Peripheral Nerve Biopsy Research Articles

PATHOGENESIS, CLINICAL AND LABORATORY FEATURES OF CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired progressive or relapse-remitting immunemediated disease of peripheral nervous system. CIDP has typical and atypical variants. Typical variant includes development of symmetric motor and sensory nerve fibers functions abnormalities. The diagnosis of CIDP reveals on clinical presentation and electrophysiological data. There aren’t any biomarkers of such disease. Cerebrospinal fluid analysis, magnetic resonance tomography of peripheral nerves and nerve biopsy may be additional methods to confirm the diagnosis. Instead of international criteria of CIDP diagnosis and large variety of laboratory and instrumental methods, there are many difficulties to make the appropriate diagnosis. This review discusses current concepts of pathogenesis, clinical diagnostics and laboratory and instrumental methods used for differential diagnosis and confirmation of the diagnosis of CIDP and new areas in CIDP research.

Macrophage Depletion Ameliorates Peripheral Neuropathy in Aging Mice.

Aging is known as a major risk factor for the structure and function of the nervous system. There is urgent need to overcome such deleterious effects of age-related neurodegeneration. Here we show that peripheral nerves of 24-month-old aging C57BL/6 mice of either sex show similar pathological alterations as nerves from aging human individuals, whereas 12-month-old adult mice lack such alterations. Specifically, nerve fibers showed demyelination, remyelination and axonal lesion. Moreover, in the aging mice, neuromuscular junctions showed features typical for dying-back neuropathies, as revealed by a decline of presynaptic markers, associated with α-bungarotoxin-positive postsynapses. In line with these observations were reduced muscle strengths. These alterations were accompanied by elevated numbers of endoneurial macrophages, partially comprising the features of phagocytosing macrophages. Comparable profiles of macrophages could be identified in peripheral nerve biopsies of aging persons. To determine the pathological impact of macrophages in aging mice, we selectively targeted the cells by applying an orally administered CSF-1R specific kinase (c-FMS) inhibitor. The 6-month-lasting treatment started before development of degenerative changes at 18 months and reduced macrophage numbers in mice by ∼70%, without side effects. Strikingly, nerve structure was ameliorated and muscle strength preserved. We show, for the first time, that age-related degenerative changes in peripheral nerves are driven by macrophages. These findings may pave the way for treating degeneration in the aging peripheral nervous system by targeting macrophages, leading to reduced weakness, improved mobility, and eventually increased quality of life in the elderly.SIGNIFICANCE STATEMENT Aging is a major risk factor for the structure and function of the nervous system. Here we show that peripheral nerves of 24-month-old aging mice show similar degenerative alterations as nerves from aging human individuals. Both in mice and humans, these alterations were accompanied by endoneurial macrophages. To determine the pathological impact of macrophages in aging mice, we selectively targeted the cells by blocking a cytokine receptor, essential for macrophage survival. The treatment strongly reduced macrophage numbers and substantially improved nerve structure and muscle strength. We show, for the first time, that age-related degenerative changes in peripheral nerves are driven by macrophages. These findings may be helpful for treatment weakness and reduced mobility in the elderly.

Immunohistochemestry for nerve morphometry?

Peripheral nerve biopsy is an invaluable aid to diagnosis carefully selected patients. The nerves histological evaluation gives clues for investigating diseases mechanisms and causes, as well as guides the therapeutic planning of inflammatory, infectious, demyelinating or degenerative lesions [1]. Nerves histological processing method that provides the best image quality is the epoxy resin embedding. Thus, nerve sections can be observed by light and/or transmission electron microscopy (TEM) and classes of nerve fibers can be morphometrically identified and studied. Epoxy resin embedding and TEM is considered the gold standard method for unmyelinated fibers identification and quantification. More recently, the immunohistochemistry technique (IHC) is being added to the inflammatory neuropathy investigation and the most important of the panel of antibodies employed are those needed to differentiate lymphocytes into T (CD3þve) and B cells (CD20þve). In addition, antibodies against macrophages, myelin basic protein, neurofilaments, and epithelial membrane antigen (EMA) (for perineurial cells) are included [1]. Neurotransmitters and their fiber “carrier” are much less explored. We suggest that it would be possible to use the IHC to identify nerve fiber classes as an alternative to TEM and morphometry, with the gain on functional information. To investigate this hypothesis we used IHQ and immunofluorescence (IF) to immunolabel small myelinated and unmyelinated fibers in sural nerves of rats. The nerves were surgically removed, immersed in paraformaldehyde 4% for 18 hours, and cryoprotected in increasing concentrations of sucrose solutions, before transversal cryosectioning (12μm). For IHC, sections were incubated in rabbit polyclonal antibody anti‐substance P (1:5.000, 18h) followed by anti‐rabbit IgG (1:500; 2h) and Extravidin‐HRP (1:1500, 2h). A reaction with diaminobenzidine intensified with nickel revealed immunoreactivity, observed by light microscopy. For IF, sections were incubated in rabbit polyclonal antibody anti‐substance P (1:1.000, 18h) followed by anti‐rabbit IgG (Alexa Fluor® 594) (1:200, 2h). The immunoreactivity was observed by fluorescence microscopy. Both protocols worked on transverse sections to identify substance P immunolabeled small myelinated and unmyelinated fibers. Results were compared with transverse sections prepared for TEM and the IHC results showed labeled small myelinated and unmyelinated axons intermingled with large unlabeled myelinated axons, with preservation of their myelin sheath. The IHC transverse sections were comparable to the epoxy resin embedded for small fiber localization in the endoneural space. Further studies on quantification of these fibers will be performed comparing both methods (IHC and IF) with the TEM images in order to show that IHC might also be a reliable method for quantifying axons.Support or Funding InformationFinancial support: FAPESP, CNPq, CAPES and FAEPAThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Conference lecture: Electrophysiological diagnosis of inflammatory demyelinating neuropathies

Electrophysiology plays a crucial role in the characterization and diagnosis of peripheral neuropathies. It provides insight in the type and mechanism of peripheral neuropathy by giving information on the spatial pattern, the fibre type involved, pathology (axonal, demyelinating), and the severity and time course. Inflammatory demyelinating neuropathies constitute a significant proportion of the acquired peripheral neuropathies. They include Guillain-Barre syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN), multifocal demyelinating neuropathy with persistent conduction block (Lewis-Sumner syndrome), and paraproteinemic neuropathies. A proper diagnosis as early as possible is very important because timely immune treatment can largely reduce morbidity and disability. The diagnosis is based on a constellation of clinical and laboratory features, including electrophysiological studies, spinal fluid examination, and in selected cases serological studies and peripheral nerve biopsy. Electrophysiological studies are key in the early detection and characterization of inflammatory demyelinating neuropathies and in differentiating these from primary axonal neuropathies. In CIDP, electrophysiological criteria for demyelination are designed to exclude abnormalities that can be explained by axonal degeneration (Eur J Neurol 2010). Therefore, lesser degrees of demyelination cannot be defined with certainty. Optimised electrophysiological criteria are capable, however, to support the diagnosis with different levels of probability (possible, probable, definite) in the very large majority of cases. In GBS, much effort has gone into developing criteria which can distinguish axonal and demyelinating subtypes. The discovery of reversible conduction failure (RCF) has led to the concept of nodopathy/paranodopathy, where conduction slowing and conduction block are due to the immune attack mainly at the nodal axolemma level. There is no actual demyelinisation as defined pathologically and if the immune attack continues, conduction failure may not reverse and axonal degeneration will ensue. Recent electrophysiological studies support this pathophysiological mechanism and show that the dichotomous distinction between axonal and demyelinating in GBS is not tenable (Muscle nerve, 2018).

Neuroinfectious Diseases: Guillain Barre Syndrome Clinical Features Suggestive of Early Diagnosis

Guillain Barré syndrome is one of the best examples of a post infectious immune disease and offers insights into the mechanism of tissue damage in other more common autoimmune diseases. Controlled epidemiological studies have linked it to infection with Campylobacter jejuni in addition to other viruses including cytomegalovirus and Epstein Barr virus. The syndrome includes several pathological subtypes, of which the most common is a multifocal demyelinating disorder of the peripheral nerves in close association with macrophages. Evidence from histological examination of peripheral nerve biopsy and postmortem samples suggests that both cell mediated and humoral mechanisms are involved in the pathogenesis. Immunological studies suggest that at least one third of patients have antibodies against nerve gangliosides, which in some cases also react with constituents of the liposaccharide of C jejuni. In the Miller Fisher variant of the disease, these antiganglioside antibodies have been shown to produce neuromuscular block, and may in part explain the clinical signs of that disorder. Treatment with both intravenous immunoglobulin and plasma exchange reduces the time taken for recovery to occur, although mortality remains around 8%, with about 20% of patients remaining disabled.

The intercostal nerve as a target for diagnostic biopsy.

OBJECTIVE Peripheral nerve biopsy is a useful tool in diagnosing peripheral neuropathies. Sural and gracilis nerves have become the most common targets for nerve biopsy. However, the yield of sural nerve biopsy is limited in patients who have motor neuropathies, and gracilis nerve biopsy presents technical challenges and increased complications. The authors propose the intercostal nerve as an alternative motor nerve target for biopsy. METHODS A total of 4 patients with suspected peripheral neuropathies underwent intercostal nerve biopsy at the authors' institution. A rib interspace that is inferior to the pectoralis muscle and anterior to the anterior axillary line is selected for the procedure. Generally the lower intercostal nerves (i.e., T7-11) are targeted. An incision is made over the inferior aspect of the superior rib at the chosen interspace. Blunt dissection is carried down to the neurovascular bundle and the nerve is isolated, ligated, and cut to send for pathological examination. RESULTS The average operative time for all cases was 73 minutes, with average blood loss of 8 ml. Biopsy results from 1 patient exhibited axonopathy, and the other 3 patients demonstrated axonopathy with demyelination. There were no short- or long-term postoperative complications. None of the patients reported sensory or motor deficits related to the biopsy at 6 weeks postoperatively. CONCLUSIONS The intercostal nerve can be an alternative target for biopsy, especially in patients with predominantly motor neuropathies, due to its mixed sensory and motor fibers, straightforward anatomy, minimal risk of serious sensory deficits, and no risk of motor impairment.

Chronic inflammatory demyelinating polyneuropathy: A case report

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a treatable autoimmune neuropathic condition, which characterize progressive and relapsing stages. Major clinical presentations are gradatory increasing sensory loss and weakness interrelated with loss of reflexes. Relapse can occur at any time for CIDP patients. Diagnosis is based on cerebrospinal fluid protein, electromyography, nerve conduction velocity (NCV) test, peripheral nerve biopsy and electron micrograph of peripheral nerve. Standard treatments for CIDP are corticosteroids, Intravenous Immune Globulin (IVIG), plasma exchange or plasmapheresis. Second line drugs commonly used are immunosuppressant and immune modulatory agents, there are usually chemotherapy drugs which should be only given in special circumstances by specialist in their use. A 55 year old female encountered in the department of neurology, old case of Guillain-Barre Syndrome (GBS) was treated with steroids, later developed CIDP and was on reduced dose of prednisolone. Now presented with complaints of numbness and difficulty in walking, diagnosed to have CIDP relapse. Started treatment with corticosteroid [Tab. Wysolone (prednisolone) 50mg 1-0-0] and immunosuppressant [Tab. Cellcept (mycophenolate mofetil) 500mg 1-0-1]. Patient had significant improvement in symptoms. This case of CIDP relapse is effectively treated with corticosteroid and immunosuppressant with tapering of steroid dose.

THE SPECTRUM OF CONGENITAL MYOPATHIES IN ROMANIA – A PATHOLOGICAL RETROSPECTIVE STUDY

Objectives. Congenital myopathies (CM) are a highly heterogeneous group of disorders with genetic cause, characterized by motor deficit and weakness usually manifesting in the neonatal period, with slowly progressive or non-progressive course and affecting both sexes. MC classification has undergone many changes over time, and in recent years molecular genetic studies have enabled identification of novel genes and mutations, thus increasing the diagnostic complexity. We wanted to study the incidence and morphological features of the CM cases diagnosed by muscle biopsy in the Pathology Department of Colentina University Hospital over a period of 10 years (09.2005- 09.2015). Materials and methods. We retrospectively reviewed all the muscle biopsies diagnosed with different types of CM. Muscle biopsies were performed and specifically processed using routine and special stains on cryosections, semithin and ultrathin sections for ultrastructural examination. In all the cases we reassessed the clinical and laboratory data. Results. From a number of 1,530 peripheral nerve and muscle biopsies performed and analyzed in the 10 years period we diagnosed CM in 15 cases, representing 1.03% of the total. Of these, five were “central core myopathies”, five centronuclear/myotubular myopathies, one case of nemaline myopathy, one case of “reducing body myopathy” and three cases with congenital fiber type disproportion. Reassessment of morphological data in the clinical context allowed us to identify numerous overlaps between subtypes both in the clinical and pathological picture. Conclusions. The reduced number of MC identified in our country suggests that these diseases are probably underdiagnosed or diagnosed late, requiring a better understanding of the various clinical and pathological particularities. In the accurate diagnostic algorithm, muscle biopsy remains essential to establish the type of CM and thus to direct genetic tests.

Downregulation of the sodium channel Nav1.6 by potential transcriptomic deregulation may explain sensory deficits in critical illness neuropathy.

Sepsis patients and other patients in the critical care settings are at very high risk of mortality due to the primary illness. However, a fraction of patients, even after showing initial clinical improvement, deteriorates relentlessly at later stages. Increasingly, it is being identified that this is mostly due to dysfunction of the neurological system. We obtained peripheral nerve biopsies from the sural nerve from ICU patients. Nav1.6 expression was significantly diminished. The expression of cellular membrane anchoring protein for Nav1.6, ankyrin, remained unaffected, suggesting that genomic repression may be responsible for the diminished expression of the sodium channels. We examined the expression of two regulatory transcription factors: (a) a positive regulator YY1 that binds to the promoter region of sodium channels and (b) an upstream negative neuronal regulator REST. REST expression was significantly elevated, while YY1 expression was diminished. Finally, we also observed that the cholinergic synthetic enzyme acyltransferase was also significantly diminished in sensory nerve lysates. Finally, circulating antibodies was detected in the peripheral blood against all the major sodium channels Nav1.6, 1.8 and 1.9, which contribute to the development and propagation of action potentials. This may potentially explain why its dysfunction affects neurological functions across all systems of the body during critical illness. The underlying mechanism of why the expression of the REST transcriptional factor is affected in critical illnesses remains our future goals of investigation.

Optical Biopsy of Peripheral Nerve Using Confocal Laser Endomicroscopy: A New Tool for Nerve Surgeons?

Peripheral nerve injuries remain a challenge for reconstructive surgeons with many patients obtaining suboptimal results. Understanding the level of injury is imperative for successful repair. Current methods for distinguishing healthy from damaged nerve are time consuming and possess limited efficacy. Confocal laser endomicroscopy (CLE) is an emerging optical biopsy technology that enables dynamic, high resolution, sub-surface imaging of live tissue. Porcine sciatic nerve was either left undamaged or briefly clamped to simulate injury. Diluted fluorescein was applied topically to the nerve. CLE imaging was performed by direct contact of the probe with nerve tissue. Images representative of both damaged and undamaged nerve fibers were collected and compared to routine H&E histology. Optical biopsy of undamaged nerve revealed bands of longitudinal nerve fibers, distinct from surrounding adipose and connective tissue. When damaged, these bands appear truncated and terminate in blebs of opacity. H&E staining revealed similar features in damaged nerve fibers. These results prompt development of a protocol for imaging peripheral nerves intraoperatively. To this end, improving surgeons' ability to understand the level of injury through real-time imaging will allow for faster and more informed operative decisions than the current standard permits.

Protocolo diagnóstico de la mononeuritis y multineuritis

Mononeuropathies are a frequent complaint. The most common cause of acute mononeuropathy is trauma, and the most common cause of chronic mononeuropathy is entrapment in anatomical locations where the nerves are most vulnerable to compression. Mononeuropathy includes carpal tunnel syndrome. A neurophysiological examination is essential for establishing the level and degree of injury, thereby guiding the therapy. Multiple mononeuropathies can be secondary to systemic diseases such as vasculitis and infections (e.g., HIV, borreliosis and leprosy). The study protocol can be complex and includes an electrophysiological study, autoantibody measurements, serology, cerebrospinal fluid analysis and peripheral nerve biopsy. When there is clinical suspicion, it is vitally important to schedule a study rationally and quickly, due to the possibility of treatment of many of its causes.

Neuropatías, radiculopatías y plexopatías

Peripheral neuropathies are common and complex neurological diseases due to the considerable variety of causes that can result in the same pattern of clinical impairment. These diseases are characterized by motor, sensory and autonomic symptoms that can follow various distribution patterns (mononeuropathy, multiple mononeuropathy, polyradiculoneuropathy and distal symmetrical polyneuropathy). After conducting clinical typing, various additional tests (electrodiagnostic study, laboratory tests, lumbar puncture, peripheral nerve or skin biopsy) should be performed to determine the possible etiology of the clinical pattern presented by the patient. It is important to reach an etiological diagnosis for those neuropathies susceptible to treatment. Radiculopathy is another common disease of the peripheral nervous system and is generally due to mechanical pressure on the root due to degenerative causes (spondyloarthrosis, herniated disc). Brachial plexus or lumbosacral lesions are less common and can be caused by trauma, postradiotherapy lesions and metastatic infiltration, among others.

AN EVALUATION OF THE USEFULNESS OF PERIPHERAL NERVE BIOPSIES

Peripheral nerve biopsy may be useful in selected patients, but practice varies, partly due to continued uncertainty over usefulness of biopsy. An audit was completed of all patients who had undergone nerve biopsy over a 3 year period (2009–2012) at a tertiary regional neuroscience centre. 61 patients were identified and medical information of 54 patients was obtained (33 male, 21 female patients; mean age 63.6 years). The sural nerve was the most commonly biopsied nerve (94.4%). Complications (pain, stitch extrusion, dysaesthesia, infection) occurred in 7.4%. Neurophysiological pre-biopsy diagnosis was axonal in 74.1% (37.5% vasculitic); demyelination in 14.8% (all CIDP); axonal and demyelinating in 9.3%, and MND in 1.9%. Overall, biopsy led to diagnostic confirmation in 14.8% of patients, change of diagnosis in 11.1%, and change to treatment in 9.3%. As some patients were represented in more than one of these groups, overall 72.2% of biopsies yielded neither further diagnostic information, nor led to change in diagnosis or treatment. Nerve biopsy was of clinical benefit to 1 in 4 patients and management was directly altered in 1 in 11 patients. Nerve biopsy remains of use, and has an acceptable complication rate in diseases with significant burden from ineffective or inappropriate treatment.

Evaluation of simultaneous muscle and nerve biopsies for the diagnosis of neuromuscular diseases.

Skeletal muscle and peripheral nerve are occasionally simultaneously biopsied with the goal of increasing diagnostic yield in patients with an uncertain clinical diagnosis or in cases where the pathology is known to be focal or multifocal (eg, vasculitis or amyloidosis). The purpose of the present study is to evaluate the diagnostic utility of performing simultaneous muscle and nerve biopsies. A surgical pathology database was searched from 1993 to 2011 to identify patients who had concomitant skeletal muscle and peripheral nerve biopsies. Demographic and pathologic findings were recorded for all cases. Two hundred eighty-seven patients were included for study. There were 161 (56%) males and 126 (44%) females with a mean age at the time of biopsy of 51 years. The most commonly sampled sites were gastrocnemius muscle (n=186, 65%) and sural nerve (n=264, 92%). Most cases (n=166, 58%) were found to have a definitive diagnosis in either muscle or nerve. Of the cases with definitive diagnoses, 44 (27%) were based off the muscle only, 100 (60%) off the nerve only, and 22 (13%) had a definitive diagnosis in both the muscle and nerve. The most common diagnoses made on muscle biopsy alone were denervation atrophy (n=34) and inflammatory myopathy (n=7). The most common diagnosis made on nerve biopsy alone was a moderate or greater degree of axonal loss (n=82). Vasculitis was found in muscle in 2 cases, in the nerve in 14 cases, and both muscle and nerve in 4 cases. Amyloidosis was exclusive to muscle in no cases, was seen in nerve only in 1 case, and was found in both muscle and nerve in 4 cases. Performing simultaneous muscle and nerve biopsies can improve diagnostic yield (from 8% to 58% in the current study).

1. Electrophysiology in the diagnosis of inflammatory demyelinating neuropathies

Inflammatory demyelinating neuropathies constitute a significant proportion of the acquired peripheral neuropathies. They include Guillain–Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN), multifocal demyelinating neuropathy with persistent conduction block (Lewis–Sumner syndrome), and paraproteinemic neuropathies. Inflammatory demyelinating neuropathies are receiving increasing attention because they are treatable. A proper diagnosis as early as possible is very important because timely immune treatment can largely reduce morbidity and disability. The diagnosis is based on a constellation of clinical and laboratory features, the latter including electrodiagnostic (nerve conduction) studies, spinal fluid examination, and in selected cases serological studies and peripheral nerve biopsy. Electrodiagnostic studies play a key role in the early detection and characterization of inflammatory demyelinating neuropathies. Making the diagnosis of inflammatory demyelinating neuropathy, in particular when the disease course is chronic, is often difficult. Diagnostic criteria are very important but given the lack of a definitive diagnostic marker and the limitations of laboratory studies, it appears impossible to reach a definitive diagnosis in all patients. By definition, electrophysiological criteria for primary demyelination are designed to exclude abnormalities that can be explained by axonal degeneration. Therefore, lesser degrees of demyelination can not be defined with complete certainty electrophysiologically. Optimised electrophysiological criteria are capable, however, to support the diagnosis with different levels of probability (possible, probable, definite) in the very large majority of cases.

Intra‐axonal protein aggregation in the peripheral nervous system

Intracellular protein aggregates are common pathological hallmarks of many neurodegenerative disorders, and a defect in axonal transport is also incriminated. Here, we studied intra-axonal abnormal protein aggregation and axonopathy by using immunohistochemistry and electron microscopy on peripheral nerve biopsies from 12 patients with chronic axonal peripheral neuropathy (PN) of unknown etiology. Among these patients, three had idiopathic Parkinson's disease (PD). Intra-axonal ubiquitin aggregates were more numerous in the patients with PD. Intra-axonal aggregates of tau AT8 were found in five patients without PD. Phosphorylated α-synuclein aggregation was absent in all cases, while intra-axonal colocalization of 14-3-3 β and ubiquitin was observed in two PD cases. Electron microscopy revealed enlarged axons crowded with organelles in six cases, including the three patients with PD, thus attesting a slowing of the axoplasmic flux. The number of ubiquitin aggregates was correlated with features of reduced axonal flux, while no such correlation was found for tau and 14-3-3 β. Age did not correlate with the number of tau, ubiquitin, and 14-3-3 aggregates. Thus, both ubiquitin and/or abnormal tau intra-axonal aggregates may be found in chronic axonal PN. Ubiquitin aggregates might reduce the axonal flux or result from a disease producing slowing of axonal transport.

An Attempt to Improve Pure Neural Leprosy Diagnosis Using Immunohistochemistry Tests in Peripheral Nerve Biopsy Specimens

The diagnosis of pure neural leprosy (PNL) is based on clinical and laboratory data, including the histopathology of nerve biopsy specimens and detection of Mycobacterium leprae DNA by polymerase chain reaction (PCR). Given that histopathologic examination and PCR methods may not be sufficient to confirm the diagnosis, immunolabeling of lipoarabinomanan (LAM) and/or phenolic glycolipid 1 (PGL-1) M. leprae wall components was utilized in the present investigation in an attempt to detect any vestigial presence of M. leprae in acid-fast bacilli (AFB) nerve samples. Twenty-three PNL nerve samples (6 AFB and 17 AFBPCR) were cryosectioned and subjected to LAM and PGL-1 immunohistochemical staining by immunoperoxidase. Five nonleprosy nerve samples were used as controls. The 6 AFB samples showed LAM/PGL-1 immunoreactivity. Among the 17 AFB samples, 8 revealed LAM and/or PGL-1 immunoreactivity. In 17 AFBPCR patients, just 7 yielded LAM and/or PGL-1 nerve results. In the PNL cases, the detection of immunolabeled LAM and PGL-1 in the nerve samples would have contributed to an enhanced diagnostic efficiency in the absence of molecular diagnostic facilities.

Anti-GQ1b ganglioside positive Miller Fisher syndrome – evidence of paranodal pathology on nerve biopsy

Miller Fisher syndrome is a regional variant of Guillain-Barre syndrome with a characteristic clinical triad of ophthalmoplegia, areflexia and ataxia and occasionally distal limb sensory loss. 90% of patients have associated antibodies to the GQ1b ganglioside. The pathophysiology of antibody-mediated peripheral nerve impairment remains uncertain. This report includes the first description of a peripheral sensory nerve biopsy in Miller Fisher syndrome. A single case report is described of a 46 year old woman who presented with 2 weeks of distal glove and stocking sensory loss to both deep and superficial sensory modalities, areflexia and weight loss. This was followed by rapid onset of ataxia, ophthalmoplegia, and bulbar impairment. Peripheral neurophysiology showed reduced sensory nerve amplitudes with preserved conduction velocities in keeping with an axonal pattern of impairment. Clinical concerns of a systemic inflammatory disorder led to a diagnostic peripheral nerve biopsy from the sensory branch of the radial nerve. However she subsequently made a complete recovery over 5 weeks. Combinatorial glycoarrays confirmed restricted serum binding for GQ1b in acute serum which later resolved in a convalescent sample. The nerve biopsy showed lengthening of nodes of Ranvier, myelin splitting and macrophage internodal axonal invasion without any features of demyelination. The pathological features were strikingly similar to those found in acute motor axonal neuropathy and indicate the region of the node of Ranvier to be a primary focus of GQ1b induced damage in Miller Fisher syndrome, at least in this particular overlap syndrome with prominent sensory nerve involvement.

P72: Can violations of nitric oxide and superoxide anion radical cycles influence the process of demyelination-remyelination at Guillain–Barre syndrome?

Many medical specialists investigated the role of NO and NO-synthases in biological systems. To our mind, many incomprehensible phenomena and facts that are contradictory at the first sight could be explained based on the concepts of the nitric oxide and superoxide anion radical cycles [1] , [2] . Relevance histochemical research on the dynamics NO-synthase/NADPH-diaphorase in biopsies of peripheral nerve due to the fact that they can give an answer to the question: how Schwann cells using intracellular “nanotechnology” with NO, solve problems repair nerve conductive paths in normal conditions and pathology [3] . We examined the NADPH-diaphorase histochemistry in Guillain–Barre syndrome in the six peripheral nerve biopsies in the period from 11 to 52 days. Tissue samples were examined by electron microscopy and light and electron microscopy NADPH-diaphorase histochemistry, using the tetrazolium method in our modification [3] , [4] . This modification allowed the visualization of one the same object on adjacent sections at the level of light and electron histochemistry. We have investigated the localization of marker NO-synthase/NADPH-diaphorase in peripheral nerve biopsy of the skin (nerve suralis), taken at different stages of the flow of severe Guillain–Barre syndrome-an inflammatory demyelinating disease. It has been shown that, depending on the stage of the disease, changes in the distribution of NO-synthase/NADPH-diaphorase in Schwann and immune cells. The dynamics of growth and decline NO-synthase/NADPH-diaphorase activity in these cells was different. These data suggest that the activation of the mechanism of demyelination in Schwann cells surrounding the peripheral nerves of the skin, changes NO-synthase/NADPH-diaphorase distribution, which may indicate the important role of NO and products of metabolism in the development of Guillain–Barre syndrome. Comparison of the results of light and electron histochemistry, with survey data obtained by electron microscopy and ultrastructural pathology allowed to associate with the cellular and sub-cellular parameters reflecting NO-synthase/NADPH-diaphorase localization and activity of this enzyme. Histochemical analysis of data on changes in NO-synthase/NADPH-diaphorase Schwann and immune cells in the development of Guillain–Barre syndrome-a demyelinating disease conducted from the standpoint of normal physiological disorders of regulatory mechanisms that operate in a cyclic or periodic mode [1] , [2] , [3] , [4] . Supported by a research grant from RFFI.

The “multifaceted” onset of vasculitis neuropathy

The article from Lozeron et al. [1], published in this issue of Internal and Emergency Medicine, underscores the importance of recognizing or suspecting a systemic vasculitis in patients who complain of atypical or refractory sciatica-like symptoms. Vasculitides is a group of systemic diseases characterized by a protean clinical presentation, usually with a pattern of multi-organ involvement, which if not promptly diagnosed, may be responsible for severe morbidity and mortality [2]. The following article reminds us that besides usual peripheral neurological presentations classically associated with systemic vasculitides, i.e., multifocal motor neuropathy or less frequently symmetric peripheral neuropathies, unusual neurological symptoms can in rare instances mark the disease onset [3]. Even if lumbosacral radiculoplexus neuropathy is mainly associated with microischemic events and diabetes mellitus, which was correctly ruled out in 8 of the study patients, it is also described in non-diabetic patients who probably suffered an underlying autoimmune microvasculitis process [4]. The possibility of an autoimmune lombosacral plexus radiculitis should be particularly looked for when sciatica-like symptoms, in non-diabetic patients, are not fully explained by radiological spine findings; or when the controlateral limb is subsequently involved, in a pattern ultimately resembling a multifocal neuropathy. Furthermore, these patients often undergo unnecessary and repeated spine surgery procedures. Besides the importance of a thorough history taking and physical examination, the authors underscore the role of correctly performing a nerve conduction study. This examination shows axonal damage and asymmetric multifocal involvement, giving an early basis for suspecting a vasculitis, and for performing subsequent investigations. The other fundamental step is a peripheral nerve biopsy, a very useful procedure especially when a vasculitis is suspected in patients with an atypical neurologic pattern of presentation. In this following study, biopsy specimens show fibrinoid necrosis in all patients, histologically supporting the classification criteria for diagnosing polyarteritis nodosa, confirming the well-known concept that this entity is probably the vasculitis most often associated with peripheral multifocal neuronal involvement [5, 6]. In summary, this article should remind us of what suspecting a rare disease in clinical practice means for doctors, and the importance of looking ‘‘beyond’’ common symptoms when these are atypical or refractory to standard treatment [7]. Regarding this last matter in particular, it is really worthwhile to underscore the fundamental role of tertiary referring centers for rare diseases, such as the center for rare peripheral neuropathies that conducted the study, since they probably represent the place where difficult-to-treat or refractory patients can have the best or the only chance to achieve a definitive and correct diagnosis.