Neuromuscular Biopsy Research Articles

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).

Neuropathies périphériques au cours des maladies de système : partie II (vascularites)

Primary systemic vasculitides, mainly of the small and medium-sized vessels, are frequently associated with peripheral neuropathies. When the disease is already known, the appearance of a neuropathy should suggest a specific injury, especially when associated with other systemic manifestations. Conversely, when neuropathy is inaugural, close collaboration between neurologists and internists is necessary to reach a diagnosis. A standardized electro-clinical investigation specifying the topography, the evolution and the mechanism of the nerve damage enables the positive diagnosis of the neuropathy. Several elements orient the etiological diagnosis and allow to eliminate the main differential diagnosis: non systemic vasculitic neuropathy. The existence of associated systemic manifestations (glomerular or vascular nephropathy, interstitial lung disease, intra-alveolar hemorrhage, ENT involvement…), biological markers (ANCA, cryoglobulinemia, rheumatoid factor), and invasive examinations allowing histological analysis (neuromuscular biopsy) are all useful tools for.

Pheochromocytoma presenting as an authentic small vessel vasculitis and complicated with pulmonary embolism: An original presentation

Diagnosis of pheochromocytoma can be simple when classic manifestations are present. It can also be challenging and complicated in some cases because of its wide array of faces and presentations. We present a case of a 30-year-old female patient who came with acute respiratory distress, chest pain, hemoptysis, asthenia, anorexia, weight loss of 20kg, and paresthesia in her lower limbs. Clinical examination found high blood pressure, accelerated heart and respiratory rates, signs of acute right heart failure with jugular venous distention and ankle edema, reticularis livedo in the four limbs, ulcers in both knees and in the 3rd metacarpo-phalangeal articulations and necrotic lesions in both calcaneal tendons and in the right toes. Further investigations concluded on myocarditis associated with alveolar hemorrhage, pericardic and pleuritic effusions and a segmental pulmonary embolism of the right inferior lobe. Neuro-muscular biopsy was suggestive of myositis. Cutaneous biopsy found nonspecific chronic dermatitis. ANCA antibodies were tested twice and were negative. Cryoglobulinemia was also negative. Thoraco-abdomino-pelvic scan was performed showing a large right adrenal mass suggestive of pheochromocytoma. Diagnosis of right adrenal pheochromocytoma was confirmed by MIBG-I123 hyperfixation findings and urinary normetanephrin levels. The patient was treated surgically. Postoperative outcomes were remarkably favorable with a complete regression of the cutaneous lesions and normalization of the blood pressure. Paresthesia significantly decreased. Control echocardiography at 3 months showed an improved heart function with a persistent apical and septal akinesis.

Mutations in GFPT1-related congenital myasthenic syndromes are associated with synaptic morphological defects and underlie a tubular aggregate myopathy with synaptopathy.

Mutations in GFPT1 (glutamine-fructose-6-phosphate transaminase 1), a gene encoding an enzyme involved in glycosylation of ubiquitous proteins, cause a limb-girdle congenital myasthenic syndrome (LG-CMS) with tubular aggregates (TAs) characterized predominantly by affection of the proximal skeletal muscles and presence of highly organized and remodeled sarcoplasmic tubules in patients' muscle biopsies. We report here the first long-term clinical follow-up of 11 French individuals suffering from LG-CMS with TAs due to GFPT1 mutations, of which nine are new. Our retrospective clinical evaluation stresses an evolution toward a myopathic weakness that occurs concomitantly to ineffectiveness of usual CMS treatments. Analysis of neuromuscular biopsies from three unrelated individuals demonstrates that the maintenance of neuromuscular junctions (NMJs) is dramatically impaired with loss of post-synaptic junctional folds and evidence of denervation-reinnervation processes affecting the three main NMJ components. Moreover, molecular analyses of the human muscle biopsies confirm glycosylation defects of proteins with reduced O-glycosylation and show reduced sialylation of transmembrane proteins in extra-junctional area. Altogether, these results pave the way for understanding the etiology of this rare neuromuscular disorder that may be considered as a "tubular aggregates myopathy with synaptopathy".

Clinicopathological features of multiple mononeuropathy associated with systemic lupuserythematosus: a multicenter study.

Multiple mononeuropathy (MM) occurs rarely during systemic lupus erythematosus (SLE) but may lead to major disability. The aim of this study was to investigate the clinic-pathological presentations of MM during SLE, as well as long-term outcomes. We conducted a multicentric retrospective study that included patients receiving a diagnosis of MM during SLE. Ten patients were included (8 women and 2 men, median age at MM diagnosis: 40.4years). SLE was diagnosed before MM in 9/10 patients (median time 8.2years). When MM occurred, the SLEDAI score was ≥6 for 6/9 patients. Presenting symptoms consisted of sensory deficits (n=10), neuropathic pain (n=9), and/or motor deficits (n=9), sometimes symmetrical, affecting the lower limbs (10/10) and occasionally the upper limbs (5/10). All patients presented with uni- or bilateral damage of the common fibular nerve, with less frequent involvement of the tibial nerve. Serum cryoglobulinemia was positive in 5/9 patients. Electrophysiological studies confirmed the non-symmetrical involvement of multiple nerve trunks in all patients. Neuromuscular biopsy (performed in five patients) showed histological signs of vasculitis in two patients and perivascular lymphocytic inflammatory infiltrates in two others. All patients were treated with glucocorticosteroids combined with cyclophosphamide (n=6), rituximab (n=3), or mycophénolate-mofétil (n=1). The median follow-up was 5years. Two patients relapsed during follow-up. All patients had motor and/or sensory sequelae upon follow-up. MM associated with SLE is frequently caused by a vasculitis mechanism. Patients improve with steroids and immunosuppressive drugs. Long-term outcomes include frequent clinical sequelae and possible relapses.

Etanercept induces remission of polyarteritis nodosa: a case report.

Etanercept induces remission of polyarteritis nodosa: a case report.

Clinical Neuropathology practice guide 3-2014: Combined nerve and muscle biopsy in the diagnostic workup of neuropathy – the Bordeaux experience

Simultaneous combined superficial peroneal nerve and peroneous brevis muscle biopsy, via the same cutaneous incision, allows examination of several tissue specimens and significantly improves the diagnosis of systemic diseases with peripheral nerve involvement. Vasculitides are certainly the most frequently diagnosed on neuro-muscular biopsies, but this procedure is also well advised to asses a diagnosis of sarcoidosis or amyloidosis. More occasionally, combined nerve and muscle biopsy may reveal an unpredicted diagnosis of cholesterol embolism, intra-vascular lymphoma, or enables complementary diagnosis investigations on mitochondrial cytopathy or storage disease.

The evaluation of muscle biopsy findings in children with neuromuscular disorders

Objective: The studies considering the clinical and histopathological features of childhood muscle disease are scarce in number worldwide. This study aims to examine the histopathological profile of the children’s muscle biopsies evaluated at the Behcet Uz Children’s Hospital (BUCH) and determine their correlation with clinical diagnosis. Methods: We retrospectively reviewed 323 children who underwent muscle biopsy examination between 2004 and 2011 at pathology laboratory of Izmir BUCH. All patients were clinically diagnosed as neuromuscular disorders and biopsy specimens were collected from 5 different centers of neurological disorders. Results: The mean age of the patients was 6.15 years (3 weeks-18 years). Only 22 cases (6.8%) were older than 14 and 39 (12.07%) were younger than twelve months. Spinal muscular atrophy (n=11; 28.2%) was the most common disease in the infantile group. Dystrophies were diagnosed in 148 (45.7%) patients and 102 of them were dystrophinopathies. Other disorders were 23 primary, 16 inflammatory and 19 metabolic/mitochondrial myopathies and 28 neuropathies. Seventy three (22.9%) patients had similarly affected family members. Consanguinity rate was 25.1%. Serum enzymes alterations, EMG pathologies and fiber type disproportion were determined in 109 (33.7%), 188 (58.2%) and 85 (26.3%) of the patients respectively. There were statistical significant correlations between the types of disease and serum enzyme levels (p= 0.001), and age (p=0.015) of the patients. Conclusion: The present study revealed the panorama of the childhood muscle diseases in western Turkey. We conclude that if avoidance from unnecessary diagnostic and therapeutic interventions was desired, we must be aware of the limitation and diagnostic value of muscle biopsy evaluations in childhood muscle diseases.

重症筋無力症の進歩：Lrp4抗体陽性MGの発見

Myasthenia gravis (MG) is caused by the failure of neuromuscular transmission mediated by pathogenic autoantibodies (Abs) against acetylcholine receptor (AChR) and muscle-specific receptor tyrosine kinase (MuSK). The seropositivity rates for routine AChR binding Ab and MuSK Ab in MG are 80-85% and 5-10% for MG patients in Japan, respectively. The autoimmune target in the remaining patients is unknown. In 2011, autoantibodies against low-density lipoprotein receptor-related protein 4 (Lrp4) were identified in Japanese MG patients and thereafter have been reported in Germany and the USA. We developed a simple technique termed Gaussia luciferase immunoprecipitation for detecting antibodies to Lrp4. As a result, nine generalized MG patients from 300 lacking AChR Ab are positive for Lrp4 antibodies. Thymoma was not observed in any of these patients. These antibodies inhibit binding of Lrp4 to its ligand and are predominantly of the IgG1 subclass. In other reports of Lrp4 ab, Lrp4 ab positive sera inhibited agrin-induced aggregation of AChRs in cultured myotubes, suggesting a pathogenic role regarding the dysfunction of the neuromuscular endplate. These results indicate that Lrp4 is a third autoantigen in patients with MG, and anti-Lrp4 autoantibodies may be pathogenic. Further studies including neuromuscular junction biopsy are needed to clarify the pathomechanism of Lrp4 ab positive MG.

Neuromuscular biopsy: A review of 3 years national experience

In this paper we present the experience with 162 consecutive neuromuscular biopsies analyzed in the period from 2009 to 2012. Neuromuscular diseases are a large group of inherited and acquired diseases that are characterized by loss of muscle mass and muscle weakness. d istinguishing myopathies from peripheral neuropathy, diseases of the anterior horn cells of the spinal cord and the diseases of the neu- romuscular junction requires careful clinical evalua tion, laboratory, neurophysiological and electromyo- graphical examination, radiological tests, muscle bi- opsy and genetic testing. Muscle biopsy results can solely be interpreted in the context of the above tests. In serbia, 2009. in department of Clinical Pathology Clinical Hospital Center Zemun, a decision by the serbian Ministry of Health, began a routine diagno- stic biopsy specimens in the NMB muscles, nerves and skin.

Muscle power failure in mobility-limited older adults: preserved single fiber function despite lower whole muscle size, quality and rate of neuromuscular activation

This study investigated the physiological and gender determinants of the age-related loss of muscle power in 31 healthy middle-aged adults (aged 40-55 years), 28 healthy older adults (70-85 years) and 34 mobility-limited older adults (70-85 years). We hypothesized that leg extensor muscle power would be significantly lower in mobility-limited elders relative to both healthy groups and sought to characterize the physiological mechanisms associated with the reduction of muscle power with aging. Computed tomography was utilized to assess mid-thigh body composition and calculate specific muscle power and strength. Surface electromyography was used to assess rate of neuromuscular activation and muscle biopsies were taken to evaluate single muscle fiber contractile properties. Peak muscle power, strength, muscle cross-sectional area, specific muscle power and rate of neuromuscular activation were significantly lower among mobility-limited elders compared to both healthy groups (P ≤ 0.05). Mobility-limited older participants had greater deposits of intermuscular adipose tissue (P < 0.001). Single fiber contractile properties of type I and type IIA muscle fibers were preserved in mobility-limited elders relative to both healthy groups. Male gender was associated with greater decrements in peak and specific muscle power among mobility-limited participants. Impairments in the rate of neuromuscular activation and concomitant reductions in muscle quality are important physiological mechanisms contributing to muscle power deficits and mobility limitations. The dissociation between age-related changes at the whole muscle and single fiber level suggest that, even among older adults with overt mobility problems, contractile properties of surviving muscle fibers are preserved in an attempt to maintain overall muscle function.

Microscopic polyangiitis presenting with peripheral and central neurological manifestations

Although peripheral neuropathy is a common complication of microscopic angiitis, manifestations involving the muscle and the central nervous system have been rarely reported. We describe a 48-year-old man who rapidly developed a clinical picture of mononeuritis multiplex. A month after the appearance of the primary symptoms, he became comatose and had left hemiplegia in relation with a massive cerebral haematoma. Laboratory data revealed signs of inflammation, glomerular dysfunction with microhaematuria, and positive myeloperoxidase-antineutrophil cytoplasmic antibodies. The neuromuscular biopsy disclosed a small-vessel vasculitis, consisting with microscopic angiitis, associated with myositis and extensive axonal loss. The patient had surgical evacuation of the haematoma and received immunosuppressive therapy with good outcome. Thus, microscopic angiitis should be considered as a differential diagnosis in cases of myositis and intracerebral haemorrhage.

Chronic inflammatory demyelinating polyneuropathy in Waldenström's macroglobulinemia

Waldenström's disease (WD) is frequently associated with a predominantly sensory neuropathy with a progressive course due to the monoclonal IgM activity against Myelin Associated Glycoprotein (MAG). However, neurolymphomatosis or chronic demyelinating inflammatory polyneuropathy (CDIP) may occur in some patients with WD. We report a case of Waldenström's macroglobulinemia in an adult male presenting with cranial nerve palsy and rapidly progressive asymmetric polyneuropathy. Intravenous IgM treatment that provided transient amelioration was followed by a relapse involving tetraparesis. Cerebrospinal fluid analysis, medullar magnetic resonance imaging, and electrophysiological studies led to equivocal findings suggesting the presence of either neurolymphomatosis or CIDP. Finally, sural nerve biopsy results supported the diagnosis of CIDP, which then received appropriate treatment. In patients with WD, the possible occurrence of CIDP should be investigated with a neuromuscular biopsy when other investigations are equivocal since the disease calls for a specific treatment.

Myopathy

Published with permission from Bjorn Oskarsson, MD This brief review touches on 5 relatively new things that ought to be useful for neurologists in general practices. The chosen topics include common conditions, techniques that are rapidly growing in utilization, and new developments that mandate new paradigms of treatment. Furthermore, all topics have had important developments in the last 5 years. The first section discusses the very common myalgias, myopathies, and rare rhabdomyolysis occurring with statin use. Next, the recently established necrotizing myopathy associated with statins is described. The third topic is muscle imaging with MRI and ultrasound, which are techniques used in conjunction with neuromuscular examination, EMG, and muscle biopsies, all of which remain the mainstay of diagnostic studies for muscle disease. The fourth topic reviewed is the myositis-specific autoantibodies and their relationship to the inflammatory myopathies. Finally, enzyme replacement therapy for Pompe disease is reviewed. This is the first limb-girdle syndrome for which we have a specific treatment and this has increased the importance of firmly establishing the underlying diagnosis in patients with these phenotypes. Before proceeding, it should be acknowledged that the review will not cover other interesting developments in the field of muscle diseases, particularly the muscular dystrophies and mitochondrial muscle diseases, where huge steps in our understanding of these conditions have been made. Also, while the term myositis is often used interchangeably with myopathy in both clinical practice and in the literature, in this review the term myositis will be used exclusively for the inflammatory myopathies. It is important to be aware that the term often is used to refer to all myopathies, inflammatory or not, and that it can not be taken to imply an inflammatory etiology. Statin drugs are being used more and more frequently, with up to 29.7 million people using them in …

Clinical, biochemical, and pathological characteristics of clevudine-associated myopathy

The aim of this study was to define the clinical, biochemical, and pathological characteristics of myopathy developed during clevudine therapy. We prospectively enrolled 36 consecutive myopathy patients who were receiving clevudine therapy for the treatment of chronic hepatitis B (CHB). We evaluated patients with a complete medical history, neurologic examination with a questionnaire on neuromuscular diseases, laboratory tests, electrophysiology studies, and muscle biopsies. The median duration of clevudine therapy was 18.0 months (ranging from 9 to 24 months). The chief complaint was weakness of the lower extremities in 30 patients (83.3%) and asthenia in five patients (13.9%). One patient (2.8%) had only persistently elevated serum muscle enzyme without any symptoms. Weakness of the lower extremity mainly involved proximal muscle group of the lower extremity, characterized by difficulty in climbing stairs (83.3%), a decrease in exercise capacity (75.0%) and difficulty in walking (55.6%). All patients showed an elevation of more than two of serum creatine kinase, lactate dehydrogenase, and lactate levels. Muscle biopsies performed in 23 patients revealed myopathic features with abnormal mitochondria in 21 patients, and nonspecific myositis in two patients. Motor weakness gradually improved after discontinuation of clevudine. Myopathy associated with clevudine is characterized by a weakness in proximal muscles of the lower extremities with elevated muscle enzymes and presumably caused by mitochondrial toxicities. Careful medical and serologic examinations are essential for the early detection and management of this potential adverse reaction in CHB patients under clevudine therapy.

Corrélations anatomocliniques des neuropathies périphériques cryoglobulinémiques secondaires à l’hépatite C. Série consécutive de 22 cas

Cryoglobulinemic neuropathies caused by hepatitis C virus are frequent and may have severe clinical outcomes. The aim of this study was to clarify the clinical and anatomical correlations of these neuropathies. Between 1992 and 2007, 22 consecutive patients with cryoglobulinemic neuropathies caused by hepatitis C virus were retrospectively included. Patients were evaluated clinically, electrophysiologically and underwent a neuromuscular biopsy. The group of patients with vasculitis on nerve biopsy was compared with the group without vasculitis. All the neuropathies were axonal with 11 polyneuropathies and 11 mononeuropathies multiplex. The seven patients with medium-sized vasculitis on the nerve biopsy presented an acute sensorimotor mononeuropathy multiplex in six cases (85%), with ischemic conduction block in three cases (42%) and wallerian degeneration in four cases (57%). Among the four patients with small-sized vasculitis, two had a mononeuropathy multiplex (50%) without conduction block (0%) and with wallerian degeneration in one case (25%). The 11 patients without vasculitis (nine lymphocytic perivascular infiltrates and two non inflammatory biopsies) had a polyneuropathy in eight cases (72%) without conduction block and wallerian degeneration (0%). The type of neuropathy was different in the group of patients with vasculitis compared with the group without vasculitis. The neuropathies with vasculitis were significantly different with more frequent mononeuropathies multiplex (p<0.05), acute early stage (p<0.01), disability (p<0.05) and wallerian degeneration (p=0.01). Among hepatitis C patients with cryoglobulinemia, neuropathies with small-sized vasculitis show a pattern between severe mononeuropathies multiplex with medium-sized vasculitis and moderate polyneuropathies with lymphocytic perivascular infiltrates. In cryoglobulinemic vasculitis with hepatitis C, the severity of the neuropathy depends on the nature of the cellular inflammation and the size of the vessel involvement.

Maladie des embolies de cristaux de cholestérol révélée par un tableau de mononeuropathie

Cholesterol crystal embolism is observed in polyvascular patients usually following a medical procedure. We report a 93-year-old patient with lower limb mononeuropathy in whom cholesterol crystal embolism was confirmed by neuromuscular biopsy. Previously, an ophthalmoscopy and a livedo biopsy had been performed and the results were normal. Mononeuropathy simplex or multiplex is a clinical expression for cholesterol crystal embolism that may thus be confounded with polyarteritis nodosa. Neuromuscular biopsy can provide accurate diagnosis if other investigations are inconclusive.

Undesirable Distant Effects Following Botulinum Toxin Type A Injection

To study the incidence of clinical signs linked to botulinum toxin type A (BoNTA) spread from the injection site. Single-center, retrospective, cohort study. All patients who received BoNTA injections for spasticity treatment were assessed 1 month postinjection. Adverse effects indicative of BoNTA treatment were systematically sought. Any patient with adverse effects possibly due to BoNTA spread underwent further clinical examination and single-fiber electromyography. One patient underwent neuromuscular biopsy. Between January and September 2005, 266 BoNTA injection sessions (187 patients) were performed (233 BOTOX, 33 Dysport). Five patients presented with clinical signs of toxin spread. Four of these underwent single-fiber electromyography, which showed increased jitter. Neuromuscular biopsy detected signs of recent denervation without signs of reinnervation. Diffusion diagnosis of BoNTA from the injection site depends on clinical, temporal, and electromyographic factors. Clinical expression of spread varies widely, with mechanisms remaining largely unknown, and further prospective, randomized clinical trials are required.

Direct stimulation

Direct muscular stimulation is quick, simple, non-invasive and can be carried out at the patient's bedside. More importantly, it is reliable even when the patients cannot cooperate or are comatose. From the small amount of data available, it seems to be as accurate as neuromuscular biopsy in diagnosing critical illness myopathy. It would therefore be advisable to use it in everyday clinical practice.

Diagnostic and prognostic relevance of neuromuscular biopsy in primary Sjögren's syndrome–related neuropathy

To evaluate the clinicobiologic presentation in patients with primary Sjögren's syndrome (SS)-related peripheral neuropathy, the histologic results of neuromuscular biopsy (NMB), and clinical outcome, and to identify prognostic factors. We retrospectively studied clinical and biologic presentation of 40 patients with primary SS-related neuropathy who underwent NMB. Prognostic factors of clinical outcome were assessed by univariate and multivariate analysis. Patients with vasculitis (lymphocytic [n = 8] or necrotizing [n = 14]) had a higher prevalence of acute-onset neuropathy, multiple mononeuropathy, sensorimotor involvement, vascular purpura, general symptoms, increased C-reactive protein level, positivity for rheumatoid factor, hypocomplementemia, and monoclonal gammopathy compared with those without vasculitis (n = 18). Comparison between patients with necrotizing or lymphocytic vasculitis did not reveal significant differences in clinical or biologic presentation except for the presence of general symptoms and rheumatoid factor. Regarding clinical evolution, the results of NMB (P < 0.0001), in particular the presence of necrotizing vasculitis (P < 0.001), an acute neuropathy onset (P < 0.0001), general symptoms (P < 0.0001), multiple mononeuropathy (P = 0.0007), presence of sensorimotor involvement (P = 0.002), and increased C-reactive protein level (P = 0.008), were significantly associated with a better outcome in univariate analysis. In multivariate analysis, NMB resulting in the identification of patients with necrotizing vasculitis was the only variable that remained significantly associated with a better outcome (P = 0.01). NMB is necessary to identify patients with necrotizing vasculitis, who have a better response to immunosuppressive therapy. NMB might therefore have both a diagnostic and prognostic relevance in primary SS-related neuropathy.