Conduction blocks of the median nerve at the wrist in pregnancy and postpartum carpal tunnel syndromes.

INTRODUCTION/AIMS: The aim in this study is to describe the clinical and electrophysiological patterns of pregnancy-related carpal tunnel syndrome (PRCTS) occurring during pregnancy or after delivery. METHODS: Clinical, epidemiological, and electrodiagnostic (EDx) data were studied in 130 women with PRCTS onset during pregnancy (n = 80) or after delivery (n = 50). Twenty-six women with PRCTS underwent EDx analysis during pregnancy and 104 after delivery (83 within 6 months of delivery and 21 up to 24 months after pregnancy onset). PRCTS was compared with idiopathic CTS in a control group consisting of 57 age-matched women with 98 cases of CTS. Twenty-four women with PRCTS had clinical and electrophysiological follow-up after corticosteroid injection (CSI) at the wrist. RESULTS: Clinical analysis showed a higher rate of bilateral and diurnal/permanent paraesthesia and more severe symptoms in PRCTS compared with idiopathic CTS. EDx analysis showed more severe abnormalities in classical tests and a higher rate of conduction block (CB) in PRCTS. Statistical analysis showed a strong negative correlation between the incidence and importance of CB and the time interval at which PRCTS women underwent EDx examination, between pregnancy onset and 24 months later. CSI resulted in significant clinical and EDx improvement in 22 of 24 PRCTS women, with disappearance of all motor and most sensory CBs. DISCUSSION: The EDx pattern of PRCTS is an acute/subacute median nerve lesion at the wrist identified by many CBs. This occurs concurrently with hormonal changes, is responsible for more severe clinical symptoms and EDx data, and it explains why CSI is so effective.

Early shoulder-girdle MRI findings in severe COVID-19-related intensive care unit-acquired weakness: a prospective cohort study.

OBJECTIVE: To describe clinical and early shoulder-girdle MR imaging findings in severe COVID-19-related intensive care unit-acquired weakness (ICU-AW) after ICU discharge. METHODS: A single-center prospective cohort study of all consecutive patients with COVID-19-related ICU-AW from November 2020 to June 2021. All patients underwent similar clinical evaluations and shoulder-girdle MRI within the first month and then 3 months (± 1 month) after ICU discharge. RESULTS: We included 25 patients (14 males; mean [SD] age 62.4 [12.5]). Within the first month after ICU discharge, all patients showed severe proximal predominant bilateral muscular weakness (mean Medical Research Council total score = 46.5/60 [10.1]) associated with bilateral, peripheral muscular edema-like MRI signals of the shoulder girdle in 23/25 (92%) patients. At 3 months, 21/25 (84%) patients showed complete or quasi-complete resolution of proximal muscular weakness (mean Medical Research Council total score > 48/60) and 23/25 (92%) complete resolution of MRI signals of the shoulder girdle, but 12/20 (60%) patients experienced shoulder pain and/or shoulder dysfunction. CONCLUSIONS: Early shoulder-girdle MRI findings in COVID-19-related ICU-AW included muscular edema-like peripheral signal intensities, without fatty muscle involution or muscle necrosis, with favorable evolution at 3 months. Precocious MRI can help clinicians distinguish critical illness myopathy from alternative, more severe diagnoses and can be useful in the care of patients discharged from intensive care with ICU-AW. KEY POINTS: • We describe the clinical and shoulder-girdle MRI findings of COVID-19-related severe intensive care unit-acquired weakness. • This information can be used by clinicians to achieve a nearly specific diagnosis, distinguish alternative diagnoses, assess functional prognosis, and select the more appropriate health care rehabilitation and shoulder impairment treatment.

The supraclavicular nerve.

INTRODUCTION/AIMS: The aim of this study was to describe a new method for studying the supraclavicular nerve (SCN) conduction and to report four cases with SCN lesions. METHODS: The SCN was antidromically recorded with a pair of self-adhesive electrodes located in the middle of the clavicle. Stimulation (<5 mA) was delivered 7 cm proximally with a bar electrode. To facilitate recording, it was explained to the participant that they would feel a very faint electrical sensation locally and an electrical tingle upward (ear) or downward (shoulder/clavicle). Each participant was asked to say when the tingling moved downward. RESULTS: In normal subjects, median values were 16 µV (range: 9-33) for sensory nerve action potential (SNAP) amplitude; 1.2 ms (range: 1-1.5) for onset latency; and 1.25 (range: 1-1.7) for side-to-side amplitude ratio. In the four patients, the SCN SNAP was absent on the pathological side and normal on the healthy side. All four patients complained of unilateral neuropathic hypoesthesia on the anterior aspect of the neck, chest, and shoulder that occurred after radical neck surgery for thyroid or larynx cancer (x3) and first rib resection (x1). DISCUSSION: A comparison with previous reports shows that this simple method provides similar or highest SNAP amplitudes. SCN lesions are rare, and rarely referred for electrodiagnosis, and often overlooked. However, the SCN conduction study, which causes very slight inconvenience (low-intensity stimulation), allows a better understanding of the origin of the complaints and permits the patient to benefit of more suitable treatment.

Neuralgic amyotrophy and COVID-19 infection: 2 cases of spinal accessory nerve palsy.

OBJECTIVE: Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome is often triggered by mechanical stress or viral infections. We reported 2 cases of shoulder weakness and amyotrophy related to spinal accessory nerve (SAN) palsy due to neuralgic amyotrophy occurring after COVID-19 infection. METHODS: For both patients, clinical history, clinical examination, electrodiagnostic (EDX), and imaging examinations invalidated other diagnoses but confirmed NA diagnosis. RESULTS: The NA involved only the SAN in both cases. EDX revealed a characteristic axonal lesion found in NA. SAN conduction study revealed normal latencies and low compound motor action potential amplitude for trapezius muscle when needle examination demonstrated a neurogenic pattern and denervation signs in the trapezius muscle. Both patient's MRI revealed denervation T2 hyper signal in impaired muscles, without any mass, cyst, injury, fibrous band, or tearing signs along SAN course. CONCLUSIONS: The COVID-19 infection could be the trigger for NA as many other viruses, and as it is a possible trigger for Guillain-Barré syndrome.

Neuralgic amyotrophy and hepatitis E infection: 6 prospective case reports.

INTRODUCTION: Hepatitis E virus (HEV) represents the main cause of enterically transmitted hepatitis worldwide. It is known that neuralgic amyotrophy (NA) is one of the most frequent neurological manifestations of HEV. However, clinical, electrodiagnostic (EDX) and MRI characteristics, as well as long-term follow-up of HEV-related NA have not been fully described yet. CASE REPORTS: We describe longitudinally clinical, EDX, biological and MRI results of six cases of HEV-associated NA, diagnosed from 2012 to 2017. Patients were between the ages of 33 and 57 years old and had a positive HEV serology. Clinical patterns showed the whole spectrum of NA, varying from extensive multiple mononeuropathy damage to single mononeuropathy. EDX results showed that the patients totalised 26 inflammatory mononeuropathies (1 to 8 per patient). These involved classical nerves such as suprascapular (6/6 cases), long thoracic (5/6 cases) and accessory spinal nerves (2/6 cases) and, some less frequent more distal nerves like anterior interosseous nerve (3/6 cases), as well as some unusual ones such as the lateral antebrachial cutaneous nerve (1/6 case), sensory fibres of median nerve (1/6 case) and phrenic nerves (1/6 case). After 2 to 8 years, all nerves had clinically recovered (muscle examination above 3/5 on MRC scale for all muscles except in one patient). DISCUSSION: HEV should be systematically screened when NA is suspected, whatever the severity, if the onset is less than 4 months (before IgM HEV-antibodies disappear) and appears to be frequently associated with severe clinical and EDX pattern, without increasing the usual recovery time.

Voluntary winging of the scapula: Proposed diagnostic criteria.

We report a series of 10 patients with unilateral, dynamic, winged scapula (WS), without cause, that was diagnosed as voluntary winging of the scapula (VWS). We compared clinical, electrodiagnostic, and other examination data for 10 patients with VWS and 146 with dynamic WS-related neuromuscular disorders, to establish a detailed pattern of the VWS subtype. In VWS, electrodiagnostic and other examinations did not reveal any neuromuscular or orthopedic cause. Winging was dynamic, obvious, neither medial nor lateral, and mainly involved the inferior angle of the scapula, in young patients. VWS never appeared during floor push-ups. Patients could produce WS at will with the index and healthy shoulder, between 25° and 65° of anterior elevation, or with shoulder internal rotation. VWS is a benign disorder that can be distinguished from neuromuscular WS by normal electrodiagnostic results for muscles and nerves of both shoulders and two specific clinical tests.

Infraspinatus muscle palsy involving suprascapular nerve, brachial plexus or cervical roots related to inflammatory or mechanical causes: Experience of 114 cases.

OBJECTIVES: To report a large series of neurogenic infraspinatus muscle (ISM) palsy, in order to improve knowledge of diagnosis, diverse etiologies and care management. METHODS: Clinical and electrodiagnostic (EDX) data for 114 cases of ISM palsy were collected over a 21-year period. Cases were attributed to 4 clinical conditions: (1) isolated suprascapular nerve mononeuropathy (n=48), (2) multiple mononeuropathies (n=33), (3) plexus lesions (n=17), and (4) cervical radiculopathy (n=16). These were related to 2 mechanisms: inflammatory (dysimmune) and mechanical. RESULTS: Group 1 cases were younger, had the most severe ISM palsies, were mostly related to inflammatory lesions (81%) such as neuralgic amyotrophy (NA), and frequently had delayed diagnosis because disability was mild. Group 2 cases were all related to inflammatory lesions and had slightly less severe ISM palsies that were frequently hidden by winged scapula. In groups 3 and 4, ISM palsies were milder and all cases were related to mechanical lesions such as brachial plexus trauma or C4-C5-C6 radiculopathy. In these cases, deltoid and ISM palsies were equal in frequency and severity whereas biceps brachii impairment was less frequent and much milder. Deltoid palsy frequently appeared predominant as compared with ISM palsy, because upper limb elevation palsy was more disabling than external rotation palsy. CONCLUSIONS: ISM palsy is a rare condition, often under-diagnosed and misidentified. The 4 main conditions of ISM palsy may be recognized by careful clinical, EDX and other examinations when necessary. Analysis of the present series highlights some clinical and EDX points that should help non-specialist and even specialist clinicians who are faced with this rare condition, to distinguish mechanical and inflammatory causes, and thus adapt patient management accordingly.

Unilateral winged scapula: Clinical and electrodiagnostic experience with 128 cases, with special attention to long thoracic nerve palsy.

INTRODUCTION: In this study we report a large series of patients with unilateral winged scapula (WS), with special attention to long thoracic nerve (LTN) palsy. METHODS: Clinical and electrodiagnostic data were collected from 128 patients over a 25-year period. RESULTS: Causes of unilateral WS were LTN palsy (n = 70), spinal accessory nerve (SAN) palsy (n = 39), both LTN and SAN palsy (n = 5), facioscapulohumeral dystrophy (FSH) (n = 5), orthopedic causes (n = 11), voluntary WS (n = 6), and no definite cause (n = 2). LTN palsy was related to neuralgic amyotrophy (NA) in 61 patients and involved the right side in 62 patients. DISCUSSION: Clinical data allow for identifying 2 main clinical patterns for LTN and SAN palsy. Electrodiagnostic examination should consider bilateral nerve conduction studies of the LTN and SAN, and needle electromyography of their target muscles. LTN palsy is the most frequent cause of unilateral WS and is usually related to NA. Voluntary WS and FSH must be considered in young patients. Muscle Nerve 57: 913-920, 2018.

Selective anterior interosseous nerve conduction study: Coaxial needle versus surface electrode recordings.

OBJECTIVES: The aim is to determine which method provides the most selective motor nerve conduction of the anterior interosseous nerve (AIN), when the stimulation cannot be restricted to this nerve. METHODS: The AIN was stimulated at the elbow, along with the whole median nerve. The motor action potential (MAP) of the AIN was recorded with 2 different methods: 1 - a coaxial needle inserted in the pronator quadratus muscle (PQ); 2 - a pair of surface electrodes fixed on the PQ. Twenty-two controls and 4 patients with AIN palsy were studied with both methods. Two among the patients were also examined with a 3rd method involving a pair of surface electrodes fixed on the flexor pollicis longus. RESULTS: For controls, with needle recording, distal motor latency (DML) to the PQ was 4.2ms and PQ MAP amplitude was 15.0mV. With surface recording, distal motor latency (DML) to the PQ was 3.1ms and PQ compound MAP (CMAP) amplitude was 5.1mV. For patients, with needle recording, DML was normal, and MAP amplitude was drastically decreased as compared with controls, while with surface recording, DML and CMAP amplitude showed no substantial change. DISCUSSION AND CONCLUSIONS: These results demonstrate that recording with a coaxial needle electrode inserted in the PQ is the only method to provide a specific NCS of the AIN, and permit the diagnosis of isolated AIN lesions, which could otherwise be missed.

Diagnosis of unilateral trapezius muscle palsy: 54 Cases.

INTRODUCTION: We assessed medical and surgical causes of unilateral trapezius muscle (TM) palsy and/or wasting. METHODS: Clinical and electrodiagnostic data were collected in 54 patients with TM impairment over 21 years. RESULTS: In total, 35 cases had a medical origin: neuralgic amyotrophy (NA, n = 22), idiopathic unilateral TM palsy (n = 5), regional neck radiotherapy for different conditions (n = 2), facioscapulohumeral dystrophy (FSH) (n = 4), abnormal loop of the jugular vein (n = 1), or basilar impression (n = 1). Other etiologies were neck surgery (n = 16), cervicofacial lift (n = 2), or trauma (n = 1). CONCLUSIONS: There were 5 main diagnostic findings in unilateral TM palsy: (1) dynamic examination of the scapula provides a new clinical sign; (2) NA is the most frequent medical cause; (3) in medical cases, partial preservation of the upper TM can offer good recovery; (4) FSH must be considered, especially in young patients; and (5) minor neck surgery can lead to severe TM palsy. Muscle Nerve 56: 215-223, 2017.

Neuralgic amyotrophy. An update.

A century after the first description of neuralgic amyotrophy (NA), its pathophysiology remains unknown. An inflammatory (auto)immune pathophysiology is presumed, with mechanical or infectious precipitating conditions, which triggers attacks. Clinically, NA is an acute and painful unique or multiple mononeuropathy that causes palsy, amyotrophy and sensory loss in an asymmetric and patchy distribution. It involves the upper brachial plexus rather than the other parts but also may involve the cervical plexus, lumbosacral plexus and cranial nerves. The impairment can be restricted to one fascicule of one nerve, plexus or root; limited to a few ones; or extensive, involving both upper limbs. Its evolution is usually monophasic and auto-limited and never leads to generalized polyneuropathy. Electrodiagnostically, NA is characterized by severe axonal damage. The recovery is usually good after 6 months to 3 years in 80% of cases. Persistent disability is present in 20% of idiopathic NA cases and is more frequent in hereditary NA, with frequent recurrences, more frequent bilateral impairment, and more atypical distribution (cervical plexus, lumbosacral plexus or cranial nerves) than with idiopathic NA. Hereditary NA is mainly linked to a mutation in the gene of the Septin-9 protein. When the patient is seen early after disease onset, treatment with corticosteroids for 2 weeks seems to shorten the pain duration and the delayed recovery. With diagnosis during the palsy period, treatment is based on pharmacologic and non-pharmacologic therapies according to the complaints of the patient.

[Neuromuscular dynamic scapular winging: Clinical, electromyographic and magnetic resonance imaging diagnosis]. / Scapula alata dynamique d'origine neuromusculaire : diagnostic clinique, électromyographique et à l'imagerie par résonance magnétique.

Dyskinesia of the scapula is a clinical diagnosis and includes all disorders affecting scapula positioning and movement whatever its etiology. Scapular winging is a subtype of scapular dyskinesia due to a dynamic prominence of the medial border of the scapula (DSW) secondary to neuromuscular imbalance in the scapulothoracic stabilizer muscles. The two most common causes of DSW are microtraumatic or idiopathic lesions of the long thoracic nerve (that innerves the serratus anterior) or the accessory nerve (that innerves the trapezius). Diagnosis of DSW is clinical and electromyographic. Use of magnetic resonance imaging (MRI) could be of interest to distinguish lesion secondary to a long thoracic nerve from accessory nerve and to rule out scapular dyskinesia related to other shoulder disorders. Causal neuromuscular lesion diagnosis in DSW is challenging. Clinical examinations, combined with scapular MRI, could help to their specific diagnosis, determining their stage, ruling out differential diagnosis and thus give raise to more targeted treatment.

Severe and extreme idiopathic median nerve lesions at the wrist: new insights into electrodiagnostic patterns and review of the literature.

INTRODUCTION: We evaluated the electrodiagnostic (EDX) pattern of severe and extreme median nerve lesions at the wrist (MNLW) in patients with idiopathic carpal tunnel syndrome. METHODS: EDX data were recorded in 229 patients with 314 severe and extreme MNLW and 447 patients with 777 non-severe MNLW. We recorded distal motor latency (DML) to abductor pollicis brevis (APB) and second lumbricalis (2L), sensory conduction (SC) from digits 2 and 3, and needle examination of APB. RESULTS: Preservation rate of DML to APB and 2L and of SC from digits 2 and 3 were 100%, 100%, 85%, and 76%, respectively, for severe MNLW, and 37%, 90%, 36%, and 26% for extreme MNLW. Active denervation, as demonstrated by fibrillation potentials, was found in 1% of non-severe NMLW, 7% of severe MNLW, and 56% of extreme MNLW cases. CONCLUSIONS: In idiopathic severe and extreme MNLW, the DML to the 2L and averaged SC from digit 2 can be present when other responses are absent.

Prevalence of obesity and obesity as a risk factor in patients with severe median nerve lesion at the wrist.

OBJECTIVE: To evaluate the relationship among obesity, incidence of idiopathic median nerve lesion at the wrist (MNLW), idiopathic severe MNLW and diabetes mellitus type 2 (DMT2)-associated severe MNLW. METHODS: Clinical and electrodiagnostic data were prospectively collected from 676 patients (≥20 years, 76% females) with carpal tunnel syndrome who were referred to our electrodiagnostic laboratories. In total, 229 patients had 314 cases of severe idiopathic MNLW, 447 had 777 cases of idiopathic non-severe MNLW, and 43 DMT2 patients had 62 cases of severe MNLW. We computed the standardized prevalence ratio (SPR) for obesity and compared the prevalence of obesity and body mass index (BMI) in patients with idiopathic MNLW and the 2009 OBesity EPIdemilogic (OBEPI) sample representing the prevalence of obesity in 24,455 French adults. We compared the prevalence of obesity in DMT2 patients and the Échantillon national témoin représentatif des personnes diabétiques (ENTRED) sample representing the prevalence of cardiovascular risk factors, including obesity, in 3894 French patients with DMT2. RESULTS: The SPR for obesity was 1.60 (95% confidence interval 1.23-2.07) for idiopathic severe MNLW as compared with the OBEPI sample, and 1.72 (1.17-2.46) for DMT2-associated severe MNLW as compared with the ENTRED sample. The risk of severe MNLW increased with BMI: the adjusted odds ratio was 1.09 (1.05-1.13) for each 1-point increase in BMI. This risk was not significant for patients 60 years and older. DISCUSSION: The prevalence of obesity is increased for patients with severe MNLW and DMT2-associated severe MNLW as compared with their respective general populations.

Ulnar nerve lesion at the wrist related to pisotriquetral joint arthropathy.

INTRODUCTION: Ulnar nerve lesions at the wrist (UNLW) are always difficult to localize clinically and sometimes electrophysiologically. Finding conduction block when studying ulnar motor nerve conduction (CB) across the wrist is sometimes the only way to demonstrate that the ulnar deep motor branch (UDMB) is entrapped. METHODS: An elderly woman who had bilateral carpal tunnel syndrome (CTS) and thumb osteoarthritis for many years experienced worsening of left hand impairment recently. RESULTS: Electrodiagnostic and ultrasound examinations revealed an acute and severe UDMB lesion related to pisotriquetral joint effusion. The patient received a local injection of a corticosteroid that provided rapid recovery. CONCLUSIONS: The diagnosis of UDMB lesion is especially difficult when CTS coexists, but CTS may allow for early diagnosis, if CB at the wrist is not overlooked. Chondrocalcinosis was responsible for the systemic inflammation, the CTS, the pisotriquetral joint effusion, and the UDBM compression, which has not been reported previously.

Hand workload, computer use and risk of severe median nerve lesions at the wrist.

OBJECTIVE: To evaluate the effect of hand workload, especially computer use, on the incidence of severe, idiopathic median nerve lesions at the wrist (MNLW) in patients with idiopathic CTS. METHODS: Data were prospectively collected for 444 patients with classic or probable CTS who were of working age and referred to our electrodiagnostic (EDX) laboratories. Clinical items recorded were age, gender, intensity of hand workload, BMI and bilaterality of the MNLW. EDX data recorded were results of needle examination of the abductor pollicis brevis (APB), distal motor latency (DML) to the APB and orthodromic sensory conduction velocity. MNLW was considered severe if the DML to the APB was ≥6.0 ms. Patients were divided into two groups: those exhibiting at least one severe MNLW or not. They were classified into three categories according to occupational activity related to the intensity of hand workload: (i) non-workers (reference category); (ii) white-collar workers using computers; and (iii) blue-collar or manual workers. We determined factors associated with severe and non-severe MNLW. RESULTS: We investigated 92 patients with 119 severe MNLW and 352 with 589 non-severe MNLW. The risk of severe MNLW was similar for non-workers and blue-collar workers and was 2.5-fold higher than for workers using computers [adjusted odds ratio = 0.41; (95% CI)] after adjusting for age, gender and BMI. CONCLUSION: Workers who use computers, who represent, in many countries, a large number of compensation claims, have a lower risk of severe MNLW as compared with blue-collar workers and also non-workers.