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Introduction/Aims Methods Results Discussion In vasculitic neuropathy (VN), it is not known whether nerve conduction studies (NCSs) showing low amplitude sensory nerve action potentials (SNAPs) or those with absent responses have a higher yield in detecting appropriate nerves for pathological confirmation. Our goal was to describe NCS findings of nerves prior to biopsy in patients with VN.We performed a retrospective study between January 2000 and April 2021 in patients with VN who either met pathological definite criteria for VN or criteria for clinically probable VN and had NCS of the sural or superficial radial sensory nerves prior to biopsy of the same nerve.We included 61 patients with VN. The pathological findings showed 37 (60.7%) definite, 14 (23%) probable, and 2 (3.3%) possible VN; eight (13%) samples did not meet Peripheral Nerve Society pathological criteria. Most patients who met definite (20 out of 37, 54%) and probable (9 out of 14, 64%) VN pathological criteria had absent SNAPs. Only three out of eight (37.5%) patients without VN pathological findings had absent SNAPs. There was no statistically significant correlation between pathological diagnosis and SNAP amplitude (χ2 = 1.98, p = .58). Additionally, no association was found between VN pathological criteria and use of immunomodulatory treatment (p = .67) or corticosteroids (p = .52).Most nerves with pathological VN findings showed no response on NCS. In patients with suspected VN, sural or superficial radial sensory nerves with absent responses on NCS are adequate biopsy targets as compared to nerves in which SNAPs can be recorded. [ABSTRACT FROM AUTHOR]

Objectives To assess self-reported symptoms of neuropathy, disability, pain, health-related quality of life (HR-QOL) and autonomic dysfunction in patients with vasculitis. Methods Patients with vasculitis (with or without neuropathy) were invited by Vasculitis UK to complete an anonymous online survey. Results Three hundred and twelve patients (71% female) responded. Median age was 61–70 years. Median duration of vasculitis was 4 years (<2 months to >15 years). Vasculitic types included granulomatosis with polyangiitis (34%), unspecified ANCA-associated vasculitis (13%), microscopic polyangiitis (11%), eosinophilic granulomatosis with polyangiitis (11%), giant cell arteritis (10%), non-systemic vasculitic neuropathy (2%) and other (19%). Many patients reported foot/hand symptoms suggestive of neuropathy, including numbness (64%), pain (54%) or weakness (40%). Two hundred and forty-two patients (78%) met our definition of probable vasculitic neuropathy: diagnosis of neuropathy by vasculitis team OR numbness OR weakness in feet/hands. Only 52% had been formally diagnosed with neuropathy. Compared with 70 patients without neuropathy, neuropathy patients had greater disability measured by the inflammatory Rasch-built Overall Disability Scale (centile mean 63.1 [ s. d. 17.3] vs 75.2 [16.7]; P  < 0.0001), Inflammatory Neuropathy Cause and Treatment scale (median 2 [interquartile range 1–4] vs 0.5 [0–2]; P  < 0.0001) and modified Rankin scale (median 2 [interquartile range 1–3] vs 2 [1–2)]; P  = 0.0002); greater pain on an 11-point rating scale (mean 4.6 [ s. d. 2.6] vs 3.5 [2.8]; P  = 0.0009); and poorer HR-QOL on the EQ5D-3L (summary index mean 0.58 [ s. d. 0.29] vs 0.69 [0.28]; P  < 0.0001). Two-thirds reported autonomic symptoms (not associated with neuropathy). Conclusion Neuropathy is common and associated with significant disability, pain and impaired HR-QOL in patients with systemic vasculitis. [ABSTRACT FROM AUTHOR]

Anti-synthetase syndrome (AS) is a subset of idiopathic inflammatory myopathy (IIM) characterized by the presence of anti-aminoacyl-transfer RNA synthetase accompanied by myositis, interstitial lung disease and other clinical features. According to a recent multicentric study, 31% of AS patients present skin lesions compatible with dermatomyositis, but sclerodermiform features are rare. Therefore, we aimed to report the case of a patient with simultaneous diagnosis of AS, deep morphea, vasculitic neuropathy, and myelodysplastic syndrome and review the current literature regarding these uncommon associations. A 57 year old man with axial and symmetrical proximal muscle weakness, skin thickening and B symptoms, later diagnosed with PL7 + AS, deep morphea, myelodysplastic syndrome (MDS) and vasculitic neuropathy documented by histopathologic studies and immunologic assessments. Since both AS and deep morphea share the vasculopathic changes and type II interferon-induced inflammation, we hypothesize that they may share pathogenic mechanisms. The muscle biopsy of the patient was consistent with AS and showed focal neutrophil infiltration. The patient received intensive immunosuppressive therapy for AS and vasculitic neuropathy, with high dose steroids, intravenous immunoglobulin (IVIg) and rituximab. Nonetheless, he suffered an unfavorable evolution with a fatal outcome due to septic shock. Albeit sclerodermiform features are rare in patients with AS, we propose a pathogenic link among AS, deep morphea and the autoimmune/autoinflammatory signs of MDS. The vasculopathic changes along with the activation of the innate and adaptive immune system leading to the production of proinflammatory cytokines may have been one of the contributing factors for the coexisting diagnosis of the patient. [ABSTRACT FROM AUTHOR]

Introduction: Peripheral neuropathy is common in clinical practice, with a reported prevalence of 2.4% in the general population. There are numerous aetiologies for peripheral neuropathy like diabetes, ischaemia, vasculitis, inflammatory demyelinating disorders, nutritional deficiencies, paraproteinemic disorders, paraneoplastic syndromes, toxic exposures, and hereditary neuropathies. An exhaustive haematological, biochemical, and serological work-up, cerebrospinal fluid evaluation, electrodiagnostic tests, and nerve biopsy are required when overlapping clinical features present a diagnostic challenge. Aim: To analyse the histopathological characteristics of nerve biopsies in individuals with peripheral neuropathy. Materials and methods: This cross-sectional study was conducted in the Department of Pathology at Kasturba Medical College from January 2011 to December 2016. Nerve biopsies received in the Department of Pathology, Kasturba Medical College and Hospitals in the Ambedkar Circle and Attavar area, as well as at Government Wenlock Hospital, Mangaluru, Karnataka, India were studied. Clinical and laboratory data were collected from biopsy requisition forms and patient case records from the aforementioned hospitals. Results were presented in numbers and percentages. Results: A total of 134 nerve biopsies were included in the study. The age range of all cases studied was 7-86 years, with a mean age of 51.8 years. The study population consisted of 63.4% males and 36.6% females, resulting in a male-to-female ratio of 1.7:1. Vasculitic Neuropathy (VN) accounted for 38.1% cases, followed by chronic inflammatory neuropathies (21.7%) and Diabetic Neuropathy (DN) (12.6%). Other diagnosis included ischaemic neuropathy (6.7%), Hereditary Motor and Sensory Neuropathy (HMSN) (3.7%), subacute inflammatory demyelinating neuropathy (3.0%), as well as two cases each of Hansen’s neuritis, amyloid neuropathy, and acute inflammatory demyelinating neuropathy (1.5% each). One case of toxic neuropathy (0.7%) was identified, while 9.0% of cases displayed histological features that were either non specific or not characteristic of any specific diagnosis. Conclusion: Vasculitic neuropathy was found to be the most common aetiology of peripheral neuropathy, followed by Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and DN. The histopathological examination of nerve biopsies is a useful tool in distinguishing between diseases with overlapping clinical features, confirming or excluding vasculitis, and diagnosing hereditary conditions in settings where genetic testing is unavailable or unaffordable.

A 54‐year‐old man with diabetes mellitus presented with fever, pain, muscle weakness, and sensory disturbances in the lower limbs. His serum C‐reactive protein level was markedly increased; However, no autoantibodies, other than anti‐glutamic acid decarboxylase antibody, were detected. Nerve conduction studies revealed axonal polyneuropathy. 18F‐fluorodeoxyglucose positron emission tomography/computed tomography revealed patchy uptake patterns specific to restricted lower‐limb vasculitis. The muscle and nerve biopsy specimens suggested vasculitic neuropathy. Treatment with oral prednisolone and cyclophosphamide pulse therapy markedly improved his lower‐limb weakness and paresthesia. Clinicians should consider the involvement of vasculitic neuropathy, as well as myopathy, in patients with restricted lower‐limb vasculitis. [ABSTRACT FROM AUTHOR]

Vasculitic neuropathy has a broad range of etiologies, and roughly comprises nonsystemic vasculitic neuropathy and neuropathies accompanied by antineutrophil cytoplasmic antibody‐associated vasculitis (AAV). Recent morphological analyses of sural nerve specimens from patients with vasculitic neuropathy showed some distinct pathogeneses within vasculitic neuropathy. Several randomized, controlled studies and updated practice guidelines cover immunotherapies for AAV, whereas there is a paucity of evidence for vasculitic neuropathy, including neuropathies associated with AAV. Corticosteroids have been the mainstay of immunotherapy for vasculitic neuropathy, and cyclophosphamide is indispensable for refractory cases. Recent AAV guidelines are shifting their recommendations toward minimizing the harm caused by corticosteroids and cyclophosphamide with a reduced‐dose corticosteroid regimen and the recent advent of various optional drugs, especially molecular‐targeted agents. Clinicians expect the efficacy of reduced‐dose corticosteroid regimens and molecular‐targeted agents in treating vasculitic neuropathy to be verified, and clarification of the mechanism of vasculitic neuropathy might lead to the development of the best treatment based on the background pathogenesis of individual cases. [ABSTRACT FROM AUTHOR]

Aim: The morphometry of sural nerve biopsies, such as fibre diameter and myelin thickness, helps us understand the underlying mechanism of peripheral neuropathies. However, in current clinical practice, only a portion of the specimen is measured manually because of its labour‐intensive nature. In this study, we aimed to develop a machine learning‐based application that inputs a whole slide image (WSI) of the biopsied sural nerve and automatically performs morphometric analyses. Methods: Our application consists of three supervised learning models: (1) nerve fascicle instance segmentation, (2) myelinated fibre detection and (3) myelin sheath segmentation. We fine‐tuned these models using 86 toluidine blue‐stained slides from various neuropathies and developed an open‐source Python library. Results: Performance evaluation showed (1) a mask average precision (AP) of 0.861 for fascicle segmentation, (2) box AP of 0.711 for fibre detection and (3) a mean intersection over union (mIoU) of 0.817 for myelin segmentation. Our software identified 323,298 nerve fibres and 782 fascicles in 70 WSIs. Small and large fibre populations were objectively determined based on clustering analysis. The demyelination group had large fibres with thinner myelin sheaths and higher g‐ratios than the vasculitis group. The slope of the regression line from the scatter plots of the diameters and g‐ratios was higher in the demyelination group than in the vasculitis group. Conclusion: We developed an application that performs whole slide morphometry of human biopsy samples. Our open‐source software can be used by clinicians and pathologists without specific machine learning skills, which we expect will facilitate data‐driven analysis of sural nerve biopsies for a more detailed understanding of these diseases. [ABSTRACT FROM AUTHOR]

Purpose of review: To describe the clinical presentation, diagnosis, and treatment options of vasculitic neuropathies. Overall, vasculitic neuropathies can be divided into systemic and nonsystemic. Systemic vasculitic neuropathies form part of rheumatological diseases, where in some cases, the vasculitic is the predominant feature, and these are called primary vasculitis, while in others, the vasculitis is secondary to a connective tissue disease. Nonsystemic vasculitic neuropathies involve only the peripheral nervous system, and thus, diagnosis is more challenging as it requires a high degree of suspicion and confirmation with nerve biopsy results. Recent findings: Over the past few years, rituximab has been increasingly used for induction and maintenance treatment of vasculitis due to a more favorable side effect profile and similar efficacy when compared to cyclophosphamide. Summary: Herein, we describe the different types of vasculitic neuropathies. Regarding their treatment, have focused on the indications, dosing, and side effects for the most common options for primary systemic vasculitic neuropathies, as these tend to be similar for the classical nonsystemic vasculitic neuropathy phenotype. [ABSTRACT FROM AUTHOR]

Introduction: Mononeuritis multiplex is frequently related to vasculitic neuropathy and has been reported only sporadically as an adverse event of immune checkpoint inhibitors. Methods: Case series of three patients with mononeuritis multiplex--all with mesothelioma--identified in the databases of two French clinical networks (French Reference Center for Paraneoplastic Neurological Syndromes, Lyon; OncoNeuroTox, Paris; January 2015--October 2022) set up to collect and investigate n-irAEs on a nationwide level. Results: Three patients (male; median age 86 years; range 72--88 years) had pleural mesothelioma and received 10, 4, and 6 cycles, respectively, of first-line nivolumab plus ipilimumab combined therapy. In patient 1, the neurological symptoms involved the median nerves, and in the other two patients, there was a more diffuse distribution; the symptoms were severe (common terminology criteria for adverse events, CTCAE grade 3) in all patients. Nerve conduction studies indicated mononeuritis multiplex in all patients. Peripheral nerve biopsy demonstrated necrotizing vasculitis in patients 1 and 3 and marked IgA deposition without inflammatory lesions in patient 2. Immune checkpoint inhibitors were permanently withdrawn, and corticosteroids were administered to all patients, leading to complete symptom regression (CTCAE grade 0, patient 2) or partial improvement (CTCAE grade 2, patients 1 and 3). During steroid tapering, patient 1 experienced symptom recurrence and spreading to other nerve territories (CTCAE grade 3); he improved 3 months after rituximab and cyclophosphamide administration. Discussion: We report the occurrence of mononeuritis multiplex, a very rare adverse event of immune checkpoint inhibitors, in the three patients with mesothelioma. Clinicians must be aware of this severe, yet treatable adverse event. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

IntroductionMononeuritis multiplex is frequently related to vasculitic neuropathy and has been reported only sporadically as an adverse event of immune checkpoint inhibitors.MethodsCase series of three patients with mononeuritis multiplex—all with mesothelioma—identified in the databases of two French clinical networks (French Reference Center for Paraneoplastic Neurological Syndromes, Lyon; OncoNeuroTox, Paris; January 2015–October 2022) set up to collect and investigate n-irAEs on a nationwide level.ResultsThree patients (male; median age 86 years; range 72–88 years) had pleural mesothelioma and received 10, 4, and 6 cycles, respectively, of first-line nivolumab plus ipilimumab combined therapy. In patient 1, the neurological symptoms involved the median nerves, and in the other two patients, there was a more diffuse distribution; the symptoms were severe (common terminology criteria for adverse events, CTCAE grade 3) in all patients. Nerve conduction studies indicated mononeuritis multiplex in all patients. Peripheral nerve biopsy demonstrated necrotizing vasculitis in patients 1 and 3 and marked IgA deposition without inflammatory lesions in patient 2. Immune checkpoint inhibitors were permanently withdrawn, and corticosteroids were administered to all patients, leading to complete symptom regression (CTCAE grade 0, patient 2) or partial improvement (CTCAE grade 2, patients 1 and 3). During steroid tapering, patient 1 experienced symptom recurrence and spreading to other nerve territories (CTCAE grade 3); he improved 3 months after rituximab and cyclophosphamide administration.DiscussionWe report the occurrence of mononeuritis multiplex, a very rare adverse event of immune checkpoint inhibitors, in the three patients with mesothelioma. Clinicians must be aware of this severe, yet treatable adverse event.

Abstract Background Carpal tunnel syndrome is the most common focal mononeuropathy which presents with pain in the wrist and hand, paresthesia, loss of sensation in the distribution of the median nerve, and in more severe cases, weakness and atrophy of the thenar muscles. Meanwhile, carpal tunnel syndrome can present as an initial manifestation of underlying systemic vasculitis disorder and result in severe physical disabilities. Case presentation A 27-year-old Iranian man was referred to our electrodiagnosis center with a clinical diagnosis of carpal tunnel syndrome in April 2020. Surgical intervention had been taken into account for him because of unsuccessful conservative therapies. On admission, thenar eminence was reduced. Electrodiagnostic findings were not compatible with median nerve entrapment at the wrist. All sensory modalities in the distribution of the right median nerve were decreased. Additionally, a mild increase in erythrocyte sedimentation rate was noted in laboratory tests. Because of the high vasculitis suspicion, we recommended the nerve biopsy and/or starting a high-dose corticosteroid. However, the surgery release was performed. After 6 months, the patient was referred for progressive weakness and numbness in the upper and lower limbs. After documentation of vasculitis neuropathy by biopsy, a diagnosis of non-systemic vasculitic neuropathy was confirmed. A rehabilitation program started immediately. Rehabilitation led to gradual improvement and recovery of function and muscle strength, and no complications remained, except mild leg paralysis. Conclusions Physicians should be suspicious of the median nerve vasculitis mononeuropathy in a patient with carpal tunnel syndrome-like symptoms. Median nerve vasculitis mononeuropathy as an initial presenting feature of vasculitis neuropathy can further result in severe physical impairments and disabilities.

Purpose of eview: The aim of this review is to discuss the presentation, diagnosis, and management of polyneuropathy (PN) in selected infections. Overall, most infection related PNs are an indirect consequence of immune activation rather than a direct result of peripheral nerve infection, Schwann cell infection, or toxin production, though note this review will describe infections that cause PN through all these mechanisms. Rather than dividing them by each infectious agent separately, we have grouped the infectious neuropathies according to their presenting phenotype, to serve as a guide to clinicians. Finally, toxic neuropathies related to antimicrobials are briefly summarized. Recent findings: While PN from many infections is decreasing, increasing evidence links infections to variants of GBS. Incidence of neuropathies secondary to use of HIV therapy has decreased over the last few years. Summary: In this manuscript, a general overview of the more common infectious causes of PN will be discussed, dividing them across clinical phenotypes: large- and small-fiber polyneuropathy, Guillain-Barré syndrome (GBS), mononeuritis multiplex, and autonomic neuropathy. Rare but important infectious causes are also discussed. [ABSTRACT FROM AUTHOR]

Introduction/Aims: Nonsystemic vasculitic neuropathy (NSVN) is characterized by a predominant lower limb involvement in many patients. Motor unit changes in upper extremity muscles have not been investigated in this subgroup but may be of interest for improving our understanding of the multifocal nature of the disease and counseling of patients about potential future symptoms. In this study we aimed to better understand subclinical motor involvement in the upper extremity muscles of patients with lower limb–predominant NSVN using the new motor unit number estimation (MUNE) method MScanFit. Methods: In this single‐center, cross‐sectional study, 14 patients with biopsy‐proven NSVN, with no clinical signs of upper extremity motor involvement, were investigated and compared with 14 age‐matched healthy controls. All participants were assessed clinically and by the MUNE method MScanFit to the abductor pollicis brevis muscle. Results: The number of motor units and peak CMAP amplitudes were significantly reduced in patients with NSVN (P =.003 and P =.004, respectively). Absolute median motor unit amplitudes and CMAP discontinuities were not significantly different (P =.246 and P =.1, respectively). CMAP discontinuities were not significantly correlated with motor unit loss (P =.15, rho = 0.4). The number of motor units did not correlate with clinical scores (P =.77, rho = 0.082). Discussion: Both MUNE and CMAP amplitudes showed motor involvement in upper extremity muscles in lower limb–predominant NSVN. Overall, there was no evidence of significant reinnervation. Investigations of the abductor pollicis brevis muscle did not show a correlation with overall functional disability of the patients. [ABSTRACT FROM AUTHOR]

Abstract Background No controlled studies for non-systemic vasculitic neuropathy treatment exist (NSVN). We compared the treatment response to induction therapy commonly used in clinical practice in NSVN. Methods In this retrospective single-center study, 43 patients with biopsy-proven NSVN were analyzed. Patients were subdivided into groups depending on their initial treatment. Relapse rates, changes of motor and sensory symptoms, adverse events, predictors of relapses, and second-line treatment were compared. Results Initial treatment regimens were corticosteroid monotherapy, cyclophosphamide monotherapy, pulsed corticosteroid therapy, and combination therapy. Discontinuation due to adverse events occurred in 6 of 43 patients. Clinical data did not differ between treatment groups. Within 12 months, 24.3% of patients relapsed. The median time to relapse was 4 (1.5, 6) months. No relapse occurred in the combination therapy group. However, there was no statistically significant difference in relapse-free survival between treatment groups (p = 0.58). Neither clinical data nor biopsy analysis predicted relapses sufficiently. As a second-line treatment, cyclophosphamide as mono- or combination therapy was used (7 of 9 patients) most frequently. One patient was treated with methotrexate, and one with IVIG. Conclusions Induction therapy used in clinical practice is effective and mainly well-tolerated in NSVN. Our data do not support an overall advantage of cyclophosphamide over corticosteroid monotherapy. Controlled trials comparing the effectiveness of induction and maintenance therapy in NSVN are warranted.

Background: Carpal tunnel syndrome is the most common focal mononeuropathy which presents with pain in the wrist and hand, paresthesia, loss of sensation in the distribution of the median nerve, and in more severe cases, weakness and atrophy of the thenar muscles. Meanwhile, carpal tunnel syndrome can present as an initial manifestation of underlying systemic vasculitis disorder and result in severe physical disabilities. Case presentation: A 27-year-old Iranian man was referred to our electrodiagnosis center with a clinical diagnosis of carpal tunnel syndrome in April 2020. Surgical intervention had been taken into account for him because of unsuccessful conservative therapies. On admission, thenar eminence was reduced. Electrodiagnostic findings were not compatible with median nerve entrapment at the wrist. All sensory modalities in the distribution of the right median nerve were decreased. Additionally, a mild increase in erythrocyte sedimentation rate was noted in laboratory tests. Because of the high vasculitis suspicion, we recommended the nerve biopsy and/or starting a high-dose corticosteroid. However, the surgery release was performed. After 6 months, the patient was referred for progressive weakness and numbness in the upper and lower limbs. After documentation of vasculitis neuropathy by biopsy, a diagnosis of non-systemic vasculitic neuropathy was confirmed. A rehabilitation program started immediately. Rehabilitation led to gradual improvement and recovery of function and muscle strength, and no complications remained, except mild leg paralysis. Conclusions: Physicians should be suspicious of the median nerve vasculitis mononeuropathy in a patient with carpal tunnel syndrome-like symptoms. Median nerve vasculitis mononeuropathy as an initial presenting feature of vasculitis neuropathy can further result in severe physical impairments and disabilities. [ABSTRACT FROM AUTHOR]

Introduction/aims: In vasculitic neuropathy (VN), a 50% side‐to‐side difference in the amplitude of compound muscle action potentials and sensory nerve action potentials is considered meaningful, but unequivocal evidence is lacking. The aim of this study is to characterize electrodiagnostic features that best distinguish VN from other axonal polyneuropathies. Methods: We conducted a case–control study between January 2000 and April 2021. We reviewed the records of patients with VN who had bilateral nerve conduction studies (NCS) and evaluated different electrodiagnostic models to help distinguish VN from non‐inflammatory axonal polyneuropathies. Results: We identified 82 cases, and 174 controls with non‐inflammatory axonal neuropathies. The amplitude percent difference Z‐score model showed the best discriminatory capability between cases and controls (area under the curve [AUC] 0.87; 95% confidence interval [CI] 0.82, 0.93), and the number of nerves tested did not significantly influence the model. Individually, the ulnar motor nerve (AUC 0.86; 95% CI 0.77, 0.94) and median motor nerve (AUC 0.85; 95% CI 0.77, 0.94) showed the best discriminatory capability. A 50% amplitude difference between at least two bilateral nerves, either in the upper (AUC 0.85; 95% CI 0.77, 0.93) or lower (AUC 0.79; 95% CI 0.71, 0.87) extremity showed good discriminatory threshold for detecting VN. Discussion: The best electrodiagnostic criteria for VN utilizes z‐scores of percent differences in nerve amplitudes, but this approach may be difficult to implement at the bedside. Alternately, a 50% amplitude difference in at least two nerves is a reasonable approximation. [ABSTRACT FROM AUTHOR]

• Nerve biopsies have limited role if the clinical diagnosis is unclear. • Nerve biopsies are helpful in the diagnoses of vasculitis and amyloidosis. • Careful selection of cases for nerve biopsy is crucial to increase the diagnostic yield. With progress made in neurogenetics and neuroinflammation, the indications and value of nerve biopsies in the diagnostic evaluation of peripheral neuropathies are less clear. In this study, we aimed to evaluate the diagnostic yield of nerve biopsies in patients with peripheral neuropathies. We performed a retrospective review of nerve biopsy reports from April 1998 to June 2021 of patients with peripheral neuropathies presenting to the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The diagnostic value of the biopsies was determined based on the criteria by Midroni and Bilbao as follows: contributive (essential and helpful), non-contributive and inadequate. A total of 107 nerve biopsies were analysed. Sixty-four (60 %) were males and the mean age was 52 years, ranging from 13 to 86 years. Ninety-four (88 %) were sural nerve biopsies; and only one patient (1 %) each had superficial peroneal and superficial radial nerve biopsy. The indications for the procedure were vasculitis (34 %), peripheral neuropathy of unknown aetiology (34 %), amyloidosis (14 %) and chronic inflammatory demyelinating polyneuropathy (10 %). In 68 (63 %) biopsies, the diagnostic value was contributive. Of these, 28 (26 %) were essential and 40 (37 %) were helpful. In contrast, 35 (33 %) biopsies were non-contributive and 4 (4 %) were inadequate. In 66 % (71/107) of cases, the nerve biopsy did not reveal a definite pathological diagnosis. However, in the remainder, a diagnosis of vasculitis (18 %, 19/107), followed by amyloidosis (10 %, 11/107) could be determined. For 32/71 biopsies with undetermined pathological diagnosis, neuropathy remained cryptogenic in 22 % (7/32) upon follow up. With the exception of vasculitis and amyloidosis, there is limited value in performing nerve biopsies in the evaluation of patients with peripheral neuropathy. However, this should be interpreted with caution as the number of patients with a clinical diagnosis of vasculitis and amyloidosis were relatively larger than patients with other diagnosis. Refinement and careful selection of cases are required to increase the diagnostic yield of nerve biopsy. [ABSTRACT FROM AUTHOR]

Background: No controlled studies for non-systemic vasculitic neuropathy treatment exist (NSVN). We compared the treatment response to induction therapy commonly used in clinical practice in NSVN. Methods: In this retrospective single-center study, 43 patients with biopsy-proven NSVN were analyzed. Patients were subdivided into groups depending on their initial treatment. Relapse rates, changes of motor and sensory symptoms, adverse events, predictors of relapses, and second-line treatment were compared. Results: Initial treatment regimens were corticosteroid monotherapy, cyclophosphamide monotherapy, pulsed corticosteroid therapy, and combination therapy. Discontinuation due to adverse events occurred in 6 of 43 patients. Clinical data did not differ between treatment groups. Within 12 months, 24.3% of patients relapsed. The median time to relapse was 4 (1.5, 6) months. No relapse occurred in the combination therapy group. However, there was no statistically significant difference in relapse-free survival between treatment groups (p = 0.58). Neither clinical data nor biopsy analysis predicted relapses sufficiently. As a second-line treatment, cyclophosphamide as mono- or combination therapy was used (7 of 9 patients) most frequently. One patient was treated with methotrexate, and one with IVIG. Conclusions: Induction therapy used in clinical practice is effective and mainly well-tolerated in NSVN. Our data do not support an overall advantage of cyclophosphamide over corticosteroid monotherapy. Controlled trials comparing the effectiveness of induction and maintenance therapy in NSVN are warranted. [ABSTRACT FROM AUTHOR]

Vasculitic neuropathy can present associated with both primary and secondary systemic vasculitis as a result from underlying diseases such as rheumatic diseases and infections, Moreover, confined vasculitis in the peripheral nervous system may be present. Thus, the diagnosis and management of vasculitic neuropathy require multidisciplinary approaches. Current views as well as relevant clinical research on the diagnosis, assessment, and management of vasculitic neuropathy are reviewed to suggest appropriate treatment strategies. We searched PubMed and Google Scholar for reports published between July 2017 and July 2022. For the treatment of vasculitic neuropathy, determining the causative primary disease is important and often requires diagnosis by tissue biopsy. Due to the scarce research on the treatment of vasculitic neuropathy, treatment is empirically based on findings from studies of systemic vasculitides involving other organs, particularly antineutrophil cytoplasmic antibody-associated vasculitis. In addition to conventional glucocorticoids and immunosuppressive agents, complement-targeted therapy, anti-B-cell therapy, and disease-specific molecular targeted therapies have recently gained relevance. Future research is needed to develop new patient-specific therapeutic options. [ABSTRACT FROM AUTHOR]

Abstract Background Eosinophilic granulomatosis with polyangiitis (EGPA) is associated with vasculitic neuropathy and being rare can present as subacute symmetric sensorimotor quadriparesis mimicking Guillain–Barre syndrome (GBS). It warrants timely diagnosis as treatment for both conditions is different and vasculitic neuropathy needs long-term immunosuppression. Nerve biopsy of our patient showed eosinophilic infiltration along with mononuclear infiltrate. Typical histopathological presentations of EGPA are different among different organs and eosinophilic infiltration is rarely observed in peripheral nerve and kidney involvements. Case presentation A 49-year-old female with a history of asthma with 3-week duration of acute onset ascending weakness, preceded by severe pain and burning in glove and stocking pattern. Nerve conduction studies could not rule out Guillain–Barre syndrome initially, but subsequent studies show axonal affection and she received intravenous immunoglobulin (IVIg) but her weakness progressed after slight improvement. Her bloodwork revealed marked eosinophilia (> 50%) with computed tomography (CT) paranasal sinuses showing pansinusitis with background history of asthma led us towards eosinophilic granulomatosis with polyangiitis and later antineutrophil cytoplasmic antibodies came out positive with nerve biopsy showing perivascular mononuclear inflammation with eosinophils. She was started on steroids immediately and then received intravenous rituximab in view of long-term immunosuppression with maintenance steroids and on follow-up she improved. Conclusion Eosinophilic granulomatosis with polyangiitis is a small-vessel vasculitis associated with antineutrophil cytoplasmic antibodies with significant paranasal sinuses involvement. Mononeuritis multiplex is the most common presentation of vasculitic neuropathy of eosinophilic granulomatosis with polyangiitis, but they can mimic Guillain–Barre syndrome and should always be considered in the differential diagnosis, since the treatment strategies for these conditions are radically different.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a systemic disorder that frequently affects the peripheral nervous system and consists of three distinct conditions: microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA, previously Wegener's granulomatosis), and eosinophilic granulomatosis with polyangiitis (EGPA, previously Churg-Strauss syndrome). The neuropathic features associated with this condition usually include mononeuritis multiplex, which reflects the locality of lesions. Findings suggestive of vasculitis are usually found in the epineurium and occur diffusely throughout the nerve trunk. Nerve fiber degeneration resulting from ischemia is sometimes focal or asymmetric and tends to become conspicuous at the middle portion of the nerve trunk. The attachment of neutrophils to endothelial cells in the epineurial vessels is frequently observed in patients with ANCA-associated vasculitis; neutrophils play an important role in vascular inflammation by binding of ANCA. The positivity rate of ANCA in EGPA is lower than that in MPA and GPA, and intravascular and tissue eosinophils appear to participate in neuropathy. Immunotherapy for ANCA-associated vasculitis involves the induction and maintenance of remission to prevent the relapse of the disease. A combination of glucocorticoids along with cyclophosphamide, rituximab, methotrexate, or mycophenolate mofetil is considered depending on the severity of the condition of the organ to induce remission. A combination of low-dose glucocorticoids and azathioprine, rituximab, methotrexate, or mycophenolate mofetil is recommended to maintain remission. The efficacy of anti-interleukin-5 therapy (i.e., mepolizumab) was demonstrated in the case of refractory or relapsing EGPA. Several other new agents, including avacopan, vilobelimab, and abatacept, are under development for the treatment of ANCA-associated vasculitis. Multidisciplinary approaches are required for the diagnosis and management of the disorder because of its systemic nature. Furthermore, active participation of neurologists is required because the associated neuropathic symptoms can significantly disrupt the day-to-day functioning and quality of life of patients with ANCA-associated vasculitis. [ABSTRACT FROM AUTHOR]

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is associated with vasculitic neuropathy and being rare can present as subacute symmetric sensorimotor quadriparesis mimicking Guillain-Barre syndrome (GBS). It warrants timely diagnosis as treatment for both conditions is different and vasculitic neuropathy needs long-term immunosuppression. Nerve biopsy of our patient showed eosinophilic infiltration along with mononuclear infiltrate. Typical histopathological presentations of EGPA are different among different organs and eosinophilic infiltration is rarely observed in peripheral nerve and kidney involvements. Case presentation: A 49-year-old female with a history of asthma with 3-week duration of acute onset ascending weakness, preceded by severe pain and burning in glove and stocking pattern. Nerve conduction studies could not rule out Guillain-Barre syndrome initially, but subsequent studies show axonal affection and she received intravenous immunoglobulin (IVIg) but her weakness progressed after slight improvement. Her bloodwork revealed marked eosinophilia (> 50%) with computed tomography (CT) paranasal sinuses showing pansinusitis with background history of asthma led us towards eosinophilic granulomatosis with polyangiitis and later antineutrophil cytoplasmic antibodies came out positive with nerve biopsy showing perivascular mononuclear inflammation with eosinophils. She was started on steroids immediately and then received intravenous rituximab in view of long-term immunosuppression with maintenance steroids and on follow-up she improved. Conclusion: Eosinophilic granulomatosis with polyangiitis is a small-vessel vasculitis associated with antineutrophil cytoplasmic antibodies with significant paranasal sinuses involvement. Mononeuritis multiplex is the most common presentation of vasculitic neuropathy of eosinophilic granulomatosis with polyangiitis, but they can mimic Guillain-Barre syndrome and should always be considered in the differential diagnosis, since the treatment strategies for these conditions are radically different. [ABSTRACT FROM AUTHOR]

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. A review of the pathophysiology of the autoimmune neuropathies, to identify those that are likely to be complement mediated. 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. [ABSTRACT FROM AUTHOR]

Background: Vasculitic neuropathies are an uncommon heterogeneous group of nerve disorders characterized by inflammation of the vasa nervorum, which may be either systemic vasculitic neuropathy (SVN) or non-SVN (NSVN). Settings and Design: This is a retrospective, observational study. Materials and Methods: Nerve biopsy-proven cases of vasculitic neuropathy (VN) from January 2011 to December 2017 were included in the study. Results: Twenty-five percent (40/156) patients had vasculitis on biopsy, 62.5% were male and the mean age was 52.8 ± 14.9 years. The median (interquartile range) duration of symptoms before diagnosis was 75 (345) days. Thirty (75%) patients had NSVN and 10 (25%) patients had SVN. The clinical pattern of peripheral nervous system involvement was as follows: 20 (50%) had polyneuropathy, 13 (32.5%) had mononeuritis multiplex, and 7 (32.5%) had polyradiculoneuropathy. Twenty-three (57.5%) patients received immunomodulatory therapy. Conclusion: VN has a wide spectrum of clinical presentation. High index of suspicion followed by nerve biopsy is needed for diagnosis. Early treatment may improve prognosis in this group of patients.

Vasculitis is a clinically diverse group of diseases with histopathological signs of blood vessel inflammation, which contributes to vascular damage and ischemic damage to the affected tissues. Vasculitic neuropathy is a common complication of the primary systemic vasculitides, such as polyartertis nodosa and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, systemic diseases of the connective tissue - systemic lupus erythematosus and Sjogren syndrome, vasculitis associated with infection, most often viral hepatitis C and B and non - systemic vasculitis neuropathy. Vessels of medium and small caliber are involved in the pathological process in these diseases. With all vasculitis, except for those caused by the direct effect of the infectious trigger on the blood vessel walls, the main pathogenetic mechanism is an autoimmune process with the development of vasa nervorum vasculitis - small arteries and vessels that supply peripheral nerves, and the outcome - nerve ischemia. The classic clinical presentation is an acute or subacute painful multifocal neuropathy that has a predilection for the lower extremities, affects two or more named nerves, and progresses in a step wise manner. However, vasculitic neuropathy can manifest in a variety of ways, including asymmetric polyneuropathies and distal symmetric sensory neuropathies, and it also can be slowly progressive, particularly in cases of nonsystemic vasculitic neuropathy (NSVN), a form of vasculitis that clinically remains restricted to peripheral nerves. Nerve biopsy can help establish the diagnosis of a systemic vasculitis, particularly when other organ involvement is not clinically apparent, and is required for diagnosis of NSVN. Neuropathy due to systemic vasculitis should be treated in accordance with the recommendations for the treatment of the underlying disease. In NSVH, the main medicine of choice are glucocrticoids, and in severe/progressive cases, pulse therapy with cyclophosphamide.

Objective Limited evidence exists to guide treatment of refractory vasculitic neuropathy. While rituximab (RTX) and IVIG have both been proposed as individual treatment options for these patients, combination therapy has never been reported. Methods Written informed consent was obtained from three patients with refractory vasculitic neuropathy who were treated with combination RTX and IVIG. Their electronic medical records were reviewed and clinical and functional outcomes were reported. Results Two male patients with non-systemic vasculitic neuropathy and one male patient with granulomatosis with polyangiitis were treated with combination RTX and IVIG therapy. All three patients demonstrated clinical improvement with at least partial functional recovery and a reduction in corticosteroid dose. This combination was generally well tolerated. Conclusions Combination RTX and IVIG therapy may be a safe and effective treatment option for patients with refractory vasculitic neuropathy. Further studies are needed to better characterize the risks and benefits of this combination. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Immune axonal neuropathies are a particular group of immune-mediated neuropathies that occasionally accompany systemic autoimmune rheumatic diseases such as connective tissue dissorders and primary systemic vasculitides. Apart from vasculitis of vasa nervorum, various other mechanisms are involved in their pathogenesis, with possible therapeutic implications. Immune axonal neuropathies have highly heterogeneous clinical presentation and course, ranging from mild chronic distal sensorimotor polyneuropathy to severe subacute mononeuritis multiplex with rapid progression and constitutional symptoms such as fever, malaise, weight loss and night sweats, underpinning a vasculitic process. Sensory neuronopathy (ganglionopathy), small fiber neuropathy (sensory and/or autonomic), axonal variants of Guillain-Barré syndrome and cranial neuropathies have also been reported. In contrast to demyelinating neuropathies, immune axonal neuropathies show absent or reduced nerve amplitudes with normal latencies and conduction velocities on nerve conduction studies. Diagnosis and initiation of treatment are often delayed, leading to accumulating disability. Considering the lack of validated diagnostic criteria and evidence-based treatment protocols for immune axonal neuropathies, this review offers a comprehensive perspective on etiopathogenesis, clinical and paraclinical findings as well as therapy guidance for assisting the clinician in approaching these patients. High quality clinical research is required in order to provide indications and follow up rules for treatment in immune axonal neuropathies related to systemic autoimmune rheumatic diseases.

Background: Perls Prussian blue stain (PPB) for hemosiderin, a marker of vascular injury is often employed as an adjunct in the diagnosis of vasculitic neuropathies. However, inflammation/vascular injury is also seen in leprosy, immune mediated, paraproteinemic, diabetic neuropathies, etc. The frequency of detection of hemosiderin in these neuropathies and its utility in diagnosis of vasculitis has not been explored.Objective: We evaluated 208 peripheral nerve biopsies for hemosiderin deposits by PPB stain in vasculitis (78) and compared with inflammatory/immune neuropathies [leprous neuritis-32, chronic inflammatory demyelinating polyneuropathy (CIDP)-15, paraproteinemic neuropathies (POEMS)-12, diabetic neuropathy-37] and nonimmune neuropathies [Charcot-Marie-Tooth (CMT) disease-15, vitamin B12 deficiency-7, and ischemic neuropathy in aged-12)].Results: Hemosiderin deposits were most frequent in vasculitis (48.72%) [59.2% in systemic; 43.1% in nonsystemic vasculitides] and enhanced the sensitivity of diagnosis in "probable" vasculitis (34.48%) that lacked transmural inflammation. Hemosiderin was also detected in infectious/immune-mediated neuropathies (leprous neuritis-56%, POEMS-33.3%, diabetes-18.9%) but absent in CMT, B12 deficiency, and ischemic neuropathy. Hemosiderin deposits involved epineurium in vasculitis, compared to endoneurial/perineurial location in leprosy and perineurial in POEMS and diabetic neuropathy. The sensitivity of detection was high in vasculitic neuropathy (49.35%) compared to other inflammatory neuropathies (22.3%) (P < 0.05) with high specificity (77.69% [positive predictive value (PPV)-56.71%; negative predictive value (NPV)-71.6%]. The specificity increased to 89% if leprous neuropathy was excluded, with PPV-77.5% while NPV dropped to 68.5%.Conclusion: These findings suggest that PPB stain for detection of hemosiderin is a useful adjunct in diagnosis of vasculitic neuropathy with high specificity but low sensitivity. [ABSTRACT FROM AUTHOR]

Nerve biopsy represents the conclusive step in the diagnostic work-up of peripheral neuropathies, and its diagnostic yield is still debated. The aim of this study is to consider the impact of nerve biopsy on reaching a useful diagnosis in different peripheral neuropathies and its changing over time. We retrospectively analyzed 1,179 sural nerve biopsies performed in the period 1981–2017 at Neurological Clinic of Policlinico San Martino (Genoa). We relied on medical records and collected both clinical and pathological data in a database. Biopsy provided univocal diagnoses in 53% of cases (with an increase over time), multiple diagnostic options in 14%, while diagnosis was undetermined in 33% (undetermined reports decreased during the years). In 57% of patients, the pre-biopsy suspicion was confirmed, while in 43% sural biopsy modified the clinical diagnosis. The highest yield was in axonal neuropathies (29% undetermined reports vs. 40% in demyelinating and 48% in mixed neuropathies). In 68% of patients with vasculitic neuropathy, this etiology was already suspected, whereas in 32% nerve biopsy modified the clinical diagnosis. During the years, the number of annually performed biopsies decreased significantly (p = 0.007), with an increase in the mean age of patients (p < 0.0001). The percentage of hereditary neuropathies had a significant decrease (p = 0.016), while the rate of vasculitic and chronic inflammatory neuropathies increased (p < 0.0001). This is the largest Italian study addressing the yield of sural nerve biopsy. During the years, we observed a progressive refinement of the indication of this procedure, which confirms its utility for interstitial neuropathies, particularly if non-systemic vasculitic neuropathy is suspected.

Rheumatoid vasculitis which affects small-to-medium-sized vessels is a rare and late complication of rheumatoid arthritis. It is defined histologically as immune complex deposition in venules, capillaries and arterioles.1 Vasculitis in the vasa nervorum leads to infarction of peripheral nerves which leads to neuropathy. We present a case of mononeuritis multiplex due to rheumatoid vasculitis.

Peripheral neuropathy is a common feature of systemic vasculitis and can also occur when vessel wall inflammation is confined to the vasa nervorum, as a tissue-specific condition—non-systemic vasculitic neuropathy (NSVN). Typically, the clinical picture in both systemic and non-systemic cases is of a lower limb predominant, distal, asymmetric or multifocal neuropathy, which is painful and subacute in onset. For NSVN, nerve biopsy is required to make the diagnosis, and nerve biopsy also has a role when vasculitic neuropathy is suspected and a systemic process has not yet declared itself. Early recognition of the disorder is important, because it is treatable, and without treatment potentially disabling, or even lethal if part of an undiagnosed systemic process. Treatment is generally with combination therapy (glucocorticoid plus other immunosuppressant), after which motor and sensory recovery are likely to occur, albeit slowly, but the patient may be left with chronic neuropathic pain. [ABSTRACT FROM AUTHOR]

Nerve biopsy represents the conclusive step in the diagnostic work-up of peripheral neuropathies, and its diagnostic yield is still debated. The aim of this study is to consider the impact of nerve biopsy on reaching a useful diagnosis in different peripheral neuropathies and its changing over time. We retrospectively analyzed 1,179 sural nerve biopsies performed in the period 1981–2017 at Neurological Clinic of Policlinico San Martino (Genoa). We relied on medical records and collected both clinical and pathological data in a database. Biopsy provided univocal diagnoses in 53% of cases (with an increase over time), multiple diagnostic options in 14%, while diagnosis was undetermined in 33% (undetermined reports decreased during the years). In 57% of patients, the pre-biopsy suspicion was confirmed, while in 43% sural biopsy modified the clinical diagnosis. The highest yield was in axonal neuropathies (29% undetermined reports vs. 40% in demyelinating and 48% in mixed neuropathies). In 68% of patients with vasculitic neuropathy, this etiology was already suspected, whereas in 32% nerve biopsy modified the clinical diagnosis. During the years, the number of annually performed biopsies decreased significantly (p = 0.007), with an increase in the mean age of patients (p < 0.0001). The percentage of hereditary neuropathies had a significant decrease (p = 0.016), while the rate of vasculitic and chronic inflammatory neuropathies increased (p < 0.0001). This is the largest Italian study addressing the yield of sural nerve biopsy. During the years, we observed a progressive refinement of the indication of this procedure, which confirms its utility for interstitial neuropathies, particularly if non-systemic vasculitic neuropathy is suspected. [ABSTRACT FROM AUTHOR]

A 21-year-old female born of nonconsanguineous marriage presented with gradually progressive quadriplegia for 3 years. Weakness was distal more than proximal, with wasting. She also had moderate pain in extremities. She had significant weight loss. Clinically, she had lower motor neuron flaccid quadriplegia with absent deep tendon jerks. Sensations of touch and pain were diminished in bilateral feet till ankle joints. Peripheral nerves were not thickened. Nerve conduction study was suggestive of pure axonal sensorimotor polyneuropathy. All routine hematological and biochemical parameters, erythrocyte sedimentation rate, antinuclear antibodies, and antinuclear cytoplasmic antibodies were negative. Cerebrospinal fluid showed no cells, normal sugar, and raised proteins. Biopsy of sural nerve was suggestive of vasculitic neuropathy. This was a case of nonsystemic vasculitic neuropathy that responded to steroids.