Nerve ultrasound: A reproducible diagnostic tool in peripheral neuropathy

Establishing Reference Values in the Neuromuscular Ultrasound Laboratory Using the e-Norms Method: A Feasibility Study

INTRODUCTION/AIMS

The standard procedure to establish reference values in a neuromuscular laboratory involves examining healthy controls, as nerve size varies with the population and muscle echo intensity (EI) is device-specific. We aimed to derive these reference values by extrapolation from a studied sample (the e-norms method), compare them with published reference values, and determine their diagnostic accuracy.

METHODS

We retrospectively analyzed data from consecutive patients who underwent nerve and/or muscle ultrasound in our ultrasound laboratory, which is a tertiary referral center for neuromuscular diseases in Southern Poland in the years 2018-2023. We plotted the cross-sectional area (CSA) of the nerve segments and EI of the individual muscles and derived descriptive statistics from the plateau of the e-norms curve. We compared the mean difference of the nerve size to other studies and determined the ability of the muscle EI to discriminate myopathic versus healthy subjects using receiver operator characteristics curves.

RESULTS

We analyzed 1124 nerves and 1154 muscles from 109 and 99 subjects, respectively. The derived reference values for nerve CSA were mostly concordant with other studies, including all nerve segments in the legs and with the exception of compression sites and the most proximal nerve segments in the arms. Using the reference values for muscle EI established with the e-norms method, we were able to discriminate myopathic from healthy subjects with 85% sensitivity and 92% specificity.

DISCUSSION

The e-norms is a feasible method to establish reference values in the neuromuscular ultrasound laboratory.

Nerve cross-sectional area from childhood to old age: A high-resolution nerve ultrasound study

BACKGROUND AND PURPOSE

Nerve cross-sectional area (CSA) is not constant over the human lifespan. The relationship between an increasing CSA and age has been described as a linear positive correlation, but few studies have found a linear decrease in nerve size with older age. The aim of the present study was to analyze the development of nerve CSA in a healthy population from early childhood to old age using high-resolution ultrasound.

METHODS

The median, ulnar, radial and sural nerves were examined bilaterally at 18 nerve sites in 110 healthy children, adolescents and adults aged between 2 and 98 years. The CSA of every nerve site was evaluated separately and in different age groups. The correlation of CSA with age, height and weight was analyzed in a linear, logarithmic and quadratic model and correlation coefficients were compared in a goodness-of-fit analysis. Models were then adjusted for weight and height.

RESULTS

Linear CSA-age correlations showed the lowest correlation coefficients for all nerve sites. An inverted parabolic curve suggesting a quadratic correlation of CSA and age was the best-fitting model. Weight and height had a higher predictive value than age in adjusted models.

CONCLUSIONS

There is an increase in nerve size during childhood and adolescence and a trend towards a decrease in old age, suggesting an inverted parabolic curve partly explained by age-related changes in weight and height. Enlarged nerves in elderly individuals should not be attributed to age alone.

Cross-Sectional Area and Echogenicity Reference Values for Sonography of Peripheral Nerves in the Lithuanian Population

OBJECTIVES

We aimed to provide data of nerve sizes and echogenicity reference values of the Lithuanian population.

METHODS

High-resolution ultrasound was bilaterally performed according to the Ultrasound Pattern Sum Score and Neuropathy ultrasound protocols for healthy Lithuanian adults. Cross-sectional area (CSA) measurement and echogenicity were used as the main parameters for investigation. Echogenicity was evaluated using ImageJ, and nerves were categorized in classes according to echogenicity.

RESULTS

Of 125 subjects enrolled, 63 were males (mean age 47.57 years, range 25-78 years) and 62 were females (mean age 50.50 years, range 25-80 years). Reference values of nerve sizes and values of echogenicity as a fraction of black in percentage of cervical roots, upper and middle trunks of the brachial plexus and the following nerves: vagal, median, ulnar, radial, superficial radial, tibial, fibular, and sural in standard regions were established. Mild to moderate correlations were found between nerves CSA, echogenicity values and anthropometric measurements with the differences according to sex. Inter-rater (ICC 0.93; 95% CI 0.92-0.94) and intra-rater (ICC 0.94; 95% CI 0.93-0.95) reliability was excellent.

CONCLUSIONS

Reference values of nerve size and echogenicity of Lithuanians were presented for the first time as a novel such kind of publication from the Baltic countries.

Challenges in the Early Diagnosis and Treatment of Chronic Inflammatory Demyelinating Polyradiculoneuropathy in Adults: Current Perspectives

Diagnosing Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) poses numerous challenges. The heterogeneous presentations of CIDP variants, its mimics, and the complexity of interpreting electrodiagnostic criteria are just a few of the many reasons for misdiagnoses. Early recognition and treatment are important to reduce the risk of irreversible axonal damage, which may lead to permanent disability. The diagnosis of CIDP is based on a combination of clinical symptoms, nerve conduction study findings that indicate demyelination, and other supportive criteria. In 2021, the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) published a revision on the most widely adopted guideline on the diagnosis and treatment of CIDP. This updated guideline now includes clinical and electrodiagnostic criteria for CIDP variants (previously termed atypical CIDP), updated supportive criteria, and sensory criteria as an integral part of the electrodiagnostic criteria. Due to its many rules and exceptions, this guideline is complex and misinterpretation of nerve conduction study findings remain common. CIDP is treatable with intravenous immunoglobulins, corticosteroids, and plasma exchange. The choice of therapy should be tailored to the individual patient's situation, taking into account the severity of symptoms, potential side effects, patient autonomy, and past treatments. Treatment responses should be evaluated as objectively as possible using disability and impairment scales. Applying these outcome measures consistently in clinical practice aids in recognizing the effectiveness (or lack thereof) of a treatment and facilitates timely consideration of alternative diagnoses or treatments. This review provides an overview of the current perspectives on the diagnostic process and first-line treatments for managing the disease.

High-resolution nerve ultrasound and corneal confocal microscopy in taxane-induced polyneuropathy

BACKGROUND AND PURPOSE

The role of high-resolution nerve ultrasound (HRUS) and corneal confocal microscopy (CCM) in the early detection of taxane-induced polyneuropathy (TIPN) is unclear. The present prospective longitudinal controlled observational pilot study estimates the role of HRUS and CCM in the early diagnosis of TIPN in breast cancer patients.

METHODS

Fifteen breast cancer patients receiving paclitaxel and 15 healthy age matched controls were included. Visits before and 3 weeks, 8 weeks and 6 months after treatment included clinical examination, the total neuropathy score, nerve conduction studies (NCS), monocular CCM including corneal nerve fibre length, density and branching and HRUS of bilateral median, ulnar, radial, tibial, peroneal and sural nerves. Patients were compared between different visits and to healthy controls.

RESULTS

Total neuropathy score increased from 2.2 at baseline to 5.8 (p < 0.001) at week 8. NCS showed a decreased sensory amplitude in the sural, radial, ulnar and median nerve after 6 months (p < 0.001). HRUS revealed a significant increase of cross-sectional area in the sural nerve (p = 0.004), the median nerve (p = 0.003) at the carpal tunnel and the ulnar nerve in the forearm (p = 0.006) after 6 months. CCM showed no changes at different visits.

CONCLUSIONS

Corneal confocal microscopy and HRUS do not detect early signs of TIPN during the paclitaxel treatment period. HRUS and NCS might detect congruent signs of an axonal, predominantly sensory polyneuropathy after 6 months. The clinical examination remains the most sensitive tool in the early detection of TIPN in breast cancer patients.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

Neuromuscular ultrasound standardized scanning techniques and protocols: Expert panel recommendations

Neuromuscular ultrasound has become an integral part of the diagnostic workup of neuromuscular disorders at many centers. Despite its growing utility, uniform standard scanning techniques do not currently exist. Scanning approaches for similar diseases vary in the literature creating heterogeneity in the studies as reported in several meta-analysis. Moreover, neuromuscular ultrasound experts including the group in this study have different views with regards to technical aspects, scanning protocols, and the parameters that should be assessed. Establishing standardized neuromuscular scanning protocols is essential for the development of the subspeciality to ensure uniform clinical and research practices. Therefore, we aimed to recommend consensus-based standardized scanning techniques and protocols for common neuromuscular disorders using the Delphi approach. A panel of 17 experts participated in the study, which consisted of three consecutive electronic surveys. The first survey included voting on six scanning protocols addressing the general scanning technique and five common categories of suspected neuromuscular disorders. The subsequent surveys focused on refining the protocols and voting on new steps, rephrased statements, or areas of non-agreement. A high degree of consensus was achieved on the general neuromuscular ultrasound scanning technique and the scanning protocols for focal mononeuropathies, brachial plexopathies, polyneuropathies, amyotophic lateral sclerosis, and muscle diseases. In this study, a group of neuromuscular ultrasound experts developed six consensus-based neuromuscular ultrasound scanning protocols that may serve as references for clinicians and researchers. The standardized protocols could also aid in achieving high-quality uniform neuromuscular ultrasound practices.

Neuromuscular ultrasound protocols: First steps, future challenges

See article on pages 375–379 in this issue.

Vagus nerve cross-sectional area decreases in Parkinson's disease

INTRODUCTION

Morphological alterations of the vagus nerve (VN) in Parkinson's disease (PD) are discussed controversially. Several studies reported no difference in VN cross-sectional area (CSA) in PD patients in nerve ultrasound, others found a reduced CSA interpreted as atrophy of the VN and involvement of the dorsal nucleus of VN.

METHODS

In a prospective comparative cross-sectional study, CSA of the VN bilaterally and the right ulnar nerve, clinical PD scales, non-motor symptoms and autonomic tests were compared between 49 PD patients and 24 healthy controls. Nerve ultrasound was performed by two independent investigators, patients and controls were compared at Bonferroni corrected p < 0.025 using results of both investigators and averaged results. Blinding included CSA measurements and PD scores, but not PD diagnosis.

RESULTS

Bilateral averaged VN CSA was significantly lower in PD patients than in controls (Right VN PD mean 2.70 mm2 SD 0.69, controls 3.30 mm2 SD 0.49, p < 0.001. Left VN PD mean 2.45 mm2 SD 0.57, controls 2.77 mm2 SD 0.46, p = 0.012). No difference was found in the ulnar nerve. There was a weak negative correlation between the right VN CSA and the Unified Parkinson Disease Rating Scale (-0.08 mm2 per 10 points). The area under the receiver operating characteristic curve for the right VN was 0.78 (p < 0.001).

CONCLUSION

The present results support the hypothesis of atrophy of the VN in PD. Reduction of VN CSA is a weak marker of disease progression. Nerve ultrasound of the VN might represent a supplementary method in diagnosis of PD.

Sonographic peripheral nerve cross-sectional area in adults, excluding median and ulnar nerves: A systematic review and meta-analysis

INTRODUCTION/AIMS

Although electromyography remains the "gold standard" for assessing and diagnosing peripheral nerve disorders, ultrasound has emerged as a useful adjunct, providing valuable anatomic information. The objective of this study was to conduct a systematic review and meta-analysis evaluating the normative sonographic values for adult peripheral nerve cross-sectional area (CSA).

METHODS

Medline and Cochrane Library databases were systematically searched for healthy adult peripheral nerve CSA, excluding the median and ulnar nerves. Data were meta-analyzed, using a random-effects model, to calculate the mean nerve CSA and its 95% confidence interval (CI) for each nerve at a specific anatomical location (= group).

RESULTS

Thirty groups were identified and meta-analyzed, which comprised 16 from the upper extremity and 15 from the lower extremity. The tibial nerve (n = 2916 nerves) was reported most commonly, followed by the common fibular nerve (n = 2580 nerves) and the radial nerve (n = 2326 nerves). Means and 95% confidence interval (CIs) of nerve CSA for the largest number of combined nerves were: radial nerve assessed at the spiral groove (n = 1810; mean, 5.14 mm2 ; 95% CI, 4.33 to 5.96); common fibular nerve assessed at the fibular head (n = 1460; mean, 10.18 mm2 ; 95% CI, 8.91 to 11.45); and common fibular nerve assessed at the popliteal fossa (n = 1120; mean, 12.90 mm2 ; 95% CI, 9.12 to 16.68). Publication bias was suspected, but its influence on the results was minimal.

DISCUSSION

Two hundred thirty mean CSAs from 15 857 adult nerves are included in the meta-analysis. These are further categorized into 30 groups, based on anatomical location, providing a comprehensive reference for the clinician and researcher investigating adult peripheral nerve anatomy.

Ultrasound of peripheral nerves distinguishes inherited sensory neuronopathy of cerebellar ataxia with neuropathy and vestibular areflexia syndrome from inherited axonopathy

Introduction/Aims Recent studies have shown that ultrasound of peripheral nerves can distinguish inherited sensory neuronopathy from acquired axonopathy with a high degree of accuracy. In this study we aimed to determine whether ultrasound can also distinguish inherited sensory neuronopathy from inherited axonopathy. Methods We compared the ultrasound cross-sectional areas (CSAs) of the median, ulnar, sural, and tibial nerves of retrospectively recruited patients with cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS), in whom sensory neuronopathy is a cardinal feature, with Charcot-Marie-Tooth type 2 (CMT2) disease patients, who have an inherited axonopathy, using the Kruskal-Wallis test and receiver-operating characteristic curves. Results There were 17 patients with CANVAS and 18 with CMT2. The upper limb nerve CSAs were significantly smaller in CANVAS than in CMT2 (P < .001), with the CSAs of the median nerve at mid-forearm and ulnar nerve at mid-arm being a third or less the size of those of the CMT2 patients. Nerve ultrasound reliably distinguished CANVAS from CMT2 with ROC areas under the curve between 0.97 and 0.99. The lower limb CSAs of the two patient groups were not significantly different. Discussion Ultrasound of the upper limb nerves distinguishes CANVAS sensory neuronopathy from inherited axonopathy with high accuracy and can therefore be proposed as a reliable additional tool in the investigation of these diseases.

Enlarged cross-sectional area in peripheral nerves in Swedish patients with hereditary V30M transthyretin amyloidosis

INTRODUCTION

In hereditary transthyretin amyloidosis (ATTRv), two different fibrillar forms causing the amyloid deposition, have been identified, displaying substantially cardiac or neuropathic symptoms. Neuropathic symptoms are more frequent in early-onset patients, whereas late-onset patients, besides cardiac symptoms, seem to develop carpal tunnel syndrome, more often. With ultrasonography (US) of peripheral nerves, it is possible to distinguish structural changes, and enlarged cross-sectional area (CSA). The main purpose of this study was, for the first time, to elucidate US of peripheral nerves in Swedish ATTRv patients at an early stage of the disease, and to evaluate possible early enlarged CSA.

MATERIAL AND METHODS

This prospective study included first visit data of 13 patients, aged 30-88 years, of which 11 with late-onset age. All had a positive V30M mutation. Eight men and six women (aged 28-74 years) served as controls.

RESULTS

Significantly enlarged CSA was seen in ATTRv patients for the tibial nerve at the ankle (p = .001), the sural nerve (p < .001), the peroneal nerve at the popliteal fossa (p = .003), and the ulnar nerve at the middle upper arm (p = .007).

CONCLUSION

US of peripheral nerves could be a valuable tool in disease evaluation and could facilitate monitoring of disease progression.

High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients. However, physicians adopting state-of-art diagnostic strategies, including nerve imaging, may improve the detection rate and management of neuropathies. In particular, a diagnostic approach relying exclusively on clinical history and nerve conduction studies may not be sufficient to disclose the etiology of the nerve damage and its anatomical location and thus requires integration with morphological studies. High-Resolution Ultrasound (HRUS) is increasingly adopted to support the diagnosis and follow-up of both joint disorders in rheumatology and peripheral neuropathies of different etiologies. In this review, the different types of nerve disorders associated with the most common syndromes of rheumatological interest are discussed, focusing on the distinctive sonographic features.

Cervical Root Enlargement in Segmental Zoster Paresis: A Study with Magnetic Resonance Imaging and Nerve Ultrasound

A 72-year-old woman presented with acute-progressive muscle weakness after a rash in the left upper limb. Muscle weakness was restricted to the left C5 innervated muscles. Short inversion time inversion recovery magnetic resonance imaging (MRI) showed a high-intensity signal in the left C5 nerve root, and nerve ultrasound showed its enlargement. She was diagnosed with segmental zoster paralysis (SZP) and treated with acyclovir and methylprednisolone. Her muscle strength gradually recovered, and the abnormal signal and enlargement in the left C5 nerve root improved. This is the first SZP case of confirmed improvement of abnormal findings on MRI and nerve ultrasound in association with muscle power recovery.

Management Strategies for Descending Thoracic Aortic Thrombus: A Review of the Literature

Descending thoracic aortic thrombus (DTAT) is an under-recognized source of systemic emboli with potential catastrophic consequences. Imaging modalities such as echocardiography, computed tomography, magnetic resonance imaging, and angiography can help identify and characterize the extent of embolic events. Established guidelines regarding the management of DTAT are currently lacking. Multiple treatment modalities are available; however, the effectiveness of each approach remains to be determined. In this study, we performed a review to examine the clinical presentation, diagnostic methods and findings, and outcomes of various treatment options for patients with DTAT. Medical management is the least invasive and most frequently chosen initial approach, offering a high reported success rate, whereas endovascular therapy can have a role in thrombus exclusion should conservative management fail.

Application and Research Progress of High Frequency Ultrasound in the Diagnosis of Chronic Inflammatory Neuropathies

In recent years, clinicians have gradually improved their understanding of multiple neuropathy and have done some studies about chronic inflammatory neuropathies, for example, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and Lewis-Sumne syndrome. The early diagnosis is very important for the next step treatment and long-term prognosis. At present, the disease mainly depends on clinical and neural electrophysiological examination, but imaging studies are few. In recent years, with the rapid development of high frequency ultrasound, it could clearly show the morphology of the nerve, and it has been an emerging diagnosis tool of polyneuropathies. This article mainly reviews the application and the latest research progress of high frequency ultrasound in these diseases.

Contemporary challenges in the diagnosis and management of chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

Despite extensive research, multiple inter-related diagnostic and management challenges remain for chronic inflammatory demyelinating polyneuropathy (CIDP).

AREAS COVERED

A literature review was performed on diagnosis and treatment in CIDP. The clinical features and disease course were evaluated. Investigative techniques, including electrophysiology, cerebrospinal fluid examination, neuropathology, imaging and neuroimmunology, were considered in relation to technical aspects, sensitivity, specificity, availability and cost. Available evidenced-based treatments and those with possible efficacy despite lack of evidence, were considered, as well as current methods for evaluation of treatment effects.

EXPERT OPINION

CIDP remains a clinical diagnosis, supported first and foremost by electrophysiology. Other investigative techniques have limited impact. Most patients with CIDP respond to available first-line treatments and immunosuppression may be efficacious in those who do not. Consideration of the natural history and of the high reported remission rate, of under-recognised associated disabling features, of treatment administration modalities and assessment methods, require enhanced attention.

Evidence base for investigative and therapeutic modalities in chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy

Chronic inflammatory demyelinating polyneuropathy, its variants and multifocal motor neuropathy belong to a spectrum of peripheral nerve disorders with complex dysimmune disease mechanisms. Awareness of the unique clinical phenotypes but also heterogeneity between patients is vital to arrive at early suspicion and ordering appropriate tests. This includes requirements for optimal electrodiagnostic protocol, aimed to capture sufficient electrophysiologic evidence for relevant abnormalities, a case-based approach on the eventual need to further expand the diagnostic armamentarium and correct reading of their results. Considerable phenotypical variation, diverse combinations of abnormalities found on diagnostic tests and heterogeneity in disease course and treatment response, all contribute to widespread differences in success rates on timely diagnosis and optimal treatment. We aim to provide a practical overview and guidance on relevant diagnostic and management strategies, including pitfalls and present a summary of the relevant novel developments in this field.

Assessment of Operator Reliability in Ultrasound of the Median and Ulnar Nerve Using Bland-Altman Analysis

Currently, there is no standardized method to evaluate operator reliability in nerve ultrasound. A short prospective protocol using Bland–Altman analysis was developed to assess the level of agreement between operators with different expertise levels. A control rater without experience in nerve ultrasound, three novices after two months of training, an experienced rater with two years of experience, and a reference rater performed blinded ultrasound examinations of the left median and ulnar nerve in 42 nerve sites in healthy volunteers. The precision of Bland–Altman agreement analysis was tested using the Preiss–Fisher procedure. Intraclass correlation coefficients (ICC), coefficients of variation, and Bland–Altman limits of agreement were calculated. The sample size calculation and Preiss–Fisher procedure showed a sufficient precision of Bland–Altman agreement analysis. Limits of agreement of all trained novices ranged from 2.0 to 2.9 mm² and were within the test’s maximum tolerated difference. Ninety-five percent confidence intervals of limits of agreement revealed a higher precision in the experienced rater’s measurements. Operator reliability in nerve ultrasound of the median and ulnar nerve arm nerves can be evaluated with a short prospective controlled protocol using Bland–Altman statistics, allowing a clear distinction between an untrained rater, trained novices after two months of training, and an experienced rater.

Peripheral neuropathy in systemic lupus erythematosus: what can neuromuscular ultrasonography (NMUS) tell us? A cross-sectional study

OBJECTIVE

To evaluate peripheral nerve involvement in patients with SLE with neuromuscular ultrasonography (NMUS) and understand its role in investigating SLE-related peripheral neuropathy.

METHODS

This is an observational cross-sectional study on patients with SLE and healthy controls. Five nerves in each patient were examined bilaterally with NMUS, and the cross-sectional area (CSA) of each nerve at certain sites was estimated. The mean CSA at each site, for each nerve, in each group was statistically analysed and compared between groups.

RESULTS

370 nerves were evaluated in 37 patients. By nerve conduction study (NCS), 36 patients had polyneuropathy (80.6% mixed type, 19.4% sensory). Significant mean CSA enlargement was present among the ulnar nerve at the Guyon's canal and mid-humerus (both p=0.001); tibial nerve at the distal leg and proximal to the tarsal tunnel (p=0.003 and p=0.001, respectively); and peroneal nerve at the popliteal fossa (p=0.042). The mean CSA showed high specificity compared with NCS.

CONCLUSION

Our study shows that CSA could be a complementary tool to NCS for studying peripheral neuropathy in SLE. Furthermore, NMUS provides data on the different pathophysiological aspects of nerve involvement in SLE. Future studies using more than one sonographic parameter in combination with NCS and nerve histopathology are recommended to further investigate SLE-related neuropathy.Trial registration number NCT04527172.

Early and late manifestations of neuropathy due to HSPB1 mutation in the Jewish Iranian population

OBJECTIVE

Mutations in the HSPB1 gene are associated with a distal hereditary motor neuropathy type 2 (dHMN2) or Charcot-Marie-Tooth disease type 2F (CMT2F), usually with autosomal dominant inheritance. This study aimed to describe the phenotype of the HSPB1 c.407G>T (p.Arg136Leu) mutation at early and late stages of the disease course.

METHODS

We identified this mutation (previously reported in patients from Italy) in a heterozygous state, among 14 individuals from eight families of Jewish Iranian descent. The clinical, electrophysiological and ultrasonographic features were evaluated during early (less than 5 years, N = 9) or late disease course (N = 5).

RESULTS

The majority of subjects were males with a mean age at onset of 43.4 years (range 21-67). Common initial symptoms were gait imbalance, distal (often asymmetric) lower limb weakness and feet numbness. Neurological examination in early disease course showed distal lower extremity weakness in nearly all cases, and absent Achilles tendon reflex in about half. A minority had distal loss of pain, vibration or position sensation. These findings were more prevalent in late disease stage. Electrodiagnostic studies demonstrated a length-dependent axonal motor neuropathy, with typical preferential involvement of the tibial nerve. Muscle ultrasound showed a corresponding length-dependent increase of homogeneous echo-intensity, most noticeably in the gastrocnemius. One patient had a dual diagnosis of CMT2F and CMT2W.

INTERPRETATION

The HSPB1 c.407G>G (p.Arg136Leu) mutation causes an adult-onset, predominantly motor, axonal neuropathy in individuals of Jewish Iranian descent. Variable manifestations are noticed, and sensory involvement is more prominent in prolonged disease duration.

Prognostic value of nerve ultrasonography: A prospective multicenter study on the natural history of chronic inflammatory neuropathies

BACKGROUND AND OBJECTIVE

Nerve ultrasound is a promising new tool in chronic inflammatory neuropathies. The aim of this study was to determine its prognostic value in a prospective multicenter cohort study including incident and prevalent patients with CIDP and MMN.

METHODS

We enrolled 126 patients with CIDP, and 72 with MMN; 71 were treatment-naive. Patients with chronic idiopathic axonal polyneuropathy (CIAP; n = 35) were considered as disease controls. Standardized neurological examination, questionnaires, and nerve ultrasonography were obtained at time of inclusion and 1-year follow-up. Nerve size development over time and correlation between nerve size and clinical outcome measures were determined using linear mixed effects models.

RESULTS

Nerve size development over time was heterogeneous. Only in MMN was there a correlation between C5 nerve root size and deterioration of grip strength (-1.3 kPa/mm² (95% confidence interval [CI] -2.3 to -0.2). No other significant correlations between nerve size and clinical outcome measures were found. In MMN, presence of nerve enlargement at inclusion predicted deterioration of grip strength, and MMN patients with enlargement confined to the brachial plexus seemed to have more favorable outcomes. No other predictive effects of sonographic nerve size were found.

CONCLUSIONS

The present study indicates that the natural course of nerve size development in CIDP and MMN is heterogeneous, and that the prognostic value of sonographic nerve enlargement is limited. It had some predictive effect in patients with MMN. Further research in specific subgroups of chronic inflammatory neuropathy is necessary to determine the usefulness of nerve ultrasonography after the diagnostic phase.

Ultrasound scanning in the diagnosis of peripheral neuropathies

Nerve ultrasound scanning has become a valuable diagnostic tool in the routine workup of peripheral nerve disorders, effectively complementing conventional electrodiagnostic studies. The most relevant sonographic features are nerve size and structural integrity. Several peripheral neuropathies show characteristic and distinct patterns of nerve enlargement, allowing their early and accurate identification, and reducing test-burden and diagnostic delay for patients. In mononeuropathies such as carpal tunnel syndrome and ulnar neuropathy at the elbow, nerve enlargement develops only at specific sites of entrapment, while in polyneuropathy the nerve enlargement may be multifocal, regional or even diffuse. Nerve ultrasound scanning can reliably identify chronic inflammatory neuropathies, even when extensive electrodiagnostic studies fail, and it should therefore be embedded in routine diagnostic workup of peripheral neuropathies. In this paper we describe a potential diagnostic strategy to achieve this.

Diagnostic challenges in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) consists of a spectrum of autoimmune diseases of the peripheral nerves, causing weakness and sensory symptoms. Diagnosis often is challenging, because of the heterogeneous presentation and both mis- and underdiagnosis are common. Nerve conduction study (NCS) abnormalities suggestive of demyelination are mandatory to fulfil the diagnostic criteria. On the one hand, performance and interpretation of NCS can be difficult and none of these demyelinating findings are specific for CIDP. On the other hand, not all patients will be detected despite the relatively high sensitivity of NCS abnormalities. The electrodiagnostic criteria can be supplemented with additional diagnostic tests such as CSF examination, MRI, nerve biopsy, and somatosensory evoked potentials. However, the evidence for each of these additional diagnostic tests is limited. Studies are often small without the use of a clinically relevant control group. None of the findings are specific for CIDP, meaning that the results of the diagnostic tests should be carefully interpreted. In this update we will discuss the pitfalls in diagnosing CIDP and the value of newly introduced diagnostic tests such as nerve ultrasound and testing for autoantibodies, which are not yet part of the guidelines.

Nerve ultrasound for diagnosing chronic inflammatory neuropathy: A multicenter validation study

OBJECTIVE

To validate the diagnostic accuracy of a previously described short sonographic protocol to identify chronic inflammatory neuropathy (CIN), including chronic inflammatory demyelinating polyneuropathy (CIDP), Lewis Sumner syndrome, and multifocal motor neuropathy (MMN), and to determine the added value of nerve ultrasound to detect treatment-responsive patients compared to nerve conduction studies (NCS) in a prospective multicenter study.

METHODS

We included 100 consecutive patients clinically suspected of CIN in 3 centers. The study protocol consisted of neurologic examination, laboratory tests, NCS, and nerve ultrasound. We validated a short sonographic protocol (median nerve at forearm, upper arm, and C5 nerve root) and determined its diagnostic accuracy using the European Federation of Neurological Societies/Peripheral Nerve Society criteria of CIDP/MMN (reference standard). In addition, to determine the added value of nerve ultrasound in detecting treatment-responsive patients, we used previously published diagnostic criteria based on clinical, NCS, and sonographic findings and treatment response (alternative reference standard).

RESULTS

Sensitivity and specificity of the sonographic protocol for CIN according to the reference standard were 87.4% and 67.3%, respectively. Sensitivity and specificity of this protocol according to the alternative reference standard were 84.6% and 72.8%, respectively, and of NCS 76.1% and 93.4%. With addition of nerve ultrasound, 44 diagnoses of CIN were established compared to 33 diagnoses with NCS alone.

CONCLUSIONS

A short sonographic protocol shows high diagnostic accuracy for detecting CIN. Nerve ultrasound is able to detect up to 25% more patients who respond to treatment.

CLASSIFICATION OF EVIDENCE

This multicenter study provides Class IV evidence that nerve ultrasound improves diagnosis of CIN.

Nerve ultrasound improves detection of treatment-responsive chronic inflammatory neuropathies

OBJECTIVE

To examine the diagnostic accuracy of nerve ultrasound in a prospective cohort of consecutive patients with a clinical suspicion of chronic inflammatory neuropathies, including chronic inflammatory demyelinating polyneuropathy, Lewis-Sumner syndrome, and multifocal motor neuropathy, and to determine the added value in the detection of treatment-responsive patients.

METHODS

Between February 2015 and July 2018, we included 100 consecutive incident patients with a clinical suspicion of chronic inflammatory neuropathy. All patients underwent nerve ultrasound, extensive standardized nerve conduction studies (NCS), and other relevant diagnostic investigations. We evaluated treatment response using predefined criteria. A diagnosis of chronic inflammatory neuropathy was established when NCS were abnormal (fulfilling criteria of demyelination of the European Federation of Neurological Societies/Peripheral Nerve Society) or when the degree of nerve enlargement detected by sonography was compatible with chronic inflammatory neuropathy and there was response to treatment.

RESULTS

A diagnosis of chronic inflammatory neuropathy was established in 38 patients. Sensitivity and specificity of nerve ultrasound and NCS were 97.4% and 69.4% and 78.9% and 93.5%, respectively. The added value of nerve ultrasound in detection of treatment-responsive chronic inflammatory neuropathy was 21.1% compared to NCS alone.

CONCLUSIONS

Nerve ultrasound and NCS are complementary techniques with superior sensitivity in the former and specificity in the latter. Addition of nerve ultrasound significantly improves the detection of chronic inflammatory neuropathies. Therefore, it deserves a prominent place in the diagnostic workup of chronic inflammatory neuropathies.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that nerve ultrasound is an accurate diagnostic tool to detect chronic inflammatory neuropathies.

Diagnostic accuracy of MRI and ultrasound in chronic immune-mediated neuropathies

OBJECTIVE

To assess and compare the diagnostic performance of qualitative and (semi-)quantitative MRI and ultrasound for distinguishing chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) from segmental spinal muscular atrophy (sSMA).

METHODS

Patients with CIDP (n = 13), MMN (n = 10), or sSMA (n = 12) and healthy volunteers (n = 30) were included. MRI of the brachial plexus, using short tau inversion recovery (STIR), nerve-specific T2-weighted (magnetic resonance neurography [MRN]), and diffusion tensor imaging (DTI) sequences, was evaluated. Furthermore, with ultrasound, cross-sectional areas of the nerves were evaluated. Three radiologists blinded for diagnosis qualitatively scored hypertrophy and increased signal intensity (STIR and MRN), and intraobserver and interobserver agreement was assessed. For the (semi-)quantitative modalities, group differences and receiver operator characteristics were calculated.

RESULTS

Hypertrophy and increased signal intensity were found in all groups including healthy controls. Intraobserver and interobserver agreements varied considerably (intraclass correlation coefficients 0.00-0.811 and 0.101-0.491, respectively). DTI showed significant differences (p < 0.05) among CIDP, MMN, sSMA, and controls for fractional anisotropy, axial diffusivity, and radial diffusivity in the brachial plexus. Ultrasound showed significant differences in cross-sectional area (p < 0.05) among CIDP, MMN, and sSMA in upper arm and brachial plexus. For distinguishing immune-mediated neuropathies (CIDP and MMN) from sSMA, ultrasound yielded the highest area under the curve (0.870).

CONCLUSION

Qualitative assessment of hypertrophy and signal hyperintensity on STIR or MRN is of limited value. DTI measures may discriminate among CIDP, MMN, and sSMA. Currently, ultrasound may be the most appropriate diagnostic imaging aid in the clinical setting.

Ulnar nerve instability in the cubital tunnel of asymptomatic volunteers

PURPOSE

Ulnar nerve instability (UNI) in the cubital tunnel is defined as ulnar nerve subluxation or dislocation. It is a common disorder that may be noted in patients with neuropathy or in the asymptomatic. Our prospective, single-site study utilized high-resolution ultrasonography (US) to evaluate the ulnar nerve for cross-sectional area (CSA) and measures of shear-wave elastography (SWE). Mechanical algometry was obtained from the ulnar nerve in the cubital tunnel to assess pressure pain threshold (PPT).

METHODS

Forty-two asymptomatic subjects (n = 84 elbows) (25 males, 17 females) aged 22-40 were evaluated. Two chiropractic radiologists, both with 4 years of ultrasound experience performed the evaluation. Ulnar nerves in the cubital tunnel were sampled bilaterally in three different elbow positions utilizing US, SWE, and algometry. Descriptive statistics, two-way ANOVA, and rater reliability were utilized for data analysis with p ≤ 0.05.

RESULTS

Fifty-six percent of our subjects demonstrated UNI. There was a significant increase in CSA in subjects with UNI (subluxation: 0.066 mm² ± 0.024, p = 0.027; dislocation: 0.067 mm² ± 0.024, p = 0.003) compared to controls (0.057 mm² ± 0.017) in all three elbow positions. There were no significant group differences in SWE or algometry. Inter- and intra-observer agreements for CSA of the ulnar nerves within the cubital tunnel were assessed using intraclass correlation coefficient (ICC) and demonstrated moderate (ICC 0.54) and excellent (ICC 0.94) reliability.

CONCLUSIONS

Most of the asymptomatic volunteers demonstrated UNI. There was a significant increase in CSA associated with UNI implicating it as a risk factor for ulnar neuropathy in the cubital tunnel. There were no significant changes in ulnar nerve SWE and PPT. Intra-rater agreement was excellent for the CSA assessment of the ulnar nerve in the cubital tunnel. High-resolution US could be utilized to assess UNI and monitor for progression to ulnar neuropathy.