Peripheral nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy detected by ultrasonography

Cross-sectional area reference values for high-resolution ultrasonography of the lower extremity nerves in healthy Korean adults

The cross-sectional area (CSA) reference values of the lower extremity nerves in Asians have been rarely reported. For this study, 107 sex- and age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years) were recruited. All subjects underwent standardized nerve conduction studies of the upper and lower extremities. The CSA was measured unilaterally at 12 sites in the lower extremity nerves, including the femoral, lateral femoral cutaneous, sciatic, common peroneal, superficial peroneal, deep peroneal, tibial, and sural nerves. The CSA significantly correlated with height, weight, and body mass index. The CSA was significantly larger in males than females at most nerves except for the lateral femoral cutaneous, common peroneal (fibular head), and superficial peroneal nerves (distal calf). There was no statistically significant difference between the age groups except for the tibial nerve (ankle). The results of this study provide CSA reference values for the lower extremity nerves including small branches and the values can be useful in the ultrasonographic investigation of various peripheral neuropathies in East Asian populations.

Nerve ultrasound findings in Sjögren's syndrome-associated neuropathy

BACKGROUND AND PURPOSE

The phenotype of Sjögren's syndrome-associated neuropathy has been better characterized in recent years. However, Sjögren's syndrome-associated neuropathy remains an underdiagnosed entity with only few insights considering the pathomechanisms of nerve damage. Nerve ultrasound has proven to be a useful and efficient tool in detecting nerve damage of autoimmune origin. We, therefore, aimed to evaluate this method for Sjögren's syndrome-associated neuropathy.

METHODS

Patients with Sjögren's syndrome and clinical signs of neuropathy underwent sonographic examination of both median and ulnar nerves. Nerve thickening was classified for cross-sectional areas of >12 mm² at the median nerve and for >10 mm² at the ulnar nerve. Fascicle thickening was documented for cross-sectional areas ≥5 mm² at the median and ≥3 mm² at the ulnar nerve.

RESULTS

Forty-three patients were included in the analysis (median age 60 years [interquartile range 53-73 years], female rate 60%). 31/43 patients (72%) showed abnormalities on nerve ultrasound, while nerve thickening was found more frequently than fascicle thickening (90% vs. 52% of patients with sonographic abnormalities, respectively). Abnormal findings were observed more frequently at the median nerve and in proximal localization. Abnormal findings on nerve conduction studies were evident in 36/43 patients (84%). Nerve conduction studies revealed a tendency of demyelinating nerve damage patterns being associated with abnormal findings on nerve ultrasound.

CONCLUSIONS

In addition to nerve conduction studies, nerve ultrasound may have a supporting role in the diagnosis of Sjögren's syndrome-associated neuropathy. Also, our data support an immune-mediated inflammatory demyelinating pathogenesis of Sjögren's syndrome-associated neuropathy.

Cross-sectional area reference values for high-resolution ultrasonography of the upper extremity nerves in healthy Asian adults

In this study, multiple-site, cross-sectional area (CSA) reference values were established for major peripheral nerves, including small branches, in the upper extremity of a healthy Asian population.This study included 107 prospectively recruited age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years). All subjects underwent standardized nerve conduction studies for the median, ulnar, peroneal, posterior tibial, and sural nerves. CSA was measured unilaterally at 21 sites of the median, ulnar, radial, posterior interosseous, superficial radial sensory, musculocutaneous, lateral antebrachial cutaneous, and medial antebrachial cutaneous nerves.According to their age, the subjects were assigned to the younger group (20-40 years, n = 40), the middle group (40-59 years, n = 40), and the older group (60-80 years, n = 27). The significant differences of CSA values between age groups were found only at certain sites, such as the median (wrist, P = .003), ulnar (medial epicondyle, P = .031; forearm, P = .022), radial (antecubital fossa, P = .037), and superficial radial sensory nerve (P = .028). The CSA significantly correlated with gender, height, weight, and body mass index.This study provides CSA reference values for nerves, including small sensory nerves in the upper extremity, which can be useful in the ultrasonographic investigation of various peripheral neuropathies in the upper extremity.

Nerve Ultrasound as Helpful Tool in Polyneuropathies

Background: Polyneuropathies (PNP) are a broad field of diseases affecting millions of people. While the symptoms presented are mostly similar, underlying causes are abundant. Thus, early identification of treatable causes is often difficult. Besides clinical data and basic laboratory findings, nerve conduction studies are crucial for etiological classification, yet limited. Besides Magnetic Resonance Imaging (MRI), high-resolution nerve ultrasound (HRUS) has become a noninvasive, fast, economic and available tool to help distinguish different types of nerve alterations in neuropathies. Methods: We aim to describe typical ultrasound findings in PNP and patterns of morphological changes in hereditary, immune-mediated, diabetic, metabolic and neurodegenerative PNP. Literature research was performed in PubMed using the terms ‘nerve ultrasound’, neuromuscular ultrasound, high-resolution nerve ultrasound, peripheral nerves, nerve enlargement, demyelinating, hereditary, polyneuropathies, hypertrophy’. Results: Plenty of studies over the past 20 years investigated the value of nerve ultrasound in different neuropathies. Next to nerve enlargement, patterns of nerve enlargement, echointensity, vascularization and elastography have been evaluated for diagnostic terms. Furthermore, different scores have been developed to distinguish different etiologies of PNP. Conclusions: Where morphological alterations of the nerves reflect underlying pathologies, early nerve ultrasound might enable a timely start of available treatment and also facilitate follow up of therapy success.

Nerve ultrasound in polyneuropathies

Ultrasound can be used to visualize pathology in the peripheral nerves of patients with polyneuropathy. Nerve enlargement is the most frequent pathology, but other abnormalities, including abnormal nerve echogenicity and vascularity, are also encountered. This monograph presents an overview of the role of nerve ultrasound in the evaluation and management of both inherited and acquired polyneuropathies. A description of the sonographic techniques and common abnormalities is provided, followed by a presentation of typical findings in different neuropathies. Scoring systems for characterizing the presence and pattern of nerve abnormalities as they relate to different polyneuropathies are presented. Muscle Nerve 57: 716-728, 2018.

Ultrasonographic reference values for peripheral nerves and nerve roots in the normal population of children and adolescents: study protocol for an observational-prospective trial

BACKGROUND

High-resolution ultrasonography is a new and promising technique to evaluate peripheral and spinal nerves. Its validity as a diagnostic tool in neurological diseases has been demonstrated in adults. Up to now no reference values have been published in children and adolescents although this technique would be ideal in this population as it is fast and non-invasive.

METHODS/DESIGN

Our aim is to generate ultrasonographic reference values for several peripheral nerves (median, ulnar, radial, tibial, sural, peroneal and tibial nerve) as well as for the spinal nerves C5 and C6 and the vagus nerve in children and adolescents. In an observational prospective study, we will recruit 205 children and adolescents aged between ≥2 and ≤18 years without neuromuscular symptoms/signs and without a history of neuromuscular disease. After the collection of demographic and anthropometric data (height, weight, body mass index, age, gender and handedness) and a neurologic examination, a high-resolution ultrasonography of peripheral and spinal nerves at several anatomic landmarks will be performed. These data will be used to estimate age-dependent percentile curves and to evaluate inter-rater, intrarater and interequipment reliability of the measurements.

ETHICS AND DISSEMINATION

This study was approved by the local ethics committee (EKNZ 2015-210). The findings from this study will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT02570802, pre-results publication.

Nerve Ultrasound in Peripheral Neuropathies: A Review

Peripheral neuropathies are one of the most common reasons for seeking neurological care in everyday practice. Electrophysiological studies remain fundamental for the diagnosis and etiological classification of peripheral nerve impairment. The recent technological development though of high resolution ultrasound has allowed the clinician to obtain detailed structural images of peripheral nerves. Nerve ultrasound mainly focuses on the evaluation of the cross sectional area, cross sectional area variability along the anatomical course, echogenity, vascularity and mobility of the peripheral nerves. An increase of the cross sectional area, hypervascularity, disturbed fascicular echostructure and reduced nerve mobility are some of the most common findings of entrapments neuropathies, such as the carpal or cubital tunnel syndrome. Both the cross-sectional area increase and the hypervascularity detected with the Doppler technique seem to correlate significantly with the clinical and electrophysiological severity of the later mononeuropathies. Significantly greater cross sectional area values of the clinically affected cervical nerve root are often detected in cases of cervical radiculopathy. In such cases, the ultrasound findings seem also to correlate significantly with disease duration. On the other hand, multifocal cross sectional area enlargement of cervical roots and/or peripheral nerves is often documented in cases of immune-mediated neuropathies. None of the later pathological ultrasound findings seem to correlate significantly with the electrophysiological parameters or the functional disability. The aim of this review is to provide a timely update on the role of neuromuscular ultrasound in the diagnostic of the most common entrapment and immune-mediated peripheral neuropathies in clinical practice.

Different patterns of nerve enlargement in polyneuropathy subtypes as detected by ultrasonography

The purpose of our study was to examine how the pathologic type of polyneuropathy affects nerve size as assessed by high-resolution ultrasonography with a 15 MHz transducer. Cross-sectional area (CSA) of the C5-C7 nerve roots and several upper and lower limb nerves at multiple sites was measured in 38 patients with acquired diffuse sensorimotor demyelinating or axonal polyneuropathy and in 34 healthy control subjects. Significant differences were found among the groups for all nerve and root segments: Both types of polyneuropathy are characterized by nerve enlargement in comparison to controls, but in different patterns. In demyelinating polyneuropathies, an additional degree of nerve thickening appears in proximal upper limb nerves and cervical nerve roots compared with axonal polyneuropathies. With respect to the other nerves, a similar degree of nerve enlargement was observed in both patient groups. These results highlight that ultrasonography may be a complementary tool in differentiating polyneuropathies.

Ultrasound and neurophysiological correlation in common fibular nerve conduction block at fibular head

OBJECTIVE

Ultrasound (US) and neurophysiological examination are useful tools in the evaluation of common fibular mononeuropathy. There is only a report comparing US and electrophysiological parameters in patients with common fibular nerve (CFN) conduction block at fibular head. We investigated the correlation between US and neurophysiologic findings in this condition.

METHODS

We retrospectively reviewed patients with CFN assessed in our lab during last 2 years. Each patient underwent to clinical, neurophysiological and ultrasound evaluations. Cross sectional area (CSA) of CFN at fibular head was assessed.

RESULTS

Twenty-four patients were included. Motor nerve conduction study showed a reduction of distal compound muscle action potential (CMAP) amplitude in 10 patients (mean 1.3 mV). US showed an increased CSA in 10 patients. Statistical analysis revealed a strong correlation between the increased CSA and the CMAP reduction of CFN.

CONCLUSION

Our data suggest that usually US examination is normal in CFN conduction block at fibular head. However the association with axonal damage is frequently accompanied by an increase of CSA.

SIGNIFICANCE

Ultrasound evaluation may represent a powerful diagnostic/prognostic tool in cases with CPN conduction block at fibular head because it usually shows normal pattern in pure conduction block and increase of CSA in associated axonal damage.

Ultrasound of inherited vs. acquired demyelinating polyneuropathies

We compared features of nerve enlargement in inherited and acquired demyelinating neuropathies using ultrasound. We measured median and ulnar nerve cross-sectional areas in proximal and distal regions in 128 children and adults with inherited [Charcot-Marie-Tooth-1 (CMT-1) (n = 35)] and acquired [chronic inflammatory demyelinating polyneuropathy (CIDP) (n = 55), Guillaine-Barre syndrome (GBS) (n = 21) and multifocal motor neuropathy (MMN) (n = 17)] demyelinating neuropathies. We classified nerve enlargement by degree and number of regions affected. We defined patterns of nerve enlargement as: none, no enlargement; mild, nerves enlarged but never more than twice normal; regional, nerves normal in at least one region and enlarged more than twice normal in at least one region; diffuse, nerves enlarged at all four regions with at least one region more than twice normal size. Nerve enlargement was commonly diffuse (89 %) and generally more than twice normal size in CMT-1, but not (p < 0.001) in acquired disorders which mostly had either no, mild or regional nerve enlargement [CIDP (64 %), GBS (95 %), and MMN (100 %)]. In CIDP, subjects treated within 3 months of disease onset had less nerve enlargement than those treated later. Ultrasound identified patterns of diffuse nerve enlargement can be used to screen patients suspected of having CMT-1. Normal, mildly, or regionally enlarged nerves in demyelinating polyneuropathy suggests an acquired etiology. Early treatment in CIDP may impede nerve enlargement.

Heterogeneity of root and nerve ultrasound pattern in CIDP patients

OBJECTIVE

The few published ultrasound (US) studies on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) report diffusely increased cross-sectional area (CSA) of nerves. The data are, however, heterogeneous and correlations with clinical history or disease severity are lacking.

METHODS

Thirty-four patients with CIDP underwent US nerve evaluation by two neurologists blinded to clinical data. US nerve pattern for each patient was defined by a third neurologist blinded to clinical data. Three US classes were identified based on CSA and echogenicity: large nerves with hypoechoic nerves/fascicles (class 1); large nerves with heterogeneous hypo- and hyperechoic fascicles (class 2); normal size nerve but abnormal hyperechoic array (class 3).

RESULTS

In all patients, US nerve changes were observed: in most of the cases, enlarged nerves or nerve segments were observed. The three 'classes' of US nerve changes significantly correlated (R: 0.68, p<0.001) with disease duration, but not with age or Inflammatory Neuropathy Cause and Treatment (INCAT) disability score.

CONCLUSIONS

US may be of adjunctive diagnostic value in CIDP assessment. Nerve morphological changes may mirror the underlying pathophysiological mechanisms and seem to correlate with disease duration.

SIGNIFICANCE

These results offer the possibility of exploring the use of US to assess CIDP disease activity and treatment.

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

OBJECTIVE

Detection 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.

METHODS

Eleven 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.

RESULTS

In 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).

CONCLUSION

Multiple 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.

SIGNIFICANCE

Our findings of nerve enlargement and increased nerve vascularization may be tools to monitor disease activity in CIDP, but further studies are needed.

Measurement of cross-sectional area of cervical roots and brachial plexus trunks

INTRODUCTION

The aim of this study was to determine normal reference values for cross-sectional area (CSA) and the correlation between demographic factors and CSA in the cervical roots and brachial plexus trunks using ultrasonography.

METHODS

Ninety-five age-matched healthy individuals were studied. Ultrasonographic tests were performed via nerve tracing from the cervical root to the brachial plexus trunk. The CSA of each nerve was measured in the C5-8 ventral roots and brachial plexus (trunk level).

RESULTS

Normal values of each cervical root were: C5, 5.66 ± 1.02 mm(2); C6, 8.98 ± 1.65 mm(2); C7, 10.43 ± 1.86 mm(2); and C8, 10.76 ± 2.02 mm(2). Values for the brachial plexus were: upper trunk, 16.70 ± 2.88 mm(2); middle trunk, 14.01 ± 2.70 mm(2); and lower trunk, 13.75 ± 2.57 mm(2). The side-to-side discrepancy was 11.91 ± 11.11%. Body mass index (BMI) and height correlated frequently with nerve CSA.

CONCLUSIONS

These reference values may be helpful in investigating pathologies involving the cervical area.

Nerve ultrasound follow-up in a child with Guillain-Barré syndrome

INTRODUCTION

Nerve ultrasound has been used increasingly in neurophysiology laboratories, but data on Guillain-Barré syndrome (GBS) are still limited, and no follow-up studies are available.

CASE REPORT

An 8-year-old boy was admitted with severe demyelinating GBS. Serial neurophysiological evaluations were performed initially and in follow-up. Ultrasound studies showed diffuse and heterogeneous nerve swelling and focal enlargement of single fascicles inside the nerve. Together with clinical and electrophysiological improvement, progressive normalization of ultrasound changes was seen.

CONCLUSIONS

Ultrasound demonstrated structural nerve abnormalities in GBS. These changes normalized as the patient improved clinically and electrophysiologically. Further studies are needed to elucidate the diagnostic and prognostic value of ultrasound in GBS.

Ultrasonography in the diagnosis of peripheral nerve disease

INTRODUCTION

High-resolution ultrasound (US) of the peripheral nerves is now a standard means of assessing neuromuscular disorders in many centers. Currently used in conjunction with electrodiagnostic (EDX) studies, nerve US is especially effective in the diagnosis of entrapment neuropathies.

AREAS COVERED

This article reviews the basic physics of peripheral nerve US, guidelines for its current use and future directions. Advantages of using nerve US alongside EDX studies are outlined along with current limitations of testing. The role of US in the diagnosis of entrapment neuropathy is emphasized, particularly in carpal tunnel syndrome (CTS). US assisted diagnosis of peripheral nerve tumors, hereditary neuropathy and dysimmune neuropathy and traumatic injuries is also described.

EXPERT OPINION

US is a powerful tool in the assessment of peripheral nerve disease. Nerve US is an evolving, young discipline. There is still much to learn, but current evidence supports US imaging of all patients presenting for evaluation of possible mononeuropathy. With improvements in resolution, the introduction of US contrast agents and objective measures of nerve echogenicity, there is promise for further expanding its role in the diagnosis of all peripheral neuropathies.

Intra- and internerve cross-sectional area variability: new ultrasound measures

INTRODUCTION

Nerve involvement in immune-related neuropathies is non-homogeneous, and therefore characterization of ultrasound (US) abnormalities is difficult. We developed two measures to quantify US abnormalities in immune-related neuropathies.

METHODS

Intranerve cross-sectional area (CSA) variability for each nerve was calculated as: maximal CSA/minimal CSA. Internerve CSA variability for each patient was calculated as: maximal intranerve CSA variability/minimal intranerve CSA variability. Six patients underwent US evaluation of the median, ulnar, and fibular nerves, and the abnormalities were scored with our newly developed measures.

RESULTS

The new measures were applicable to all nerves and patients. The highest degree of intra- and internerve CSA variability was observed in multifocal motor neuropathy, consistent with the asymmetric characteristics of this neuropathy.

CONCLUSIONS

The application of intra- and internerve CSA variability measures allows us to quantify the heterogeneity of nerves and nerve segments and identify different US patterns in diverse immune-related neuropathies.

Ultrasonography of MADSAM neuropathy: focal nerve enlargements at sites of existing and resolved conduction blocks

Using the emerging technique of peripheral nerve ultrasonography, multiple focal nerve swellings corresponding to sites of existing conduction blocks have been described in demyelinating polyneuropathies. We report two cases of multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). In the first, multiple focal nerve enlargements were detected by ultrasound at sites of previous conduction blocks, well after complete clinical and electrophysiological resolution. In the second case, existing proximal conduction blocks could be localized by ultrasound. Our cases highlight the importance of nerve ultrasound in identifying conduction blocks and demonstrate that ultrasonographic morphological changes may outlast functional recovery in demyelinating neuropathies.

Sonographic features in hereditary neuropathy with liability to pressure palsies

INTRODUCTION

Diagnostic nerve ultrasound is becoming more commonly used by both radiologists and clinicians. The features of different neuromuscular conditions must be described to broaden our understanding and ability to interpret findings.

METHODS

Our study examines the sonographic features of 7 subjects with hereditary neuropathy with liability to pressure palsies (HNPP) in comparison to 32 controls by measuring the nerve cross-sectional area (CSA) of the median, ulnar and tibial nerves.

RESULTS

Significant differences (P < 0.05) in nerve size were found. The HNPP group had a larger CSA for the median nerve at the wrist and ulnar nerve at the elbow (entrapment sites), but not the forearms. The tibial nerve at the ankle was also larger in the HNPP group, suggesting possible concomitant tibial neuropathy at the ankle.

CONCLUSION

These results will help shape imaging protocols to better detect conditions with non-uniform nerve enlargements.

Sonographic evaluation of peripheral nerve injuries following the Wenchuan earthquake

PURPOSE

To analyze retrospectively the sonographic characteristics of the peripheral nerve injuries (PNIs) resulted from Wunchuan earthquake.

METHODS

The sonographic images of 38 patients with surgically proved PNIs were reviewed and compared with the surgical findings.

RESULTS

A total of 78 nerves in 38 patients were found injured in surgery, which included 16 median nerves in the forearm (20.5%), 6 ulnar nerves in the forearm or arm (7.7%), 8 radial nerves in upper limb (10.0%), 8 sciatic nerves (10.3%) in gluteal region, 17 tibial nerves in the leg (21.8%), and 23 peroneal nerves (29.5%). The most common injured nerve in the lower extremity was the peroneal nerve (29.5%) and in upper extremity was the median nerve (20.5%). Sonography correctly diagnosed 72 earthquake-related nerve injuries (92.3%), which included 5 complete disruption (6.4%), 4 partial disruption (5.1%), 63 nerve entrapment (88.5%, included 1 entrapment by bone calus, 38 entrapments by the scar tissue, 13 entrapments by the thickened muscle or tendinous arch, and 11 entrapment in the narrowed osteofibrous tunnels).

CONCLUSIONS

Nerve entrapment injury was the common sonographic finding in earthquake-related PNI.