Hourglass-like constrictions of the radial nerve in the neuralgic amyotrophy: A case report.

Neuralgic amyotrophy (NA) is a peripheral nerve disorder that has a classical presentation as motor deficit after severe pain, but it is still overlooked or misdiagnosed. Formerly, the diagnosis was based on the clinical picture and electrophysiology; however, sophisticated imaging and surgical modalities showed structural abnormalities such as hourglass-like constrictions of the nerves. In this article, we present a case presenting with drop hand mimicking radial nerve entrapment. The patient was diagnosed with NA and surgery revealed hourglass-like constrictions. The clinical findings were improved after neurorrhaphy and physical therapy. In conclusion, hourglass-like constrictions can be prognostic factors of NA and should be searched carefully.

Neurolysis of the Long Thoracic Nerve for Scapular Winging due to Isolated Serratus Anterior Palsy: Early and Midterm Results in 29 Patients.

Objective: This study aimed to report our surgical outcomes of thoracic long thoracic nerve (LTN) decompression in patients with isolated LTN palsy, using a clinical scoring system designed to facilitate the grading of scapular winging severity. Methods: This was a retrospective review of patients who had undergone decompression and neurolysis of the LTN for scapular winging. Each patient underwent needle electromyography of the serratus anterior for confirmation of diagnosis and were refractory to a minimum of 6 months of nonoperative management. Preoperatively and at final follow-up, shoulder range of motion and the Wrightington Winging Score (WWS) was used to objectively grade the dynamic and static components of winging. Results: Between 2014 and 2020, 29 patients who underwent thoracic neurolysis for scapular winging were analyzed. These were 16 males and 13 females with a mean age of 37 years. The injury mechanism was due to trauma in 19 cases and neuralgic amyotrophy in 10. The median duration between winging onset and surgery was 30 months. There were significant improvements in mean active shoulder abduction and forward flexion. Winging was noticeably improved in 22 patients. At presentation, the median WWS was 3, which improved to 1 at final follow-up. Conclusion: In patients with isolated LTN palsy causing persistent scapular winging which is not responsive to conservative treatment, neurolysis of the thoracic portion of the LTN can be considered. Level of Evidence: IV.

A case report of neuralgic amyotrophy.

Neuralgic muscular atrophy is not uncommon in clinical practice. Due to the different branches of brachial plexus involved in the lesion, the clinical symptoms are different, and there is a lack of clear imaging diagnostic criteria, so the diagnosis of this disease brings great challenges to clinicians. We have certain experience in the diagnosis and treatment of this disease, and hereby select a representative case of neuralgic muscular atrophy to share its diagnosis and treatment process, focusing on analyzing the characteristic symptoms of this disease, valuable imaging data and targeted treatment, so as to enable clinicians to better understand this disease.

Bilateral Phrenic Nerve Palsy Associated With Neuralgic Amyotrophy.

Neuralgic amyotrophy (NA) is a multifocal inflammatory neuropathy accompanied by acute pain and muscle atrophy. NA commonly affects the upper extremities, but rarely affects the phrenic nerve. Here, we report a male with neck pain, orthopnea, difficulty sleeping in the supine position, and inability to slurp. His saturated oxygen level decreased from 97% to 86% in the supine position. His right shoulder showed muscle atrophy. Chest X-ray examination in the supine position and a nerve conduction study showed phrenic palsy. We diagnosed it as bilateral phrenic nerve palsy associated with NA. NA sometimes causes phrenic nerve palsy and may cause slurping difficulty.

Parsonage-Turner Syndrome following COVID-19 Vaccination: A Systematic Review.

BACKGROUND: Parsonage-Turner syndrome (PTS) is an inflammatory condition of the brachial plexus, with more than half of patients presenting a trigger, such as infection or vaccination. Our objective was to synthesize the clinical and paraclinical features, therapeutic responses, and outcomes of PTS post-COVID-19 vaccination. METHODS: We systematically reviewed two databases (LitCOVID and the WHO database on COVID-19) up to January 2024 following a published protocol (OSF registries). RESULTS: We included 59 cases. PTS occurred more frequently in males (61.1% mRNA group, 83.3% viral vector group). Patients in the mRNA group were younger (41.7% between 41 and 50 years vs. 38.9% between 61 and 70 years). Most cases had sudden pain within two weeks. Unilateral PTS was present in 94.4% of mRNA and all viral vector-vaccinated cases. Symptoms included pain (97.1% and 92.3%, respectively), usually followed within two weeks by motor deficits (97.2% and 94.1%, respectively), amyotrophy (30% and 81.8%, respectively), paresthesia (50% and 27.3%, respectively), and sensory loss (33.3% and 38.5%, respectively). Viral vector vaccine recipients had nerve involvement outside the brachial plexus. Ancillary investigations revealed CSF albuminocytological dissociation (33.3% and 100%, respectively) and ipsilateral axillary lymphadenopathy. Two PTS cases worsened after the second mRNA dose, and another recurred after influenza vaccination. One patient well tolerated the second dose of the viral vector vaccine, but symptoms reemerged in another. CONCLUSIONS: Current evidence suggests PTS may occur after all COVID-19 vaccine types, with some subgroup differences. Also, PTS might recur with subsequent similar or unrelated vaccines.

Neuralgic amyotrophy with multiple hourglass-like constrictions of anterior interosseous nerve: a case report.

Hourglass-like constrictions (HLCs) of peripheral nerves in the upper extremity were a rare form of neuralgic amyotrophy, often characterized by the sudden onset of pain in the shoulder or arm, followed by muscle weakness and amyotrophy, with limited sensory involvement. We present a case of multiple HLCs of the anterior interosseous nerve (AIN) in a 22-year-old female with left upper arm pain, finger numbness, and limited activity for 1 month. Physical examination showed weakness of the left index flexor digitorum profundus and flexor pollicis longus, with mild hypoesthesia in the first three fingers and the radial half of the ring finger. Electromyography suggested a median nerve (mainly AIN) lesion. Ultrasonographic imaging of the median nerve shows AIN bundle swelling and multiple HLCs at left upper arm. Despite conservative treatment, which included 15 days of steroid pulse therapy, Etoricoxib, and oral mecobalamin, the patient still complained of extreme pain at night without relief of any symptoms. Operation was recommended for this patient with thorough concerns of surgical advantages and disadvantages. During surgery, a total of 7 HLCs were found in her median nerve along and above the elbow joint. Only Interfascicular neurolysis was performed because the nerve constrictions were still in the early stage. The pain was almost relieved the next day. One month after surgery, she could bend her thumb and index fingers, although they were still weak. 4 months after the surgery, she was able to bend affected fingers, with muscle strength M3 level. At the same time, her fingers had fewer numbness symptoms. There was still controversy regarding treatment strategy; however, early diagnosis and surgical treatment for nerve HLCs might be a better choice to promote nerve recovery.

Neuralgic Amyotrophy and Hourglass Nerve Constriction/Nerve Torsion: Two Sides of the Same Coin? A Clinical Review.

Neuralgic amyotrophy, also called Parsonage-Turner syndrome, in its classic presentation is a brachial plexopathy or a multifocal neuropathy, involving mainly motor nerves of the upper limb with a monophasic course. Recently, a new radiological entity was described, the hourglass constriction, which is characterized by a very focal constriction of a nerve, or part of it, usually associated with nerve thickening proximally and distally to the constriction. Another condition, which is similar from a radiological point of view to hourglass constriction, is nerve torsion. The pathophysiology of neuralgic amyotrophy, hourglass constriction and nerve torsion is still poorly understood, and a generic role of inflammation is proposed for all these conditions. It is now widely accepted that nerve imaging is necessary in identifying hourglass constrictions/nerve torsion pre-surgically in patients with an acute mononeuropathy/plexopathy. Ultrasound and MRI are useful tools for diagnosis, and they are consistent with intraoperative findings. The prognosis is generally favorable after surgery, with a high rate of good motor recovery.

[MR neurography reveals fascicular constriction of the median nerve in a patient with neuralgic amyotrophy].

Diagnosing neuralgic amyotrophy can be challenging in clinical practice. Here, we report the case of a 37-years old Japanese woman who suddenly developed neuropathic pain in the right upper limb after influenza vaccination. The pain, especially at night, was severe and unrelenting, which disturbed her sleep. However, X-ray and MRI did not reveal any fractures or muscle injuries, and brain MRI did not reveal any abnormalities. During neurological consultation, she was in a posture of flexion at the elbow and adduction at the shoulder. Manual muscle testing suggested weakness of the flexor pollicis longus, pronator quadratus, flexor carpi radialis (FCR), and pronator teres (PT), while the flexor digitorum profundus was intact. Medical history and neurological examination suggested neuralgic amyotrophy, particularly anterior interosseous nerve syndrome (AINS) with PT/FCR involvement. Innervation patterns on muscle MRI were compatible with the clinical findings. Conservative treatment with pain medication and oral corticosteroids relieved the pain to minimum discomfort, whereas weakness remained for approximately 3 months. For surgical exploration, lesions above the elbow and fascicles of the median nerve before branching to the PT/FCR were indicated on neurological examinations; thus, we performed high-resolution imaging to detect possible pathognomonic fascicular constrictions. While fascicular constrictions were not evident on ultrasonography, MR neurography indicated fascicular constriction proximal to the elbow joint line, of which the medial topographical regions of the median nerve were abnormally enlarged and showed marked hyperintensity on short-tau inversion recovery. In patients with AINS, when spontaneous regeneration cannot be expected, timely surgical exploration should be considered for a good outcome. In our case, MR neurography was a useful modality for assessing fascicular constrictions when the imaging protocols were appropriately optimized based on clinical assessment.

Neurological manifestation of HEV infection: still a rare disease entity?

Hepatitis E virus (HEV) infection is the most common form of viral hepatitis and is reported to cause neurological manifestation in up to 30% of diagnosed infections. We evaluated the medical reports of all patients (n = 29,994) who were discharged from the Department of Neurology of Ulm University between 01.01.2015 and 30.09.2022 to detect neurological manifestations of HEV. In addition, we retrospectively analyzed the serum samples of n = 99 patients representing different neurological diseases possibly related to HEV for anti-HEV-IgM and anti-HEV-IgG. At the time of discharge from hospital, the etiology of neurological symptoms in these patients was unclear. Overall, five cases of extrahepatic neurological manifestation of HEV (defined as anti-HEV-IgM and HEV-IgG positive) could be detected. An increase of both, anti-IgM- and anti-IgG-serum levels was significantly more common in neuralgic amyotrophy/plexus neuritis/radiculitis than in AIDP/CIDP (P = 0.01), meningitis/encephalitis (P = 0.02), idiopathic peripheral facial paralysis (P = 0.02) and tension headache (P = 0.02). In 15% (n = 15 out of 99) of retrospectively analyzed serum samples, conspicuous positive anti-HEV-IgG levels were detected. This finding was most common in AIDP/CIDP. In conclusion, results of this study indicate neurological manifestation of HEV to be a rare but still underestimated course of disease, occurring at any age and gender. Therefore, testing for HEV should be considered in patients with neurological symptoms of unknown origin, especially in those with neuralgic amyotrophy/plexus neuritis.

Neuropathies related to hepatitis E virus infection: A prospective, matched case-control study.

BACKGROUND: Acute hepatitis E virus (HEV) infection has recently emerged as a potential trigger for acute dysimmune neuropathies, but prospective controlled studies are lacking. AIMS: To compare the frequency of concomitant acute HEV infection in patients with neuralgic amyotrophy (NA), Guillain-Barré syndrome (GBS), and Bell's palsy with a matched control population. METHODS: Swiss multicenter, prospective, observational, matched case-control study over 3 years (September 2019-October 2022). Neurological cases with NA, GBS, or Bell's palsy were recruited within 1 month of disease onset. Healthy controls were matched for age, sex, geographical location, and timing of blood collection. Diagnostic criteria for acute hepatitis E were reactive serum anti-HEV IgM and IgG assays (ELISA test) and/or HEV RNA detection in serum by real-time polymerase chain reaction (RT-PCR). RT-PCR was performed on sera to confirm IgM positivity. RESULTS: We included 180 patients (59 GBS, 51 NA, 70 Bell's palsy cases) and corresponding matched controls (blood donors) with median age 51 years for both groups and equal gender distribution. Six IgM+ cases were detected in the NA, two in the GBS, and none in the Bell's palsy group. Two controls were anti-HEV IgM-positive. At disease onset, most cases with acute HEV infection had increased liver enzymes. A moderate association (p = 0.027, Fisher's exact test; Cramér's V = -0.25) was observed only between acute HEV infection and NA. CONCLUSION: This prospective observational study suggests an association between concomitant acute HEV infection and NA, but not with GBS or Bell's palsy.

Application of a nerve stereoscopic reconstruction technique based on ultrasonic images in the diagnosis of neuralgic amyotrophy.

Objective: To propose a nerve stereoscopic reconstruction technique based on ultrasound imaging for site diagnosis, intuitive reflection of disease severity, and classification of neuralgic amyotrophy (NA). Methods: We enrolled 44 patients with NA who underwent high-frequency ultrasonography examination. Multiple sites on the normal side and the affected side were scanned to calculate the ratio of the cross-section area (CSA) of the affected side to the normal side at each location measured, i.e., the cross-section area swelling ratio (CSASR). The CSASR of 44 patients and 30 normal controls was analyzed to determine their threshold value for the diagnosis of NA. Then, ultrasound images of the cross-section were used to reconstruct the stereoscopic model of the nerve on the affected side and the normal side. Using the CSASR values in each measurement location, a CSASR stereoscopic model was developed. Results: The threshold value of CSASR for ultrasound diagnosis of NA was 1.55. The average diseased segments per patient was 2.49 ± 1.97, with an average overall length of 10.03 ± 7.95 cm. Nerve stereoscopic reconstruction could be conducted for swelling, torsion, incomplete constriction, and complete constriction. Conclusion: The ultrasound image reconstruction method proposed in this study can accurately determine the site, range, and type of neuropathies in patients with NA, and simultaneously provide complete and accurate data information and intuitive morphological information.

Persistent Hourglass Constriction in Recovered Anterior Interosseous Nerve Palsy Due to Neuralgic Amyotrophy: A Case Report.

The current articles recommended the interfascicular neurolysis for anterior interosseous nerve (AIN) palsy with hourglass-like fascicular constrictions (FCs) detected by ultrasonography or surgical exploration to realign to the fascicular torsion for those who failed to recover spontaneously. We present the case report of spontaneous AIN palsy recovered after conservative treatment; however, ultrasonographic findings showed persistent FCs of AIN in the arm at the beginning, at 6 weeks, and subsequent 3-year follow-ups, even after complete clinical recovery of palsy. This finding calls into question the current notion that AIN paralysis is due to FCs and that neurolysis is the best surgical treatment when spontaneous recovery does not occur for a considerable observation period. Level of Evidence: Level V (Therapeutic).

Hourglass-like constrictions on MRI are common in electromyography-confirmed cases of neuralgic amyotrophy (Parsonage-Turner syndrome): A tertiary referral center experience.

INTRODUCTION/AIMS: Hourglass-like constrictions (HGCs) of involved nerves in neuralgic amyotrophy (NA) (Parsonage-Turner syndrome) have been increasingly recognized with magnetic resonance neurography (MRN). This study sought to determine the sensitivity of HGCs, detected by MRN, among electromyography (EMG)-confirmed NA cases. METHODS: This study retrospectively reviewed records of patients with the clinical diagnosis of NA, and with EMG confirmation, who underwent 3-Tesla MRN within 90 days of EMG at a single tertiary referral center between 2011 and 2021. "Severe NA" positive cases were defined by a clinical diagnosis and specific EMG criteria: fibrillation potentials or positive sharp waves, along with motor unit recruitment (MUR) grades of "discrete" or "none." On MRN, one or more HGCs, defined as focally decreased nerve caliber or diffusely beaded appearance, was considered "imaging-positive." Post hoc inter-rater reliability for HGCs was measured by comparing the original MRN report against subsequent blinded interpretation by a second radiologist. RESULTS: A total of 123 NA patients with 3-Tesla MRN performed within 90 days of EMG were identified. HGCs were observed in 90.2% of all NA patients. In "severe NA" cases, based on the above EMG criteria, HGC detection resulted in a sensitivity of 91.9%. Nerve-by-nerve analysis (183 nerve-muscle pairs, nerves assessed by MRN, muscles assessed by EMG) showed a sensitivity of 91.0%. The second radiologist largely agreed with the original HGC evaluation, (94.3% by subjects, 91.8% by nerves), with no significant difference between evaluations (subjects: χ2 = 2.27, P = .132, nerves: χ2 = 0.98, P = .323). DISCUSSION: MRN detection of HGCs is common in NA.

Hereditary Neuralgic Amyotrophy with a Lesion Distal to the Brachial Plexus on Magnetic Resonance Imaging.

A 35-year-old woman first experienced left upper limb weakness at 17 years old, after which it repeatedly recurred and then remitted. She was diagnosed with carpal tunnel syndrome with median nerve hyperintensity by magnetic resonance imaging (MRI). Surgical treatment was ineffective. We suspected hereditary neuralgic amyotrophy because of enlargement distal to the brachial plexus on MRI and administered steroid therapy, after which the weakness improved. Genetic testing revealed a point mutation in SEPT9. Because lesions outside the brachial plexus can be seen in hereditary neuralgic amyotrophy, the diagnosis should be based on typical characteristics and the family history.

Autoimmune polyneuropathies.

The autoimmune peripheral neuropathies with prominent motor manifestations are a diverse collection of unusual peripheral neuropathies that are appreciated in vast clinical settings. This chapter highlights the most common immune-mediated, motor predominant neuropathies excluding acute, and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP, respectively). Other acquired demyelinating neuropathies such as distal CIDP and multifocal motor neuropathy will be covered. Additionally, the radiculoplexus neuropathies, resulting from microvasculitis-induced injury to nerve roots, plexuses, and nerves, including diabetic and nondiabetic lumbosacral radiculoplexus neuropathy and neuralgic amyotrophy (i.e., Parsonage-Turner syndrome), will be included. Finally, the motor predominant peripheral neuropathies encountered in association with rheumatological disease, particularly Sjögren's syndrome and rheumatoid arthritis, are covered. Early recognition of these distinct motor predominant autoimmune neuropathies and initiation of immunomodulatory and immunosuppressant treatment likely result in improved outcomes.

Patient with recurrent neuralgic amyotrophy; right brachial plexitis and left posterior interosseous neuropathy.

Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome or idiopathic brachial plexopathy, is a multifocal inflammatory neuropathy that usually affects the upper limbs. The classic picture is a patient with acute onset of asymmetric upper extremity symptoms, excruciating pain, rapid onset of multifocal paresis often involving winged scapula, and a monophasic course of the disease. 
We present an unusual case of recurrent NA characterized first by right brachial plexitis and then isolated left posterior interosseous nerve palsy. 

Clinical Spectrum of Postsurgical Parsonage-Turner Syndrome: A Perspective From an Electrodiagnostic Laboratory.

BACKGROUND: Parsonage-Turner syndrome (PTS) is an underdiagnosed disorder characterized by the acute onset of severe pain in the shoulder/scapula/arm followed by muscle weakness/numbness in the distribution of nerves derived from the brachial plexus (BP). Surgical procedures are one of several antecedent events of PTS. This study describes the clinical spectrum of postsurgical Parsonage-Turner syndrome (PSPTS) in a large cohort of patients. MATERIALS AND METHODS: Charts of patients diagnosed with PTS during a 16-year (2006-2022) retrospective review were analyzed to identify cases of PSPTS. The clinical criteria for PSPTS included the new onset of severe pain two days to four weeks after a surgical procedure followed by weakness of muscles innervated by one or more nerves arising from the BP. EDX criteria consist of denervation localized to branches of the BP. PSPTS cases were subdivided into two categories: definite PSPTS (surgery at a remote site) and probable PSPTS (surgery of the ipsilateral upper extremity or the cervical spine). RESULTS: Of 202 patients (204 episodes) diagnosed with PTS, 111 (54%) were idiopathic and 61 (30%) were PSPTS. Of the 61 PSPTS episodes, 26 were definite and 35 were probable PSPTS. The anterior interosseous nerve (AIN) was most affected, followed by the posterior interosseous (PIN), and suprascapular nerve. CONCLUSION: In this series, surgery was the most commonly recognized antecedent event for PTS, and the AIN and PIN were the most frequent nerves affected. Surgeons should consider PTS in patients who develop postoperative severe shoulder pain and weakness of muscles innervated by the BP.

Increased 18 F-FDG uptake in denervated muscles in a case of Parsonage-Turner syndrome.

BACKGROUND: Parsonage-Turner Syndrome (PTS) is a rare brachial plexopathy characterized by the sudden onset of pain in the shoulder girdle followed by upper limb weakness. PTS is frequently under-recognized or misdiagnosed as other more common neurological disorders presenting in a similar fashion, such as cervical radiculopathy which may require surgical intervention. Accurate diagnosis and prompt management implicate a good prognosis. Although electrophysiological studies are considered the most important for evaluating peripheral nerve injuries, it usually takes time, up to 3 weeks after the initial insult of the nerve for electromyogram (EMG) and nerve conduction studies (NCS) to display abnormalities. In the cases of PTS, especially when initial EMG/NCS and magnetic resonance neurography (MRN) results are inconclusive, 18 F-FDG positron emission tomography and computed tomography (18 F-FDG PET-CT) may be useful in helping the early detection of muscle denervation. CASE PRESENTATION: A 60-year-old right-handed Taiwanese woman presented with sudden onset of intense and sharp left shoulder girdle pain without radiating to the arm, followed by muscle weakness of her left arm in abduction and elevation 3 days after the onset of pain. A detailed neurological examination and EMG and NCS suggested the clinical diagnosis of left brachial plexopathy. MRN imaging revealed no significant abnormality. 18 F-FDG PET-CT showed increased uptake in denervated muscles (supraspinatus, deltoid, and biceps muscles). Treatment with oral prednisolone and physiotherapy significantly improved pain and muscle weakness. CONCLUSIONS: We present increased 18 F-FDG uptake in denervated muscles detected by 18 F-FDG PET-CT. 18 F-FDG PET-CT may serve as an adjunct examination to evaluate PTS, which has been suggested previously but rarely reported.

Association of Parsonage-Turner syndrome with COVID-19 infection and vaccination: a systematic review.

OBJECTIVES: The exact etiology of Parsonage-Turner syndrome is unknown, but it is known to be preceded by infection, vaccination, or surgical intervention. In this review, we describe associations of Parsonage-Turner syndrome with COVID-19 infection and vaccination. METHODS: A systematic literature search was conducted using PubMed/MEDLINE, ScienceDirect, and Google Scholar. Microsoft Excel was used for data extraction and statistical analysis. The quality of case reports and case series was assessed using the Joanna Briggs Institute Critical Appraisal Tool. RESULTS: We selected 44 case reports and 10 case series, including 68 patients (32 post-vaccination and 36 with post-COVID-19 infection Parsonage-Turner syndrome). Middle-aged males were predominantly affected in both groups. The most frequently administered vaccine was Comirnaty (Pfizer) (53%). The mean latency was 11.7 days in the post-vaccination group and 20.3 days in the post-infection group. The most affected nerves in both groups were the axillary, suprascapular, and musculocutaneous nerves; and 78.1% and 38.9% of patients showed partial amelioration of their symptoms in the post-vaccination and post-infection groups, respectively. CONCLUSION: Post-vaccination Parsonage-Turner syndrome presents earlier than post-infection disease. Pain and sensorimotor deficits of the upper limb are common in both situations. Complete or partial recovery occurs in most cases.

Long Thoracic Nerve Palsy: When Is Decompression Indicated.

Scapular winging due to long thoracic nerve palsy can occur through traumatic injuries and nontraumatic events. The traditional view is that most patients will achieve spontaneous recovery within 2 years of winging onset. However, there is evidence that points to a less clear-cut natural history, with residual winging, muscle weakness, and fatigability being exhibited in a significant percentage of patients. Reports from proponents of a more proactive approach have shown that the surgical decompression of the long thoracic nerve beyond 12 months, through thoracic, supraclavicular, or combined approaches, can yield satisfactory results. This review examines our current understanding of long thoracic nerve palsy and explores the varying treatment strategies with their reported outcomes.