Autoimmune neuropathies associated to rheumatic diseases

Neuropsychiatric manifestations in systemic lupus erythematosus and Sjogren's disease

INTRODUCTION

Autoimmune diseases often present in a systemic manner, affecting various organs and tissues. Involvement of the central and peripheral nervous system is not uncommon in these conditions and is associated with high morbidity and mortality. Therefore, early recognition of the neuropsychiatric manifestations associated with rheumatologic diseases is essential for the introduction of appropriate therapies with the objective of providing a better quality of life for individuals.

OBJECTIVE

To provide a literature review of the neuropsychiatric manifestations related to Systemic Lupus Erythematosus (SLE) and primary Sjögren's Disease (pSD), through the description of signs, symptoms, and immunological variables associated with these conditions.

METHODS

A literature review was conducted by searching for national and international articles available in the SciELO and PubMed databases related to the description of neurological and psychiatric manifestations in patients with the rheumatologic diseases of interest in this study.

RESULTS

The main NP manifestations presented in SLE and pSD are discussed, focusing on clinical presentation and etiology. Treatment option are, however, mainly based on expert opinion, since a few randomized controlled trials have been done.

CONCLUSIONS

There is a high prevalence of neuropsychiatric manifestations associated with SLE and pSD. The variety of physiopathology pathways may explain the variety of symptoms, however pathological findings are rare. Multicenter studies on attribution protocols and treatment are necessary to address the current gaps.

What is known about the effects of vitamin D in neuropsychiatric lupus?

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect several organs and systems. The central and/or peripheral nervous system can suffer from complications known as neuropsychiatric lupus (NPSLE). Studies have associated the manifestations of SLE or NPSLE with vitamin D deficiency. It has been shown that hypovitaminosis D can lead to cognition deficits and cerebral hypoperfusion in patients with NPSLE. In this review article, we will address the main features related to vitamin D supplementation or serum vitamin D levels with neuropsychiatric manifestations, either in patients or in animal models of NPSLE.

Peripheral Neuropathy in Systemic Autoimmune Rheumatic Diseases-Diagnosis and Treatment

Peripheral neuropathy (PN) is frequently observed in systemic rheumatic diseases and is a challenge in clinical practice. We aimed to review the evidence on the subject and proposed a comprehensive approach to these patients, facilitating diagnosis and management. We searched the MEDLINE database for the terms (and its respective Medical Subject Headings (MeSH) terms): "peripheral neuropathy" AND "rheumatic diseases" OR "systemic lupus erythematosus", "rheumatoid arthritis", "Sjogren syndrome", and "vasculitis" from 2000 to 2023. This literature review focuses on the diagnostic workup of PNs related to systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, and systemic vasculitis. For every type of PN, we provide a pragmatic flowchart for diagnosis and also describe evidence-based strategies of treatment.

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.

Sensory neuronopathy is a specific and disabling neurological manifestation of autoimmune hepatitis

BACKGROUND AND PURPOSE

Neurological manifestations have been identified in the context of autoimmune hepatitis (AIH). Previous case reports highlighted the association between AIH and sensory neuronopathy (SN). Despite that, little is known about the frequency of AIH-related SN and its clinical/neurophysiological profile. Moreover, it is not clear whether SN is an AIH-specific manifestation or related to chronic liver damage.

METHODS

Seventy consecutive AIH patients were enrolled and their characteristics were compared with 52 consecutive patients with chronic active hepatitis B. All subjects underwent clinical and neurophysiological evaluation. Further comparisons were performed between AIH SN and AIH non-SN patients.

RESULTS

Mean ages and male:female proportions in the AIH and chronic active hepatitis B groups were 42.2 ± 16.3/51.7 ± 13.6 years and 14:56/29:23, respectively. The frequencies of carpal tunnel syndrome, radiculopathy and polyneuropathy were similar between groups. In contrast, SN was identified only in AIH patients (5/70 vs. 0/52, P = 0.04); the overall prevalence of AIH-related SN was 7% with an average profile of a woman in her 40s with asymmetric onset of sensory deficits that chronically evolved to disabling proprioceptive ataxia associated with marked dysautonomia. Neurological disability and hepatocellular damage did not follow in parallel. Anti-fibroblast growth factor receptor type 3 antibodies were found in 3/5 (60%) of the patients with AIH-related SN. Clinical or demographic predictors of SN in the context of AIH could not be identified.

CONCLUSION

Sensory neuronopathy, but not other peripheral nervous system diseases, is a specific AIH neurological manifestation. It is often disabling and, in contrast to hepatocellular injury, does not respond to immunosuppression.

[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.

Misdiagnosis and diagnostic delay in non-paraneoplastic sensory neuronopathies

METHODS

Sensory neuronopathies (SN) are a group of peripheral nerve disorders characterized by multifocal non-length-dependent sensory deficits and sensory ataxia. Its recognition is essential not only for proper management but also to guide the etiological investigation. The uncommon SN clinical picture and its rarity set the conditions for the misdiagnosis and the diagnostic delay, especially in non-paraneoplastic SN. Therefore, our objectives were to characterize the diagnostic odyssey for non-paraneoplastic SN patients, as well as to identify possible associated factors. We consecutively enrolled 48 non-paraneoplastic SN patients followed in a tertiary neuromuscular clinic at the University of Campinas (Brazil). All patients were instructed to retrieve their previous medical records, and we collected the data regarding demographics, disease onset, previous incorrect diagnoses made and the recommended treatments.

RESULTS

There were 34 women, with a mean age at the diagnosis of 45.9 ± 12.2 years, and 28/48 (58%) of the patients were idiopathic. Negative sensory symptoms were the heralding symptoms in 25/48 (52%); these were asymmetric in 36/48 (75%) and followed a chronic course in 35/48 (73%). On average, it took 5.4 ± 5.3 years for SN to be diagnosed; patients had an average of 3.4 ± 1.5 incorrect diagnoses. A disease onset before the age of 40 was associated to shorter diagnosis delay (3.7 ± 3.4 vs. 7.8 ± 6.7 years, p = 0.01).

CONCLUSIONS

These results suggest that diagnostic delay and misdiagnosis are frequent in non-paraneoplastic SN patients. As in other rare conditions, increased awareness in all the healthcare system levels is paramount to ensure accurate diagnosis and to improve care of these patients.

Sensory ataxia rating scale: Development and validation of a functional scale for patients with sensory neuronopathies

Sensory neuronopathies (SN) result from dorsal root ganglia damage and manifest with a combination of sensory deficits and proprioceptive ataxia. Characterization of the natural history and development of therapeutic trials are hampered by the lack of clinical scales that capture the whole spectrum of SN-related manifestations. We propose and validate a rating instrument for SN. Three experienced neuromuscular specialists developed items to rate SN. The resultant instrument was later validated by the assessment of the intra-class correlation coefficient, for inter-rater validity in 48 SN patients, and later in a smaller subset of 16 patients to assess its intra-rater validity. Standardized Crombach's alpha and Oblimin rotation analysis were performed to verify internal consistency and items' relationship, respectively. Evaluation of Sensory Ataxia Rating Scale (SEARS)'s external validity was performed by comparison to: scale for the assessment and rating of ataxia (SARA), Beck balance scale (BBS), and INCAT sensory sum score (ISS). A 10-item scale with an intra-class correlation coefficient >0.95 for intra- and inter-rating measurements with a good internal consistency (standardized Cronbach's alpha of 0.83) were observed. There was a normal distribution of the scores without a floor or ceiling effect. A moderate to good correlation between SEARS and SARA, BBS, and ISS was observed. SEARS is a reliable, easy-to-perform and consistent instrument to rate SN. Larger cohorts and multicenter studies are needed to validate its usefulness towards possible treatment trials.

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.

Peripheral nervous system involvement in systemic lupus erythematosus: Prevalence, clinical and immunological characteristics, treatment and outcome of a large cohort from a single centre

Disorders of peripheral nervous system in patients with systemic lupus erythematosus (PNS-SLE) are a major cause of morbidity. The aims of the present study were to determine the prevalence of PNS-SLE involvement in a large cohort of SLE patients from a single centre, to characterize such involvement, treatment modalities and outcome, and to identify the possible variables that may be associated with its presence. We performed an observational cross-sectional study that included all SLE patients being followed in our department between March and December 2015 who met at least one of the PNS-SLE case definitions proposed in 1999 by the American College of Rheumatology. Overall, 93 out of 524 (17,7%) patients presented with PNS-SLE syndrome; 90 (96.8%) of them were women with a mean age at PNS-SLE syndrome diagnosis was 44.8±14.1years and the average time from diagnosis of SLE to PNS-SLE diagnosis was 88 (range, 541-400) months. The most frequent manifestation was polyneuropathy (36.6%), followed by non-compression mononeuropathy (23.7%), cranial neuropathy and myasthenia gravis (7.5%, each), and Guillain-Barré syndrome (1.1%). The most frequent electrodiagnostic tests (EDX) pattern was axonal degeneration, present in 49 patients that corresponded to 80.3% of the overall EDX patterns. Mixed sensory-motor neuropathy was the most common type of involvement accounted for 56% of cases. Thirty-six out of 90 (40%) received glucocorticoids and/or immunosuppressant agents. Overall, global response (complete and/or partial) to treatments was achieved in 77.4% of patients without differences between the types of PNS-SLE involvement. Older age at SLE diagnosis (37.3±14.8 versus 30.8±12; p=0.001) and absence of hematologic involvement as cumulative SLE manifestation (11.8% versus 21.5%; p=0.034) had independent statistical significant associations with PNS-SLE development. The PNS-SLE involvement is not uncommon. Its most frequent manifestation is sensory-motor axonal polyneuropathy. The involvement occurs more frequently in patients who are diagnosed with SLE at older age. Prospective studies are needed to establish the incidence of PNS-SLE syndromes and the role of hematological manifestations in their development.