Ultrasound of peripheral nerves in neuralgic amyotrophy

Introduction: Neuralgic amyotrophy (NA) can often be difficult to diagnose. Nerve ultrasound (US) is potentially useful, but it is operator-dependent, especially for small nerves. Methods: Fifty-one consecutive patients with NA (mean duration 16 months) and 50 control subjects underwent US of the brachial plexus and major nerves of the upper extremity at predefined sites. We compared cross-sectional areas (CSAs) of affected and unaffected sides with controls and sides within patients. Results: The median nerve and radial nerve at the level of the upper arm were enlarged on the affected sides compared with controls and the unaffected sides of patients. Enlargement was most pronounced for affected sides vs. controls (median 44%, radial 67%). Discussion: NA patients showed increased CSAs, especially in the major nerves of the upper limb, even after longer disease duration. This could make US a useful adjunct in diagnosing NA. Muscle Nerve 59 :55–59, 2019     

Neuroimaging of classic neuralgic amyotrophy

Introduction: Neuralgic amyotrophy (NA) often imposes diagnostic problems. Recently, MRI and high‐resolution ultrasound (HRUS) have proven useful in diagnosing peripheral nerve disorders. Methods: We performed a chart and imaging review of patients who were examined using neuroimaging and who were referred because of clinically diagnosed NA between March 1, 2014 and May 1, 2015. Results: Six patients were included. All underwent HRUS, and 5 underwent MRI. Time from onset to evaluation ranged from 2 weeks to 6 months. HRUS showed segmental swelling of all clinically affected nerves/trunks. Atrophy of muscles was detected in those assessed >1 month after onset. MRI showed T2‐weighted hyperintensity in all clinically affected nerves, except for the long thoracic nerve, and denervation edema of muscles. Conclusions: HRUS and MRI are valuable diagnostic tools in NA. This could change the diagnostic approach from one now focused on excluding other disorders to confirming NA through imaging markers. Muscle Nerve 54 : 1079–1085, 2016     

The neuralgic amyotrophy consultation

Abstract Neuralgic amyotrophy is a distinct clinical syndrome with acute severe pain and patchy paresis in the shoulder and arm region. The clinical phenotype was recently found to be more comprehensive and the long-term prognosis less optimistic than usually assumed for many patients. The disorder can be idiopathic or hereditary in an autosomal dominant fashion, with only few phenotypical variations between the two. This article provides a practical overview of current knowledge on the clinical presentation, diagnosis, pathogenesis and the treatment of pain and complications.     

So-called neuralgic amyotrophy: clinical features and long term follow-up

The clinical features of 61 patients with Neuralgic Amyotrophy are analysed with special reference to recovery time, recurrence and residual deficits in 42 of these patients. Although the etiology is still unknown, N.A. has a characteristic clinical picture with a fairly typical pattern of symptoms and signs. A correct diagnosis is important because in spite of the severity and extent of the initial symptoms the overall prognosis in good.

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Sommario Gli Autori riportano un'analisi delle caratteristiche cliniche presentate da 61 pazienti affetti da Amiotrofia Nevralgica con particolare riferimento ai tempi di guarigione, alle recidive ed ai deficit residuati in 42 pazienti. Sebbene l'Amiotrofia Nevralgica sia a tutt'oggi un'affezione ad eziologia sconosciuta essa presenta un caratteristico quadro clinico con segni e sintomi abbastanza tipici. È importante formulare una corretta diagnosi, perchè nonostante la gravità del quadro sintomatologico iniziale la prognosi è in definitiva buona.

     

Distal neuralgic amyotrophy

Neuralgic amyotrophy consists of severe pain around the shoulder and arm followed by weakness in one or several muscles of the same area. We describe four patients with distal neuralgic amyotrophy in whom acute, severe, and transient pain around the shoulder or arm was followed by weakness of the forearm and hand muscles only. Minor sensory symptoms were present in only one patient. The presence of structural lesions causing the extent of the forearm and hand motor deficit was excluded by ancillary examinations. Electrophysiological studies showed a motor axonopathy and minimal sensory axonopathy. A follow-up of 2 years or longer showed either spontaneous improvement or residual motor deficit. Unfamiliarity with a clinically distal localization of neuralgic amyotrophy may result in misdiagnosis of lower cervical (poly)radiculopathy in view of the distal localization of the motor deficit and the high prevalence of coincidental abnormalities of the lower cervical spine on plain radiography, computed tomography, or magnetic resonance imaging. Received: 10 July 1998 Received in revised form: 22 October 1998 Accepted: 29 October 1998     

Cerebrospinal fluid profile and seroprevalence of antiganglioside reactivity in patients with neuralgic amyotrophy

Neuralgic amyotrophy (NA), also known as acute brachial plexitis, is postulated as an autoimmune pathogenesis. In a well‐defined cohort of patients with NA, we analyzed the cerebrospinal fluid (CSF) profile and the prevalence of antiganglioside antibodies. Patients with Varicella zoster‐associated radiculitis and healthy blood donors served as controls. An abnormal routine laboratory CSF profile was found in 29% of those with NA, mostly showing a disruption of the blood–brain barrier. Antibodies predominantly from the immunoglobulin M (IgM) isotype against at least one human ganglioside were detected in 36% of sera from patients with NA but in only 2% of controls. An NA‐specific reactivity pattern was not detected, and there was no significant association with clinical or CSF parameters. This suggests that the seroprevalence of antiganglioside autoantibodies in patients with NA is nonspecific.     

Isolated sensory manifestations in neuralgic amyotrophy: report of eight cases

A series of eight patients with isolated clinical and electrophysiological sensory deficit related to neuralgic amyotrophy (NA) is reported. NA was diagnosed by clinical and electrodiagnostic features and disease course. Imaging and laboratory investigations excluded other disorders. The results showed mild to severe involvement of eight individual sensory nerves: lateral antebrachial cutaneous nerve lesions in three instances and partial lesions of the median nerve in five cases. Our findings suggest that isolated clinical and electrodiagnostic sensory involvement in NA is not exceptional but rather is unrecognized. The pattern of these nerve lesions agrees with the most typical pattern of NA, which is a mononeuritis or mononeuritis multiplex. The present study also shows that the spectrum of NA is diverse and may vary from pure motor to pure sensory deficit, according to the nature of the involved nerve fibers.     

Assessment of obstetric brachial plexus injury with preoperative ultrasound

Introduction: Tools used in the assessment of obstetric brachial plexus injuries (OBPIs) have traditionally included electrodiagnostic studies, computerized tomography with myelography, and MRI. However, the utility of ultrasound (US) in infants for such assessment has not been extensively examined. Methods: This retrospective case series reports the preoperative brachial plexus US findings in 8 patients with OBPI and compares US with intraoperative findings. When available, the preoperative US was compared with the preoperative MRI. Results: US revealed abnormalities in all 8 patients. Although MRI detected abnormalities in the majority of patients, US provided accurate information regarding severity and anatomic location of injury in some patients. Conclusions: US is a relatively inexpensive, noninvasive, painless diagnostic modality that can be used to assess OBPI. This case series suggests that US is a valuable adjunct to current diagnostic modalities. Muscle Nerve 53 : 946–950, 2016     

Collet-Sicard syndrome mimicking neuralgic amyotrophy

A man with shoulder pain, wasting, and weakness had ipsilateral cranial nerve abnormalities. Electrodiagnostic studies supported a diagnosis of neuralgic amyotrophy, but we later demonstrated a spinal accessory mononeuropathy with ipsilateral hypoglossal weakness (Collet-Sicard syndrome). Magnetic resonance imaging demonstrated an inaccessible occipital condyle mass, and disseminated adenocarcinoma was subsequently diagnosed. Although cranial mononeuropathies can occur in neuralgic amyotrophy, this case illustrates the importance of identifying a focal lesion, and highlights the localizing value of electrodiagnosis. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20:1173–1177, 1997     

Notalgia paresthetica following neuralgic amyotrophy: a case report

Abstract. We report the case of a patient who developed notalgia paresthetica during the recovery from a neuralgic amyotrophy. A 23-year-old woman had a typical neuralgic amyotrophy (severe shoulder pain, followed by a long thoracic nerve palsy); five months after the onset of pain, when scapular winging was improving, she began to feel a burning sensation in a restricted interscapular area, on the same side. Electromyography was consistent with a long thoracic nerve neuropathy, with minor neurogenic changes in deltoid and biceps brachii. Radiography of the spine was unremarkable. The notalgia paresthetica disappeared shortly before the complete recovery of scapular winging. The abnormal activation of shoulder girdle and spine extensor muscles during the time of long thoracic nerve palsy may explain the association between the two disorders.     

Structure of the brachial plexus root and adjacent regions displayed by ultrasound imaging

Brachial plexuses of 110 healthy volunteers were examined using high resolution color Doppler ultrasound. Ultrasonic characteristics and anatomic variation in the intervertebral foramen, interscalene, supraclavicular and infraclavicular, as well as the axillary brachial plexus were investigated. Results confirmed that the normal brachial plexus on cross section exhibited round or elliptic hypoechoic texture. Longitudinal section imaging showed many parallel linear hypo-moderate echoes, with hypo-echo. The transverse processes of the seventh cervical vertebra, the scalene space, the subclavian artery and the deep cervical artery are important markers in an examination. The display rates for the interscalene, and supraclavicular and axillary brachial plexuses were 100% each, while that for the infraclavicular brachial plexus was 97%. The region where the normal brachial plexus root traversed the intervertebral foramen exhibited a regular hypo-echo. The display rate for the C 5-7 nerve roots was 100%, while those for C 8 and T 1 were 83% and 68%, respectively. A total of 20 of the 110 subjects underwent cervical CT scan. High-frequency ultrasound can clearly display the outline of the transverse processes of the vertebrae, which were consistent with CT results. These results indicate that high-frequency ultrasound provides a new method for observing the morphology of the brachial plexus. The C 7 vertebra is a marker for identifying the position of brachial plexus nerve roots.     

Neuralgic amyotrophy: variable expression in 40 patients

This study looks at disease diversity, location of lesions, and progression of neuralgic amyotrophy (NA). Forty patients (28 male and 12 female, age range 15 to 70 years) were clinically examined. Muscle atrophy, weakness, and sensory impairment were assessed. Needle EMG and conduction velocities were performed. Careful clinical, electrophysiological, laboratory, and radiological studies excluded other illness. Twenty-two patients were followed for 2 years. Antecedent fever and upper-respiratory tract infection was seen in 22 cases. Pain of sudden onset was always the initial symptom, followed by weakness, mainly in the proximal muscles of shoulder. The affectation was bilateral in 7 cases. Seven cases had a recurrent form of the disease. Clinical and electrophysiological findings suggest axonal lesions of the peripheral nerves, occurring singly (mononeuritis) or in various combinations (mononeuropathy multiplex). Unusual features, such as VII and XI cranial nerves, phrenic nerve, and lateral antebrachial cutaneous nerve affectation, were found. Follow-up showed good function recovery at variable times, even in 1 case with associated myotonic dystrophy (MD). NA is a well-defined entity, with variable clinical expression and data consistent with mononeuropathy or mononeuropathy multiplex, axonal in type. The overall prognosis is good. The progression in a patient with MD suggests that the capability of muscle fiber membrane to accept regenerating nerve sprouts remains in dystrophic muscles.     

Conduction block in neuralgic amyotrophy

We describe two cases of neuralgic amyotrophy with electrophysiological evidence of conduction block across the lower trunk of the brachial plexus. Low-output impedance stimulation of the cervical spinal roots in combination with collision was used to accurately demonstrate the conduction block. Complete electrophysiological recovery of the conduction block occurred within 3 months. Early clinical and electrophysiological recovery in both patients suggests that, in some cases, demyelination may predominate early in the course of neuralgic amyotrophy.