Anti-peripheral nerve myelin antibodies and terminal activation products of complement in serum of patients with acute brachial plexus neuropathy

The Utility of an Epidural Steroid Injection for the Treatment of Idiopathic Brachial Neuritis

Idiopathic brachial neuritis is an uncommon disorder that predominately affects the superior and middle trunks of the brachial plexus. Severe throbbing and aching shoulder pain is initially present for a period of days to weeks, followed by severe weakness and atrophy that can develop for an extended period of months to years. There are currently no known treatments for brachial neuritis, with the standard of care consisting of analgesics and corticosteroids, which typically provide minimal to no benefit in most cases. In this case, we will present a case of a patient who was diagnosed with idiopathic brachial neuritis and underwent an interlaminar epidural steroid injection (ESI) for treatment. Following treatment with the ESI, the patient had a subsequent resolution of symptoms. This case underscores the value of early recognition for the diagnosis of brachial neuritis and the utility of an ESI as a treatment option, thus preventing long-term pathological sequalae. To our knowledge, this is the first known reported case to have successfully cured brachial neuritis.

Parsonage-Turner Syndrome Following SARS-CoV-2 Infection: A Systematic Review

Parsonage-Turner syndrome (PTS) is an inflammatory disorder of the brachial plexus. Hypothesized underlying causes focus on immune-mediated processes, as more than half of patients present some antecedent event or possible predisposing condition, such as infection, vaccination, exercise, or surgery. Recently, PTS was reported following the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We aimed to investigate data on PTS triggered by SARS-CoV-2 infection to provide an extensive perspective on this pathology and to reveal what other, more specific, research questions can be further addressed. In addition, we aimed to highlight research gaps requiring further attention. We systematically reviewed two databases (LitCOVID and the World Health Organization database on COVID-19) to January 2023. We found 26 cases of PTS in patients with previous SARS-CoV-2 infection. The clinical and paraclinical spectrum was heterogeneous, ranging from classical PTS to pure sensory neuropathy, extended neuropathy, spinal accessory nerve involvement, and diaphragmatic palsy. Also, two familial cases were reported. Among them, 93.8% of patients had severe pain, 80.8% were reported to present a motor deficit, and 53.8% of patients presented muscle wasting. Paresthesia was noted in 46.2% of PTS individuals and a sensory loss was reported in 34.6% of patients. The present systematic review highlights the necessity of having a high index of suspicion of PTS in patients with previous SARS-CoV-2 infection, as the clinical manifestations can be variable. Also, there is a need for a standardized approach to investigation and reporting on PTS. Future studies should aim for a comprehensive assessment of patients. Factors including the baseline characteristics of the patients, evolution, and treatments should be consistently assessed across studies. In addition, a thorough differential diagnosis should be employed.

Off-Label Use of Intravenous Immunoglobulin with Methylprednisolone to Treat Parsonage-Turner Syndrome in a United States Marine

Neuralgic amyotrophy (NA) also known as Parsonage-Turner syndrome is an inflammatory disorder of the brachial plexus characterized by sudden, acute onset of severe pain of the arm and/or shoulder followed by muscle weakness and sensory abnormalities. Although management may involve physical therapy, immunomodulatory drugs, and analgesics, there is nothing specific for the treatment of NA. Full functional recovery can take months to years, but recurrence and/or persistence of symptoms and disability are frequent. This case reports a 22-year-old male who recovered from NA within 3 months following treatment with 1000 mg of methylprednisolone and off-label use of 0.5 g/kg of intravenous immunoglobulins (IVIG) for four consecutive days. Three years later, the patient experienced soreness and paresthesia of the shoulder following a military shooting exercise, and 0.75 g/kg of IVIG and 1000 mg of MP were prescribed for 2 consecutive days resulting in complete recovery and no recurrences to date. EMG findings, 3.5-year postinitial treatment, revealed improvement in the brachial plexopathy. This provides support for the combined use of IVIG and glucocorticoids in the treatment of NA and highlights the need for further studies investigating whether this combined treatment regimen may accelerate recovery and improve long-term outcomes for patients diagnosed with NA.

Isolated Musculocutaneous Neuropathy Secondary to an Immune-Mediated Brachial Plexopathy: A Case Report of a Rare Phenotype With a Side Note on Patterns of Weakness and an Update on Nerve Pathology

We describe a 50-year-old man who developed a low-frequency pattern of weakness, musculocutaneous neuropathy, with weakness of the biceps, coracobrachialis and brachialis in an immune-mediated brachial plexopathy. The aim of this article is to highlight both the low- and high-frequency patterns of weakness of the immune-mediated brachial plexopathies, and we focus on the patterns of recognition. We then segue into the pathology of the immune-mediated plexopathies and highlight the recent spectacular magnetic resonance imaging studies that demonstrate hourglass constrictions of peripheral nerves outside of the brachial plexus in afflicted patients. This opens up a window for the exciting possibility of neurolysis of constricted nerves in patients who have not responded adequately to immunotherapy.

Herpes zoster increased risk of neuralgic amyotrophy: a retrospective, population-based matched cohort study

Although neuralgic amyotrophy (NA) has occasionally been reported to be associated with reactivated herpes zoster, their associated risk remains unknown. The aim of this study was to assess the risk of developing NA following preceding herpes zoster. The authors used the National Health Insurance Research Database of Taiwan to select 41,548 patients with newly diagnosed herpes zoster during the period 2000 to 2010 and randomly extracted 166,192 matched control subjects. All participants in the study and control groups were followed for 3 months after the diagnosis to identify those who developed NA. Cox proportional hazards regression analyses were performed to evaluate the subsequent risk of NA. Twenty-one subjects from the group with herpes zoster (0.05%) developed NA over the 3-month period and 46 from the group without herpes zoster (0.03%). The patients with herpes zoster had a higher risk of developing NA (adjusted hazard ratio = 1.408, 95% confidence interval = 1.013-2.319, P = 0.030). In the patients with herpes zoster, female sex, age ≥ 65, hepatitis E virus (HEV), and having had a recent infectious event including pneumonia and influenza were risk factors for developing NA (adjusted HR 2.746, 1.998, 2.735, 2.016, and 1.718, respectively, all P < 0.05). Patients with herpes zoster attack have a higher risk of developing NA over a 3-month period after diagnosis, especially those who are female, age ≥ 65, HEV, or have experienced a recent infectious event or pneumonia and influenza.

Chronic Brachial Plexus Neuritis That Developed into Typical Neuralgic Amyotrophy and Positively Responded to Immunotherapy

Based on the hypothesis that autoimmunity plays a role in the pathogenesis of neuralgic amyotrophy (NA), immunotherapy is sometimes administered. Early intervention is recommended for a good prognosis. We herein report the case of a 55-year-old man who presented with neuralgia, weakness, and muscle atrophy in his right shoulder girdle and upper arm, which progressed for ten months following a marine sports accident. The patient was diagnosed with NA. His neurological deficits gradually improved after several courses of immunotherapy, suggesting that in addition to being effective for treating early-stage disease, immunotherapy may be effective for treating chronic cases.

Atypical presentation of Parsonage-Turner syndrome confounded by surgical rotator cuff injury

Parsonage-Turner syndrome (PTS) is a rare neuropathy that commonly presents as unexpected severe shoulder and arm pain that eventually subsides while weakness or paralysis ensues. During exceptions to this classic presentation, confirming PTS can be challenging. Alternative causes of upper extremity pain may confound the diagnostic algorithm. Moreover, objective findings from necessary diagnostic tests depend on when those tests are performed. We present an atypical onset of PTS, whereby the initial presentation of severe neuropathic pain was preceded by mild shoulder pain that should decrease one's clinical suspicion for PTS. This milder pain coincided with the presence of a rotator cuff injury, whereby surgical intervention preceded impending paralysis and hindered postoperative rehabilitation. Physicians should be aware of the possibility of atypical presentations of PTS in hopes of avoiding either untimely surgery or delays in diagnosis.

Idiopathic Brachial Neuritis in a Patient with Multiple Myeloma

Idiopathic Brachial Neuritis (IBN), is a rare brachial plexopathy with an unknown aetiology. Multiple myeloma is a neoplastic plasma cell disease characterised by bone lesions. In this article, we present the case of a 59-year-old male patient with IBN associated with multiple myeloma, who was admitted to our clinic with right shoulder pain and right arm weakness. He experienced muscle weakness and atrophy in his right arm after a sudden onset of pain attack in the shoulder. Plexus and cervical vertebral MRI showed no pathology. Electrodiagnostic studies showed upper and middle trunk plexopathies. Laboratory analysis revealed anaemia, hypercalcaemia, renal dysfunction and monoclonal gammopathy in immunoglobulin electrophoresis. A bone marrow biopsy established the diagnosis of IgG kappa multiple myeloma. This is the first case report that presents the association of multiple myeloma and IBN.

The electrodiagnostic natural history of parsonage-turner syndrome

INTRODUCTION

Recovery from Parsonage-Turner syndrome (PTS) is generally favorable, although recovery times have been shown to vary, in part because there are no universally accepted outcome measures. In this study, we describe the electrodiagnostic natural history of this condition based on objective electrodiagnostic testing, and propose that complete electrodiagnostic recovery can be seen as early as 1 year.

METHODS

Twenty-six subjects with 29 affected nerves confirmed as PTS were followed every 3 months for electrodiagnostic testing, or until full reinnervation was confirmed.

RESULTS

Twenty-three cases (79.3%) demonstrated electrodiagnostic evidence of initial recovery at a mean of 5.8 months. Nine cases (31%) showed complete electrodiagnostic recovery at a mean of 1 year. When excluding cases with <1 year of follow-up, 52.9% achieved complete electrodiagnostic recovery.

CONCLUSIONS

In contrast to previous reports, full electrodiagnostic recovery of PTS was demonstrated at a mean of 1 year in > 50% of patients with longer term follow-up. Muscle Nerve 56: 737-743, 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.

Neuralgic amyotrophy: An update on diagnosis, pathophysiology, and treatment

In this review we provide a current overview of the clinical features, pathophysiology, epidemiology, and diagnostic and therapeutic strategies in neuralgic amyotrophy (NA). The disorder has several phenotypic variations, with a classic form in 70% of the patients. It is not rare, with an incidence of 1 per 1,000 individuals, but it is still often missed. Recurrences are common, yet the proposed multifactorial etiology, which includes genetic, biomechanical, and immunologic factors, limits our capacity to predict or prevent them. NA is a clinical diagnosis, and ancillary studies serve to exclude infectious or malignant causes or to assess a differential diagnosis. If patients are seen early and are still in pain, a short trial of high-dose oral corticosteroids is advised, and adequate analgesia may require opioids and non-steroidal anti-inflammatory drugs. Persistent complaints are common, and a multidisciplinary rehabilitation approach focusing on scapular coordination, energy distribution strategies, and self-management is indicated.

Spinal Cord Stimulation for Refractory Neuropathic Pain of Neuralgic Amyotrophy

The aim of this paper was to report the effect of temporary and chronic spinal cord stimulation for refractory neuropathic pain in neuralgic amyotrophy (NA). A 35-year-old female presented with two-months history of a severe, relentless neuropathic pain of the left shoulder, forearm, palm, and fingers. The neuropathic pain was refractory to various medical treatments, including nonsteroidal anti-inflammatory drugs, opiates, epidural and stellate ganglion blocks, and typically unrelenting. The diagnosis of NA was made with the characteristic clinical history and magnetic resonance imaging. The patient underwent a temporary spinal cord stimulation to achieve an adequate pain relief because her pain was notoriously difficult to control and lasted longer than the average duration (about 4 weeks on average) of a painful phase of NA. Permanent stimulation was given with paddle lead. The neuropathic pain in her NA persisted and she continued using the spinal cord stimulation with 12 months after development of NA. The temporary spinal cord stimulation was effective in a patient with an extraordinary prolonged, acute painful phase of NA attack, and the subsequent chronic stimulation was also useful in achieving an adequate analgesia during the chronic phase of NA.

Improved regeneration after femoral nerve injury in mice lacking functional T- and B-lymphocytes

The immune system plays important functional roles in regeneration after injury to the mammalian central and peripheral nervous systems. After damage to the peripheral nerve several types of immune cells, invade the nerve within hours after the injury. To gain insights into the contribution of T- and B-lymphocytes to recovery from injury we used the mouse femoral nerve injury paradigm. RAG2-/- mice lacking mature T- and B-lymphocytes due to deletion of the recombination activating gene 2 were subjected to resection and surgical reconstruction of the femoral nerve, with the wild-type mice of the same inbred genetic background serving as controls. According to single frame motion analyses, RAG2-/- mice showed better motor recovery in comparison to control mice at four and eight weeks after injury. Retrograde tracing of regrown/sprouted axons of spinal motoneurons showed increased numbers of correctly projecting motoneurons in the lumbar spinal cord of RAG2-/- mice compared with controls. Whereas there was no difference in the motoneuron soma size between genotypes, RAG2-/- mice displayed fewer cholinergic and inhibitory synaptic terminals around somata of spinal motoneurons both prior to and after injury, compared with wild-type mice. Extent of myelination of regrown axons in the motor branch of the femoral nerve measured as g-ratio was more extensive in RAG2-/- than in control mice eight weeks after injury. We conclude that activated T- and B-lymphocytes restrict motor recovery after femoral nerve injury, associated with the increased survival of motoneurons and improved remyelination.

Role of cytokines and Toll-like receptors in the immunopathogenesis of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune disease of the peripheral nervous system, mostly triggered by an aberrant immune response to an infectious pathogen. Although several infections have been implicated in the pathogenesis of GBS, not all such infected individuals develop this disease. Moreover, infection with a single agent might also lead to different subtypes of GBS emphasizing the role of host factors in the development of GBS. The host factors regulate a broad range of inflammatory processes that are involved in the pathogenesis of autoimmune diseases including GBS. Evidences suggest that systemically and locally released cytokines and their involvement in immune-mediated demyelination and axonal damage of peripheral nerves are important in the pathogenesis of GBS. Toll-like receptors (TLRs) link innate and adaptive immunity through transcription of several proinflammatory cytokines. TLR genes may increase susceptibility to microbial infections; an attenuated immune response towards antigen and downregulation of cytokines occurs due to mutation in the gene. Herein, we discuss the crucial role of host factors such as cytokines and TLRs that activate the immune response and are involved in the pathogenesis of the disease.

Brachial Neuritis With Phrenic Nerve Involvement in a Patient With a Possible Connective Tissue Disease

Background. Brachial neuritis (BN) is a rare inflammatory condition of peripheral nerves, usually involving the cervicobrachial plexus. These patients present with sudden onset of shoulder and arm pain that evolves into muscle weakness and atrophy.. Case Report. A 33-year-old woman presented with a 1-month history of diffuse pain in her thorax. She had no trauma or inciting incident prior to the onset of this pain and was initially treated for muscle spasms. The patient was seen in the emergency room multiple times and was treated with several courses of antibiotics for pneumonia on the basis of clinical symptoms and abnormal x-rays. The pleuritic chest pain persisted for at least 4 months, and the patient was eventually admitted for worsening pain and dyspnea. On physical examination, crackles were heard at both lung bases, and chest inspection revealed increased expansion in the upper thorax but poor expansion of the lower thorax and mild paradoxical respiration. “Sniff” test revealed no motion of the left hemidiaphragm and reduced motion on the right hemidiaphragm. Her computed tomography scan revealed bilateral atelectasis, more severe at the left base. She reported no symptoms involving her joints or skin or abdomen. Her presentation and clinical course are best explained by BN with a bilateral diaphragmatic weakness. However, she had a positive ANA, RF, anti-RNP antibody, and anti SS-A. Conclusion. Patients with BN can present with diffuse thoracic pain, pleuritic chest pain, and diaphragmatic weakness. Our patient may represent a case of connective tissue disease presenting with brachial plexus neuritis.

Challenging pain syndromes: Parsonage-Turner syndrome

Parsonage-Turner syndrome (PTS) is a rare disorder typically characterized by an abrupt onset of upper extremity pain followed by progressive neurologic deficits, including weakness, atrophy, and occasionally sensory abnormalities. The exact cause and pathophysiology of PTS are complex and incompletely understood. Autoimmune, genetic, infectious, and mechanical processes have all been implicated. No specific treatments have been proven to reduce neurologic impairment or improve the prognosis of PTS. Most patients with PTS are treated with a multidisciplinary approach that includes both physical therapy and pharmacologic treatment, often with multiple agents. Further research is needed.

Neuralgic amyotrophy and hepatitis E virus infection

OBJECTIVE

To determine whether there is an association between an acute preceding hepatitis E virus (HEV) infection and neuralgic amyotrophy (NA), and if so, whether patients with HEV-related NA differ from patients without an associated HEV infection.

METHODS

HEV testing was conducted in a retrospective cohort of 28 Cornish patients with NA (2011-2013) and a prospective cohort of 38 consecutive Dutch patients with NA (2004-2007). Acute-phase serum samples were analyzed for the presence of anti-HEV immunoglobulin (Ig) M and IgG and HEV RNA (quantitative real-time PCR).

RESULTS

Five cases (10.6%) of acute hepatitis E infection were identified in a total group of 47 patients with NA of whom serum samples were available. In 4 patients, HEV RNA was detected in serum samples taken at presentation. All patients with HEV-associated NA had clinical and electrophysiologic evidence of bilateral brachial plexus involvement. Anti-HEV IgM positivity was not related to age, sex, disease severity, disease course, or outcome.

CONCLUSIONS

Acute hepatitis E is found in 10% of patients with NA from the United Kingdom and the Netherlands. Further research is required to investigate the role of HEV in NA in other geographical locations and to determine pathophysiologic mechanisms.

Role of Campylobacter jejuni infection in the pathogenesis of Guillain-Barré syndrome: an update

Our current knowledge on Campylobacter jejuni infections in humans has progressively increased over the past few decades. Infection with C. jejuni is the most common cause of bacterial gastroenteritis, sometimes surpassing other infections due to Salmonella, Shigella, and Escherichia coli. Most infections are acquired due to consumption of raw or undercooked poultry, unpasteurized milk, and contaminated water. After developing the diagnostic methods to detect C. jejuni, the possibility to identify the association of its infection with new diseases has been increased. After the successful isolation of C. jejuni, reports have been published citing the occurrence of GBS following C. jejuni infection. Thus, C. jejuni is now considered as a major triggering agent of GBS. Molecular mimicry between sialylated lipooligosaccharide structures on the cell envelope of these bacteria and ganglioside epitopes on the human nerves that generates cross-reactive immune response results in autoimmune-driven nerve damage. Though C. jejuni is associated with several pathologic forms of GBS, axonal subtypes following C. jejuni infection may be more severe. Ample amount of existing data covers a large spectrum of GBS; however, the studies on C. jejuni-associated GBS are still inconclusive. Therefore, this review provides an update on the C. jejuni infections engaged in the pathogenesis of GBS.

Acute brachial neuritis following influenza vaccination

Brachial neuritis following vaccination is an uncommon but clinically important presentation of severe shoulder and arm pain associated with globally reduced range of movement. It may be confused with the more common diagnoses of rotator cuff pathology, adhesive capsulitis (frozen shoulder), shoulder arthritis or cervical spondylosis. We present a case of acute brachial neuritis, which posed a clinical diagnostic challenge to emergency, acute medical and rheumatology clinicians.

Neuralgic amyotrophy (Parsonage-Turner syndrome)

Neuralgic amyotrophy (Parsonage-Turner syndrome or brachial plexus neuritis) is an uncommon syndrome whose cause is unknown. The suprascapular and axillary nerves and corresponding muscles are affected most frequently. The disorder exhibits a broad range of clinical manifestations, and patients frequently present to physicians of different subspecialties. Accurate diagnosis can be challenging and requires a thorough history and physical examination. Nerve conduction velocity and imaging studies assist in the evaluation. Treatment consists of symptomatic management. Symptoms can persist for more than than a year, but most patients note resolution of symptoms over time.

Intravenous immunoglobulin (IVIg) with methylprednisolone pulse therapy for motor impairment of neuralgic amyotrophy: clinical observations in 10 cases

BACKGROUND

Neuralgic amyotrophy (NA) is a distinct peripheral nervous system disorder characterized by attacks of acute neuropathic pain and rapid multifocal weakness and atrophy unilaterally in the upper limb. The current hypothesis is that the episodes are caused by an immune-mediated response to the brachial plexus, however, therapeutic strategies for NA have not been well established.

METHODS AND RESULTS

We retrospectively reviewed 15 case series of NA; 10 of the 15 patients received intravenous immunoglobulin (IVIg) with methylprednisolone pulse therapy (MPPT) and 9 of these 0 patients showed clinical improvement of motor impairment.

CONCLUSION

Our clinical observations do not contradict the possibility that IVIg with MPPT may be one of the potential therapeutics for NA, however the efficacy remains to be established. Further confirmatory trials are needed in patients with various clinical severities and phases of NA. Further basic research and confirmatory trials should be performed to survey the efficacy of such immunomodulation therapy for NA.

Clinical and pathophysiological concepts of neuralgic amyotrophy

Neuralgic amyotrophy--also known as Parsonage-Turner syndrome or brachial plexus neuritis--is a distinct and painful peripheral neuropathy that causes episodes of multifocal paresis and sensory loss in a brachial plexus distribution with concomitant involvement of other PNS structures (such as the lumbosacral plexus or phrenic nerve) in a large number of patients. The phenotype can be limited or extensive and the amount of disability experienced also varies between patients, but many are left with residual disabilities that affect their ability to work and their everyday life. Both idiopathic and hereditary forms exist. The latter form is genetically heterogeneous, but in 55% of affected families, neuralgic amyotrophy is associated with a point mutation or duplication in the SEPT9 gene on chromosome 17q25. The disease is thought to result from an underlying genetic predisposition, a susceptibility to mechanical injury of the brachial plexus (possibly representing disturbance of the epineurial blood-nerve barrier), and an immune or autoimmune trigger for the attacks. The precise pathophysiological mechanisms are still unclear; treatment is empirical, and preventive measures are not yet available. This Review provides an overview of the current clinical and pathophysiological concepts and research topics in neuralgic amyotrophy.

A4V superoxide dismutase mutation in apparently sporadic ALS resembling neuralgic amyotrophy

We report a case of apparently sporadic amyotrophic lateral sclerosis (ALS) in a young pregnant woman presenting subacutely with severe left shoulder pain followed by progressive weakness and wasting of the left arm, mimicking neuralgic amyotrophy. She was later found electrophysiologically to have widespread denervation involving more than just the arm and an alanine for valine substitution in codon 4 (A4V) in the gene for Cu/Zn superoxide dismutase 1 (SOD1). Her case illustrates that pain on initial presentation, though uncommon, does not exclude a diagnosis of ALS.

Neuralgic amyotrophy

Neuralgic amyotrophy has a broad variety of clinical manifestations. Although it was initially thought to be a plexopathy, its diverse presentation can include isolated sensory nerves or even cranial nerves. Although neuralgic amyotrophy is usually a benign condition with a good recovery, pain can be a disabling feature. NSAIDs and short-term narcotics are appropriate treatments. There is lack of evidence whether the use of corticosteroids has an impact on the duration of the disease or the neuropathic pain. However, given the few adverse effects in a selective population and low cost, short-term steroids can be an option for the treatment of these patients.

Neuralgic amyotrophy

Neuralgic amyotrophy is an uncommon condition characterised by the acute onset of severe pain in the shoulder and arm, followed by weakness and atrophy of the affected muscles, and sensory loss as the pain subsides. The diversity of its clinical manifestations means that it may present to a variety of different specialties within medicine. This article describes the epidemiology, aetiopathogenesis, clinical features, differential diagnoses, investigations, treatment, course and prognosis of the condition.

Lumbosacral plexitis

Lumbosacral plexitis (LSP) is an uncommon idiopathic disorder characterized by the acute onset of severe lower extremity pain followed by wasting and weakness of leg muscles with variable sensory loss. Muscles innervated by multiple roots and multiple nerves are affected, and other causes of lumbosacral plexopathy such as mass lesions and trauma must be excluded. Postulated causes of LSP include vasculitis with subsequent axonal injury and autoimmune-related demyelination, although evidence is accumulating that the former pathophysiology is more likely. Recovery is variable but is often quite slow and incomplete. Immunomodulatory therapies such as corticosteroids, intravenous immunoglobulin, and plasma exchange are inconsistent in their efficacy.

Intravenous immunoglobulin therapy for idiopathic postoperative lumbosacral plexopathy

We report a patient who developed an acute lumbosacral plexopathy (LSP) following spinal surgery on lumbos segments. He recovered dramatically following treatment with high-dose intravenous immunoglobulin (IVIg). A 66-year-old man who underwent an L4 to S1 decompressive laminectomy required re-admission after developing contralateral leg pain. Follow-up lumbosacral magnetic resonance imaging showed only mild postoperative changes. Ten days after re-admission, he developed relatively rapid onset ipsilateral inguinal pain and weakness of all his leg muscles with diminished sensation in a lumbosacral plexus distribution. Re-exploration revealed no specific lesion except for adhesions and resulted in no improvement. Following treatment with IVIg (0.4 g/kg daily) for five days, he showed dramatic resolution of motor weakness and pain. There has been no relapse following six months follow-up. Although IVIg treatment does not guarantee a positive response in all types of LSP, it should be considered for severe, rapidly progressive and even for postoperative cases.

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.

Magnetic resonance imaging features of subacute idiopathic brachial neuritis

A 60-year-old man presented with sudden onset of left shoulder pain followed 2 weeks later by the development of left shoulder girdle weakness. A clinical and electrophysiological diagnosis of subacute idiopathic brachial neuritis was made. The MRI features of subacute muscular denervation in this patient are discussed and the relevant literature reviewed.

Motor root conduction in neuralgic amyotrophy: evidence of proximal conduction block

OBJECTIVE

To determine the presence and role of proximal conduction block in neuralgic amyotrophy.

METHODS

Percutaneous electrical stimulation of cervical roots and brachial plexus was employed in eight patients with neuralgic amyotrophy. Root to Erb's point compound muscle action potential amplitude ratios for abductor digiti minimi, extensor digitorum communis, biceps, and deltoid muscles were compared with results obtained from 10 healthy controls.

RESULTS

Conduction block in the nerve to one muscle was found in three of eight patients (38%) suggesting focal proximal demyelination. Repeat studies showed axonal degeneration, resolution, and persistence of conduction block in these three patients respectively.

CONCLUSION

Focal conduction block plays a significant part in the pathogenesis of neuralgic amyotrophy, which is generally regarded as an axon loss process. Therapeutic intervention should be directed to patients with persistent conduction block, with the aim of eradicating the block and possibly minimising subsequent axon loss.