Epidemic neuropathy in Cuba: Morphological characterization of peripheral nerve lesions in sural nerve biopsies

More than 50 000 patients were affected in Cuba during an epidemic outbreak of peripheral neuropathy from January 1992 until September 1993. The disease presented as either a retrobulbar optic neuropathy, a predominantly sensory peripheral neuropathy, a dorsolateral myeloneuropathy, or as mixed forms. The morphological findings in sural nerve biopsies from 34 patients with various forms of the disease are presented here. Frozen, paraffin and semi-thin sections were prepared for light and electron microscopy, immunohistochemistry and morphometric analysis. Every case presented morphological alterations ranging from mild axonal dystrophy (9 cases, or 27%) to moderate and severe axonal damage (25 cases, or 73%). In 6 cases (18%), axonal damage was accompanied by perineural fibrosis and vascular abnormalities. Axonal regeneration was noted in 8 cases (23%) and remyelination in 9 (26%). Morphometric analysis showed a predominant loss of myelinated fibers in 92% of the patients. Quantification of myelinated fiber loss in 11 patients revealed a remarkable decrease in large caliber fibers. Scarce mononuclear cells were observed in 17 cases. No virus-like elements were seen. The morphological features found in this study indicate that, regardless of the clinical presentation, peripheral nerve lesions of the epidemic neuropathy in Cuba correspond to an axonal neuropathy. These lesions are compatible with nutritional, toxic, or metabolic etiologies. An inflammatory etiology would be unusual with these lesions.     

Diabetic peripheral neuropathy: A clinicopathologic and immunohistochemical analysis of sural nerve biopsies

We performed quantitative immunohistochemical studies of sural nerve biopsy specimens from 20 patients to determine whether endoneurial and epineurial lymphocytic infiltration occurs in diabetic nerves. The diabetic nerves contained a mean of 129 CD3⁺ cells per tissue section compared to 19 cells in patients with chronic neuropathy matched for the histologic severity of disease, and 0–5 cells in normal control nerves. The T-cell infiltrates in the diabetic nerves were predominantly of the CD8⁺ cell type. Activated endoneurial lymphocytes expressed immunoreactive cytokines and major histocompatibility class II antigens. Microvasculitis was found in 12 (60%) patients. Infiltrative T cells may contribute to the pathogenesis of diabetic neuropathy through a variety of effector mechanisms. © 1996 John Wiley & Sons, Inc.     

Sequelae of sural nerve biopsies

Sequelae of sural nerve biopsy were examined in 24 patients. Fourteen subjects reported persisting pain or dysaesthesias for more than one year. In nine patients the symptoms were mild, in five severe. Hypaesthesia of the lateral aspect of the foot was found in 17 out of 18 patients with otherwise normal or only slightly impaired sensory function. In one patient sural nerve biopsy did not cause permanent sensory loss. Pain and dysaesthesia were not significantly related to post-biopsy or generalized hypaesthesia.     

Polyglucosan bodies in sural nerve biopsies

Summary The presence of polyglucosan bodies in sural nerves collected over a 16-year period was studied in relation to age, sex, presence of polyneuropathy, and concomitant presence of central nervous system disorder. Polyglucosan bodies have been seen in only one patient without a polyneuropathy. This patient was suffering from Lafora's disease. In all other sural nerves positive for polyglucosan bodies a polyneuropathy was present. Within this group the prevalence of polyglucosan bodies was positively correlated with age, and if a central nervous system disorder was associated, this prevalence was more distinct. With semiquantitative measurements of the surface of polyglucosan bodies a significant correlation was found between age and percentage of large bodies.     

Inflammatory infiltrates in sural nerve biopsies in Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy

Prompted by observations in experimental autoimmune neuritis we reanalyzed immunohistochemically the inflammatory infiltrates in sural nerve biopsies of 22 cases with Guillain-Barré syndrome (GBS) and 13 cases with chronic inflammatory demyelinating polyneuropathy (CIDP). Endoneurial infiltration of CD3+ T cells was found in 20 cases of GBS (median 5.5 cells/mm²) and in 10 cases of CIDP (5 cells). Epineurial T cells were present in all GBS cases (19.5 cells) and in 11 CIDP cases (21 cells). CD68+ macrophages were abundant in these neuropathies and often occurred in endoneurial perivascular clusters. In GBS subgroups the number of endoneurial T cells was significantly higher in patients with hypoesthesia and abnormal electrophysiological findings in the sural nerve. In CIDP hypoesthesia was associated with significantly higher numbers of macrophages. Our study also indicates that other factors including the time point of biopsy or previous corticosteroid treatment may influence the inflammatory cell profile. Quantifying cell infiltration may aid in establishing the diagnosis of an immunoneuropathy in patients with mild and noncharacteristic pathology. © 1996 John Wiley & Sons, Inc.     

Phenytoin neuropathy: structural changes in the sural nerve

Phenytoin has been implicated as a causative agent in peripheral neuropathy, although structural changes in nerve have not been characterized. A 47-year-old man was seen with clinical and electrophysiological signs of peripheral neuropathy after 30 years of phenytoin administration. Despite a modest dose of phenytoin (300 mg/day) blood levels were 31 to 38 micrograms/ml. A sural nerve biopsy showed a loss of large myelinated nerve fibers and a nonrandom clustered distribution of segmental demyelination and remyelination. The latter findings were accompanied by axonal shrinkage. Sixteen months after phenytoin was stopped, the patient's clinical and electrophysiological findings reflected improvement. These data indicate that long-term phenytoin administration can cause a reversible neuropathy characterized by axonal shrinkage and secondary demyelination.     

Occupational neuropathy of the sural nerve

A 20-year-old carpet-layer with compression of the right sural nerve due to the peculiar posture maintained during his work is described, and electromyographic findings are presented.

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Sommario Il presente lavoro riporta i risultati ottenuti dallo studio elettromiografico eseguito su un posatore di “moquette” di 20 anni affetto da una compressione del nervo surale destro causata dalla peculiare postura mantenuta durante il lavoro.

     

HLA-DR-expressing cells and T-lymphocytes in sural nerve biopsies

Thirty-five sural nerve biopsies were stained immunohistochemically for HLA-DR antigen. HLA-DR was expressed on nonmyelinating Schwann cells, macrophages, vascular endothelium, and perineurium. By means of double immunofluorescence staining the identity of the HLA-DR presenting structures was confirmed. HLA-DR expression was found in all biopsies and thus was not restricted to any particular type of neuropathy. The HLA-DR expression appeared to correlate with severity and activity of the neuropathy. HLA-DR-expressing macrophages wrapping myelinated fibers were prominent in primary demyelinating neuropathies. T-cells were found in 6 out of 15 nerves examined. Their presence correlated with moderate to strong HLA-DR expression of nonmyelinating Schwann cells, and they occurred during active disease.     

Complications following sural and peroneal nerve biopsies

Nerve biopsy is used as part of the investigation of patients with peripheral neuropathy and is particularly useful in confirming the diagnosis of peripheral nerve vasculitis. Previous studies have suggested that sampling the peroneal nerve, in combination with peroneus brevis, is more sensitive than the sural nerve for this diagnosis but there are no published data on the complication rate of peroneal nerve biopsies. We have assessed the complications in 50 patients undergoing nerve biopsy, and have shown that although biopsy of the peroneal nerve may result in a larger area of sensory loss in some patients, other complications are not increased when compared with sural nerve biopsy.     

Peripheral nerve changes in porphyric neuropathy: Findings in a sural nerve biopsy

Summary The changes in a sural nerve biopsy of a patient with porphyric neuropathy were studied by light and electron microscopy. Linear arrays of myelin ovoids constituted the most common abnormality in whole mounts of teased-fiber preparations. Round or irregular formations of variable osmiophilia were the most frequent finding in thick-section preparations examined by phase contrast microscopy. Lamellar whorls represented the most prevalent lesion in thinsections studied under the electron microscope. In addition, along the teased fibers, segmental demyelination was definitely detected, although rarely; in thick sections, the true extent of the nerve fiber loss was fully appreciated; in thin sections, a variety of axon and myelin changes of a distinct character were discovered. The studies demonstrate that in peripheral nerves of porphyric neuropathy, axonand myelin changes generally run together and proceed pari passu in the same segment of nerve fiber. Furthermore, among the pathogenetic mechanisms invoked to account for the neuropathic changes none are favored to the exclusion of others by these studies. Therefore, a primary axonaland myelinic disorder on the basis of a deranged porphyrin metabolism is as good a possibility as any hitherto advanced explanation of the pathogenesis of the neuropathic changes. The secondary lesions of Wallerian degeneration and segmental demylination may simple be grafted upon the primary lesions evoked by the metabolic abnormality.     

Clinico-pathologic correlations in 78 biopsies of the sural nerve

Peripheral nerve biopsies when processed with conventional techniques for paraffin embedding usually do not provide sufficient data for the diagnostic conclusion. However, if the nerve is processed for resin embedding for semi and ultra-thin sections and teasing of fibres, several aspects can be analysed including quantitative and morphometric data. We studied the sural nerve biopsy of 78 patients examined at the Antonio Pedro University Hospital, Niterói RJ, applying those techniques and we found that in 55 cases (70.5%) the pathologic diagnosis was conclusive, in 11 (14.1%) although the nerve had abnormalities it was not possible to establish a diagnosis, and in 12 (15.4%) the nerve was normal. In 68 cases there was a clinical diagnosis which was confirmed in 49 but not in the remaining 19, since 8 had non-specific changes and 11 were normal. From the 10 cases which did not have a clinical diagnosis the biopsy was conclusive in 6, showed non-specific changes in 4, and was normal in 1 case. The pathologic conclusion in most of our cases was possible because not only we had the clinical data but all the nerves were processed for resin embedding.     

Clinical syndromes associated with tomacula or myelin swellings in sural nerve biopsies

OBJECTIVES: To describe the neuropathological features of clinical syndromes associated with tomacula or focal myelin swellings in sural nerve biospies and to discuss possible common aetiopathological pathways leading to their formation in this group of neuropathies. METHODS: Fifty two patients with sural nerve biopsies reported to show tomacula or focal myelin swellings were reviewed, light and electron microscopy were performed, and tomacula were analysed on teased fibre studies. Molecular genetic studies were performed on those patients who were available for genetic testing. RESULTS: Thirty seven patients were diagnosed with hereditary neuropathy with liability to pressure palsies (HNPP), four with hereditary motor and sensory neuropathy type I (HMSN I) or Charcot-Marie-Tooth disease type 1 (CMT1), four with HMSN with myelin outfolding (CMT4B), three with IgM paraproteinemic neuropathy, three with chronic inflammatory demyelinating polyneuropathy (CIDP), and one with HMSN III (CMT3). CONCLUSIONS: Most of these syndromes were shown to be related to genetic or immunological defects of myelin components such as peripheral myelin protein 22 (PMP22), myelin protein zero (P0), or myelin associated glycoprotein (MAG). These proteins share the HNK-1 epitope which has been implicated in cell adhesion processes. Impaired myelin maintenance may therefore contribute to the formation of tomacula and subsequent demyelination.     

Cytokines in sural nerve biopsies from inflammatory and non-inflammatory neuropathies

Proinflammatory cytokines are supposed to play a major role in the pathophysiology of vasculitis and in the development of neuropathic pain. Here we studied the cytokine expression in sural nerve biopsy specimens from patients with vasculitic and other inflammatory and non-inflammatory neuropathies, and investigated whether an increased cytokine expression was correlated with the presence of neuropathic pain. We used immunohistochemistry including double labeling and morphometry to localize and quantify the expression of interleukin-1 beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF) in sural nerve biopsy samples of 41 patients with vasculitic neuropathy (VANP), chronic inflammatory demyelinating neuropathy (CIDP), non-inflammatory chronic axonal neuropathy (CANP), and 3 controls. Overall cytokine immunoreactivity was highest in VANP, less strong in CIDP and lowest in CANP. Cytokine immunoreactivity was directly correlated with the degree of axonal degeneration, endoneurial macrophages and epineurial T cells. In VANP and CANP, a higher cytokine content was associated with neuropathic pain.     

Application of immunohistochemical techniques to sural nerve biopsies.

The role of immunohistochemistry in the day-to-day diagnostic work of a peripheral nerve laboratory is not yet clearly established, although for conditions such as amyloid neuropathy, immunohistochemistry appears to be a useful adjunct to conventional techniques. Immunohistochemistry has provided new information about some neuropathies in which immune dysfunction is believed to play a central role. Immunohistochemical data about normal human nerve are scarce; a better appreciation of the normal cellular constituents of nerve, particularly the endoneurium, is needed. In the future, the techniques may be a means to understand better the pathogenesis of other types of neuropathy, such as inherited or toxic neuropathies, or to examine fundamental pathologic events such as axonal degeneration.     

Digital electron microscopic examination of human sural nerve biopsies

Diabetic peripheral polyneuropathy is characterized by axonal degeneration and regeneration as well as by Schwann cell and microvascular changes. These changes have been described at both the light (LM) and the electron microscopic (EM) levels; however, EM has not been applied to large clinical trials. Our goal was to adapt the rigorous techniques used for quantifying human biopsies with LM image analysis to accommodate ultrastructural analyses. We applied digital image capture and analysis to the ultrastructural examination of axons in sural nerve biopsies from diabetic patients enrolled in a multicenter clinical trial. The selection of sural nerve biopsies was based on the quality of specimen fixation, absence of physical distortion, and nerve fascicle size (> or =100,000; < or =425,000 microm2). Thin sections were collected on formvar-coated slot grids, stabilized with carbon and scanned on a Phillips CM100 transmission electron microscope. Digital images were captured with a Kodak Megaplus 1.6 camera. A montage was constructed using software derived from aerial mapping applications, and this virtual image was viewed by EM readers. Computer-assisted analyses included identification and labeling of individual axons and axons within regenerating clusters. The average density of regenerating myelinated axon clusters per mm2 was 65.8 +/- 5.1, range of 0-412 (n = 193). These techniques increase the number of samples that may be analyzed by EM and extend the use of this technique to clinical trials using tissue biopsies as a primary endpoint.     

Diagnostic value of sural nerve biopsy in patients with suspected Borrelia neuropathy

Abstract   Peripheral neuropathy is a recognized but incompletely understood manifestation of borreliosis. As the pathology of this neuropathy has been described only in small case series, the value of nerve biopsy findings for the pathologic diagnosis of Borrelia -associated neuropathy is unclear. We collected and investigated 21 patients with peripheral neuropathy and with typical clinical and serologic signs of neuroborreliosis [ Borrelia neuropathy (BN)]. Standard histology and immunohistochemistry were performed on sural nerve biopsies using antibodies to CD4, CD68 and membrane attack complex C5b-9, intercellular adhesion molecule (ICAM)-1, tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6. Nine patients with idiopathic vasculitic neuropathy (VN) and 14 with idiopathic axonal neuropathy (AN) served as disease controls. In BN, the characteristic histology was that of an AN with transmural or perivascular lymphocytic infiltration of nerve vessels. In BN, but less in VN and AN, perineurial thickening and neovascularization were observed. For BN but not for VN, this thickening correlated with increased perineurial immunoreactivity (IR) to TNF-α, C5b-9, and ICAM-1. In comparison to AN, both BN and VN displayed increased perineurial T-cell infiltration and human leukocyte antigen (HLA)-DR3-IR. In the endoneurium, cytokine (IL-1β, IL-6, TNF-α), HLA-DR3, and ICAM-1 expression was more pronounced in VN but not in BN. The neuropathy in patients with neuroborreliosis resembles idiopathic VN but shows some distinctive features. None of the findings of this study are disease specific but as a pattern may help support the diagnosis of inflammatory neuropathy in patients with serological evidence for Borrelia infection.     

Ultrastructure of sural nerve in a case of arsenical neuropathy

Summary Examination of electron microscopical and teased preparations of a biopsied sural nerve from a patient with arsenical neuropathy is reported. Teased preparations and toluidine blue stained epon sections showed a decrease in the number of myelinated fibres and Wallerian degeneration. Electron microscopy revealed destruction of myelin sheaths, further disintegration associated with degeneration or disappearance of myelinated axons and numerous degenerative changes in the Schwann cell cytoplasm. There was no evidence of segmental demyelination. Occasional onion-bulb-like structures, however, associated with proliferation of Schwann cells, were observed. Obvious elongation of the basement membrane, except in an onion-bulb-like structure, or collagen fibril proliferation or evidence of phagocytosis was not found. These findings are considered to correspond mainly with Wallerian degeneration. Some consideration as given to the unusual onion-bulb-like structures.

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Zusammenfassung Es werden die elektronenmikroskopischen Beobachtungen und Zupf-befunde an der Nervenbiopsie eines Patienten mit Arsenneuropathie mitgeteilt. Die Zupf-methode und die mit Toluidinblau gefärbte Epon-präparate zeigten eine Verminderung der markhaltigen Achsencylinder und Veränderungen nach Art der Wallerschen Degeneration. Elektronenmikroskopische Befunde zeigten Markscheidenzerstörungen mit Achsencylinder-degeneration und Verlust bemarkter Axone sowie häufige degenerative Veränderungen im Cytoplasma der Schwann-Zellen. Keine Hinweise auf segmentale Demyelinisation, aber seltene zwiebelschalenähnliche Strukturen mit Schwann-Zellproliferation wurden beobachtet. Außerhalb der zwiebelschalenähnlichen Strukturen war keine wesentliche Verbreitung der Basalmembran und Vermehrung von Kollagenfasern sowie keine Phagocytose vorhanden. Diese Befunde werden im wesentlichen als Folge der Wallerschen Degeneration betrachtet. Es werden einige Betrachtungen über die ungewöhnlichen zwiebelschalenähnlichen Strukturen angestellt.

     

Postoperative effects and value of sural nerve biopsies: a retrospective study

In order to compare the adverse effects with the benefits for the characterization of neuropathies after complete sural nerve biopsy, 56 out of 80 patients were examined postoperatively. Preoperatively, sensory deficits were reported by 30 patients (53%), paresthesia and dysesthesia by 18 (32%), and pain by 16 (28%). Twenty-one months after biopsy on the average, persistent loss of sensation was found in 52 patients (93%), persistent paresthesia and dysesthesia in 17 (30%) patients each, and persistent pain in 14 (25%) patients. Pain and paresthesia showed better postoperative improvement than the other sensory symptoms. 15 cases (27%) were diagnosed by histology alone. In 21 cases (37%), nonspecific histological findings contributed valuable diagnostic information. The remaining 20 cases (36%) continued to be unclear despite histology. Demyelinating or mixed-type neuropathies did not yield better results than purely axonal forms. We conclude that sural nerve biopsy is a valuable diagnostic tool, but its side-effects require careful selection of fully informed patients.