Peripheral Nerve Vasculitis

Ways to think about vasculitic neuropathy

PURPOSE OF REVIEW

Vasculitis as a pathomechanism for neuropathy can be isolated to the peripheral nervous system, a part of a systemic autoimmune condition or a component of another syndrome. This review aims to discuss the broad range of diagnoses in which vasculitic neuropathy can be encountered, highlight the progress in imaging techniques in identifying vasculitis, and the new drugs developed for other autoimmune diseases that may be applied to neurological conditions.

RECENT FINDINGS

Advances in imaging modalities, ultrasound, MRI and FDG-PET scanning for neuromuscular applications has redefined many aspects of vasculitic neuropathies. The benefit of dividing vasculitides by vessel size is becoming less absolute as diagnostic approaches advance. MRI and FDG-PET are widely used in diagnosis, defining extent of involvement of disease and monitoring. In neuralgic amyotrophy, the identification of hourglass-like constrictions on imaging has changed the treatment paradigm to include surgical interventions. These diagnostic approaches are supported by new immunomodulating and immunosuppression techniques.

SUMMARY

Vasculitic neuropathies are a broad group of conditions with a range of causes and associations. Increased use of imaging techniques impacts our traditional definitions and classifications. The growth in treatment options for other autoimmune conditions are likely to infiltrate the neurological landscape.

A great simulator in clinical practice: mononeuritis multiplex in HIV infection

HIV infection is a chameleon, mimicking several diseases. Herein, we report a previously healthy 39-year-old woman who, over 2 months, developed arthritis, weight loss, and confluent multiple mononeuropathy. Extensive laboratory investigation showed positive serology for HIV, with a CD4 count of 100 cells, and necrotizing vasculitis on a nerve biopsy not associated with CMV co-infection, allowing the diagnosis of polyarteritis nodosa-like vasculitis in an HIV-infected patient. Apart from the infection, HIV-related autoimmunity can affect any organ and contribute to the complexity of the clinical presentation of HIV infection.

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.

A, Feinstein D, Traisak P, Eid H, Karpoff M. An Unusual Case of Peripheral Nerve Vasculitis

Peripheral neuropathy is a common manifestation of systemic vasculitis. The etiology of vasculitic peripheral neuropathy is generally classified into two groups: systemic and nonsystemic. In systemic vasculitic neuropathy (SVN), neuropathy is a consequence of a systemic disease, most commonly involving medium and small vessels throughout the body. There are three main clinical presentations: multifocal neuropathy, distal symmetric polyneuropathy, and overlapping multifocal neuropathy. Specifically, distal symmetric polyneuropathy affects multiple somatic nerves diffusely in a symmetric and length-dependent pattern (also known as the classic stocking-glove pattern). This case represents an atypical presentation of SVN, presenting with widespread symmetric polyneuropathy.A 73-year-old woman presented with distal acute on chronic bilateral upper and lower extremity weakness, sensory changes, and widespread pain. Symptoms started about three months prior and gradually worsened with progressive difficulty with ambulation and required assistive devices. Elevated ESR is at 70 mm/hour, CRP at 25.66 mg/dL, elevated c-ANCA titers at 1 : 320 and PR3 at 5.0 AI, and elevated creatine kinase (CK) at 500-600 U/L. A muscle biopsy of the left vastus showed neurogenic atrophy without myositis. Initial improvement was with oral prednisone, but was stopped on discharge. Many purpuric and petechial lesions were developed on distal legs/feet and right fourth digit distal gangrene. EMG showed distal, symmetric, and axonal polyneuropathy affecting the upper and lower extremities and acute denervation in more distal muscles. The patient received pulse dose steroids and two doses of rituximab induction therapy and was discharged with an oral steroid taper. The patient's symptoms started as distal symmetric neuropathy at the onset and progressively worsened over the course of 3 months. Neuropathy, both on the exam and on EMG, seemed to have developed more rapidly than expected, regardless of its distribution. The EMG showed severe peripheral nerve damage and denervation, which is unusual for ANCA-associated systemic vasculitis.

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.

Small fiber neuropathy associated with ANCA positivity: a case series and brief literature review

INTRODUCTION

Small fiber neuropathy [SFN] is a common peripheral neurologic disorder with a vast array of implicated etiologies. It has previously been proposed that some forms of immune-mediated small fiber neuropathy are driven by vasculitis, though antinuclear cytoplasmic antibodies [ANCA] antibodies have not commonly been reported in association with SFN, thus far. We present this case series to discuss the observation of a possible novel association between ANCA and SFN.

METHODS

This is a retrospective case series of 6 patients with SFN and ANCA positivity, with and without systemic manifestations. Patients included were diagnosed with SFN by skin biopsy or autonomic function testing and were seropositive for ANCA by ELISA.

RESULTS

Six patients are outlined, including 4 females and 2 males. Antigen specific antibodies were MPO alone in 4 cases, PR3 alone in 1 case and both MPO and PR3 in 1 case. Systemic vasculitis was noted in 2 patients. Five patients received immunosuppression. Three patients experienced partial improvement, while symptoms stabilized in 3 patients.

DISCUSSION

This is the first series of patients with suspected immune-mediated SFN and ANCA antibody positivity, raising the possibility of ANCA mediated isolated SFN. This is in contradistinction to the more typical ANCA-mediated peripheral neuropathy manifestations of mononeuropathy multiplex or axonal sensorimotor neuropathy. We cannot unequivocally prove ANCA-associated vasculitis [AAV] causality in these cases; however, the stabilization in SFN symptomatology and associated improvement in ANCA antibody titer, after AAV treatment, may be indicative of an association.

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.

Central and Peripheral Nervous System Complications of Vasculitis Syndromes from Pathology to Bedside: Part 2-Peripheral Nervous System

PURPOSE OF REVIEW

Peripheral nervous system vasculitides (PNSV) are a heterogeneous group of disorders with a clinical subset that may differ in prognosis and therapy. We provide a comprehensive update on the clinical assessment, diagnosis, complications, treatment, and follow-up of PNSV.

RECENT FINDINGS

Progress in neuroimaging, molecular testing, and peripheral nerve biopsy has improved clinical assessment and decision-making of PNSV, also providing novel insights on how to prevent misdiagnosis and increase diagnostic certainty. Advances in imaging techniques, allowing to clearly display the vessel walls, have also enhanced the possibility to differentiate inflammatory from non-inflammatory vascular lesions, while recent histopathology data have identified the main morphological criteria for more accurate diagnosis and differential diagnoses. Overall, the identification of peculiar morphological findings tends to improve diagnostic accuracy by defining a clearer boundary between systemic and non-systemic neuropathies. Therefore, the definition of epineurium vessel wall damage, type of vascular lesion, characterization of lymphocyte populations, antibodies, and inflammatory factors, as well as the identification of direct nerve damage or degeneration, are the common goals for pathologists and clinicians, who will both benefit for data integration and findings translation. Nevertheless, to date, treatment is still largely empiric and, in some cases, unsatisfactory, thus often precluding precise prognostic prediction. In this context, new diagnostic techniques and multidisciplinary management will be essential in the proper diagnosis and prompt management of PNSV, as highlighted in the present review. Thirty to fifty percent of all patients with vasculitis have signs of polyneuropathy. Neuropathies associated with systemic vasculitis are best managed according to the guidelines of the underlying disease because appropriate workup and initiation of treatment can reduce morbidity. Steroids, or in severe or progressive cases, cyclophosphamide pulse therapy is the standard therapy in non-systemic vasculitic neuropathies. Some patients need long-term immunosuppression. The use of novel technologies for high-throughput genotyping will permit to determine the genetic influence of related phenotypes in patients with PNSV.

[Nerve biopsy in the diagnosis of peripheral neuropathies]

The indications for nerve biopsy have diminished in recent years. This examination nevertheless remains essential in certain cases of peripheral neuropathies, making it possible to specify the diagnosis or the mechanism of injury for a therapeutic purpose. It is a simple but "invasive" procedure, which can only be performed once on the same nerve. The indications are thus discussed on a case-by-case basis and based on a range of clinical, electrophysiological, biological or even genetic arguments. This involves close collaboration between clinical physicians and pathologists. The main difficulty of this biopsy concerns the fragility of the sample and the techniques necessary for its interpretation, requiring it to be carried out in expert centers. Nerve biopsy is closely related to skin biopsy in the search for small fiber neuropathy. It is a particular technique, but very well codified. The purpose of this review is to recall the indications and contraindications of nerve biopsy, and to explain what the contributions are but also the limits of this examination as well as of skin biopsy.

Adult and childhood vasculitis

Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated, vasculitis of the nervous system leads to pervasive injury and disability, making this a disorder of paramount importance to all clinicians. There has been remarkable progress in the pathogenesis, diagnosis, and treatment of primary CNS and PNS vasculitides, predicated on achievement in primary systemic forms. Primary neurological vasculitides can be diagnosed with assurance after intensive evaluation that incudes tissue confirmation whenever possible. Clinicians must choose from among the available immune modulating, suppressive, and targeted immunotherapies to induce and maintain remission status and prevent relapse, unfortunately without the benefit of RCTs, and tempered by the recognition of anticipated medication side effects. It may be said that efforts to define a disease are attempts to understand the very concept of the disease. This has been especially evident in systemic and neurological disorders associated with vasculitis. For the past 100 years, since the first description of granulomatous angiitis of the brain, the CNS vasculitides have captured the attention of generations of clinical investigators around the globe to reach a better understanding of vasculitides involving the central and peripheral nervous system. Since that time it has become increasingly evident that this will necessitate an international collaborative effort.

The role of sural nerve biopsy in diagnosis of vasculitis

OBJECTIVE

The diagnostic yield of sural nerve biopsy (SNB) in vasculitis is uncertain. Our aim was to document relevant characteristics of patients undergoing sural nerve biopsy in the investigation of vasculitis; determine the diagnostic yield; relate positive biopsy findings to patient demographic, laboratory, and clinical parameters; and to calculate the rate of surgical complications.

METHODS

Patients with suspected vasculitis that underwent SNB as part of diagnostic evaluation at academic medical centres in Sweden and the United Kingdom were identified by searching local pathology databases and clinic registers. A structured review of medical case records and pathology reports was conducted. Histological findings were categorized as definite, probable, or no vasculitis in accordance with the 2015 Brighton Collaboration reinterpretation and update of the Peripheral Nerve Society Guidelines for Vasculitic Neuropathy. Definite and probable findings were considered positive for vasculitis.

RESULTS

Ninety-one patients that underwent SNB were identified (45% female). Forty (44%) showed histological evidence of vasculitis: 14 definite and 26 probable. A concomitant muscle biopsy conducted in 10 patients did not contribute to the diagnostic yield. Positive antineutrophil cytoplasmic antibody test, organ involvement other than the nervous system, and a longer biopsy sample were associated with a positive biopsy. The reported surgical complication rate was 15%.

CONCLUSION

Sural nerve biopsy of sufficient length is an expedient procedure to confirm a diagnosis of vasculitis.

Central and Peripheral Nervous System Complications of Vasculitis Syndromes From Pathology to Bedside: Part 1-Central Nervous System

PURPOSE OF REVIEW

The aim of this review is to provide a comprehensive update on the clinical assessment, diagnosis, complications, and treatment of primary central nervous system vasculitis (PCNSV).

RECENT FINDINGS

The developments in neuroimaging, molecular testing, and cerebral biopsy have enhanced clinical assessment and decision making, providing novel insights to prevent misdiagnosis increasing diagnostic certainty. Advances in imaging techniques visualizing the wall of intracranial vessels have improved the possibility to distinguish inflammatory from non-inflammatory vascular lesions. Large recent studies have revealed a more varied histopathological pictures and disclosed an association with amyloid angiopathy. Unfortunately, therapy remains largely empiric. PCNSV is a heterogeneous group of disorders encompassing different clinical subsets that may differ in terms of prognosis and therapy. Recent evidence has described a more benign course, with good response to therapy. New diagnostic techniques will play soon a pivotal role in the appropriate diagnosis and prompt management of PCNSV.

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.

Inpatient Diagnosis and Management of Neuromuscular Disorders

Although many neuromuscular conditions are evaluated on an outpatient basis owing to their chronic or progressive nature, more urgent evaluation and management is often required for the inpatient presenting with acute to subacute focal or generalized numbness or weakness. This review focuses on clinical pattern recognition and basic anatomic localization principles to aid in the identification of common, as well as some less frequently encountered, neuromuscular disorders in hospitalized patients. The characteristic clinical and diagnostic features, associated complications, and recommended treatments of key neuromuscular conditions with acute and subacute manifestations are discussed. These conditions can be life-threatening in some cases, such as in Guillain-Barré syndrome, owing to associated oropharyngeal weakness, respiratory failure, or marked dysautonomia. Prompt recognition of the clinical and pathologic features is therefore necessary to reduce associated morbidity and mortality.

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.

A Structured Approach to the Diagnosis of Peripheral Nervous System Disorders

PURPOSE OF REVIEW

Neuroanatomic localization and pattern recognition can be used to diagnose both focal lesions and generalized disorders of the peripheral nervous system. This article describes the nature and pattern of sensory and motor deficits associated with lesions of specific spinal nerve roots, plexus, or peripheral nerves. It also describes the patterns of sensory and motor deficits that suggest multifocal or generalized disorders of the motor neurons, sensory neurons, and peripheral nerves.

RECENT FINDINGS

The pattern of sensory and motor deficits may be used to distinguish lesions of the peripheral nervous system from those of the central nervous system. The spinal roots, nerve plexus, and peripheral nerves supply specific muscles and receive sensory input from distinctive cutaneous regions. Focal lesions of these structures therefore produce characteristic patterns of sensory and motor deficits. Multifocal or generalized disorders of the peripheral nervous system may be distinguished by categorizing their sensory and motor involvement, proximal and distal predominance, and degree of symmetry. Serum tests, CSF analysis, electrodiagnostic studies, MRI, ultrasound, nerve biopsy, and skin biopsy have unique roles in the diagnosis of suspected neuromuscular disorders.

SUMMARY

A structured approach to the diagnosis of nerve and motor neuron disorders can lead to hypothesis-driven diagnostic testing. Ancillary tests should be reserved for cases in which confirming or refuting a diagnosis will change patient management.

The prevalence of anti-neurofascin-155 antibodies in patients with neuromyelitis optica spectrum disorders

Anti-neurofascin-155 (NF155) antibodies have been observed in two cases with neuromyelitis optica spectrum disorders (NMOSD). This study investigated the prevalence of anti-NF155 antibodies in patients with NMOSD and the clinical features of anti-NF155 antibody-positive patients. Sera from 129 patients with NMOSD were screened with anti-NF155 antibodies by cell-based assay (CBA) and re-examined using immunostaining of teased mouse sciatic nerve fibres. Fifty-six patients with multiple sclerosis (MS) and 50 healthy controls (HC) were also enrolled for detecting anti-NF155 antibodies. A total of 12.40% (16 of 129) of patients with NMOSD were positive for anti-NF155 antibodies confirmed by both CBA and immunostaining. Immunoglobulin (Ig) G1 was the predominant subclass. However, none of 56 MS patients or 50 HC were positive for anti-NF155 antibodies. Anti-NF155 antibody-positive NMOSD patients had a higher proportion of co-existing with autoimmune diseases (p < 0.001) and higher positive rates of serum non-organ-specific autoantibodies, including anti-SSA antibodies (p < 0.001), anti-SSB antibodies (p = 0.008), anti-Ro-52 antibodies (p < 0.001) and rheumatoid factor (p < 0.001). Five anti-NF155 antibody-positive NMOSD patients who took part in the nerve conduction study showed mildly abnormal results. Differences in some nerve conduction study parameters were observed between anti-NF155 antibody-positive and negative patients. Anti-NF155 antibodies occurred in a small proportion of NMOSD patients. Anti-NF155 antibody-positive NMOSD patients tended to co-exist with autoimmune diseases.

Treatable, motor-sensory, axonal neuropathies with C5b-9 complement on endoneurial microvessels

INTRODUCTION

Identification and treatment of immune-mediated polyneuropathies may lead to improved strength and function. We studied the clinical and laboratory features, and treatment response, in patients with motor-sensory axonal polyneuropathies who were found to have C5b-9 complement staining on endoneurial microvessels.

METHODS

Retrospective review of 16 consecutive adults with motor-sensory axonal polyneuropathies who were then found to have C5b-9 staining of endoneurial microvessels on nerve biopsy, and subsequently treated with intravenous corticosteroids (1 g methylprednisolone for 5 consecutive days, and then weekly). Strength measurements were done using quantitative handheld dynamometry. Nerve biopsy analysis included frozen and fixed tissue.

RESULTS

Patients (mean onset age, 59 ± 4 years; range, 34-83 years; 12 of 16 were males; 9 of 16 had diabetes) had progressive (median duration, 2 years), asymmetric, distal weakness, in the lower extremities (16 of 16) and/or upper extremities (7 of 16), and panmodal sensory loss. Electrodiagnostic studies showed axon loss. Nerve pathology showed abnormal C5b-9 staining on endoneurial microvessels. Axon loss was present in all nerves, often varied among fascicles. Inflammation was uncommon. Distal strength usually improved (mean improvement of 34 ± 6% of normal strength; P = .0003) with corticosteroid treatment.

DISCUSSION

Motor-sensory axonal polyneuropathies having noninflammatory, humoral immune pathology with C5b-9 staining of endoneurial microvessels (HIEM) frequently manifest progressive asymmetric, distal, lower extremity with or without upper extremity weakness that improves rapidly during corticosteroid treatment. HIEM may represent a new class of noninflammatory-vasculopathic, treatable axonal motor-sensory neuropathies.

What Every Neuropathologist Needs to Know: Peripheral Nerve Biopsy

Peripheral neuropathy is a common disorder with many possible etiologies including metabolic diseases, inflammatory conditions, infections, malignancy, inherited diseases, drugs, and toxins. In most instances, diagnosis and treatment plan can be established based on clinical presentation, family history, laboratory results, genetic testing, and electrophysiological studies. But in some situations, a peripheral nerve biopsy remains a valuable tool. This is especially true in patients with rapidly progressive disease, with atypical presentation or for whom other approaches fail to yield a definitive diagnosis. The pathologic examination starts with basic decisions about specimen triage. A few basic questions help to provide an initial framework for the assessment of a nerve biopsy-is the specimen adequate; are there inflammatory changes; are there vascular changes; is there amyloid; are there changes to axonal density and the Schwann cell-myelin-axon unit. In the appropriate context and with such an approach peripheral nerve biopsies can still represent a clinically helpful test.

Immune-Mediated Neuropathies

The immune-mediated neuropathies are a broad category of diseases differentiated by time course, affected nerve fibers, and disease associations. This article spans the common, well-defined inflammatory demyelinating polyradiculoneuropathies (Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy) to the rarer, acquired demyelinating neuropathy variants (Miller-Fisher syndrome and multifocal motor neuropathy), vasculitic neuropathies, and sensory neuronopathies (dorsal root ganglionopathies). These case studies illustrate the characteristic clinical patterns of the immune-mediated neuropathies encountered in neurologic practice. Recommendations for diagnostic evaluation and treatment approach accompany each case. Prompt recognition of these disorders is imperative; delays in treatment may result in prolonged morbidity and permanent disability.

Vasculitis with a neuromuscular presentation and associated cancer revealed by autopsy

Peripheral neuropathy is common, but rarely due to vasculitis. This report is the case of a 74-year-old woman with systemic vasculitis who presented with progressive arm and leg weakness associated with numbness. Autopsy revealed a colon cancer, which may have triggered the vasculitis. This case illustrates the association between vasculitis and malignancy. The best treatment of vasculitis in patients with cancer-associated vasculitis is usually treatment of the cancer, which often yields remission of the vasculitis. This case also illustrates the difficulty of suspecting vasculitis since the symptoms and signs are nonspecific and protean. It is important not to miss a diagnosis of vasculitis. It is often life-threatening. It is treatable. The critical step in the diagnosis of vasculitis is to think of it.

[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.

Cognitive deficits in vasculitis of the nervous system: a cross-sectional study

Objectives: To identify the cognitive and functional deficits in a well-characterized group of patients with vasculitis of the nervous system. Methods: Sixty-seven patients diagnosed with Central Nervous System (CNS) or Peripheral nervous System (PNS) vasculitis over a 14-year period were retrospectively identified. Data on clinical presentation, laboratory, radiographic and tissue biopsy investigations, and treatment were collated. Cognitive, functional and quality of life evaluation assessments were performed in 31 patients who agreed to participate and included Addenbrooke's Cognitive Examination-revised (ACE-R), Nottingham Extended Activities of Daily Living (NEADL) and EQ-5D-3L quality of life questionnaires. Results: CNS vasculitis patients exhibited cognitive impairment, with a mean ACE-R score of 74/100 (standard deviation (SD) 16). NEADL and EQ-5D-3L scores were in the impaired range at 41/66 (SD 21) and 57/81 (SD 22), respectively. Patients with just PNS vasculitis exhibited fewer cognitive deficits with ACE-R and NEADL scores of 87 (SD 8) and 46 (SD 16) respectively. EQ-5D-3L score was in the impaired range of 65 (SD 22). Conclusions: Vasculitis of the nervous system and, in particular, CNS vasculitis causes cognitive impairment and deficits in functional ability. Such patients should be targeted for cognitive rehabilitation.