The natural history and long-term outcome of 57 limb sarcoidosis neuropathy cases

Neurosurgical Intervention for Nerve and Muscle Biopsies

(1) Background: Neurologic and musculoskeletal diseases represent a considerable portion of the underlying etiologies responsible for the widely prevalent symptoms of pain, weakness, numbness, and paresthesia. Because of the subjective and often nonspecific nature of these symptoms, different diagnostic modalities have been explored and utilized. (2) Methods: Literature review. (3) Results: Nerve and muscle biopsy remains the gold standard for diagnosing many of the responsible neurological and musculoskeletal conditions. However, the need for invasive tissue sampling is diminishing as more investigations explore alternative diagnostic modalities. Because of this, it is important to explore the current role of neurosurgical intervention for nerve and muscle biopsies and its current relevance in the diagnostic landscape of neurological and musculoskeletal disorders. With consideration of the role of nerve and muscle biopsy, it is also important to explore innovations and emerging techniques for conducting these procedures. This review explores the indications and emerging techniques for neurological intervention for nerve and muscle biopsies. (4) Conclusions: The role of neurosurgical intervention for nerve and muscle biopsy remains relevant in diagnosing many neurological and musculoskeletal disorders. Biopsy is especially relevant as a supportive point of evidence for diagnosis in atypical cases. Additionally, emerging techniques have been explored to guide diagnostics and biopsy, conduct less invasive biopsies, and reduce risks of worsening neurologic function and other symptoms secondary to biopsy.

Neurosarcoidosis

Sarcoidosis affects the nervous system in 5% of cases. 60% of cases involve the cranial and peripheral nerves, the remainder the central nervous system, in which a leptomeningitis, a pachymeningitis and a vasculitis may arise. Stroke and cerebral haemorrhage may occur, and certain infections in the brain are more likely with sarcoidosis. Patients respond well to treatment but oftentimes with residual neurological impairments which may be severe. A greater understanding of the disease and the need for early treatment and use of biological therapies have improved treatment outcome in recent times.

Bilateral Lumbosacral Plexopathy As the Initial Manifestation of Systemic Sarcoidosis: A Case Report

Neurosarcoidosis is one of the most relevant involvements in systemic sarcoidosis and can be the initial presentation. Its diagnosis is often considered difficult because of unusual clinical manifestations or diagnostic mimics. The peripheral nervous system is less frequently involved than the central nervous system, although it may also lead to irreversible neurologic impairment. Lumbosacral plexopathy in sarcoidosis is a rare presentation and has been scarcely described in anecdotal case reports and small case series. We describe the case of a 61-year-old female who presented with right inguinal pain, right thigh weakness, and gait limitation, with imaging evidence of bilateral lumbosacral plexopathy as the initial manifestation of systemic sarcoidosis and subsequently developed joint and pulmonary involvement. This case report aims to bring awareness of this involvement as a possible initial manifestation of systemic sarcoidosis and mention key features of the differential diagnosis. Prompt recognition and treatment may prevent neurologic impairment.

Focal inflammatory neuropathies

This chapter focuses on neuropathies that present with focal involvement of nerve roots, plexus, and/or peripheral nerves associated with autoimmune and inflammatory mechanisms that present with focal involvement of nerve roots, plexus and/or peripheral nerves. The clinical presentation, diagnosis, and treatment of focal autoimmune demyelinating neuropathies, focal nonsystemic vasculitic disorders (diabetic and nondiabetic radiculoplexus neuropathies, postsurgical inflammatory neuropathy, and neuralgic amyotrophy), and focal neuropathies associated with sarcoidosis and bacterial and viral infections are reviewed.

Granuloma, vasculitis, and demyelination in sarcoid neuropathy

BACKGROUND

Despite the suggestion that direct compression by granuloma and ischemia resulting from vasculitis can cause nerve fiber damage, the mechanisms underlying sarcoid neuropathy have not yet been fully clarified.

METHODS

We examined the clinicopathological features of sarcoid neuropathy by focusing on electrophysiological and histopathological findings of sural nerve biopsy specimens. We included 18 patients with sarcoid neuropathy who had non-caseating epithelioid cell granuloma in their sural nerve biopsy specimens.

RESULTS

Although electrophysiological findings suggestive of axonal neuropathy were observed, particularly in the lower limbs, all but three patients showed ≥1 abnormalities in nerve conduction velocity or distal motor latency. Additionally, a conduction block was observed in 11 of the 16 patients for whom waveforms were assessed; five of them fulfilled motor nerve conduction criteria strongly supportive of demyelination as defined in the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guideline for chronic inflammatory demyelinating polyneuropathy (CIDP). In most patients, sural nerve biopsy specimens revealed a mild to moderate degree of myelinated fiber loss. Fibrinoid necrosis was observed in one patient, and electron microscopy analysis revealed demyelinated axons close to granulomas in six patients.

CONCLUSIONS

Patients with sarcoid neuropathy may meet the EAN/PNS electrophysiological criteria for CIDP due to the frequent presence of conduction blocks. Based on our results, in addition to the ischemic damage resulting from granulomatous inflammation, demyelination may play an important role in the mechanism underlying sarcoid neuropathy.

Neurosarcoidosis: The Presentation, Diagnosis and Treatment Review of Two Cases

Sarcoidosis is a chronic granulomatous disease of unknown cause characterized by the presence of non-caseating granulomas. The disease can affect any organ including the nervous system. Neurosarcoidosis occurs in about 5% patients with sarcoidosis. The clinical presentation of neurosarcoidosis is varied, and it can involve the brain, spinal cord and peripheral nervous system, separately or in different combinations. The diagnosis of neurosarcoidosis is challenging, as biopsies from the nervous system are not readily available. Anti-TNFα agents are becoming one of the cornerstone treatments for neurosarcoidosis. In this case-based review, we discuss two cases of neurosarcoidosis with different clinical presentations. The first patient presented with confusion, while the second presented with walking difficulty and neurogenic bladder. Both patients were treated with methylprednisolone pulse therapy with rapid, but non-complete, improvement. Therefore, infliximab was initiated in both cases with subsequent improvement in the clinical manifestations and imaging findings, emphasizing the effectiveness and safety of infliximab in cases of severe neurosarcoidosis. In conclusion, the goal of neurosarcoidosis management is to prevent organ system damage and minimize the toxic cumulative adverse effects of glucocorticoid use. In this case-based review we discuss the various presentations, the diagnosis and the treatment of neurosarcoidosis.

Primary perineuritis, a rare but treatable neuropathy: Review of perineurial anatomy, clinicopathological features, and differential diagnosis

The perineurium surrounds each fascicle in peripheral nerves, forming part of the blood-nerve barrier. We describe its normal anatomy and function. "Perineuritis" refers to both a nonspecific histopathological finding and more specific clinicopathological entity, primary perineuritis (PP). Patients with PP are often assumed to have nonsystemic vasculitic neuropathy until nerve biopsy is performed. We systematically reviewed the literature on PP and developed a differential diagnosis for histopathologically defined perineuritis. We searched PubMed, Embase, Scopus, and Web of Science for "perineuritis." We identified 20 cases (11 M/9F) of PP: progressive, unexplained neuropathy with biopsy showing perineuritis without vasculitis or other known predisposing condition. Patients ranged in age from 18 to 75 (mean 53.7) y and had symptoms 2-24 (median 4.5) mo before diagnosis. Neuropathy was usually sensory-motor (15/20), painful (18/19), multifocal (16/20), and distal-predominant (16/17) with legs more affected than arms. Truncal numbness occurred in 6/17; 10/18 had elevated cerebrospinal fluid (CSF) protein. Electromyography (EMG) and nerve conduction studies (NCS) demonstrated primarily axonal changes. Nerve biopsies showed T-cell-predominant inflammation, widening, and fibrosis of perineurium; infiltrates in epineurium in 10/20 and endoneurium in 7/20; and non-uniform axonal degeneration. Six had epithelioid cells. 19/20 received corticosteroids, 8 with additional immunomodulators; 18/19 improved. Two patients did not respond to intravenous immunoglobulin (IVIg). At final follow-up, 13/16 patients had mild and 2/16 moderate disability; 1/16 died. Secondary causes of perineuritis include leprosy, vasculitis, neurosarcoidosis, neuroborreliosis, neurolymphomatosis, toxic oil syndrome, eosinophilia-myalgia syndrome, and rarer conditions. PP appears to be an immune-mediated, corticosteroid-responsive disorder. It mimics nonsystemic vasculitic neuropathy. Cases with epithelioid cells might represent peripheral nervous system (PNS)-restricted forms of sarcoidosis.

Red Flags for Chronic Inflammatory Demyelinating Polyradiculoneuropathy Associated with Sarcoidosis or Connective Tissue Diseases

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system. Diagnosis relies on clinical and electrophysiological criteria. Various disorders requiring specific treatment regimens may be associated with CIDP, including sarcoidosis (SAR-CIDP) and connective tissue disease (CTD-CIDP). Therefore, it is important to distinguish between CIDP, SAR-CIDP and CTD-CIDP. In this retrospective monocentric study, we analyzed 16 patients with SAR-CIDP and 11 with CTD-CIDP and compared them with a group of 17 patients with idiopathic CIDP. SAR-CIDP patients had a frequently acute or subacute CIDP onset. CTD-CIDPs were mostly Sjögren's syndrome and lupus, and patients had a chronic onset. An older age at onset (64.5 vs. 54 years, p = 0.04), more atypical presentation (19/25 (76%) vs. 6/17 (35%), p = 0.008), acute/subacute onset of symptoms (15/25 (60%) vs. 1/17 (6%), p = 0.0004) and more frequent weight loss (7/16 (44%) vs. 0/17 (0%), p = 0.017) were identified SAR-CIDP and CTD-CIDP groups. Response to intravenous immunoglobulin therapy was lower in the combined SAR-CIDP and CTD-CIDP group (44% versus 82%, p = 0.005). As sarcoidosis and CTDs might be associated with CIDP and require specific management, the "red flags" mentioned above should be kept in mind by clinicians managing patients with CIDP.

Immune-mediated diseases involving central and peripheral nervous systems

BACKGROUND AND PURPOSE

In addition to combined central and peripheral demyelination, other immune diseases could involve both the central nervous system (CNS) and peripheral nervous system (PNS).

METHODS

To identify immune-mediated diseases responsible for symptomatic combined central/peripheral nervous system involvement (ICCPs), we conducted a multicentric retrospective study and assessed clinical, electrophysiological, and radiological features of patients fulfilling our ICCP criteria.

RESULTS

Thirty patients (20 males) were included and followed during a median of 79.5 months (interquartile range [IQR] = 43-145). The median age at onset was 51.5 years (IQR = 39-58). Patients were assigned to one of four groups: (i) monophasic disease with concomitant CNS/PNS involvement including anti-GQ1b syndrome (acute polyradiculoneuropathy + rhombencephalitis, n = 2), checkpoint inhibitor-related toxicities (acute polyradiculoneuropathy + encephalitis, n = 3), and anti-glial fibrillary acidic protein astrocytopathy (subacute polyradiculoneuropathy and meningoencephalomyelitis with linear gadolinium enhancements, n = 2); (ii) chronic course with concomitant CNS/PNS involvement including paraneoplastic syndromes (ganglionopathy/peripheral hyperexcitability + limbic encephalitis, n = 4); (iii) chronic course with sequential CNS/PNS involvement including POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome (polyradiculoneuropathy + strokes, n = 2), histiocytosis (polyradiculoneuropathy + lepto-/pachymeningitis, n = 1), and systemic vasculitis (multineuropathy + CNS vasculitis/pachymeningitis, n = 2); and (iv) chronic course with concomitant or sequential CNS/PNS involvement including combined central and peripheral demyelination (polyradiculoneuropathy + CNS demyelinating lesions, n = 10) and connective tissue diseases (ganglionopathy/radiculopathy/multineuropathy + limbic encephalitis/transverse myelitis/stroke, n = 4).

CONCLUSIONS

We diagnosed nine ICCPs. The timing of central and peripheral manifestations and the disease course help determine the underlying immune disease. When antibody against neuroglial antigen is identified, CNS and PNS involvement is systematically concomitant, suggesting a common CNS/PNS antigen and a simultaneous disruption of blood-nerve and blood-brain barriers.

[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).

Neurosarcoidosis: an update on diagnosis and therapy

INTRODUCTION

Clinically overt granulomatous involvement of the nervous system (i.e., neurosarcoidosis) can be seen in up to 10% of patients with sarcoidosis. Establishing a diagnosis of neurosarcoidosis is often challenging due to the heterogeneity of clinical presentations that are sometimes non-specific, and inaccessibility of tissue confirmation. Recommended treatments are based on expert opinions that are derived from clinical experience and limited data from retrospective studies, as data from randomized controlled studies are limited.

AREA COVERED

In this article, we comprehensively review all available literature on epidemiology, clinical presentations, diagnosis, treatment, and outcomes of neurosarcoidosis. We also offer our opinions on diagnostic approach and treatment strategy.

EXPERT OPINION

Given the invasive nature and the limited sensitivity of biopsy of the nervous system, diagnosis of neurosarcoidosis is usually made when ancillary tests (such as magnetic resonance imaging and cerebrospinal fluid analysis) are compatible, and alternative diagnoses are reasonably excluded in patients with established extraneural sarcoidosis. Several factors must be taken into consideration to formulate the initial treatment strategy, including the extent of the disease, severity, functional impairment, comorbidities and patient's preference. In addition, treatment regimen of neurosarcoidosis should be formulated with an emphasis on long-term strategy.

[Acute sarcoid myopathy and neuropathy aggravated by ustekinumab administration in an elderly woman with psoriasis and systemic sarcoidosis]

A 72-year old woman, who had a history of psoriasis and psoriatic arthritis from age of 69, was admitted because of acute progression of dyspnea and generalized muscle weakness after initiation of ustekinumab. She had been diagnosed as having lung and eye sarcoidosis ten months before admission. Nerve conduction studies revealed multiple mononeuropathy and needle electromyography showed myogenic changes with spontaneous activities. Muscle pathology showed non-caseating epithelioid granuloma and high expression of HLA-class I in myofibers. Diagnosis of sarcoid myopathy and neuropathy aggravated by ustekinumab was made, and ustekinumab administration was discontinued, resulting in slight improvement of her respiratory and neuro-muscular symptoms, but her symptoms remained severely disabled. Treatment with oral steroids further improved her clinical symptoms and she became able to walk independently. We considered that ustekinumab inhibited IL-12 and IL-23 signaling, which caused an imbalance in Th1/Th17 differentiation and activation of Th1 cell differentiation, thereby promoting the development of sarcoid myopathy and neuropathy.

Nerve biopsy: Current indications and decision tools

After initial investigation of patients presenting with symptoms suggestive of neuropathy, a clinical decision is made for a minority of patients to undergo further assessment with nerve biopsy. Many nerve biopsies do not demonstrate a definitive pathological diagnosis and there is considerable cost and morbidity associated with the procedure. This highlights the need for appropriate selection of patients, nerves and neuropathology techniques. Additionally, concomitant muscle and skin biopsies may improve the diagnostic yield in some cases. Several advances have been made in diagnostics in recent years, particularly in genomics. The indications for nerve biopsy have consequently changed over time. This review explores the current indications for nerve biopsies and some of the issues surrounding its use. Also included are comments on alternative diagnostic modalities that may help to supplant or reduce the use of nerve biopsy as a diagnostic test. These primarily include extraneural biopsy and neuroimaging techniques such as magnetic resonance neurography and nerve ultrasound. Finally, we propose an algorithm to assist in deciding when to perform nerve biopsies.

Sonographic Nerve Enlargement in a Patient with Sarcoidosis

We herein report a 73-year-old woman case with sarcoid neuropathy showing nerve enlargement assessed by nerve ultrasound both before and after treatment. The site of conduction block in the left tibial nerve corresponded to the site of nerve enlargement with a hypo-echoic pattern. After treatment with prednisolone, nerve ultrasound detected the remission of the nerve enlargement, and the conduction block and clinical symptoms also improved. Nerve enlargement may reflect inflammation of the peripheral nerve. A follow-up study of sonographic nerve enlargement may be of clinical significance for assessing the effectiveness of treatment for sarcoid neuropathy.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.

Peripheral nervous system manifestations of rheumatological diseases

Rheumatological diseases result in immune-mediated injury to not only connective tissue, but often components of the peripheral nervous system. These overlap conditions can be broadly categorized as peripheral neuropathies and overlap myositis. The peripheral neuropathies are distinctive as many have unusual presentations such as non-length-dependent, small fiber neuropathies and sensory neuronopathies (both due to dorsal root ganglia dysfunction), multiple mononeuropathies (e.g. vasculitic neuropathies), and even cranial neuropathies. Overlap myositis is increasingly recognized and is often associated with specific autoantibodies. Sarcoidosis also has widespread neurological manifestations and impacts both the peripheral nerves and muscle. Much work is needed to fully characterize the vast presentations of these overlap diseases. Given the rarity of these disorders, they are understudied, resulting in significant knowledge gaps with regards to their underlying pathophysiology and the best treatment approach. A basic knowledge of these disorders is mandatory for both practicing rheumatologists and neurologists as prompt recognition and early initiation of immunotherapy may prevent significant morbidity and permanent disability.

Chronic Immune-Mediated Polyneuropathies

This article discusses the chronic immune-mediated polyneuropathies, a broad category of acquired polyneuropathies that encompasses chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), the most common immune-mediated neuropathy, the CIDP variants, and the vasculitic neuropathies. Polyneuropathies associated with rheumatological diseases and systemic inflammatory diseases, such as sarcoidosis, will also be briefly covered. These patients' history, examination, serum studies, and electrodiagnostic studies, as well as histopathological findings in the case of vasculitis, confirm the diagnosis and differentiate them from the more common length-dependent polyneuropathies. Prompt identification and initiation of treatment is imperative for these chronic immune-mediated polyneuropathies to prevent disability and even death.

Disorders of the Cauda Equina

PURPOSE OF REVIEW

Cauda equina dysfunction (often referred to as cauda equina syndrome) is caused by a diverse group of disorders that affect the lumbosacral nerve roots. It is important to recognize dysfunction of the cauda equina quickly to minimize diagnostic delay and lasting neurologic symptoms. This article describes cauda equina anatomy and the clinical features, differential diagnosis, and management of cauda equina disorders.

RECENT FINDINGS

The diagnosis of disorders of the cauda equina continues to be a challenge. If a compressive etiology is seen, urgent neurosurgical intervention is recommended. However, many people with clinical features of cauda equina dysfunction will have negative diagnostic studies. If the MRI is negative, it is important to understand the diagnostic evaluation and differential diagnosis so that less common etiologies are not missed.

SUMMARY

Cauda equina dysfunction most often occurs due to lumbosacral disk herniation. Nondiskogenic causes include vascular, infectious, inflammatory, traumatic, and neoplastic etiologies. Urgent evaluation and surgical intervention are recommended in most cases of compressive cauda equina syndrome. Other types of treatment may also be indicated depending on the etiology.

The Burden of Neurosarcoidosis: Essential Approaches to Early Diagnosis and Treatment

Neurosarcoidosis (NS) is an often severe, destructive manifestation with a likely under-reported prevalence of 5 to 15% of sarcoidosis cases, and in its active phase demands timely treatment intervention. Clinical signs and symptoms of NS are variable and wide-ranging, depending on anatomical involvement. Cranial nerve dysfunction, cerebrospinal parenchymal disease, aseptic meningitis, and leptomeningeal disease are the most commonly recognized manifestations. However, non-organ-specific potentially neurologically driven symptoms, such as fatigue, cognitive dysfunction, and small fiber neuropathy, appear frequently.Heterogeneous clinical presentations and absence of any single conclusive test or biomarker render NS, and sarcoidosis itself, a challenging definitive diagnosis. Clinical suspicion of NS warrants a thorough systemic and neurologic evaluation hopefully resulting in supportive extraneural physical exam and/or tissue findings. Treatment targets the severity of the manifestation, with careful discernment of whether NS reflects active potentially reversible inflammatory granulomatous disease versus inactive postinflammatory damage whereby functional impairment is unlikely to be pharmacologically responsive. Non-organ-specific symptoms are poorly understood, challenging in deciphering reversibility and often identified too late to respond to conventional immunosuppressive/pharmacological treatment. Physical therapy, coping strategies, and stress reduction may benefit patients with all disease activity levels of NS.This publication provides an approach to screening, diagnosis, disease activity discernment, and pharmacological as well as nonpharmacological treatment interventions to reduce disability and protect health-related quality of life in NS.

Clinical Spectrum and Outcome of Neurosarcoidosis: A Retrospective Cohort Study from a Teaching Hospital in India

Context:

Neurosarcoidosis (NS) is a chronic disease with a diverse clinical spectrum, therapeutic response, and outcome. There is scarce literature from our country regarding the same.

Aims:

The aim of this study was to evaluate the clinical spectrum, therapeutic responses, and outcomes of NS in an Indian cohort.

Settings and Design:

In a cross-sectional study, we included all patients with NS treated at a quaternary care teaching hospital in India from January 2007 to October 2019.

Subjects and Methods:

Patients older than 18 years of age fulfilling the diagnostic criteria for NS from the Neurosarcoidosis Consortium Consensus Group were included in the study. The therapeutic response and the degree of disability at last follow-up were assessed.

Results:

We identified 48 patients, among them 3 were categorized as having definite NS, 30 probable NS, and 15 possible NS. Cranial neuropathy was the most common presentation (47.9%), followed by myelopathy (25%). Systemic involvement was identified in 95.83% and mediastinal lymph nodes were the most common site. Clinical improvement was seen in 65.8% and disease stabilized in 28.9%, while 5.26% deteriorated. Fifty percent recovered without any residual disability, while 26.3% had minor and 23.7% had major residual sequelae.

Conclusions:

NS is a diverse illness, with a heterogeneous spectrum of clinical presentation, treatment response, and outcome. Cranial neuropathy is the most common presenting feature and has a good prognosis while myelopathy has an unfavorable prognosis. Meningeal and brain parenchymal disease is difficult to diagnose accurately unless systemic involvement is present. The diagnosis of NS should be clinically suspected in the appropriate clinical setting, the presence of systemic involvement should be investigated, and histologic confirmation should be attempted.

Neurosarcoidosis: clinical manifestations, investigation and treatment

Sarcoidosis affects the nervous system in 10% of cases. When it does so it can affect any part of the nervous system and with all degrees of severity. It forms part of the differential diagnosis in inflammatory, infective, neoplastic and degenerative neurological diseases and may be very difficult to diagnose without histological confirmation. Recent clinical studies and the increasing availability of new biological treatments allow a much clearer understanding of the disease. This review summarises its clinical features, imaging and laboratory characteristics, treatment and outcome.

[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.

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.

Immune Axonal Polyneuropathy

PURPOSE OF REVIEW

Immune axonal polyneuropathy is caused by a diverse group of disorders that share similar presentations and treatment regimens. This article focuses on the clinical findings, evaluation, and management of immune-mediated causes of axonal polyneuropathy, focusing primarily on large fiber sensorimotor polyneuropathy.

RECENT FINDINGS

Specific characteristics of an immune-mediated polyneuropathy have been incorporated in a new diagnostic screening tool that is highly sensitive and can easily be used in the outpatient clinic setting. New insights into autoantibodies may help identify the presence of an underlying autoimmune or paraneoplastic disease as the cause of a polyneuropathy.

SUMMARY

This article provides readers with further understanding into the autoimmune causes of axonal polyneuropathy and will help the clinician recognize key clinical features that may lead to timely diagnosis and treatment.

Symptomatic muscular sarcoidosis: Lessons from a nationwide multicenter study

Objectives

To describe clinicopathologic features of muscular sarcoidosis and the associated sarcoidosis phenotype through a nationwide multicenter study.

Methods

Patients were included if they had histologically proven sarcoidosis and symptomatic muscular involvement confirmed by biological, imaging, or histologic examinations.

Results

Forty-eight patients (20 males) were studied, with a median age at muscular symptoms onset of 45 years (range 18–71). Four patterns were identified: a nodular pattern (27%); smoldering phenotype (29%); acute, subacute, or progressive myopathic type (35%); and combined myopathic and neurogenic pattern (10%). In all patterns, sarcoidosis was multivisceral with a median of 3 extramuscular organs involved (mostly lungs, lymph nodes, eyes, and skin) and a prolonged course with long-term use of corticosteroids and immunosuppressive drugs. Muscular patterns differed according to clinical presentation (myalgia, nodules, or weakness), electromyographic findings, muscular MRI, and response to sarcoidosis treatment. The myopathic and neuromuscular patterns were more severe.

Conclusion

This nationwide study of muscular sarcoidosis allowed the identification of 4 patterns of granulomatous myositis, which differed by phenotypes and the clinical course.

Association of Prognostic Factors and Immunosuppressive Treatment With Long-term Outcomes in Neurosarcoidosis

Importance

Prognostic factors are lacking in neurosarcoidosis (NS), and the association of immunosuppressive treatments with outcomes are unclear.

Objectives

To identify prognostic factors of and analyze the association of immunosuppressive treatment with relapse of NS.

Design, Setting, and Participants

In this retrospective study, a cohort of 234 patients fulfilled the diagnostic criteria for NS in a tertiary referral center in Paris, France, from January 1, 1990, through December 31, 2015. The median follow-up was 8 years (range, 2 months to 23 years).

Main Outcomes and Measures

All neurologic and extraneurologic data and treatments were analyzed. Functional outcomes measured by the absolute value and the variation from baseline of the Expanded Disability Status Scale (EDSS) score at 60 months after the diagnosis, overall survival, and relapse-free survival (RFS) were assessed. Analyses were stratified by the period of NS diagnosis (1990-1999 vs 2000-2015).

Results

The 234 patients undergoing assessment included 117 women (50.0%) and 117 men (50.0%); median age was 42 years (interquartile range, 32-53 years). The probable 10-year survival rate was 89% (95% CI, 84%-94%). Older age (hazard ratio [HR] per 10 years, 1.64; 95% CI, 1.19-2.27; P = .003), peripheral nervous system involvement (HR, 6.75; 95% CI, 2.31-19.7; P < .001), and higher baseline EDSS score (HR per point, 1.21; 95% CI, 1.06-1.39; P = .005) were associated with mortality. The estimated 10-year RFS rate was 14% (95% CI, 9%-22%) for all relapses and 28% (95% CI, 20%-38%) for neurologic relapses. Encephalic involvement was associated with shorter neurologic RFS (HR, 2.35; 95% CI, 1.44-3.83; P < .001). A lower risk for relapse was associated with cyclophosphamide (HR, 0.26; 95% CI, 0.11-0.59; P = .001), methotrexate sodium (HR, 0.47; 95% CI, 0.25-0.87; P = .02), and infliximab (HR, 0.16; 95% CI, 0.02-1.24; P = .08) treatments. Follow-up was greater than 60 months in 160 patients (68.4%). An elevated baseline EDSS score (odds ratio [OR] per point, 1.92; 95% CI, 1.55-2.37; P < .001), tobacco use (OR, 3.64; 95% CI, 1.36-9.73; P = .01), encephalic symptoms (OR, 3.04; 95% CI, 1.11-8.38; P = .03), and less than 4 extraneurologic sarcoidosis localizations (OR, 3.06; 95% CI, 1.04-8.98; P = .04) were associated with an EDSS value of at least 2.5 at 60 months. Encephalic involvement (16 of 17 patients [94.1%]; P = .008) and peripheral nervous system involvement (5 of 17 patients [29.4%]; P = .03) were associated with worsening of the EDSS score at 60 months.

Conclusions and Relevance

This study identifies putative factors affecting morbidity and mortality in patients with NS. Immunosuppressive therapies (ie, intravenous cyclophosphamide, methotrexate, and infliximab) in these patients may be associated with lower relapse rates.

Sarcoidosis-associated small fiber neuropathy in a large cohort: Clinical aspects and response to IVIG and anti-TNF alpha treatment

OBJECTIVE

Small fiber neuropathy commonly affects patients with sarcoidosis and is often refractory to standard immunosuppressive therapies used for systemic disease. The clinical features of sarcoidosis-associated small fiber neuropathy (SSFN) and its response to medical therapy have not been described in a large population.

METHODS

We performed a retrospective review of patients with SSFN seen at the Cleveland Clinic over a 4-year period.

RESULTS

SSFN was identified in 143 individuals although other causes of neuropathy were found in 28 cases. Of the remaining 115 patients, 100 (87%) were Caucasian and 72 (63%) were female. Median age at reported neuropathy onset was 46 years (range 19-77 years), while median age of systemic diagnosis was 41 years. Pain and paresthesias were the most common symptoms, of which 54% were nonlength-dependent. Dysautonomia was seen in 61 patients with cardiac symptoms (orthostasis, palpitations) as the most common presentation followed by gastrointestinal and sweating dysfunction. Symptomatic improvement with treatment was seen in 47 of 62 patients that received IVIG, 8 of 12 patients that received anti-TNF and 10 of 14 patients who received combination therapy. Of 27 patients who were untreated, 4 improved.

CONCLUSIONS

The most common presentation of SSFN in our series was a painful non-length dependent polyneuropathy with the highest overall incidence in Caucasian females. In most patients, neuropathy symptoms developed within 3 years of systemic sarcoidosis diagnosis. IVIG appeared beneficial in treating SSFN symptoms while nearly 2/3 of subjects also responded favorably to anti-TNF with or without IVIG. Further prospective studies are needed.

[Neurosarcoidosis: Diagnosis and therapeutic issues]

Neurological localizations of sarcoidosis are heterogeneous and may affect virtually every part of the central or peripheral nervous system. They are often the inaugural manifestation of sarcoidosis. The diagnosis may be difficult due to the lack of extra-neurological localization. Diagnosis may be discussed in the presence of an inflammatory neurological disease, in particular in case of suggestive radiological or biological pattern. Cerebrospinal fluid analysis shows lymphocytic pleiocytosis, often with low glucose level. The diagnosis relies on a clinical, biological and radiological presentation consistent with neurosarcoidosis, the presence of non-caseating granuloma and exclusion of differential diagnoses. Screening for other localizations of sarcoidosis, in particular cardiac disease may be obtained during neurosarcoidosis. The treatment of neurosarcoidosis relies on corticosteroids although immunosuppressive drugs are usually added because of the chronic course of this condition and to limit the side effects of steroids. Treatments and follow-up may be prolonged because of the high rate of relapses.

The devil is in the detail: Acute Guillain-Barré syndrome camouflaged as neurosarcoidosis in a critically ill patient admitted to an Intensive Care Unit

Guillain–Barré syndrome (GBS) is an acute demyelinating polyneuropathy, usually evoked by antecedent infection. Sarcoidosis is a multisystem chronic granulomatous disorder with neurological involvement occurring in a minority. We present a case of a 43-year-old Caucasian man who presented with acute ascending polyradiculoneuropathy with a recent diagnosis of pulmonary sarcoidosis. The absence of acute flaccid paralysis excluded a clinical diagnosis of GBS in the first instance. Subsequently, a rapid onset of proximal weakness with multi-organ failure led to the diagnosis of GBS, which necessitated intravenous immunoglobulin and plasmapheresis to which the patient responded adequately, and he was subsequently discharged home. Neurosarcoidosis often masquerades as other disorders, leading to a diagnostic dilemma; also, the occurrence of a GBS-like clinical phenotype secondary to neurosarcoidosis may make diagnosing coexisting GBS a therapeutic challenge. This article not only serves to exemplify the rare association of neurosarcoidosis with GBS but also highlights the need for a high index of clinical suspicion for GBS and accurate history taking in any patient who may present with rapidly progressing weakness to an Intensive Care Unit.

[Neurologic manifestations of sarcoidosis: A study of 18 cases]

INTRODUCTION

Sarcoidosis is a multisystemic granulomatous disease of unknown aetiology. Neurologic manifestations are found in 5 to 10% of cases.

PATIENTS AND METHODS

We conducted a retrospective study over 6-year period including 18 patients diagnosed with neurosarcoidosis in the Neurologic department of the Military Hospital of Instruction of Tunis. Clinical, radiological, therapeutic features and outcome were studied.

RESULTS

The mean age was 43.44 years. Neurologic signs were the first symptom in 10 cases. Peripheral nervous system impairment was often found. Meningitis was noted in 8 cases. Biological tests are not contributive for the diagnosis. The brain magnetic resonance imaging was pathologic in 10 cases. Corticosteroids were administrated in the majority of cases. Eight patients did not show any sign of improvement. Ten cases improved with treatment.

DISCUSSION AND CONCLUSION

Diagnosis of neurosarcoidosis is difficult because of its clinical and radiological polymorphism. It is based on a clinical history suggestive of neurosarcoidosis, laboratory, imaging and histological studies.

Neurosarcoidosis

Neurosarcoidosis is known as the great mimicker and may appear similar to lymphoma, multiple sclerosis, and other diseases affecting the nervous system. Although definitive diagnosis requires histologic confirmation of the affected neural tissue, characteristic clinical manifestations, gadolinium-enhanced MRI patterns and specific cerebrospinal fluid findings can help support the diagnosis in the absence of neural biopsy. An understanding of the common clinical presentations and diagnostic findings is central to the evaluation and management of neurosarcoidosis.

Lumbosacral plexopathy

PURPOSE OF REVIEW

This article provides an up-to-date review of the clinical features and pathogenesis of different types of lumbosacral plexopathy and a clinical approach to their evaluation and management. Often, the pathologic involvement is not limited to the plexus and also involves the root and nerve levels. These conditions are called lumbosacral radiculoplexus neuropathies.

RECENT FINDINGS

The pathophysiology of diabetic and nondiabetic lumbosacral radiculoplexus neuropathy has been elucidated; it is ischemic injury due to a perivascular inflammatory process and microvasculitis. The clinical and neurophysiologic features of these two entities have been found to be similar, consisting of acute or subacute onset of pain and paresthesia followed by profound motor weakness asymmetrically involving the lower limbs and associated with weight loss. A lower limb and motor predominant neuropathy without pain also occurs in diabetes mellitus and has been shown to be a form of diabetic lumbosacral radiculoplexus neuropathy and not diabetic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The pathophysiology of some cases of postsurgical lumbosacral plexopathies has recently been shown also to be inflammatory from microvasculitis, and treatment with immunotherapy in a timely fashion may be desirable.

SUMMARY

Many pathophysiologic processes, such as neoplastic, traumatic, infectious, radiation, and inflammatory/microvasculitic processes, can affect the lumbosacral plexus causing lumbosacral plexopathy. The clinical symptoms and signs depend on the part of the plexus involved and the temporal course. Management depends on the cause of the lumbosacral plexopathy. Many cases of lumbosacral plexopathy previously thought to be idiopathic have been shown to be caused by ischemic injury from microvasculitis; despite lack of evidence for efficacy in improving neurologic deficits, the authors of this article include immunotherapy in their management of patients with this condition.

Acquired immune axonal neuropathies

PURPOSE OF REVIEW

This article discusses the clinical features, pathophysiology, and management of primary and secondary acquired immune axonal neuropathies.

RECENT FINDINGS

Although there are many collagen vascular disorders associated with vasculitic neuropathy, a quarter of cases have been described to be due to nonsystemic vasculitis of the peripheral nervous system. Enhanced surveillance and aggressive treatment of conditions such as cryoglobulin-related vasculitic neuropathy with cyclophosphamide, rituximab, and alfa interferons has led to improved morbidity and mortality, however, many cases of immune axonal acquired neuropathy are still associated with poor outcomes. Acute motor axonal neuropathy (AMAN) and acute motor sensory axonal neuropathy (AMSAN) are well-characterized variants of Guillain-Barré syndrome.

SUMMARY

Characterizing the clinical and electrophysiologic phenotype can help diagnose conditions such as nonsystemic vasculitic neuropathy, AMAN, AMSAN, and immune small fiber neuropathy, while careful evaluation of systemic features is key to identifying secondary immune axonal neuropathies such as vasculitic neuropathy related to collagen vascular disease. Additional research is needed to determine the exact immune pathogenesis and optimized treatment regimens for all acquired immune axonal neuropathies.

Neurosarcoidosis

PURPOSE OF REVIEW

This article provides an update on the evaluation and treatment of neurosarcoidosis.

RECENT FINDINGS

The broad range of clinical manifestations of neurosarcoidosis has recently expanded to include painful small fiber neuropathy. Although definitive diagnosis remains a challenge, fluorodeoxyglucose positron emission tomographic (FDG-PET) scan and high-resolution CT allow for improved detection of systemic sarcoidosis. In addition, endobronchial ultrasound-guided transbronchial needle aspiration provides a less invasive means of tissue confirmation of systemic sarcoidosis than mediastinoscopy. Although not standardized, treatment strategies for neurosarcoidosis now commonly include tumor necrosis factor-α antagonists in combination with corticosteroids and other cytotoxic agents for patients with severe disease.

SUMMARY

Advances in the diagnosis and management of neurosarcoidosis may benefit the patient and clinician faced with this multifaceted disease.

Effectiveness of pregabalin as monotherapy or combination therapy for neuropathic pain in patients unresponsive to previous treatments in a Spanish primary care setting

Background and Objective

Patients from a previous study of neuropathic pain (NP) in the Spanish primary care setting still had symptoms despite treatment. Subsequently, patients were treated as prescribed by their physician and followed up for 3 months. Since pregabalin has been shown to be effective in NP, including refractory cases, the objective of this study was to assess the effectiveness of pregabalin therapy in patients with NP refractory to previous treatments.

Methods

This was a post hoc analysis of pregabalin-naïve NP patients treated with pregabalin in a 3-month follow-up observational multicenter study to assess symptoms and satisfaction with treatment. Patients were evaluated with the Douleur Neuropathique en 4 questions (DN4), the Brief Pain Inventory (BPI) and the Treatment Satisfaction for Medication Questionnaire (SATMED-Q) overall satisfaction domain.

Results

1,670 patients (mean age 58 years, 59 % women), previously untreated or treated with ≥1 drug other than pregabalin, were treated with pregabalin (37 % on monotherapy). At 3 months, pain intensity and its interference with activities decreased by half (p < 0.0001), while the number of days with no or mild pain increased by a mean of 4.5 days (p < 0.0001). Treatment satisfaction increased twofold (p < 0.0001). Patients with a shorter history of pain and those with neuralgia and peripheral nerve compression syndrome (PCS) as etiologies had the highest proportion on monotherapy and showed the greatest improvements in pain-related parameters in their respective group categories.

Conclusion

Treatment with pregabalin (as monotherapy or combination therapy) provides benefits in pain and treatment satisfaction in patients with NP, including refractory cases. Shorter disease progression and neuralgia and PCS etiologies are favorable factors for pregabalin treatment response.

Neurosarcoidosis: clinical review of a disorder with challenging inpatient presentations and diagnostic considerations

Neurosarcoidosis is frequently on the differential diagnosis for neurohospitalists. The diagnosis can be challenging due to the wide variety of clinical presentations as well as the limitations of noninvasive diagnostic testing. This article briefly touches on systemic features that may herald suspicion of this disorder and then expands in depth on the neurological clinical presentations. Common patterns of neurological presentations are reviewed and unusual presentations are also included. A discussion of noninvasive testing is undertaken, exploring dilemmas that may be encountered with sensitivity and specificity. Drawing from a broad range of clinical clues and diagnostic data, a systematic approach of pursuing a potential tissue diagnosis is then highlighted. Correctly diagnosing neurosarcoidosis is critical, as treatment with appropriate immunosuppression protocols can then be initiated. Additionally, treatment of refractory disease, the trend toward exploring targeted immunomodulation options, and other therapeutic issues are discussed.