Acute inflammatory demyelinating polyneuropathy: contribution of a dispersed distal compound muscle action potential to electrodiagnosis

Prolonged duration of the distal compound muscle action potential (DCMAP) ("DCMAP dispersion") is useful in the electrodiagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) with good specificity in distinguishing CIDP from amyotrophic lateral sclerosis (ALS) and diabetic polyneuropathy, but its role in the electrodiagnosis of acute inflammatory demyelinating polyneuropathy (AIDP) is unclear. This study addresses this issue by determining the optimal cutoff for DCMAP duration using receiver operating characteristic (ROC) analysis in 207 motor nerves from 53 clinically defined AIDP patients compared to 148 motor nerves from 55 ALS patients. We also determined whether the presence of DCMAP dispersion improves the sensitivity of four of the most sensitive published sets of electrodiagnostic criteria for AIDP. Using the ROC-derived optimal DCMAP duration cutoff of 8.5 ms, DCMAP dispersion was found in at least one motor nerve in 66% of subjects with AIDP compared to 9% of subjects with ALS. DCMAP dispersion improved the sensitivity of the four tested criteria sets to 76%-87% from 43%-77%. Moreover, of 13 AIDP patients who met none of the four published criteria sets, 5 (38%) had at least one dispersed DCMAP. These findings indicate that the presence of DCMAP dispersion adds electrodiagnostic sensitivity to the currently published criteria sets, while maintaining reasonably high specificity against a prototypical disorder of the primary motor neuron with axon loss.     

Electrodiagnostic pattern approach for childhood polyneuropathies

Electrophysiologic studies play a key role in the detection and characterization of the pattern in childhood polyneuropathies. In this study, the etiologic profile of 74 children with polyneuropathy was prospectively evaluated based on the electrophysiologic studies. Five electrodiagnostic patterns were identified in the cohort: (1) acute axonal polyneuropathy (n: 32, 43%); (2) chronic axonal polyneuropathy (n: 16, 22%); (3) demyelinating motor and sensory polyneuropathy (n: 13, 17%); (4) pure sensory polyneuropathy (n: 11, 15%); (5) high-low syndrome (n: 2, 3%). Etiologic factors were identified in all of the patients with three electrodiagnostic patterns of polyneuropathy: acute axonal, pure sensory, and high-low syndrome. However, etiologic factors could not be determined in 5 (31%) children with chronic axonal polyneuropathy and in 3 (23%) children with demyelinating sensory and motor polyneuropathy. Among children with the acute axonal pattern, toxic causes were evident in 18 (56%), acute motor axonal neuropathy in 11 (35%), and acute motor sensory axonal polyneuropathy in 3 (9%). Nine (82%) patients with pure sensory polyneuropathy had diabetes mellitus. In conclusion, a thorough history and physical examination in conjunction with specific electrodiagnostic patterns might provide a cost-effective and rational differential diagnosis of childhood polyneuropathies.     

Dispersion of the distal compound muscle action potential as a diagnostic criterion for chronic inflammatory demyelinating polyneuropathy

OBJECTIVE: To assess distal compound muscle action potential (DCMAP) duration as a diagnostic criterion for chronic inflammatory demyelinating polyneuropathy (CIDP). BACKGROUND: Current electrodiagnostic criteria for CIDP have high specificity but limited sensitivity. Prolonged DCMAP duration has been reported in acute inflammatory demyelinating polyneuropathy. The authors have compared DCMAP duration in patients with CIDP, diabetic polyneuropathy (DP), ALS, and musculoskeletal pain syndrome (MSP) to determine whether it enhances the sensitivity of electrodiagnostic criteria for CIDP. METHODS: Data from 23 CIDP, 34 DP, 34 ALS, and 54 MSP patients were reviewed. The time interval between onset of the first negative peak and return to baseline of the last negative peak of the DCMAP was calculated for each nerve. To distinguish CIDP from DP, ALS, and MSP, optimal cutoff values for DCMAP duration were achieved with receiver-operating characteristic curves. The sensitivity and specificity of these cutoff values were compared with each of four sets of electrodiagnostic criteria for CIDP. RESULTS: Mean DCMAP duration in CIDP was significantly longer than in DP, ALS, and MSP. The sensitivity of existing electrodiagnostic criteria for CIDP ranged between 0.43 and 0.61. Their specificity vs DP or ALS was 0.91 to 1. Using DCMAP duration of >/=9 milliseconds for any of four motor nerves yielded a sensitivity of 0.78 for CIDP and specificity of 0.94 vs DP or ALS. Adding DCMAP duration criteria to any one of the three accepted criteria enhanced their sensitivity with little sacrifice of specificity. CONCLUSION: Quantitation of DCMAP dispersion shows promise as a sensitive and specific adjunctive electrodiagnostic criterion for CIDP.     

Sensory nerve conduction slowing is a specific marker for CIDP

Most current diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) do not make use of sensory nerve conduction studies (NCSs). To investigate if surface sensory NCSs are clinically relevant in differentiating CIDP from axonal polyneuropathy, we conducted a retrospective cohort study of patients referred for electrodiagnostic testing to evaluate for CIDP. We found that sensory conduction velocity (CV) slowing is a highly specific, albeit insensitive, marker for differentiating CIDP from axonal polyneuropathy. Muscle Nerve 38: 1599–1603, 2008     

Comparison of electrodiagnostic criteria for primary demyelination in chronic polyneuropathy

Three sets of electrodiagnostic criteria for establishing primary demyelination in chronic polyneuropathy are evaluated. Sensitivity is assessed in 70 patients with clinically established chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The criteria use different abnormal values, one adjusts for the effects of axonal loss, while another relies only on conduction velocity. However, even when consideration is given to sufficient number of nerves tested, there is no significant difference (P = 0.37) in diagnostic sensitivity among them, with 48% to 64% of CIDP patients fulfilling criteria for primary demyelination. Specificity is assessed by applying the criteria to 47 patients with motor neuron disease and 63 patients with diabetic polyneuropathy. No patients meet any of the criteria. Further analysis shows that as sensitivity increases specificity decreases, because of overlapping distributions of nerve conduction abnormalities in these neuropathic disorders. A sensitivity of approximately 66% is a practical limit for electrodiagnostic criteria in CIDP.     

Sensory CIDP presenting as cryptogenic sensory polyneuropathy

The objective of this study was to report that patients with chronic inflammatory demyelinating polyneuropathy (CIDP) can present with a clinical picture of cryptogenic sensory neuropathy. Patients with distal sensory neuropathy and electrodiagnostic studies that are minimally abnormal or consistent with an axonal pathology are usually diagnosed as having cryptogenic sensory neuropathy if no cause for neuropathy can be found. Some of these patients, however, may have sensory CIDP. We reviewed the records of eight patients with CIDP, diagnosed by sural nerve biopsy, who presented with sensory neuropathy and electrodiagnostic studies that were minimally abnormal or revealed changes consistent with axonal neuropathy. All patients reported distal numbness and paresthesias and, on examination, had predominantly large fiber distal sensory loss and normal muscle strength. In most patients, deep tendon reflexes were reduced or absent. Sural nerve biopsies in all patients were consistent with chronic myelinopathy, with quantitative teased fiber analysis revealing segmental remyelination in 13-40% of the fibers. The four patients who received IVIg therapy had improved sensation and gait. Of the remaining four patients, one is being followed, one had spontaneous remission, one was lost to follow-up, and one, with contraindications to therapy, reported disease progression. Sensory CIDP may present as cryptogenic sensory polyneuropathy with normal or axonal electrophysiologic features. Sural nerve biopsy should be considered in patients with progressive, predominantly large fiber sensory neuropathy of otherwise unknown etiology, as they may have sensory CIDP that responds to therapy.     

Electrophysiological sensory demyelination in typical chronic inflammatory demyelinating polyneuropathy

Background: The presence of electrophysiological demyelination of sensory nerves is not routinely assessed in the evaluation of suspected chronic inflammatory demyelinating polyneuropathy (CIDP). Whether this can be useful is unknown. Methods: We compared, using surface recording techniques, in 19 patients with typical CIDP and 26 controls with distal large fibre sensory axonal neuropathy, the forearm median sensory conductions, sensory nerve action potential (SNAP) amplitudes and durations and sensory nerve conduction velocities (SNCVs) of median, radial and sural nerves. Results: Median nerve sensory conduction block (SCB) across the forearm was greater in CIDP patients than in controls (P = 0.005). SNAP durations were longer in CIDP patients for median (P = 0.001) and sural nerves (P = 0.004). Receiver operating characteristic (ROC) curves provided sensitive (>40%) and specific (>95%) cut‐offs for median nerve SCB as well as median and sural SNAP durations. SNCVs were significantly slower for median and sural nerves in CIDP patients, but ROC curves did not demonstrate cut‐offs with useful sensitivities/specificities. Median SCB or prolonged median SNAP duration or prolonged sural SNAP duration offered a sensitivity of 73.7% for CIDP and specificity of 96.2%. Used as additional parameters, they improved diagnostic sensitivity of the American Academy of Neurology (AAN) criteria for CIDP of 1991, from 42.1% to 78.9% in this population, with preserved specificity of 100%. Discussion: Sensory electrophysiological demyelination is present and may be diagnostically useful in typical CIDP. SCB detection and SNAP duration prolongation appear to represent more useful markers of demyelination than SNCV reduction.     

A European multicentre reappraisal of distal compound muscle action potential duration in chronic inflammatory demyelinating polyneuropathy

Background: The electrodiagnostic value of distal compound muscle action potential duration (DCMAPD) has been studied rarely in chronic inflammatory demyelinating polyneuropathy (CIDP). Cut‐offs proposed have not been widely evaluated. The influence of low‐cut EMG filter settings ≤ 10 Hz as used in Europe is uncertain. Methods: We retrospectively reviewed records of 110 patients with typical, treatment‐responsive CIDP, from Leicester, U.K., Paris and Angers, France. All fulfilled revised European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) clinical and electrodiagnostic criteria for typical CIDP (2010), before consideration of DCMAPD prolongation. Results were compared with those of 110 controls with chronic sensory/sensory‐motor axonal neuropathy. We constructed receiver operating characteristic (ROC) curves for each nerve and derived cut‐offs for DCMAPD prolongation, offering specificity of ≥ 98% vs. controls. Results: DCMAPD was significantly greater in all nerves for CIDP patients, compared with controls (P < 0.001). ROC curves allowed derivation of cut‐offs of sensitivities ranging from 27.1% (ulnar nerve) to 60% (tibial nerve). Using these cut‐offs to define DCMAPD prolongation in any studied motor nerve offered a sensitivity of 69.1% for CIDP and specificity of 97.3% vs. controls. Conclusion: Cut‐offs for DCMAPD are dependent on EMG filter settings. DCMAPD prolongation in any motor nerve, using our derived cut‐offs, represents a sensitive and specific marker of CIDP in patients studied with EMG equipment with low‐cut filter settings ≤ 10 Hz. Appropriate use of this parameter appears an essential criterion to consider in assessing suspected CIDP, which may be helpful in limiting extensiveness and duration of electrophysiological testing, thereby reducing patient discomfort.     

Influence of diabetes mellitus on chronic inflammatory demyelinating polyneuropathy

Patients with diabetes occasionally develop clinical and electrodiagnostic features suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP). To clarify the role of diabetes in patients with a CIDP-like syndrome, we compared the clinical, pathological, and electrodiagnostic features of 14 patients (10 men, 4 women) with diabetes and CIDP (DM-CIDP) to 60 patients with idiopathic CIDP (I-CIDP). The average duration of diabetes was 9 years. The patients with DM-CIDP were older and more often complained of imbalance compared to the idiopathic group, but the frequency of other symptoms and neurologic findings were similar. The mean amplitude of the ulnar compound muscle action potential in the DM-CIDP group was comparatively reduced, the sural sensory nerve action potential was more often absent, and axonal loss was more commonly observed on nerve biopsy. The response rate to treatment was similar, but the magnitude of functional recovery was greater in patients with I-CIDP. Thus, our patients with diabetes and CIDP had clinical features similar to those with idiopathic CIDP, but their nerve conduction studies and nerve biopsies showed more severe axonal loss and the degree of improvement following treatment was less favorable. These differences most likely reflect the additive effects of superimposed diabetic axonal polyneuropathy in patients who develop CIDP.     

Patterns of sensory nerve conduction abnormalities in demyelinating and axonal peripheral nerve disorders

The pattern of an abnormal median-normal sural (AMNS) sensory response is associated with acute and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP) and considered unusual in other types of neuropathy, although specificity and sensitivity of this pattern have not been evaluated. We compared sensory responses (patterns and absolute values) in patients with AIDP, CIDP, diabetic polyneuropathy (DP), and motor neuron disease (MND). Using strict criteria, the AMNS pattern occurred more frequently in recent onset AIDP (39%) compared with CIDP (28%), DP (14%–23%), or MND (22%) patients. This pattern was found in 3% of control subjects. The extreme pattern of an absent median-present sural response occurred only in AIDP and CIDP patients and in no other groups. Abnormalities of both nerves were more common in long-standing polyneuropathies such as CIDP and DP compared with AIDP or MND. Median nerve amplitudes were reduced significantly in AIDP, CIDP, and DP patients compared with MND patients, whereas sural nerve amplitudes were significantly reduced only in DP and CIDP patients. These findings may reflect early distal nerve involvement particularly in AIDP patients which is highlighted by differences in median and sural nerve recording electrode placement. We conclude that, in the appropriate clinical setting, the AMNS pattern, an absent median-present sural response pattern, or a reduced median amplitude compared with the sural amplitude supports a diagnosis of a primary demyelinating polyneuropathy. © 1993 John Wiley & Sons, Inc.     

Physiologic-pathologic correlation in Guillain-Barré syndrome in children

OBJECTIVE: To correlate electrophysiologic patterns with sural nerve pathology in children with Guillain-Barré syndrome (GBS). BACKGROUND: Based on electrophysiologic and pathologic observations, GBS has been divided into demyelinating and axonal subtypes. The acute motor axonal neuropathy (AMAN) involves predominantly motor nerve fibers with a physiologic pattern suggesting axonal damage, whereas the acute inflammatory demyelinating polyneuropathy (AIDP) involves both motor and sensory nerve fibers with a physiologic pattern suggesting demyelination. In this study, we sought to confirm these observations by correlating sural nerve pathology with electrophysiologic findings in GBS patients. METHODS: Biopsies of sural nerve from 29 of 50 prospectively studied GBS patients were obtained. Nerves were examined by light and electron microscopy, and with immunocytochemistry for macrophages, lymphocytes, and complement activation products. RESULTS: Sural nerves from AMAN patients were normal or had only a few (0.1% to 0.7%) degenerating fibers without lymphocytic infiltration or complement activation. One patient with reduced sural sensory nerve action potential classified as acute motor sensory axonal neuropathy (AMSAN) had many degenerating fibers (2.3%) in the sural nerve. All three AIDP patients displayed active demyelination, and in two patients, lymphocytic infiltration and complement activation products were observed on the abaxonal Schwann cell surface. CONCLUSION: Classification of Guillain-Barré syndrome subtypes based on motor conduction studies correlates closely with pathologic changes seen in sural nerve. In acute motor axonal neuropathy cases, the sural nerve is almost completely spared pathologically. In acute inflammatory demyelinating polyneuropathy cases, macrophage-mediated demyelination and lymphocytic infiltration are common in the biopsies of sural nerves.     

Electrophysiological manifestations of chronic inflammatory demyelinating polyradiculoneuropathy

There are four basic electrophysiological parameters of demyelination: reduced motor conduction velocity, prolonged distal motor latency and F waves, and motor conduction blocks. These parameters are combined to determine an electrophysiological set of criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). Whereas their specificity is good, their sensitivity level does not exceed 75 percent. However, these sets of criteria are not commonly used especially in benign forms, at the beginning of the disease, in associated forms or in case of secondary axonal degeneration. We can push the limits using others criteria such as the terminal latency index, sensory criteria, or by the contribution of others electrophysiological procedures such as the radicular stimulation or sensory evoked potentials. Due to the therapeutic implications, any axonal neuropathy without aetiologia, with at least one demyelinating electrophysiological criteria, could be considered as a putative CIDP.     

急性和慢性多发性周围神经病的电生理及形态学观察

目的寻找神经、肌肉电生理和腓肠神经病理在急性和慢性炎性脱髓鞘性多发性周围神经病(GBS和CIDP)的诊断价值。方法总结GBS和CIDP(15例和17例)的临床、电生理及病理资料进行回顾性分析。结果EMG异常而神经电生理正常共8例;临床和电生理均未提示感觉异常的患者病理发现髓鞘和轴突的丧失、髓鞘再生及许旺细胞内结构改变。结论腓肠神经活检及神经、肌电生理的测定是本组疾病相辅相成的辅助检查手段。     

New criteria for early electrodiagnosis of acute inflammatory demyelinating polyneuropathy

A variety of electrodiagnostic methods are used to confirm the diagnosis of acute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are frequent during the first few weeks of weakness. We compared the nerve conduction studies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with graded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definite) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95-100%, P < 0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute demyelination (sensitivity 48%, specificity 96%, P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory response amplitudes were lower in the CIP group, with comparable mean motor and sensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The frequency of absent or delayed F waves and absent H reflex was similar in both groups. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r = 0.9). We conclude that a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.     

Treatment of immune-mediated, dysimmune neuropathies

This review focuses on the actual status and recent advances in the treatment of immune-mediated neuropathies, including: Guillain-Barre syndrome (GBS) with its subtypes acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, Miller Fisher syndrome, and acute pandysautonomia; chronic inflammatory demyelinating polyneuropathy (CIDP) with its subtypes classical CIDP, CIDP with diabetes, CIDP/monoclonal gammopathy of undetermined significance (MGUS), sensory CIDP, multifocal motor neuropathy (MMN), multifocal acquired demyelinating sensory and motor neuropathy or Lewis-Sumner syndrome, multifocal acquired sensory and motor neuropathy, and distal acquired demyelinating sensory neuropathy; IgM monoclonal gammopathies with its subtypes Waldenstrom's macroglobulinemia, myelin-associated glycoprotein-associated gammopathy, polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome, mixed cryoglobulinemia, gait ataxia, late-onset polyneuropathy syndrome, and MGUS. Concerning the treatment of GBS, there is no significant difference between intravenous immunoglobulins (IVIG), plasma exchange or plasma exchange followed by IVIG. Because of convenience and absent invasiveness, IVIG are usually preferred. In treating CIDP corticosteroids, IVIG, or plasma exchange are equally effective. Despite the high costs and relative lack of availability, IVIG are preferentially used. For the one-third of patients, who does not respond, other immunosuppressive options are available. In MMN IVIG are the treatment of choice. Inadequate response in 20% of the patients requires adjunctive immunosuppressive therapies. Neuropathies with IgM monoclonal gammopathy may respond to various chemotherapeutic agents, although the long-term effects are unknown. In addition, such treatment may be associated with serious side effects. Recent data support the use of rituximab, a monoclonal antibody against the B-cell surface-membrane-marker CD20.     

Sural/radial amplitude ratio in the diagnosis of mild axonal polyneuropathy

As proximal nerves are relatively spared in length-dependent, axonal polyneuropathy, we theorized that a sural/radial amplitude ratio (SRAR) might be a sensitive indicator of mild polyneuropathy. In this study, sural amplitudes and SRARs in patients with signs of mild axonal polyneuropathy were compared to those of normal, age-matched control subjects. Sural and radial sensory responses were measured in a standard fashion in all subjects. Thirty polyneuropathy patients had an average SRAR of 0.29 as compared to 0.71 for the 30 normal subjects. An SRAR of less than 0.40 was a strong predictor of axonal polyneuropathy, with 90% sensitivity and 90% specificity, as compared to an absolute sural amplitude of less than 6.0 μV, which had sensitivity of only 66%. Additionally, unlike the sural amplitude, the ratio did not vary significantly with age. We conclude that the SRAR is a sensitive, specific, age-independent electrodiagnostic test for mild axonal polyneuropathy. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 1236–1241, 1997     

Superficial radial sensory nerve potentials in immune-mediated and diabetic neuropathies.

OBJECTIVE: The pattern of abnormal median-normal sural sensory nerve action potential (SNAP) is frequently found in acute/chronic inflammatory demyelinating polyneuropathy (AIDP/CIDP), whereas sural/radial SNAP amplitude ratio is sensitive to detect dying-back degeneration. To investigate whether radial SNAP and its amplitude ratio to median or sural SNAP provide additional particular patterns of sensory nerve involvement. METHODS: Superficial radial, median, and sural SNAPs were recorded in 63 normal subjects and in 132 patients with AIDP/CIDP (n = 22), diabetic neuropathy (n = 83), or other axonal polyneuropathy (n = 27). Median/radial and sural/radial amplitude ratios were examined. RESULTS: In normal subjects, median/radial ratio was 0.96 +/- 0.05 (mean +/- SEM), and sural/radial ratio was 0.50 +/- 0.03. Compared with normal controls, the median/radial ratio was lower in patients with AIDP/CIDP (0.64 +/- 0.11; P < 0.001) or diabetic neuropathy (0.75 +/- 0.04; P = 0.08), but similar in those with other neuropathy (0.94 +/- 0.10). The sural/radial ratio was higher in the AIDP/CIDP group (0.71 +/- 0.08; P = 0.10), and lower in the diabetic (0.36 +/- 0.03; P < 0.001) and other axonal neuropathy groups (0.40 +/- 0.07; P = 0.08). CONCLUSIONS: AIDP/CIDP is associated with a reduced median/radial ratio and increased sural/radial ratio, probably reflecting demyelination predominant in the distal nerve terminals. Diabetic neuropathy is characterized by decreases in both median/radial and sural/radial ratios, presumably due to coexistence of carpal tunnel pathology and dying-back degeneration. SIGNIFICANCE: Comparison of multiple SNAP amplitudes provides information about characteristic distribution patterns of sensory nerve involvement in peripheral neuropathies.     

Medial dorsal superficial peroneal nerve studies in patients with polyneuropathy and normal sural responses

We studied medial dorsal superficial peroneal (MDSP) nerves in 52 patients with clinical evidence of mild chronic sensorimotor polyneuropathy and normal sural nerve responses, in order to assess the diagnostic sensitivity and usefulness of MDSP nerve testing in electrodiagnostic practice. To determine the effect of age on MDSP nerve parameters, 98 normal subjects were also examined. Electrodiagnostic evaluation involved studies of motor nerve conduction in tibial, peroneal, and median nerves; sensory nerve conduction in sural, MDSP, median, and radial nerves; tibial and peroneal nerve F waves; H reflexes from the soleus muscles; and needle electromyography of gastrocnemius and abductor hallucis muscles. Among the patients, 49% had low-amplitude sensory responses in MDSP nerves and 57% had either slowing of sensory conduction velocity or no sensory responses on proximal stimulation. MDSP nerve amplitude, tibial nerve motor velocity, and H reflexes were the most sensitive for detection of mild chronic symmetrical axonal sensorimotor polyneuropathy. MDSP nerve testing should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses.     

Nerve ultrasound protocol in differentiating chronic immune‐mediated neuropathies

Introduction: In this study we evaluated a new neuropathy ultrasound protocol (NUP) for differentiating chronic immune‐mediated neuropathies. Methods: The NUP was evaluated in 110 patients with clinical presentations of chronic immune‐mediated neuropathy. All patients were first evaluated clinically and electrophysiologically and divided into 4 polyneuropathy groups: (a) symmetric demyelinating; (b) symmetric axonal; (c) asymmetric demyelinating; and (d) asymmetric axonal. During step 2, the NUP was evaluated prospectively for all 4 study groups. Results: Overall, the NUP led to correct classification in 42 of 49 (85.7%) patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 of 15 (86.9%) with multifocal motor neuropathy (MMN), and 5 of 5 (100%) with multifocal‐acquired demyelinating sensory and motor neuropathy (MADSAM). The NUP had >80% sensitivity and specificity in distinguishing CIDP, MMN, and MADSAM in all 4 study groups. Conclusions: The NUP is a useful addition in the differential diagnosis of chronic immune‐mediated neuropathies in everyday practice. Muscle Nerve 54 : 864–871, 2016     

Axonal and perikaryal involvement in chronic inflammatory demyelinating polyneuropathy

OBJECTIVES: To assess the extent of loss of myelinated nerve fibres and spinal motor neuron loss in chronic inflammatory demyelinating polyneuropathy (CIDP), a clinicopathological study was conducted on biopsied sural nerves and necropsied spinal cords from patients with CIDP. METHODS: The myelinated fibre pathology of 71 biopsied sural nerves and motor neuron pathology of nine necropsied spinal cords at L4 levels in patients with CIDP were quantitatively and immunohistochemically assessed. RESULTS: Myelinated nerve fibre density was significantly diminished to 65.4% of the control values (p <0.0001), correlating inversely with the extent of segmental demyelination and remyelination (r = -0.43, p < 0.0005) and duration of illness (r = -0.31, p < 0.01). Numbers of large spinal motor neurons in CIDP were variably but significantly diminished (range from 46.0 to 97.6% of the age matched control value (p < 0.005)), and reactive astrogliosis was evident in the ventral horn in CIDP. The frequency of ventral horn neurons exhibiting central chromatolysis and the accumulation of phosphorylated high molecular weight neurofilament protein was significantly higher in CIDP than in controls (p<0.01 and p<0.05). CONCLUSIONS: The loss of nerve axons and spinal motor neurons is common in CIDP, and extensive in some cases. These neuronal and axonal losses may influence the functional prognosis in CIDP.