologic phenotypes (cerebellar ataxia, 13; neuropathy, 11; dementia, 8; myeloneuropathy, 5; other, 7) and causes (autoimmune, 9; deficiencies of vitamin E, folate, or copper, 6; genetic, 6; toxic or metabolic, 4; unknown, 19) were diverse. In groups 2 and 3, 21 of 24 patients had cerebellar ataxia; none had CD. Causes of neurologic disorders in groups 2 and 3 were diverse (autoimmune, 4; degenerative, 4; toxic, 3; nutritional deficiency, 1; other, 2; unknown, 10). One or more neural-reactive autoantibodies were detected in 10 of 68 patients, all with autoimmune neurologic diagnoses (glutamic acid decarboxylase 65 IgG, 4; voltage-gated potassium channel complex IgG, 3; others, 5). Tg6-IgA/IgG was detected in 7 of 68 patients (cerebellar ataxia, 3; myelopathy, 2; ataxia and parkinsonism, 1; neuropathy, 1); the 2 patients with myelopathy had neurologic disorders explained by malabsorption of copper, vitamin E, and folate rather than by neurologic autoimmunity.

CONCLUSIONS

Our data support causes alternative to gluten exposure for neurologic dysfunction among most gliadin antibody-positive patients without CD. Nutritional deficiency and coexisting autoimmunity may cause neurologic dysfunction in CD.

Sensory neuronopathy complicating systemic lupus erythematosus: a case report

Introduction

Systemic lupus erythematosus is a multi-system connective tissue disorder. Peripheral neuropathy is a known and underestimated complication in systemic lupus erythematosus. Ganglionopathy manifests when neuronal cell bodies in the dorsal root ganglion are involved. Autoimmune disorders are a known etiology, with systemic lupus erythematosus being a rare cause.

Case presentation

A 32-year-old South Asian woman presented with oral ulceration involving her lips following initiation of treatment for a febrile illness associated with dysuria. She had a history of progressively worsening numbness over a period of 4 months involving both the upper and lower limbs symmetrically while sparing the trunk. Her vibration sense was impaired, and her reflexes were diminished. For the past 4 years, she had had a bilateral, symmetrical, non-deforming arthritis involving the upper and lower limbs. Her anti-nuclear antibody and anti-double-stranded deoxyribonucleic acid status were positive. Although her anti-Ro antibodies were positive, she did not have clinical features suggestive of Sjögren syndrome. Nerve conduction studies revealed sensory neuronopathy. A diagnosis of systemic lupus erythematosus complicated by sensory neuronopathy was made. Treatment with intravenous immunoglobulin resulted in clinical and electrophysiological improvement.

Conclusion

Peripheral neuropathy in systemic lupus erythematosus can, by itself, be a disabling feature. Nerve conduction studies should be considered when relevant. Neuropathy in systemic lupus erythematosus should be given greater recognition, and rarer forms of presentation should be entertained in the differential diagnosis when the clinical picture is atypical. Intravenous immunoglobulin may have role in treatment of sensory neuronopathy in systemic lupus erythematosus.

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.

Peripheral neuropathic symptoms in celiac disease and inflammatory bowel disease

OBJECTIVES

An association between celiac disease (CD) and peripheral neuropathy (PN) has been reported.

METHODS

Patients with CD and/or inflammatory bowel disease (IBD) were recruited from the gastroenterology clinics at a medical center and local support groups. Control subjects without CD or IBD were recruited from the staff of the medical center as well as relatives and attendees at support groups. Each participant completed a survey that used two validated PN instruments to define and characterize PN.

RESULTS

In the CD group, 38.9% met criteria for PN compared with 38.7% in the IBD group (P = 0.97) and 20.5% in the control group (P < 0.001). On multiple logistic regression, the odds of PN after adjusting for age, gender, diabetes, vitamin B12 deficiency, and cancer history were increased for CD (odds ratio, 2.51; 95% confidence interval, 1.82-3.47) and IBD (odds ratio, 2.78; 95% confidence interval, 1.85-4.18).

CONCLUSIONS

PN is more often found in patients with CD and/or IBD than in the general population.

Movement disorders in autoimmune diseases

Movement disorders have been known to be associated with a variety of autoimmune diseases, including Sydenham's chorea, pediatric autoimmune neuropsychiatric disorders associated with streptococcus, systemic lupus erythematosus, antiphospholipid syndrome, gluten sensitivity, paraneoplastic and autoimmune encephalopathies. Tremors, dystonia, chorea, ballism, myoclonus, parkinsonism, and ataxia may be the initial and even the only presentation of these autoimmune diseases. Although antibodies directed against various cellular components of the central nervous system have been implicated, the pathogenic mechanisms of these autoimmune movement disorders have not yet been fully elucidated. Clinical recognition of these autoimmune movement disorders is critically important as many improve with immunotherapy or dietary modifications, particularly when diagnosed early. We discuss here the clinical features, pathogenic mechanisms, and treatments of movement disorders associated with autoimmune diseases, based on our own experience and on a systematic review of the literature.

Neurologic and psychiatric manifestations of celiac disease and gluten sensitivity

Celiac Disease (CD) is an immune-mediated disease dependent on gluten (a protein present in wheat, rye or barley) that occurs in about 1% of the population and is generally characterized by gastrointestinal complaints. More recently the understanding and knowledge of gluten sensitivity (GS), has emerged as an illness distinct from celiac disease with an estimated prevalence 6 times that of CD. Gluten sensitive people do not have villous atrophy or antibodies that are present in celiac disease, but rather they can test positive for antibodies to gliadin. Both CD and GS may present with a variety of neurologic and psychiatric co-morbidities, however, extraintestinal symptoms may be the prime presentation in those with GS. However, gluten sensitivity remains undertreated and underrecognized as a contributing factor to psychiatric and neurologic manifestations. This review focuses on neurologic and psychiatric manifestations implicated with gluten sensitivity, reviews the emergence of gluten sensitivity distinct from celiac disease, and summarizes the potential mechanisms related to this immune reaction.

Sensory neuronopathy and autoimmune diseases

Sensory neuronopathies (SNs) are a specific subgroup of peripheral nervous system diseases characterized by primary degeneration of dorsal root ganglia and their projections. Multifocal sensory symptoms often associated to ataxia are the classical features of SN. Several different etiologies have been described for SNs, but immune-mediated damage plays a key role in most cases. SN may herald the onset of some systemic autoimmune diseases, which further emphasizes how important the recognition of SN is in clinical practice. We have thus reviewed available clinical, neurophysiological, and therapeutic data on autoimmune disease-related SN, namely, in patients with Sjögren's syndrome, autoimmune hepatitis, and celiac disease.

Gliadin allergy manifested with chronic urticaria, headache and amenorrhea

Gluten intolerance is an autoimmune enteropathy caused by heterogeneous mixture of wheat storage proteins. Malabsorption symptoms imply diarrhoea, abdominal pain/bloating and weight loss. This case describes a 22-year-old female subject, who had chronic headache, joint pain, urticaria and long period of amenorrhea. Skin prick tests revealed a sensitisation to α-gliadin, while neurological, gynaecological, endocrine and clinical-laboratory examinations did not justify the above-mentioned symptoms. Gluten-free diet resolved chronic symptoms and re-established the menstrual cycle, whereas a temporary gliadin daily diet re-exacerbated all clinical symptoms. Urticaria occurred 20 min and the chronic headache the next day after exposure to the gliadin-rich diet. In addition, the missing of the expected menstrual bleeding was observed. This case demonstrates that gliadin intake can induce malabsorption and 'idiopathic' neuronal or gynaecological symptoms.