Utility of the distal compound muscle action potential duration for diagnosis of demyelinating neuropathies

To assess the significance of distal compound muscle action potential (CMAP) duration for diagnosis of demyelinating neuropathies, electrophysiologic data were reviewed from 471 subjects, including 145 normal controls, 60 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 205 with other neuropathy, and 61 with amyotrophic lateral sclerosis (ALS). The duration of distally evoked CMAP was measured in the median, ulnar, tibial, and peroneal nerves. Optimal cut-off values were calculated with receiver-operating characteristic (ROC) curves. In comparison of normal controls and CIDP patients, ROC analyses showed the sufficient area under the curves (82-93%). When the cut-off values in the detection of demyelination were determined as the point with 98% specificity vs. normal on the ROC curves (median, 6.6 ms; ulnar, 6.7 ms; peroneal, 7.6 ms; tibial, 8.8 ms), the sensitivity was 77% for CIDP, with a specificity of 90% vs. ALS and 95% vs. diabetic neuropathy. The distal CMAP duration is a useful index for the detection of distal demyelination. We suggest the above cut-off values for each nerve as one of the electrodiagnostic criteria for demyelinating neuropathies, preferentially affecting the distal nerve terminals, such as CIDP.     

Length-dependent weakness and electrophysiological signs of secondary axonal loss in chronic inflammatory demyelinating polyradiculoneuropathy

In chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) the pathophysiology underlying permanent muscle weakness and sensory loss was studied in 22 stabilized long-term CIDP patients clinically characterized using isokinetic dynamometry, quantitative sensory testing, and neuropathy scores. Conduction velocity (CV), distal latency (DLAT), minimal F-wave latency (FLAT), compound muscle action potential (CMAP), and amplitude decay between distal and proximal stimulation sites were determined in the median, ulnar, peroneal, and tibial motor nerves and sensory CV and nerve action potentials in the median and sural nerves. Amplitude of CMAP and the DLAT were related to quantitative muscle strength, whereas CV, FLAT, amplitude decay, and dispersion were not consistently related to strength. Furthermore, CMAP and muscle strength were significantly more reduced distally than proximally. In conclusion, the electrophysiological signs of axonal loss and the associated length-dependent muscle weakness suggest secondary axonal loss in addition to primary demyelination in CIDP.     

Mixed nerve action potentials in acquired demyelinating polyneuropathy

Uncertainty about motor and sensory contributions in abnormal nerves has limited the use of mixed nerve action potentials (MNAPs). We recorded MNAPs in 21 patients with an acquired demyelinating neuropathy, 18 age-matched control subjects, and 10 patients with an axonal polyneuropathy. Bipolar and unipolar recordings from median and ulnar nerves were made above the elbow after electrical stimulation of the nerves at the wrist. Antidromic digital sensory action potentials and motor conduction velocity were also recorded for both nerves. In 19 median and 12 ulnar nerves from demyelinating polyneuropathy patients, compared with control subjects, MNAP amplitudes were significantly reduced (mean, 6 μV vs. 31 μV), MNAP velocities were mildly reduced (mean, 50 m/s vs. 62 m/s), motor conduction velocities were significantly reduced (mean, 33 m/s vs. 57 m/s), and MNAPs were significantly dispersed, with markedly prolonged rise times (mean, 2.0 ms vs. 1.0 ms). Compared with the axonal polyneuropathy group, MNAP amplitudes from the median nerve were similarly reduced (mean, 8 μV vs. 9 μV), MNAP velocities were only slightly slower (mean, 52 m/s vs. 58 m/s), but the rise times were significantly prolonged (mean, 2.0 ms vs. 1.2 ms). We conclude that, in acquired demyelinating neuropathies, the onset and, in some cases, the whole MNAP is from afferent fibers, which can be abnormally dispersed, and that, over the same segment, MNAP velocity is less affected than motor conduction velocity. 1995.© 1995 John Wiley &Sons, Inc.     

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.     

Pattern analysis of nerve enlargement using ultrasonography in chronic inflammatory demyelinating polyneuropathy

ObjectiveFocal nerve enlargement is a characteristic finding in chronic inflammatory demyelinating polyneuropathy (CIDP). We performed this study to assess the distribution of nerve enlargement through ultrasonographic examination of peripheral nerves and to correlate the ultrasonographic findings with clinical features.MethodsTo compare the ultrasonographic features of 10 subjects with CIDP with those of 18 healthy controls, we bilaterally measured the cross-sectional areas (CSA) of the vagus, brachial plexus, musculocutaneous, median, ulnar, radial, sciatic, tibial, common peroneal, and sural nerves. We also analyzed correlations between CSAs and various clinical and electrophysiological features.ResultsMean CSAs were significantly larger in CIDP patients than controls, especially at proximal and non-entrapment sites. CSAs were significantly correlated with muscle strength at initial presentation, but not at the time of ultrasonography. The CSAs of the median and ulnar nerves at the mid-forearm, tibial nerve at 7 cm proximal to the medial malleolus, and sural nerve correlated with the nerve conduction velocity of the corresponding region.ConclusionUltrasonography revealed widely distributed nerve enlargement, especially in proximal regions and non-entrapment sites, in patients with CIDP compared with healthy controls. Nerve enlargement correlated well with the electrophysiologic function of the nerve, but not current clinical status.SignificancePattern analysis of nerve enlargement using ultrasonography is a supportive tool in the diagnosis of CIDP.     

Early Electrodiagnostic Features of Upper Extremity Sensory Nerves Can Differentiate Axonal Guillain-Barré Syndrome from Acute Inflammatory Demyelinating Polyneuropathy

MethodsWe retrospectively reviewed the medical records of 70 patients with GBS who underwent NCS within 10 days of symptom onset. Patients with axonal GBS and acute inflammatory demyelinating polyneuropathy (AIDP) were selected based on clinical characteristics and serial NCSs. An antiganglioside antibody study was used to increase the diagnostic certainty.ResultsThe amplitudes of median and ulnar nerve sensory nerve action potentials (SNAPs) were significantly smaller in the AIDP group than in the axonal-GBS group. Classification and regression-tree analysis revealed that the distal ulnar sensory nerve SNAP amplitude was the best predictor of axonal GBS.ConclusionsEarly upper extremity sensory NCS findings are helpful in differentiating axonal-GBS patients with antiganglioside antibodies from AIDP patients.     

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.     

Ultrasound differentiation of axonal and demyelinating neuropathies

Introduction: Ultrasound can be used to visualize peripheral nerve abnormality. Our objective in this study was to prove whether nerve ultrasound can differentiate between axonal and demyelinating polyneuropathies (PNPs). Methods: Systematic ultrasound measurements of peripheral nerves were performed in 53 patients (25 with demyelinating, 20 with axonal, 8 with mixed neuropathy) and 8 healthy controls. Nerve conduction studies of corresponding nerves were undertaken. Results: Analysis of variance revealed significant differences between the groups with regard to motor conduction velocity, compound muscle action potential amplitude, and cross‐sectional area (CSA) of different nerves at different locations. Receiver operating characteristic curve analysis revealed CSA measurements to be well suited for detection of demyelinating neuropathies, and boundary values of peripheral nerve CSA could be defined. Conclusions: Systematic ultrasound CSA measurement in different nerves helped detect demyelination, which is an additional cue in the etiological diagnosis of PNP, along with nerve conduction studies and nerve biopsy. Muscle Nerve 50: 976–983, 2014     

Correlation between compound muscle action potential amplitude and duration in axonal and demyelinating polyneuropathy

Objective

To get a better understanding of pathophysiology in polyneuropathies (PNPs) by correlating compound muscle action potential (CMAP) amplitude with duration.

Methods

A total of 145 motor nerve conduction studies (MNCS) in 53 axonal and 132 MNCS in 45 demyelinating PNPs were analyzed. Peroneal and tibial MNCS were done by surface stimulation while for median and ulnar nerves near nerve or surface stimulations were used. CMAP amplitude and duration were compared in axonal and demyelination PNPs. Relationships between amplitude and duration of distally and proximally evoked CMAP were examined using regression analysis.

Results

CMAP amplitude was lower and duration was increased in all examined nerves in demyelinating PNPs than in axonal PNPs. In demyelinating PNPs, an inverse linear correlation between amplitude and duration was seen in distally and proximally evoked CMAP in all examined nerves. In axonal PNPs, there was no correlation in any of the nerves neither in distally nor in proximally evoked CMAP.

Conclusions

Distal CMAP duration and the relationship between CMAP amplitude and duration show supplementary electrodiagnostic potential in demyelinating PNPs.

Significance

More knowledge about the relation between amplitude and duration in axonal lesions and demyelination may help to reveal the pathophysiology in PNPs. Significant correlation between amplitude and duration in demyelination may suggest that the severe decrease in amplitude in demyelinating PNPs is probably due to the increase in duration secondary to temporal dispersion.     

Electrophysiologic study in acute lead poisoning

A 2-month-old girl with acute lead poisoning demonstrated electrophysiologic evidence of neurotoxicity. Motor nerve conduction studies of the median, ulnar, peroneal, and posterior tibial nerves revealed both axonal and demyelinating neuropathy. Somatosensory evoked potential studies of median and posterior tibial nerves demonstrated evidence of cortical involvement. Brainstem auditory evoked potential study disclosed the possibility of acoustic nerve involvement but no evidence of a brainstem lesion. Postmortem examination revealed cerebral edema and focal segmental demyelination of the median nerve.     

Peripheral nerve size in normals and patients with polyneuropathy: An ultrasound study

Ultrasound has been used for visualizing peripheral nerve pathology. Our goal was to use ultrasound to quantitate the sizes of upper extremity nerves along their length in control subjects and patients with neuropathy. We measured median and ulnar nerve cross‐sectional areas (NCSA) in the arms of 190 subjects, including 100 with neuropathies and 90 controls. We found that NCSAs in healthy child and adult controls were greater with increasing height, at proximal sites, and at sites of entrapment. Nerves were enlarged in all Charcot–Marie–Tooth 1A (CMT‐1A) (11 of 11; 100%), most chronic inflammatory demyelinating polyneuropathy (CIDP) (31 of 36; 86%), half of Guillain–Barré syndrome (GBS) (8 of 17; 47%), but few axonal neuropathy (7 of 36, 19%) subjects. In GBS, nerve enlargement occurred early and with minimal electrodiagnostic abnormalities in some patients. We conclude that NCSA measured by ultrasound is a quantifiable marker of nerve features that should be corrected for patient characteristics and nerve site. NCSA is generally larger in demyelinating than it is in axonal polyneuropathies. Muscle Nerve, 2009     

Optimizing the electrodiagnostic accuracy in Guillain-Barré syndrome subtypes: Criteria sets and sparse linear discriminant analysis

ObjectiveTo optimize the electrodiagnosis of Guillain-Barré syndrome (GBS) subtypes at first study.MethodsThe reference electrodiagnosis was obtained in 53 demyelinating and 45 axonal GBS patients on the basis of two serial studies and results of anti-ganglioside antibodies assay. We retrospectively employed sparse linear discriminant analysis (LDA), two existing electrodiagnostic criteria sets (Hadden et al., 1998; Rajabally et al., 2015) and one we propose that additionally evaluates duration of motor responses, sural sparing pattern and defines reversible conduction failure (RCF) in motor and sensory nerves at second study.ResultsAt first study the misclassification error rates, compared to reference diagnoses, were: 15.3% for sparse LDA, 30% for our criteria, 45% for Rajabally’s and 48% for Hadden’s. Sparse LDA identified seven most powerful electrophysiological variables differentiating demyelinating and axonal subtypes and assigned to each patient the diagnostic probability of belonging to either subtype. At second study 46.6% of axonal GBS patients showed RCF in two motor and 8.8% in two sensory nerves.ConclusionsBased on a single study, sparse LDA showed the highest diagnostic accuracy. RCF is present in a considerable percentage of axonal patients.SignificanceSparse LDA, a supervised statistical method of classification, should be introduced in the electrodiagnostic practice.     

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.     

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.     

Application of CMAP scan for the evaluation of patients with chronic inflammatory demyelinating polyneuropathy: a prospective study

AimsWe aimed to assess the compound muscle action potential (CMAP) scan in the follow-up of chronic inflammatory demyelinating polyneuropathy (CIDP) patients and investigate the correlation of CMAP scan parameters with functional and standard electrodiagnostic tests.MethodsWe evaluated four parameters of abductor pollicis brevis (APB) CMAP scan (i.e., step numbers, step percentage, S10, S90), functional measures (e.g., Medical Research Council Sum Scores), and electrodiagnostic tests, including nerve conduction study (NCS) and motor NCS of the median nerve in the baseline and after six months of treatment.ResultsTwenty patients completed baseline clinical and electrodiagnostic studies. However, sixteen patients completed the follow-up study. The median of step numbers at baseline was 3.5 (2–4.2), which decreased to 2.5 (0–3) (p = 0.005). After the treatment, step percentage reduced from 28.6 (23.9–38.7) to 13.4 (0–23.6) (p = 0.001). The scores obtained from the clinical scales showed significant recovery of most of the functions, while the alterations of NCSS and NCS of the median nerve were not significant.ConclusionsWe found a significant reduction in step number and step percentage after follow-up. This alteration was not reflected in standard electrodiagnostic values. The improvement of functional scales alongside the CMAP scan parameters suggests that the CMAP scan could be considered an appropriate outcome measurement in research and clinical fields.     

Nerve size in chronic inflammatory demyelinating neuropathy varies with disease activity and therapy response over time: A retrospective ultrasound study

Introduction: Nerves are often enlarged in chronic inflammatory demyelinating polyneuropathy (CIDP). In this investigation we studied changes with treatment over time. Methods: We retrospectively compared serial ultrasound measurements of median and ulnar nerve size with clinical and electrodiagnostic evaluations in 23 CIDP subjects. We defined remission as stable clinical improvement on low or decreasing amounts of medication. Results: Nerves were normal at last follow‐up more often in subjects who achieved remission than in those who did not (10 of 13 vs. 0 of 10, P = 0.0001). Nerves were normal or smaller (>30% reduction) more often in subjects whose grip strength improved or remained strong compared those whose grip strength weakened (12 of 16 vs. 0 of 3, P = 0.04), and in subjects whose demyelinating electrodiagnostic features resolved compared with those whose demyelination persisted (7 of 7 vs. 6 of 12, P = 0.04). Over time, nerve size decreased more in subjects with baseline nerve enlargement who achieved remission than in those who did not (?41% vs. 7%, P = 0.04). Conclusion: In CIDP, enlarged nerves normalized or decreased with remission. Muscle Nerve 50 : 733–738, 2014     

Multifocal sensory demyelinating neuropathy: Report of a case

Introduction: Multifocal sensory demyelinating neuropathy has not been adequately reported in the literature. Methods: A 42‐year‐old man with numbness of the left hand for 3 years and of the right hand for 6 months had a pure multifocal sensory neuropathy involving both hands, most prominently affecting 2‐point discrimination, number writing, and object recognition of the left hand. Near‐nerve needle sensory and mixed nerve conduction studies were performed on the left ulnar nerve. Results: Studies of the left ulnar nerve documented a demyelinating neuropathy characterized by temporal dispersion and marked decrease in the amplitudes of the sensory and mixed compound nerve potentials in the above‐elbow‐axilla segment. With intravenous immunoglobulin treatment, there was improvement in his neuropathic condition. Conclusion: In this study I describe a case of multifocal sensory demyelinating neuropathy as a counterpart of multifocal motor neuropathy. Muscle Nerve 56 : 825–828, 2017     

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.     

Tumor necrosis factor-α in peripheral nerve lesions

Immunocytochemical expression of tumor necrosis factor-α (TNF-α) was examined in nerve biopsy samples of patients with various disorders, focusing on nerve injury. TNF-α was mainly associated with phagocytosing macrophages in acute axonal injury, but the staining was more frequently seen in sections from patients with vasculitis than with metabolic neuropathy. Ramified macrophages outside nerve fibers were also positive for TNF-α in the acute stage of vasculitis. In active demyelinating lesions from patients with chronic inflammatory demyelinating neuropathy (CIDP), macrophages outside nerve fibers showed weak staining with TNF-α, but the cells adhering to myelinated nerve fibers showed definite staining. This may be due, in part, to the smouldering course of CIDP, and expression may be up-regulated transiently during the demyelinating process. These results indicate that macrophages, as the effector cells for both axonal injury and active demyelination, express TNF-α, but their activation mechanisms may vary among vasculitis, metabolic axonopathy and inflammatory demyelination. Received: 7 April 1997 / Revised, accepted: 23 June 1997     

Multifocal enlargement and increased vascularization of peripheral nerves detected by sonography in CIDP: A pilot study

ObjectiveDetection of nerve enlargement in polyneuropathies by sonography is a new research area. No systematic investigation has been done yet in chronic inflammatory demyelinating polyneuropathy (CIDP). Therefore we investigated this in CIDP.MethodsEleven patients with CIDP fulfilling the international criteria on CIDP underwent ultrasonographic examination of the median, ulnar, fibular and posterior tibial nerves and sometimes the brachial plexus bilaterally, using a standardized protocol. We assessed presence of nerve thickening and increased nerve vascularization.ResultsIn 7 of the 11 patients multiple nerve enlargements were detected: ulnar nerve 7, fibular nerve 5, posterior tibial nerve 4 and median nerve in 4 patients. The number of enlarged nerves was related with the MRC sum-score (p = 0.03) and the total protein in the cerebrospinal fluid (CSF) at diagnosis (p = 0.02). Increased vascularization was seen in 6 of the 11 patients: 4 in one nerve and in 2 in multiple nerves. The number of nerves with increased vascularization was associated with the number of enlarged nerves (p = 0.01) and total protein in the CSF (p = 0.006).ConclusionMultiple nerve enlargements occur in CIDP showing a relation with a lower MRC sum-score, increased nerve vascularization and a higher total protein of the CSF.SignificanceOur findings of nerve enlargement and increased nerve vascularization may be tools to monitor disease activity in CIDP, but further studies are needed.