Ataxic sensory neuropathy and dorsal root ganglionitis associated with Sjögren's syndrome

Association between geniquin therapy and the risk of developing periodontal disease in patients with primary Sjögren's syndrome: A population-based cohort study from Taiwan

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease that causes dysfunction of salivation and harmful oral conditions. The association between periodontal disease (PD) and pSS with or without geniquin therapy remains controversial. This study evaluated the association between geniquin therapy and the risk of subsequent development of PD in pSS patients. From Taiwan's National Health Insurance Research Database, we selected a control cohort of 106,818 pSS patients, followed up from 2000 to 2015, matched (1:4) by age and index year with 427,272 non-pSS patients. We also analyzed 15,149 pSS patients receiving geniquin therapy (cohort 1) and 91,669 pSS patients not receiving geniquin therapy (cohort 2). After adjusting for confounding factors, multivariate Cox proportional hazards regression analysis was used to compare the risk of PD over the 15-year follow-up. In the control cohort, 11,941 (11.2%) pSS patients developed PD compared to 39,797 (9.3%) non-pSS patients. In cohorts 1 and 2, 1,914 (12.6%) pSS patients receiving geniquin therapy and 10,027 (10.9%) pSS patients not receiving geniquin therapy developed PD. The adjusted hazard ratio (HR) for subsequent PD in pSS patients was 1.165 (95% confidence interval [CI] = 1.147-1.195, p < 0.001) and in pSS patients receiving geniquin therapy was 1.608 (95% CI = 1.526-1.702, p < 0.001). The adjusted HR for PD treatment was 1.843. Patients diagnosed with pSS showed an increased risk of developing subsequent PD and receiving PD treatment than patients without pSS, while pSS patients receiving geniquin therapy showed even higher risks.

Subacute Progressive Severe Ataxic Sensory Neuropathy with Sjögren's Syndrome

We herein report a 79-year-old woman with subacute progressive ataxic sensory neuropathy. The patient's symptoms began with numbness in the lower extremities, which rapidly deteriorated, resulting in gait disturbance and abnormal sensations in the extremities, reaching a peak over a period of approximately two months. Nerve conduction studies revealed pure axonal-type sensory polyneuropathy. The expeditious progression of the disease initially prompted suspicion of Guillain-Barré syndrome or paraneoplastic syndrome. Nevertheless, after comprehensive evaluations, the conclusive diagnosis was confirmed as ataxic sensory neuropathy with Sjögren's syndrome. Intensive immunotherapy was administered; however, it was ineffective in halting disease progression. Consequently, this case underscores the significance of an early comprehensive diagnosis and prompt immunotherapy for ataxic sensory neuropathy associated with Sjögren's syndrome.

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.

Primary Sjogren's syndrome presenting as an isolated severe autonomic dysfunction treated with steroids

Primary Sjogren's syndrome (pSS) is an autoimmune connective tissue disorder with multisystem manifestations. We here report a previously healthy woman who presented with autonomic dysfunction in the form of severe dizziness without any apparent sensory neuropathy. Detailed history and examination revealed the signs and symptoms of Sjogren's syndrome such as constipation and dry eyes and mouth, following which anti-SSA and SSB antibodies were found to be positive. Finally, a diagnosis of pSS was established after ruling out all the other causes of autonomic dysfunction in addition to the clinical and laboratory evidence. The patient was treated with the maximum doses of midodrine and fludrocortisone, yet no progress was noticed. Hence, a trial of steroids was started and she showed a significant clinical improvement. Our patient presented with pure autonomic failure associated with Sjogren's syndrome, making it an extremely rare entity.

Characteristics of primary Sjögren's syndrome-associated peripheral nervous system lesions

OBJECTIVE

The aim of this study is to investigate potential risk factors associated with peripheral nervous system lesions in primary Sjögren's syndrome (pSS) through a retrospective analysis of clinical manifestations, examination characteristics, and clinical electrophysiological features.

MATERIALS AND METHODS

A retrospective case-control study was conducted at Nanfang Hospital, including 108 patients diagnosed with pSS following the criteria revised by the American College of Rheumatology in 2016. The study spanned from January 2015 to October 2020. The patient cohort was divided into two groups, an experimental group (N = 27) consisting of patients with primary Sjögren's syndrome-peripheral nervous system lesions (pSS-PNS), and a control group (N = 81) comprising patients without peripheral neurological impairment, i.e., primary Sjögren's syndrome-non peripheral nervous system lesions (pSS-nPNS).

RESULTS

The results showed a significant correlation between immunoglobulin G (IgG), α-Fodrin immunoglobulin G (α-FIgG), platelet counts (PLT), dry mouth and peripheral neuropathy of Sjogren's syndrome (p < 0.01). The research also revealed that α-FIgG (OR 2.03; 95% CI 1.14-3.64), IgG (OR 1.23; 95% CI 1.06-1.42), and PLT (OR 1.01; 95% CI 1.00-1.01) were identified as risk factors for the onset of peripheral neuropathy of Sjogren's syndrome, while dry mouth had a negative correlation (OR 0.08; 95% CI 0.02-0.40). Remarkably, the total risk assessment of the independent variables demonstrated a high AUC (95%CI) of 0.923 (0.861-0.986; p < 0.001), indicating an excellent prediction of pSS-PNS occurrence through the ROC analysis. Additionally, high platelet counts and strong positive anti-SSB antibody titer were found to be risk factors for dual motor and sensory nerve damages among pSS-PNS patients.

CONCLUSION

IgG, α-FIgG, and PLT were identified as independent risk factors for patients with pSS-PNS. The likelihood of peripheral neuropathy appeared to increase in tandem with the elevated levels of above three factors. Interestingly, we found that dry mouth might play a protective role in this context. Our study further noted that both high platelet counts and strong positive anti-SSB antibody titer may be associated with increased risk of both motor and sensory nerve involvement in pSS-PNS patients. These findings have significant implications for both the etiologies and therapeutics of pSS-PNS.

Updated consensus statement: Intravenous immunoglobulin in the treatment of neuromuscular disorders report of the AANEM ad hoc committee

Intravenous immune globulin (IVIG) is an immune-modulating biologic therapy that is increasingly being used in neuromuscular disorders despite the paucity of high-quality evidence for various specific diseases. To address this, the AANEM created the 2009 consensus statement to provide guidance on the use of IVIG in neuromuscular disorders. Since then, there have been several randomized controlled trials for IVIG, a new FDA-approved indication for dermatomyositis and a revised classification system for myositis, prompting the AANEM to convene an ad hoc panel to update the existing guidelines.New recommendations based on an updated systemic review of the literature were categorized as Class I-IV. Based on Class I evidence, IVIG is recommended in the treatment of chronic inflammatory demyelinating polyneuropathy, Guillain-Barré Syndrome (GBS) in adults, multifocal motor neuropathy, dermatomyositis, stiff-person syndrome and myasthenia gravis exacerbations but not stable disease. Based on Class II evidence, IVIG is also recommended for Lambert-Eaton myasthenic syndrome and pediatric GBS. In contrast, based on Class I evidence, IVIG is not recommended for inclusion body myositis, post-polio syndrome, IgM paraproteinemic neuropathy and small fiber neuropathy that is idiopathic or associated with tri-sulfated heparin disaccharide or fibroblast growth factor receptor-3 autoantibodies. Although only Class IV evidence exists for IVIG use in necrotizing autoimmune myopathy, it should be considered for anti-hydroxy-3-methyl-glutaryl-coenzyme A reductase myositis given the risk of long-term disability. Insufficient evidence exists for the use of IVIG in Miller-Fisher syndrome, IgG and IgA paraproteinemic neuropathy, autonomic neuropathy, chronic autoimmune neuropathy, polymyositis, idiopathic brachial plexopathy and diabetic lumbosacral radiculoplexopathy.

Neurological Manifestations of Connective Tissue Disorders

Connective tissue disorders (CTD) are a group of disorders affecting the connective tissues. Usually the musculoskeletal and the vascular system is impacted. Along with these systems, the nervous system is also involved in CTD, which leads to various neurological manifestations. The pathophysiology of neurological complications of CTD is caused by various factors and is complicated. Disturbed immune complexes, chronic inflammation, and autoimmunity in which the body attacks its cells are considered to be responsible for the neurological complications of CTD. Additionally, the vascular symptoms that lead to decreased blood flow to the brain are also responsible for the neurological manifestations of CTD in diseases like systemic lupus erythematosus (SLE). In SLE, vessel wall integrity is compromised, which may lead to decreased blood flow leading to neurological complications. CTD can manifest a variety of neurological complications. These neurological complications can be classified into symptoms affecting the peripheral nervous system, central nervous system, and the autonomic nervous system. Some of the common neurological complications of CTD are headaches, seizures, ataxia, neuropathies leading to cranial nerve palsies, myelopathies, tremors, encephalitis, and cerebral infarction. Cranial nerve palsies can disturb sensations, vision, hearing, and mastication. Neuropsychiatric symptoms are also commonly observed in CTD. Cognitive dysfunction can be caused due to neuropsychiatric problems. Some of the cognitive dysfunctions are lack of concentration, memory loss, confusion, and coma. In this review, we will address various neurological manifestations of CTD.

Anti-AGO1 Antibodies Identify a Subset of Autoimmune Sensory Neuronopathy

BACKGROUND AND OBJECTIVES

Autoantibodies (Abs) improve diagnosis and treatment decisions of idiopathic neurologic disorders. Recently, we identified Abs against Argonaute (AGO) proteins as potential autoimmunity biomarkers in neurologic disorders. In this study, we aim to reveal (1) the frequency of AGO1 Abs in sensory neuronopathy (SNN), (2) titers and IgG subclasses, and (3) their clinical pattern including response to treatment.

METHODS

This retrospective multicentric case/control study screened 132 patients with SNN, 301 with non-SNN neuropathies, 274 with autoimmune diseases (AIDs), and 116 healthy controls (HCs) for AGO1 Abs through ELISA. Seropositive cases were also tested for IgG subclasses, titers, and conformation specificity.

RESULTS

AGO1 Abs occurred in 44 patients, comprising significantly more of those with SNN (17/132 [12.9%]) than those with non-SNN neuropathies (11/301 [3.7%]; p = 0.001), those with AIDs (16/274 [5.8%]; p = 0.02), or HCs (0/116; p < 0.0001). Ab titers ranged from 1:100 to 1:100,000. IgG subclass was mainly IgG1, and 11/17 AGO1 Ab-positive SNN (65%) had a conformational epitope. AGO1 Ab-positive SNN was more severe than AGO1 Ab-negative SNN (e.g., SNN score: 12.2 vs 11.0, p = 0.004), and they more frequently and more efficiently responded to immunomodulatory treatments than AGO1 Ab-negative SNN (7/13 [54%] vs 6/37 [16%], p = 0.02). Regarding the type of treatments more precisely, this significant difference was confirmed for the use of IV immunoglobulins (IVIg) but not for steroids or second-line treatments. Multivariate logistic regression adjusted for potential confounders showed that AGO1 Ab positivity was the only predictor of response to treatment (OR 4.93, 1.10-22.24 95% CI, p = 0.03).

DISCUSSION

Although AGO Abs are not specific for SNN, based on our retrospective data, they may identify a subset of cases with SNN with more severe features and a possibly better response to IVIg. The significance of AGO1 Abs in clinical practice needs to be explored on a larger series.

Pathogenesis and treatment of Sjogren's syndrome: Review and update

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar to that of SLE, RA, and MS, biotherapeutic strategies of SS consist of neutralizing antibodies and inflammation-related receptor blockers targeting proinflammatory signaling pathways. However, clinical research on SS therapy is comparatively rare. Moreover, the differences in the curative effects of immunotherapies among SS and other autoimmune diseases are not fully understood. We emphasize that targeted drugs, low-side-effect drugs, and combination therapies should be the focus of future research.

[Peripheral neuropathies during systemic diseases: Part I (connective tissue diseases and granulomatosis)]

Systemic diseases (connective disease, granulomatosis) may be associated with peripheral neuropathies. The diagnosis can be complex when the neuropathy is the presenting manifestation of the disease, requiring close collaboration between neurologists and internists. Conversely, when the systemic disease is already known, the main question remaining is its imputability in the neuropathy. Regardless of the situation, the positive diagnosis of neuropathy is based on a systematic and rigorous electro-clinical investigation, specifying the topography, the evolution and the mechanism of the nerve damage. Certain imaging examinations, such as nerve and/or plexus MRI, or other more invasive examinations (skin biopsy, neuromuscular biopsy) enable to specify the topography and the mechanism of the injury. The imputability of the neuropathy in the course of a known systemic disease is based mainly on its electro-clinical pattern, on which the alternatives diagnoses depend. In the case of an inaugural neuropathy, a set of arguments orients the diagnosis, including the underlying terrain (young subject), possible associated systemic manifestations (inflammatory arthralgias, polyadenopathy), results of first-line laboratory tests (lymphopenia, hyper-gammaglobulinemia, hypocomplementemia), autoantibodies (antinuclear, anti-native DNA, anti-SSA/B) and sometimes invasive examinations (neuromuscular biopsy).

Primary Sjögren syndrome-related peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Primary Sjögren syndrome (pSS) is a chronic, systemic, autoimmune disorder characterized by lymphocytic infiltrates of the exocrine organs, leading to sicca symptoms and parotid enlargement. pSS has been linked to various neurological manifestations, including peripheral neuropathy (PN). We aimed to provide a comprehensive analysis of the currently available evidence regarding pSS-related PN.

METHODS

A literature search in the PubMed database was performed, and 49 papers were eligible to be included in this systematic review and meta-analysis.

RESULTS

The pooled prevalence of PN in pSS is estimated to be 15.0% (95% confidence interval = 10.7%-20.7%). The mean age of pSS patients at PN diagnosis is 59 years. Among the patients with pSS and PN, 83% are females. Neuropathic symptoms usually precede or lead to the pSS diagnosis at a 2:1 ratio in patients with pSS-related PN. The commonest type of pSS-related PN is distal axonal polyneuropathy (80% of patients with pSS-related PN), followed by sensory ganglionopathy. Peripheral and cranial mononeuropathies-particularly trigeminal-are also frequent. Risk factors for developing PN include increasing age and presence of vasculitis. Immune-mediated pathogenetic mechanisms are discussed. Glucocorticoids are the most commonly used treatment option for managing pSS-related PN, when associated with vasculitis, followed by the use of intravenous immunoglobulin.

CONCLUSIONS

PN is very common in pSS patients. Evidence on long-term prognosis of PN in pSS is limited, and further research is needed. Research into the use of immunosuppressive medication in nonvasculitic neuropathies in the context of pSS merits further consideration.

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.

Neuropsychiatric manifestations in primary Sjogren syndrome

INTRODUCTION

Neurologic manifestations in primary Sjogren´s Syndrome (pSS) are characterized by a heterogeneity of clinical manifestations. In clinical practice, physicians are challenged with the absence of diagnostic criteria and the lack of clinical trials to support treatment. In this article, we will review epidemiology, clinical and immunological characterization, diagnosis and treatment of neurologic events in pSS.

AREAS COVERED

This narrative review provides an overview of neurologic manifestations described in pSS, complementary investigations and treatment reported. Articles were selected from Pubmed searches conducted between December 2021 and February 2022.

EXPERT OPINION

Epidemiology and clinical features of neurologic manifestations are derived from different cohort studies. Our understanding of pathophysiology of neurologic manifestations in pSS has significantly increased in the past few years, especially regarding PNS. However, there are still many knowledge gaps on therapeutics. The few available data on therapy rely upon small case series, from experiences with other autoimmune disease, such as systemic lupus erythematosus or expert opinion. There is an urgent need for well-designed clinical trials.

Investigation of nerve fibers in the skin by biopsy: technical aspects, indications, and contribution to diagnosis of small-fiber neuropathy

Skin biopsy with investigation of small-diameter nerve fibers in human epidermis and dermis has been proven to be a useful method for confirming small-fiber neuropathy. In medical practice, small-fiber neuropathy is increasingly recognized as a leading cause of neuropathic pain. It is a prevalent complaint in medical offices, brought by patients often as a “painful burning sensation”. The prevalence of neuropathic pain is high in small-fiber neuropathies of different etiologies, especially in the elderly; 7% of population in this age group present peripheral neuropathy. Pain and paresthesia are symptoms which might cause disability and impair quality of life of patients. The early detection of small-fiber neuropathy can contribute to reducing unhealthy lifestyles, associated to higher incidence of the disease.

Different perception of dry eye symptoms between patients with and without primary Sjogren's syndrome

Here, we investigated the different perception of dry eye symptoms between in patients with and without primary Sjogren’s syndrome (pSS). In this study, 221 patients with dry eye disease (DED) without pSS (non-SS DED group) and 55 patients with DED with pSS (SS DED group) were included. The ocular discomfort was evaluated using ocular surface disease index (OSDI) questionnaire and patients were further divided into 3 severity subgroups according to OSDI scores. The OSDI score was higher in the non-SS DED group even after matching corneal erosion scores despite the ocular surface erosions and tear deficiency was worse in the SS DED group. The corneal sensitivity was nearly normal in both groups without inter-group difference (Non-SS DED group: 5.82 ± 0.54 cm, SS DED group: 5.90 ± 0.29 cm, p = 0.217). Moreover, all clinical parameters were not significantly correlated with OSDI scores in both non-SS DED group and SS DED group. In the mild and severe OSDI subgroups, the ocular surface erosions and tear deficiency were worse in the SS DED group whereas the OSDI scores were not different between groups. In conclusion, clinicians should be aware that pSS patients may complain less of their discomfort unlike their actual severe status of DED.

Effects of primary Sjögren's syndrome on hearing and vestibular systems

Objective

This study aimed to evaluate primary Sjögren's syndrome patients in terms of hearing and vestibular functions.

Methods

The patient group consisted of 35 individuals diagnosed with primary Sjögren's syndrome and a control group of 35 healthy individuals similar in terms of age and gender.

Results

The rate of hearing loss in the patient group was significantly higher than in the control group (p = 0.021). The N1 latency value for the ocular vestibular-evoked myogenic potentials test was significantly longer in the patient group than in the control group (p = 0.037). Additionally, the posterior semicircular canal and lateral semicircular canal vestibulo-ocular reflex gain values were significantly lower than in the control group (p = 0.022 and p < 0.001, respectively).

Conclusion

These results indicate subclinical vestibular involvement and hearing loss in primary Sjögren's syndrome patients. Vestibular-evoked myogenic potentials and video head impulse tests can be used to detect vestibular involvement in primary Sjögren's syndrome patients.

Immune mechanisms, the role of complement, and related therapies in autoimmune neuropathies

INTRODUCTION

Autoimmune neuropathies have diverse presentations and underlying immune mechanisms. Demonstration of efficacy of therapeutic agents that inhibit the complement cascade would confirm the role of complement activation.

AREAS COVERED

A review of the pathophysiology of the autoimmune neuropathies, to identify those that are likely to be complement mediated.

EXPERT OPINION

Complement mediated mechanisms are implicated in the acute and chronic neuropathies associated with IgG or IgM antibodies that target the Myelin Associated Glycoprotein (MAG) or gangliosides in the peripheral nerves. Antibody and complement mechanisms are also suspected in the Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy, given the therapeutic response to plasmapheresis or intravenous immunoglobulins, even in the absence of an identifiable target antigen. Complement is unlikely to play a role in paraneoplastic sensory neuropathy associated with antibodies to HU/ANNA-1 given its intracellular localization. In chronic demyelinating neuropathy with anti-nodal/paranodal CNTN1, NFS-155, and CASPR1 antibodies, myotonia with anti-VGKC LGI1 or CASPR2 antibodies, or autoimmune autonomic neuropathy with anti-gAChR antibodies, the response to complement inhibitory agents would depend on the extent to which the antibodies exert their effects through complement dependent or independent mechanisms. Complement is also likely to play a role in Sjogren's, vasculitic, and cryoglobulinemic neuropathies.

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.

Acute motor and sensory axonal neuropathy in association with primary Sjögren's syndrome: a case report

BACKGROUND

Primary Sjögren's syndrome is a chronic, autoimmune, connective tissue disorder that results from the infiltration of exocrine glands, especially the lacrimal and salivary glands, by autoantibodies. Patients with Sjögren's syndrome commonly present with dry eyes (xerophthalmia) and dry mouth (xerostomia). However, the clinical manifestations of Sjögren's syndrome can be complicated and variable due to involvement of extraglandular organ systems, such as the nervous system. The neurological manifestations of this disorder often precede those of other exocrine gland symptoms. Hence, early diagnosis of Sjögren's syndrome remains a challenge.

CASE PRESENTATION

We report the case of a 63-year-old woman with primary Sjögren's syndrome who presented with acute motor and sensory axonal neuropathy (AMSAN). Treatment with glucocorticoids and immunosuppressants partially improved her muscle weakness and paresthesia.

CONCLUSIONS

This case demonstrates the importance of early recognition and diagnosis of AMSAN in association with primary Sjögren's syndrome to achieve a favorable clinical outcome. Primary Sjögren's syndrome may be underdiagnosed because of vague symptoms of the sicca complex. Comprehensive immunological testing to evaluate this condition may be performed in patients presenting with variants of Guillain-Barré syndrome.

Pruritus in autoimmune connective tissue diseases

Pruritus is one of the most common and bothersome symptoms of skin disorders, and its clinical characteristics and related pathomechanisms have been well described in certain dermatologic conditions, such as atopic dermatitis and urticaria. Although pruritus is believed to be as common in cutaneous autoimmune connective tissue diseases (ACTDs) as in other inflammatory skin disorders, its true characteristics have not been elucidated either qualitatively or quantitatively. Pruritus is present in ACTDs with various prevalence rates, characteristics, and mechanisms depending on the disease types. Pruritus most frequently and severely affects the patients with dermatomyositis, in which itch is strongly correlated with disease activity and severity, thus increased itch could also indicate a disease flare. Patients with other ACTDs, including lupus erythematosus (LE), Sjögren syndrome (SS), morphea, and systemic sclerosis (SSc), also suffer from their fair share of pruritus. Unfortunately, the currently available treatments for ACTDs seem to have only limited and unsatisfactory effects to control pruritus. The extensive impact of pruritus on the patients’ quality of life (QOL) and functioning warrants more targeted and individualized approaches against pruritus in ACTDs. This review will address the prevalence, suggested pathogenesis based on currently available evidences, and potential treatment options of pruritus in various ACTDs of the skin.

Sensory neuronopathies: new genes, new antibodies and new concepts

Degeneration of dorsal root ganglia (DRG) and its central and peripheral projections provokes sensory neuronopathy (SN), a rare disorder with multiple genetic and acquired causes. Clinically, patients with SN usually present with proprioceptive ataxia, patchy and asymmetric sensory abnormalities, widespread areflexia and no weakness. Classic causes of SN include cancer, Sjögren's syndrome, vitamin deficiency, chemotherapy, mitochondrial disorders and Friedreich ataxia. More recently, new genetic and dysimmune disorders associated with SN have been described, including RFC1 gene-linked cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) and anti-FGFR3 antibodies. In this review, we detail the pathophysiology of DRG degeneration, and the genetic and acquired causes of SN, with a special focus on the recently described CANVAS and anti-FGFR3 antibodies. We also propose a user-friendly and easily implemented SN diagnostic strategy.

Sudomotor Dysfunction

Disorders of sudomotor function are common and diverse in their presentations. Hyperhidrosis or hypohidrosis in generalized or regional neuroanatomical patterns can provide clues to neurologic localization and inform neurologic diagnosis. Conditions that impair sudomotor function include small fiber peripheral neuropathy, sudomotor neuropathy, myelopathy, α-synucleinopathies, autoimmune autonomic ganglionopathy, antibody-mediated hyperexcitability syndromes, and a host of medications. Particularly relevant to neurologic practice is the detection of postganglionic sudomotor deficits as a diagnostic marker of small fiber neuropathies. Extensive anhidrosis is important to recognize, as it not only correlates with symptoms of heat intolerance but may also place the patient at risk for heat stroke when under conditions of heat stress. Methods for assessing sudomotor dysfunction include the thermoregulatory sweat test, the quantitative sudomotor axon reflex test, silicone impressions, and the sympathetic skin response.

Transverse myelitis associated with primary biliary cirrhosis: clinical, laboratory, and neuroradiological features

PURPOSE

Only five patients diagnosed with transverse myelitis (TM) associated with primary biliary cirrhosis (PBC) have been reported in the literature to date. We report two additional patients with TM associated with PBC at our hospital and review all seven cases.

MATERIALS AND METHODS

An association between neuromyelitis optic spectrum disease (NMOSD) and PBC is reported for the first time in one of our patients. The second patient was diagnosed with TM associated with PBC without Sjögren's syndrome (SS). A literature review was performed using the PubMed database.

RESULTS

All patients diagnosed with TM associated with PBC were female with a median age of 53 years. TM was associated with SS in 71.4% of the patients. Complete TM and incomplete TM were diagnosed in 71.4% and 28.6% of the patients. The erythrocyte sedimentation rate was increased in 83.3% of patients. All patients were positive for anti-mitochondrial antibodies. Other autoantibodies, including anti-nuclear antibodies, rheumatoid factor, anti-SSA antibody, were detected in some patients. Cerebrospinal fluid analysis was abnormal in 83.3% of patients. The spinal cord lesions involved more than three vertebral segments in 85.7% of patients. Glucocorticoids were administered in 85.7% of patients, and good responses were observed.

CONCLUSIONS

The association between TM and PBC may be missed by neurologists. More attention should be paid to the association between NMOSD and PBC. Most patients show SS and may experience relapse, and there is a good rationale for early commencement of immunosuppressive therapy.

Reorganization of motor modules for standing reactive balance recovery following pyridoxine-induced large-fiber peripheral sensory neuropathy in cats

Task-level goals such as maintaining standing balance are achieved through coordinated muscle activity. Consistent and individualized groupings of synchronously activated muscles can be estimated from muscle recordings in terms of motor modules or muscle synergies, independent of their temporal activation. The structure of motor modules can change with motor training, neurological disorders, and rehabilitation, but the central and peripheral mechanisms underlying motor module structure remain unclear. To assess the role of peripheral somatosensory input on motor module structure, we evaluated changes in the structure of motor modules for reactive balance recovery following pyridoxine-induced large-fiber peripheral somatosensory neuropathy in previously collected data in four adult cats. Somatosensory fiber loss, quantified by postmortem histology, varied from mild to severe across cats. Reactive balance recovery was assessed using multidirectional translational support-surface perturbations over days to weeks throughout initial impairment and subsequent recovery of balance ability. Motor modules within each cat were quantified by non-negative matrix factorization and compared in structure over time. All cats exhibited changes in the structure of motor modules for reactive balance recovery after somatosensory loss, providing evidence that somatosensory inputs influence motor module structure. The impact of the somatosensory disturbance on the structure of motor modules in well-trained adult cats indicates that somatosensory mechanisms contribute to motor module structure, and therefore may contribute to some of the pathological changes in motor module structure in neurological disorders. These results further suggest that somatosensory nerves could be targeted during rehabilitation to influence pathological motor modules for rehabilitation.NEW & NOTEWORTHY Stable motor modules for reactive balance recovery in well-trained adult cats were disrupted following pyridoxine-induced peripheral somatosensory neuropathy, suggesting somatosensory inputs contribute to motor module structure. Furthermore, the motor module structure continued to change as the animals regained the ability to maintain standing balance, but the modules generally did not recover pre-pyridoxine patterns. These results suggest changes in somatosensory input and subsequent learning may contribute to changes in motor module structure in pathological conditions.

Multiple system atrophy pathology is associated with primary Sjögren's syndrome

BACKGROUND

Our objective was to investigate whether primary Sjögren’s syndrome (pSS) is associated with multiple system atrophy (MSA).

METHODS

We performed a retrospective cohort study assessing (a) rates of MSA in a cohort of patients with pSS and (b) rates of pSS in a cohort of patients with MSA. These data were compared with rates in respective control groups. We additionally reviewed the neuropathologic findings in 2 patients with pSS, cerebellar degeneration, parkinsonism, and autonomic dysfunction.

RESULTS

Our cohort of 308 patients with pSS had a greater incidence of MSA compared with 4 large population-based studies and had a significantly higher prevalence of at least probable MSA (1% vs. 0%, P = 0.02) compared with 776 patients in a control cohort of patients with other autoimmune disorders. Our cohort of 26 autopsy-proven patients with MSA had a significantly higher prevalence of pSS compared with a cohort of 115 patients with other autopsy-proven neurodegenerative disorders (8% vs. 0%, P = 0.03). The 2 patients we described with pSS and progressive neurodegenerative disease showed classic MSA pathology at autopsy.

CONCLUSION

Our findings provide evidence for an association between MSA and pSS that is specific to both pSS, among autoimmune disorders, and MSA, among neurodegenerative disorders. The 2 cases we describe of autopsy-proven MSA support that MSA pathology can explain neurologic disease in a subset of patients with pSS. These findings together support the hypothesis that systemic autoimmune disease plays a role in neurodegeneration.

FUNDING

The Michigan Brain Bank is supported in part through NIH grant P30AG053760.

This single-center retrospective cohort study shows an association between primary Sjogren’s syndrome and multiple system atrophy pathology.

Neuro-Sjögren: Uncommon or underestimated problem?

OBJECTIVES

Sjögren's syndrome (SS) is a chronic inflammatory disease with an autoimmune background with possible complications from peripheral (PNS) and central nervous system (CNS). The aim of this study was to assess the prevalence and to describe the phenotype of peripheral neuropathies in patients with SS.

MATERIALS & METHODS

We studied fifty patients with primary Sjögren's syndrome for peripheral nervous system involvement. All patients underwent neurological and rheumatological examination followed by nerve conduction studies (NCS) of nine peripheral nerves.

RESULTS

Thirty-six patients (72%) fulfilled the criteria for the diagnosis of neuropathy. Carpal tunnel syndrome (54%) and axonal sensorimotor neuropathy (22%) were the most common. Neurological symptoms preceded the diagnosis of SS in eight patients.

CONCLUSIONS

Peripheral neuropathies are frequent in SS patients. Neurologists should be aware of possible autoimmune causes of neuropathies because clinical manifestations of neuropathy may precede the development of other symptoms of the autoimmune disease.

Acute severe sensory ganglionopathy in systemic lupus erythematous

Sensory ganglionopathies (or neuronopathies) are a rare subgroup of neuropathies characterized by involvement of sensory neurons in the dorsal root ganglion. Although much less common than central nervous system involvement, patients with systemic lupus erythematous (SLE) can develop peripheral nervous system involvement (PNS) and most commonly a chronic length dependent symmetric sensorimotor axonal polyneuropathy as a late complication of the disease. Unlike in Sjogren's syndrome, SLE-associated sensory ganglionopathy is extremely rare and usually manifests in a chronic insidious fashion. We report a 24-year-old man with SLE-associated sensory ganglionopathy manifesting an unusually acute and severe disabling clinical course with a good response to immunosuppressive therapies. Timely recognition of this rare association and early targeted immunosuppression prevented severe neurological sequelae and preserved patient's ambulation. We demonstrate videos on the evolution of patient's neurological impairment and response to treatment, contributing to the current knowledge of the natural history of PNS involvement in SLE.

Small fiber neuropathy and related factors in patients with systemic lupus erythematosus; the results of cutaneous silent period and skin biopsy

INTRODUCTION

Evaluating small nerve fibers in patients with systemic lupus erythematosus (SLE) using cutaneous silent period (CSP) and skin biopsy and assesssing the relationship between clinical signs, autoantibodies and neuropathic pain score.

OBJECTIVE - METHODS

Fifty one SLE patients and 46 healthy volunteers were included in this study. Nerve conduction studies and CSP were performed both on upper and lower limbs in subjects. Skin biopsy was performed and the number of epidermal nerve density and IL-6 staining were evaluated.

RESULTS

In SLE patients, CSP latencies were significantly prolonged both in lower and upper limbs and lower and upper extremity CSP durations were significantly shorter when compared to controls (p < 0.001). The number of epidermal nerve was significantly lower in SLE patients when compared to healthy controls (p < 0.001).

CONCLUSION

We detected marked small nerve fiber damage in both lower and upper limbs in SLE patients using CSP. Decreased epidermal nerve density also supports this finding.

[Polyneuropathies in vasculitis and connective tissue diseases : Clinical manifestations and diagnostic recommendations]

Vasculitic neuropathies result from inflammation of the vasa nervorum followed by ischemia and destruction of the peripheral nerve. The inflammation can be systemic or localized, i.e. non-systemic. Systemic vasculitis can be divided into primary and secondary forms. The latter is associated with, e.g. connective tissue diseases, infections, cancer or induced by certain drugs. Around two thirds of patients with systemic vasculitis develop vasculitic neuropathy presenting as characteristic painful, multifocal mononeuropathy of acute onset. The group of non-systemic neuropathies has grown in recent years with the addition of diabetic and non-diabetic lumbosacral radiculoplexus neuropathies, among others. Within the group of connective tissue diseases, other non-vasculitic neuropathies can occur as nerve-entrapment syndromes and sensory ataxic neuropathy. The aim of this article is to present a condensed overview of neuropathies associated with vasculitis and connective tissue diseases and to communicate characteristic clinical symptoms supporting rapid diagnostic and therapeutic procedures.

Neurophysiological Features of Peripheral Nervous System Involvement and Immunological Profile of Patients with Primary Sjögren Syndrome

OBJECTIVE

The aim of this study was to evaluate the prevalence, type of neuropathy, and the relationship between the presence of autoantibodies and neuropathy development in patients with primary Sjögren syndrome (pSS).

METHODS

Sixty-one patients with pSS underwent a complete neurological and electrophysiological examination as well as immunological tests including rheumatoid factor (RF) and autoantibodies such as antinuclear antibodies (ANA), anti-Ro/SSa, and anti-La/SSB antibodies.

RESULTS

The axonal loss or demyelination were found in 39 patients (63.9%). Twenty-nine (47.5%) subjects fulfilled both clinical and electrophysiological criteria of peripheral neuropathy of predominantly axonal type. Seropositivity to both anti-Ro and anti-La antibodies was more frequently found in patients with normal nerve conduction study. Seropositivity to anti-Ro alone was present in the majority of patients with axonal neuropathy (P < 0.05). The presence of RF was associated with several electrodiagnostic signs of demyelination (P < 0.01). The ANA titer showed no independent association with neuropathy.

CONCLUSION

Peripheral neuropathy is a frequent complication in patients with pSS. Seropositivity limited to anti-Ro is associated with increased risk of axonal neuropathy in comparison to seropositivity to both anti-Ro and anti-La antibodies. Seropositivity to RF may contribute to demyelination.

Neurological Involvement as the Initial Manifestation in Primary Sjögren's Syndrome - A Case Report

BACKGROUND

Sjögren's syndrome is an autoimmune disease characterised by exocrinopathy mainly involving the salivary and lacrimal glands. In addition, it is a multisystemic condition (i.e., affecting multiple organs and systems). Neurological involvement has been reported in ~20% of cases, with peripheral manifestations being the most frequent.

METHODS

We analysed four cases in which neurological manifestations were the first symptoms of Sjögren's syndrome.

RESULTS

In all four cases, neurological symptoms preceded sicca symptoms. In addition, immunosuppressive treatment with steroids and, in some cases, cyclophosphamide showed improvement.

CONCLUSION

Neurological involvement in Sjögren's syndrome is common and often occurs as the first clinical manifestation. Since evidence is limited, more studies are required in order to determine appropriate diagnostic methods and treatments for each manifestation of Sjögren's syndrome.

Lymphocytic ganglionitis leading to megacolon in lymphocyte-rich glioblastoma

T-cell immune attack of cancer cells underlies the efficacy of immune checkpoint inhibitors in many cancer subtypes, but is not yet well established in the primary brain cancer glioblastoma. Immune checkpoint inhibitor treatments that disinhibit the immune system to enhance immune clearance of cancer have in rare cases resulted in T-cell attack of peripheral ganglia causing lymphocytic ganglionitis. In glioblastoma, lymphocytic ganglionitis has not been reported and checkpoint inhibitors are not routinely used. Here we report a case of glioblastoma not treated with checkpoint inhibitors in which the primary tumor and peripheral ganglia of the celiac and sympathetic chains, as well as myenteric plexus, are infiltrated by CD8⁺ cytotoxic T-cells. In addition to the marked lymphocytic infiltrates, this case is also notable for an unusually long survival (8 years) after diagnosis with glioblastoma, but an ultimately fatal outcome due to ileus. The findings suggest T-cell immune attack of glioblastoma may prolong survival, but also suggest T-cell autoimmune diseases such as lymphocytic ganglionitis could become a risk with the future use of immune-targeted therapies for glioblastoma.

[Peripheral nerve involvement in rheumatic diseases]

Peripheral neuropathies are probably an under-diagnosed complication of many rheumatic diseases. In some cases they take a mild clinical course, in others they cause severe impairment of patients' quality of life. A precise diagnosis and etiological classification are of major importance for successful treatment and prognosis of peripheral neuropathies. A detailed patient history and physical examination are the foundation of every diagnostic approach. Electrophysiological studies are obligatory when peripheral neuropathy is suspected, whereas nerve or nerve-muscle biopsies are indicated only in selected cases. Therapeutic approaches are often complicated by a lack of evidence. They correspond to frequently tested immunosuppressive treatment of the underlying disease, such as glucocorticoids, cyclophosphamide, mycophenolate mofetil and intravenous immunoglobulins and are based on the symptomatic pain treatment of other neuropathies. As first-line treatment gabapentin, pregabalin, duloxetine, venlafaxine and tricyclic antidepressants are frequently used.

Scientific Advances in and Clinical Approaches to Small-Fiber Polyneuropathy: A Review

IMPORTANCE

Small-fiber polyneuropathy involves preferential damage to the thinly myelinated A-delta fibers, unmyelinated C sensory fibers, or autonomic or trophic fibers. Although this condition is common, most patients still remain undiagnosed and untreated because of lagging medical and public awareness of research advances. Chronic bilateral neuropathic pain, fatigue, and nausea are cardinal symptoms that can cause disability and dependence, including pain medication dependence.

OBSERVATIONS

Biomarker confirmation is recommended, given the nonspecificity of symptoms. The standard test involves measuring epidermal neurite density within a 3-mm protein gene product 9.5 (PGP9.5)-immunolabeled lower-leg skin biopsy. Biopsies and autonomic function testing confirm that small-fiber neuropathy not uncommonly affects otherwise healthy children and young adults, in whom it is often associated with inflammation or dysimmunity. A recent meta-analysis concluded that small-fiber neuropathy underlies 49% of illnesses labeled as fibromyalgia. Initially, patients with idiopathic small-fiber disorders should be screened by medical history and blood tests for potentially treatable causes, which are identifiable in one-third to one-half of patients. Then, secondary genetic testing is particularly important for familial and childhood cases. Treatable genetic causes include Fabry disease, transthyretin and primary systemic amyloidosis, hereditary sensory autonomic neuropathy-1, and ion-channel mutations. Immunohistopathologic evidence suggests that small-fiber dysfunction and denervation, especially of blood vessels, contributes to diverse symptoms, including postexertional malaise, postural orthostatic tachycardia, and functional gastrointestinal distress. Preliminary evidence implicates acute or chronic autoreactivity in some cases, particularly in female patients and otherwise healthy children and young adults. Different temporal patterns akin to Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy have been described; here, corticosteroids and immunoglobulins, which are often efficacious for inflammatory neuropathic conditions, are increasingly considered.

CONCLUSIONS AND RELEVANCE

Because small fibers normally grow throughout life, improving contributory conditions may permit regrowth, slow progression, and prevent permanent damage. The prognosis is often hopeful for improving quality of life and sometimes for abatement or resolution, particularly in the young and otherwise healthy individuals. Examples include diabetic, infectious, toxic, genetic, and inflammatory causes. The current standard of care requires prompt diagnosis and treatment, particularly in children and young adults, to restore life trajectory. Consensus diagnostic and tracking metrics should be established to facilitate treatment trials.

Diagnosis and management of sensory polyneuropathy

Sensory polyneuropathies, which are caused by dysfunction of peripheral sensory nerve fibers, are a heterogeneous group of disorders that range from the common diabetic neuropathy to the rare sensory neuronopathies. The presenting symptoms, acuity, time course, severity, and subsequent morbidity vary and depend on the type of fiber that is affected and the underlying cause. Damage to small thinly myelinated and unmyelinated nerve fibers results in neuropathic pain, whereas damage to large myelinated sensory afferents results in proprioceptive deficits and ataxia. The causes of these disorders are diverse and include metabolic, toxic, infectious, inflammatory, autoimmune, and genetic conditions. Idiopathic sensory polyneuropathies are common although they should be considered a diagnosis of exclusion. The diagnostic evaluation involves electrophysiologic testing including nerve conduction studies, histopathologic analysis of nerve tissue, serum studies, and sometimes autonomic testing and cerebrospinal fluid analysis. The treatment of these diseases depends on the underlying cause and may include immunotherapy, mitigation of risk factors, symptomatic treatment, and gene therapy, such as the recently developed RNA interference and antisense oligonucleotide therapies for transthyretin familial amyloid polyneuropathy. Many of these disorders have no directed treatment, in which case management remains symptomatic and supportive. More research is needed into the underlying pathophysiology of nerve damage in these polyneuropathies to guide advances in treatment.

Clinical electrophysiology of axonal polyneuropathies

Axonal neuropathies encompass a wide range of acquired and inherited disorders with electrophysiologic characteristics that arise from the unique neurophysiology of the axon. Accurate interpretation of nerve conduction studies and electromyography requires an in-depth understanding of the pathophysiology of the axon. Here we review the unique neurophysiologic properties of the axon and how they relate to clinical electrodiagnostic features. We review the length-dependent Wallerian or "dying-back" processes as well as the emerging body of literature from acquired axonal neuropathies that highlights the importance of axonal disease at the nodes of Ranvier. Neurophysiologic features of individual inherited and acquired axonal diseases, including primary nerve disease as well as systemic immune mediated, metabolic, and toxic diseases involving the peripheral nerve, are reviewed. This comprehensive review of electrodiagnostic findings coupled with the current understanding of pathophysiology will aid the clinician in the evaluation of axonal polyneuropathies.

Brief Report: Anti-Calponin 3 Autoantibodies: A Newly Identified Specificity in Patients With Sjögren's Syndrome

OBJECTIVE

Autoantibodies are clinically useful for phenotyping patients across the spectrum of autoimmune rheumatic diseases. Using serum from a patient with Sjögren's syndrome (SS), we detected a new specificity by immunoblotting. This study was undertaken to identify this autoantibody and to evaluate its disease specificity.

METHODS

A prominent 40-kd band was detected when immunoblotting was performed using SS patient serum and lysate from rat dorsal root ganglia (DRGs). Using 2-dimensional gel electrophoresis and liquid chromatography tandem mass spectrometry peptide sequencing, the autoantigen was identified as calponin 3. Anti-calponin 3 antibodies were evaluated in sera from patients with primary SS (n = 209), patients with systemic lupus erythematosus (SLE; n = 138), patients with myositis (n = 138), patients with multiple sclerosis (MS; n = 44), and healthy controls (n = 46) by enzyme-linked immunosorbent assay. Expression of calponin 3 was assessed by immunohistochemistry.

RESULTS

Calponin 3 was identified as a new autoantigen. Anti-calponin 3 antibodies were detected in 23 (11.0%) of the 209 SS patients, 12 (8.7%) of the 138 SLE patients, 7 (5.1%) of the 138 myositis patients, 3 (6.8%) of the 44 MS patients, and 1 (2.2%) of the 46 healthy controls. Among SS patients, the frequency of anti-calponin 3 antibodies was highest in those with neuropathies (7 [17.9%] of 39). In this subset, the frequency of anti-calponin 3 antibodies differed significantly from that in the control group (P = 0.02). Calponin 3 was expressed primarily in rat DRG perineuronal satellite cells but not neurons.

CONCLUSION

Calponin 3 is a novel autoantigen. Antibodies against this protein are found in SS and associate with the subset of patients experiencing neuropathies. Intriguingly, we found that calponin 3 is expressed in DRG perineuronal satellite cells, suggesting that these may be a target in SS.

Neurological manifestations of primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune connective tissue disease affecting the exocrine glands, leading to damage of their structure and impairment of their function. In the course of pSS the internal organs may be involved and the symptoms may concern any system. Neurological disorders are one of the most common extraglandular manifestations of pSS. Available literature data estimate the prevalence of neurological symptoms as about 8.5-70% of patients diagnosed with pSS. The most common neurological complication of pSS is peripheral neuropathy, and in particular sensory polyneuropathy. Central nervous system involvement is much less common. There are also reports of various symptoms connected with damage to cranial nerves and the autonomic nervous system. A careful neurological evaluation, combined with neurophysiological tests, is recommended in patients with pSS. This review summarizes the neurological manifestations of pSS, their possible pathogenic mechanisms, diagnostic evaluation and potential treatment.

Neurological Complications of Sjögren's Syndrome: Diagnosis and Management

Opinion statement

Purpose of review

Neurologic disease is a common extraglandular manifestation of Sjögren's syndrome (SS), the study of which has been hampered both by the lack of uniform definitions for specific neurologic complications and by the imprecision of the tools used to diagnose SS. There is a great need to develop consensus criteria for classifying these varied neurologic manifestations, as has been done in systemic lupus erythematosus (SLE) "Arthritis and rheumatism 42:599-608, 1999". SS patients with certain forms of neurologic involvement, such as small fiber neuropathy and sensory ataxic ganglionopathy, frequently lack anti-SSA and anti-SSB antibodies and other serologic abnormalities. In these patients, neurologic disease is often their presenting manifestation, triggering a search for underlying SS. Given the frequent seronegativity of such patients, their diagnosis of SS rests heavily on the interpretation of a labial gland biopsy. However, these biopsies are prone to misinterpretation "Vivino etal. J Rheumatol 29:938-44, 2002", and "positive" ones are found in up to 15% of healthy volunteers "Radfar et al. Arthrit Rheumatu 47:520-4, 2002". Better diagnostic tools are needed to determine if the frequent seronegative status of these SS patients may be related to a unique disease pathogenesis.

Recent findings

Recent advances in diagnostic techniques have served to define a likely pathogenetic basis for certain neurologic manifestations of SS. The advent of punch skin biopsies to analyze intraepidermal nerve fiber density and morphology has helped define pure sensory small fiber neuropathy as common in SS and the basis for both length- and non-length-dependent patterns of neuropathic pain. New protocols for magnetic resonance imaging (MRI) have enabled the recognition of dorsal root ganglionitis, a finding originally detected in pathologic studies. The advent of the anti-aquaporin-4 (AQP4) antibody test in 2004 has Led to the appreciation that demyelinating disease in SS is often related to the presence of neuromyelitis optica spectrum disorder. The anti-AQP4 antibody is considered to be directly pathogenic in the brain, targeting the primary water channel proteins in the brain, expressed prominently on astrocytic foot processes.

Summary

There are no clinical trials evaluating the efficacy of systemic immune suppressive therapy for peripheral or central nervous system involvement. With the recent increase in clinical trials of biologic agents for SS, which utilize systemic disease manifestations as standardized outcome measures, there is an urgency to deveLop appropriate definitions of neuroLogic compLications of SS and cLear parameters for clinical improvement.

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.

Chronic Pruritus and Connective Tissue Disorders: Review, Gaps, and Future Directions

Chronic itch is a common skin manifestation in many connective tissue diseases. However, the cause of chronic itch in these diseases is still not fully understood. The complex, and in some cases incomplete understanding of, pathogenesis in each condition makes it difficult to target specific mediators of chronic itch. It is important to better understand the pathophysiology of chronic itch in these conditions, as this information might provide a fuller understanding of the pathogenesis of the diseases in general and lead to the development of more specific treatments for connective tissue diseases in patients with chronic itch. We present a review of the literature on what is known about the prevalence, possible pathophysiology, and effect on quality of life of chronic itch in patients with scleroderma, Sjögren's syndrome, dermatomyositis, systemic lupus erythematosus, cutaneous lupus erythematosus, and mixed connective tissue disease.

Ganglioradiculitis (Sensory Neuronopathy) in a Dog: Clinical, Morphologic, and Immunohistochemical Findings

A 9-year-old Labrador Retriever was diagnosed with ganglioradiculitis (sensory neuronopathy). This idiopathic disease of mature dogs is characterized by a profound loss of sensory nerve function due to mononuclear inflammatory infiltration of peripheral ganglia and spinal nerve roots, with destruction of sensory neurons. Immunohistochemistry demonstrates that the infiltrating cells are primarily T lymphocytes and that immunoglobulins are not present on the cell membranes of affected neurons. The pathogenesis of ganglioradiculitis remains unclear, but the evidence points to a cell-mediated immune mechanism.