Lambert–Eaton myasthenic syndrome (LEMS): a rare autoimmune presynaptic disorder often associated with cancer

Spontaneous regression of small cell lung cancer associated with Lambert-Eaton Myasthenic Syndrome: Case report

Spontaneous regression (SR) of cancer is very rare, especially of small cell lung cancer (SCLC). Recently, an association of paraneoplastic neurological syndrome (PNS) has been reported as a cause of SR of cancer, and onconeural antibodies are a possible factor in the SR of cancer associated with PNS. We herein report the first case of SR of SCLC combined with anti-P/Q-type of voltage-gated calcium channel (VGCC) antibody-positive Lambert-Eaton myasthenic syndrome (LEMS), a subtype of PNS. This case report suggests that SCLC may be spontaneously reduced by an autoimmune response induced by VGCC antibodies associated with LEMS. Our finding may help elucidate the mechanisms that inhibit tumor growth and cause the regression of tumors.

Durvalumab for Extensive-Stage of Small-Cell Lung Cancer With Lambert-Eaton Myasthenic Syndrome

Durvalumab is an immune checkpoint inhibitor (ICI) of anti-programmed cell death protein 1 ligand antibody. ICI-combined chemotherapy has recently become a standard regimen for extensive-stage of small-cell lung cancer (ES-SCLC). SCLC is well known to be the most likely tumor associated with Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disease of a neuromuscular junction disorder. Although LEMS has been reported to be induced by ICI as immune-mediated adverse events, it remains unknown whether ICI can deteriorate preexisting paraneoplastic syndrome (PNS) of LEMS. Our rare case was successfully treated by durvalumab plus chemotherapy without exacerbation of preexisting PNS of LEMS. We report a 62-year-old female with ES-SCLC and preexisting PNS of LEMS. She started carboplatin-etoposide in combination with durvalumab. This immunotherapy achieved nearly complete response. However, multiple brain metastases were found after two courses of maintenance durvalumab. Her symptoms and physical examinations of LEMS improved despite of no significant change in compound muscle action potential amplitude in the nerve conduction study. The titer of anti-P/Q-type voltage-gated calcium channel (VGCC) antibody decreased from 1,419.2 to 263.5 pmol/L during the immunotherapy. In conclusion, ICI in combination with platinum doublet chemotherapy is still challenging but may be a treatment option for ES-SCLC patients complicated with PNS of LEMS.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

Atezolizumab-Induced Lambert-Eaton Myasthenic Syndrome in a Patient With Small-Cell Lung Cancer

The case of a 70-year-old man who developed Lambert-Eaton myasthenic syndrome (LEMS) while receiving atezolizumab treatment for extensive-stage small-cell lung cancer (SCLC) is presented. He started receiving maintenance immunotherapy with atezolizumab following four cycles of combination therapy with atezolizumab, carboplatin, and etoposide. After five cycles of maintenance atezolizumab therapy, he complained of muscle weakness in the lower limbs and fatigue. Electromyographic findings and positive results for anti-P/Q-type voltage-gated calcium channel antibody made a diagnosis of LEMS. Based on the onset time of LEMS and the state of his underlying cancer at the time of the appearance of neurological symptoms, he was diagnosed with LEMS as an immune-related adverse event (irAE) induced by atezolizumab. After discontinuing atezolizumab treatment and initiating combination therapy with steroid pulse plus intravenous immunoglobulin, his neurological symptoms improved. Although 18 months have passed since the discontinuation of atezolizumab treatment, there has been neither recurrence of neurological symptoms nor a progression of his cancer without salvage chemotherapy. This is a rare case of LEMS as a neurological irAE induced by atezolizumab. Clinicians must be aware of the potential for LEMS to develop in SCLC patients taking atezolizumab treatment.

Clinical and imaging clues to the diagnosis and follow-up of ptosis and ophthalmoparesis

Ophthalmoparesis and ptosis can be caused by a wide range of rare or more prevalent diseases, several of which can be successfully treated. In this review, we provide clues to aid in the diagnosis of these diseases, based on the clinical symptoms, the involvement pattern and imaging features of extra-ocular muscles (EOM). Dysfunction of EOM including the levator palpebrae can be due to muscle weakness, anatomical restrictions or pathology affecting the innervation. A comprehensive literature review was performed to find clinical and imaging clues for the diagnosis and follow-up of ptosis and ophthalmoparesis. We used five patterns as a framework for differential diagnostic reasoning and for pattern recognition in symptomatology, EOM involvement and imaging results of individual patients. The five patterns were characterized by the presence of combination of ptosis, ophthalmoparesis, diplopia, pain, proptosis, nystagmus, extra-orbital symptoms, symmetry or fluctuations in symptoms. Each pattern was linked to anatomical locations and either hereditary or acquired diseases. Hereditary muscle diseases often lead to ophthalmoparesis without diplopia as a predominant feature, while in acquired eye muscle diseases ophthalmoparesis is often asymmetrical and can be accompanied by proptosis and pain. Fluctuation is a hallmark of an acquired synaptic disease like myasthenia gravis. Nystagmus is indicative of a central nervous system lesion. Second, specific EOM involvement patterns can also provide valuable diagnostic clues. In hereditary muscle diseases like chronic progressive external ophthalmoplegia (CPEO) and oculo-pharyngeal muscular dystrophy (OPMD) the superior rectus is often involved. In neuropathic disease, the pattern of involvement of the EOM can be linked to specific cranial nerves. In myasthenia gravis this pattern is variable within patients over time. Lastly, orbital imaging can aid in the diagnosis. Fat replacement of the EOM is commonly observed in hereditary myopathic diseases, such as CPEO. In contrast, inflammation and volume increases are often observed in acquired muscle diseases such as Graves' orbitopathy. In diseases with ophthalmoparesis and ptosis specific patterns of clinical symptoms, the EOM involvement pattern and orbital imaging provide valuable information for diagnosis and could prove valuable in the follow-up of disease progression and the understanding of disease pathophysiology.

Paraneoplastic Syndromes in Neuro-Ophthalmology

Paraneoplastic neurological syndromes (PNS) occur in about 1 in 300 cases of cancer. The usual mechanism is that an antigen on the cancer sets off an immune response that then cross-reacts with a nervous system antigen. The presentation is usually with a subacute progressive neurological disorder. The management of these conditions is usually of both the underlying tumor and immunomodulation to suppress the autoimmune response. There are a number of these conditions that can present to the Neuro-Ophthalmology clinic, either as a discrete condition affecting vision or eye movements or as part of a more widespread neurological disorder. This article will discuss these conditions, their management and prognosis.

Nationwide survey of Lambert-Eaton myasthenic syndrome in Japan

Background

There was no nationwide epidemiological study of Lambert-Eaton myasthenic syndrome (LEMS) in Japan; therefore, we conducted a nationwide survey.

Methods

For the first survey, we sent survey sheets to randomly selected medical departments (n=7545) to obtain the number of LEMS who visited medical departments between 1 January 2017 and 31 December 2017. For the second survey, we sent survey sheets to the corresponding medical departments to obtain clinical information on LEMS.

Results

We received 2708 responses (recovery rate: 35.9%) to the first survey. We estimated the number of LEMS as 348 (95% CI 247 to 449). The prevalence was 2.7 (95% CI 1.9 to 3.5) in 1 000 000 population. As a result of the second survey, we obtained 30 case records of 16 men and 14 women. Fourteen patients (46.7%) had a tumour, and 10 out of 14 tumours were small-cell lung carcinoma (71.4%). There was a predominance of men in the LEMS with tumour (paraneoplastic LEMS, P-LEMS) (n=11, 78.6%) and women in the LEMS without tumour (a primary autoimmune form of LEMS, AI-LEMS) (n=11, 68.8%) (p=0.0136). The onset age (mean (SD)) for the P-LEMS was 67.1 (9.0), and that for AI-LEMS was 57.8 (11.2) years old (p=0.0103). The disease duration (median) for P-LEMS was 2 years, and for AI-LEMS was 7.5 years (p=0.0134).

Conclusions

The prevalence of LEMS in Japan is similar to that in other countries. There are predominances of men in P-LEMS and women in AI-LEMS.

Paraneoplastic syndromes: A focus on pathophysiology and supportive care

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

This article aims to increase awareness of, outline pathophysiology for, and offer guidance on supportive care strategies for specific endocrine, neurological, and immunological syndromes associated with paraneoplastic syndromes (PNSs).

SUMMARY

PNS refers to remote effects that cannot be attributed to the direct or invasive effects of a malignancy. These syndromes are considered clinically important because they may provide early recognition, diagnosis, and management of the malignancy in a timely manner. Many of their presenting symptoms such as ectopic Cushing's syndrome, hypercalcemia of malignancy (HCM), syndrome of inappropriate secretion of antidiuretic hormone (SIADH), neurological dysfunctions, and paraneoplastic autoimmune thrombocytopenia overlap with those of nonneoplastic disorders, yet their pathogenesis and responses to treatment differ. Treatment for ectopic Cushing's syndrome due to a PNS consists of treatment of the underlying malignancy and its comorbidities. Drug therapies may include ketoconazole, mitotane, metyrapone, somatostatin analogs, and dopamine agonists. Hypercalcemia may be classified into cases with parathyroid hormone (PTH)-dependent causes or PTH-independent causes such as HCM, in which osteoclast inhibitors may be deployed. Treatments of PNS-mediated SIADH include treatment of the underlying malignancy and strategies to increase serum sodium levels. Amifampridine is now considered the first-line agent for paraneoplastic Lambert-Eaton myasthenic syndrome, whereas steroids, intravenous immune globulin, thrombopoietin receptor agonists (eg, romiplostim, eltrombopag, and avatrombopag), fostamatinib, and rituximab may find their niche in treatment of PNS-mediated autoimmune thrombocytopenia.

CONCLUSION

Supportive care for PNSs lends opportunities to pharmacists to add quality, value, and safety.

Total Plasma Exchange in Neuromuscular Junction Disorders—A Single-Center, Retrospective Analysis of the Efficacy, Safety and Potential Diagnostic Properties in Doubtful Diagnosis

Neuromuscular junction disorders (NJDs) are a heterogeneous group of diseases including myasthenia gravis (MG). In some cases, patients are present with myasthenic symptoms without evidence of autoimmune antibodies, making diagnosis challenging. Total plasma exchange (TPE) has proven efficacy in NJDs. The objective is to describe the safety and efficacy of TPE in NJD patients with questionable disease activity or uncertain diagnosis in order to assess the diagnostic potential of TPE. We report an observational, retrospective cohort study of clinical routine data. All the data were derived from the electronic medical records of the Department of Neurology at University Hospital Essen. We searched for patients with NJDs between 1 July 2018 and 30 June 2021. Of the 303 patients who presented to the department with NJDs, 20 were treated with TPE; 9 patients did not show a measurable benefit from TPE (45%), 6 of whom were diagnosed with seronegative MG. Of these, 3 (50%) had long-standing ocular symptoms. There were decreases in the mean arterial pressure, hemoglobin, hematocrit and fibrinogen during treatment, which were not considered clinically relevant. In (seronegative) myasthenic patients, TPE may help to verify an uncertain diagnosis or to reveal possible muscle damage, allowing unnecessary therapy to be avoided.

Lambert-Eaton Myasthenic Syndrome in Lung Cancer

The aim is to study lung cancer with Lambert-Eaton myasthenic syndrome (LEMS) with clinical and electrical characteristics of physiology and prognosis. Fourteen LEMS patients with lung cancer were studied retrospectively. The data including demographics, clinical presentation, treatments, and prognosis from the medical records were analyzed. Lung cancer coexisting with LEMS is more common in men (10/14). The median age was 67.1 years. Eleven (78.6%) patients experienced gradual onset of disease. Most patients presented nervous system lesions prior to occult tumors. The most common symptoms reported were proximal muscle weakness (92.9%), decreased or absent tendon reflexes (50%), and autonomic dysfunction (71.4%). All the patients showed reduction in action potential amplitude after repetitive peripheral never stimulation at low frequency and increased amplitude at high frequency. LEMS usually occurs prior to lung cancer with complicated and various clinical manifestations in our centers. We should improve awareness and knowledge of such disease to shorten the diagnostic delay and lead to few misdiagnoses.

Paraneoplastic syndrome in neuroophthalmology

Paraneoplastic syndrome is a group of clinical symptoms that occur in the state of systemic malignant tumors. Paraneoplastic syndrome of the nervous system can affect any part of the central and peripheral nervous system and may also affect the eyes. In neuroophthalmology, paraneoplastic syndrome has a variety of manifestations that can affect both the afferent and efferent visual systems. The afferent system may involve the optic nerve, retina and uvea; the efferent system may involve eye movement, neuromuscular joints or involuntary eye movements and pupil abnormalities and may also have other neurological symptoms outside the visual system. This article discusses the clinical manifestations, pathological mechanisms, detection methods and treatment methods of paraneoplastic syndrome in neuroophthalmology. The performance of paraneoplastic syndrome is diverse, the diagnosis is difficult, and the treatment should be considered systematically. Differential diagnosis, optimal evaluation and management of these manifestations is not only the key to treatment but also a challenge.

High expression of N-type calcium channel indicates a favorable prognosis in gliomas

For the diagnosis and prognosis of glioma, the development of prognostic biomarkers is critical. The N-type calcium channel, whose predominant subunit is encoded by calcium voltage-gated channel subunit alpha1 B (CACNA1B), is mostly found in the nervous system and is closely associated with neurosensory functions. However, the link between the expression of CACNA1B and glioma remains unknown. We used ONCOMINE to explore the differences in CACNA1B expression among different cancers. We then conducted survival analysis and COX analysis using TCGA_LGG and TCGA_GBM datasets, which were divided into CACNA1Bhigh and CACNA1Blow based on the median. We examined the differences in other favorable prognostic markers or clinical characteristics between CACNA1Bhigh and CACNA1Blow using t tests. Differentially expressed genes were identified, and KEGG pathway enrichment was performed. We compared the expression of methyltransferases and analyzed the differentially methylated regions. Immunohistochemistry results were retrieved from the Human Protein Atlas database for validation purposes. CACNA1B was expressed at lower levels in gliomas, and, for the first time, we found that high expression of CACNA1B in gliomas predicts a good prognosis. Other favorable prognostic markers, such as isocitrate dehydrogenase mutation, 1p/19q codeletion, and O6-methylguanine-DNA methyltransferase promoter methylation, were increased in tandem with high expression of CACNA1B. Differentially expressed genes were enriched in multiple pathways related to cancer progression and aberrant epigenetic alterations were significantly associated with CACNA1B. High expression of N-type calcium channels indicates a favorable prognosis for gliomas. This study provides a better understanding of the link between gliomas and N-type calcium channels and may offer guidance for the future treatment of gliomas.

Long-Standing Lambert–Eaton Myasthenic Syndrome Caused by Undetectable Small-Cell Lung Cancer: Why We Should Follow-Up LEMS

Physicians often encounter patients with unexplained muscle weakness and dysphagia. Lambert–Eaton myasthenic syndrome (LEMS) can cause unexplained weakness or dysphagia and is often accompanied by neoplastic conditions. A 64-year-old man who had several risk factors—14 kg weight loss over the last 4 years, 20 years of experience working as a coal miner, and being a 50 pack-year ex-smoker—complained of dysphagia, intermittent diplopia, mild weakness, and hypotonia. The initial computed tomography (CT) and follow-up positron emission tomography (PET) CT did not reveal any malignancy. After continuous follow-up for this LEMS, small-cell lung cancer (SCLC, cTxN1M0) was found on a serial follow-up chest CT 21 months after the LEMS diagnosis. The patient was treated with chemotherapy. LEMS is rare and is often accompanied by malignancy. This case highlights the importance of being concerned about LEMS diagnoses and of long-term follow-up for unexplained LEMS.

Paraneoplastic syndromes in ophthalmology

Paraneoplastic syndromes consist on systemic manifestations associated with certain cancers which are not a direct consequence of tumor invasion or its metastases. It is known that autoimmunity and autoantibody synthesis play an important role in its pathophysiology due to a process of molecular mimicry. Paraneoplastic syndromes in ophthalmology are rare, but it is important to recognize them clinically because in some cases symptoms preceded the diagnosis of an underlying neoplasia. Most frequently involved cancer is small cell lung carcinoma, but there is also a relationship with other tumor etiologies such as thymoma, gynecological tumors or neuroblastoma in children. Paraneoplastic syndromes with ocular involvement can be divided into those that affect the afferent visual pathway, such as cancer-associated retinopathy, melanoma-associated retinopathy, or paraneoplastic optic neuropathy; and the ones that affect the efferent visual pathway, such as bilateral tonic pupils, Myasthenia Gravis, Lambert-Eaton syndrome or paraneoplastic cerebellar degeneration. The presence of autoantibodies is helpful in clinical practice but negativity does not exclude this diagnosis. Although evolution and prognosis is linked to primary disease, in some cases specific treatment, usually immunosuppressive therapy, can help improving patients quality of life.

Plasma lncRNA LOC338963 and mRNA AP3B2 are upregulated in paraneoplastic Lambert-Eaton myasthenic syndrome

INTRODUCTION/AIMS

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune neuromuscular junction disorder. Long noncoding RNA (lncRNA) can regulate the expression of mRNA and is involved in the development of autoimmune diseases, but few genetic studies are available. In this study we aimed to explore the lncRNA and mRNA changes of LEMS.

METHODS

Plasma lncRNA and mRNA expression profiles of three LEMS patients with small cell lung cancer (SCLC) and three matched healthy controls were analyzed by microarray. Differentially expressed lncRNAs and adjacent mRNAs were jointly analyzed, and candidates were verified by quantitative real-time polymerase chain reaction (qRT-PCR). The identified genes were subsequently evaluated in 9, 8, and 4 patients with paraneoplastic LEMS, nontumor LEMS, and SCLC, respectively. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine possible functions.

RESULTS

A total of 320 lncRNA and 168 mRNAs were differentially expressed in the three LEMS with SCLC and compared with healthy controls. Among these, lncRNA LOC338963 and its neighboring mRNA AP3B2 were upregulated jointly, which was confirmed by qRT-PCR. qRT-PCR revealed significant upregulation of the two genes in patients with paraneoplastic LEMS compared with nontumor LEMS or SCLC. GO analysis of AP3B2 identified the enrichment terms anterograde synaptic vesicle transport and establishment of synaptic vesicle localization. KEEG analysis showed that AP3B2 was enriched in lysosomal pathways.

DISCUSSION

LOC338963 and AP3B2 were upregulated in patients with paraneoplastic LEMS, suggesting their involvement in pathogenesis. These genes could be targets for exploring the pathomechanism of paraneoplastic LEMS.

Accuracy of patient-reported data for an online patient registry of autoimmune myasthenia gravis and Lambert-Eaton myasthenic syndrome

Disorders of the neuromuscular junction (NMJ) comprise a spectrum of rare diseases causing muscle fatigability and weakness, leading to life-long effects on quality of life. We established the Dutch-Belgian registry for NMJ disorders, based on a unique combination of patient- and physician-reported information. Information on natural course, disease burden, prevalence of complications and comorbidity is collected through patient-reported standardized questionnaires and verified using medical documentation. Currently, the registry contains information of 565 Myasthenia Gravis (MG) patients and 38 Lambert-Eaton myasthenic syndrome (LEMS) patients, constituting approximately 25% (MG) and 80% (LEMS) of patients in the Netherlands. This is a very large registry, with the highest participation rate per capita. In addition to confirming many disease characteristics previously described in the literature, this registry provides several novel insights. The reported rate of potentially corticosteroid-related comorbidity, including hypertension, heart disease, osteoporosis and type 2 diabetes was high, emphasizing the need to commence corticosteroid-sparing immune suppressive treatment as soon as possible. The reported rate of other auto-immune diseases is far higher than previously expected: 27% of MG and 38% of LEMS patients, and a surprisingly high number of MG patients (47%) is unaware of their antibody status. In conclusion, this registry provides a valuable collection of information regarding MG and LEMS disease course. Continuous collection of annual follow-up data will provide further longitudinal insights in disease burden, course and treatment effect.

Lambert-Eaton Myasthenic Syndrome and Dermatomyositis With Anti-TIF1-gamma Autoantibody: A Unique Association of Autoimmune Neuromuscular Conditions Without Malignancy

ABSTRACT

Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic neuromuscular junction disorder, and dermatomyositis (DM) is an idiopathic inflammatory myopathy. LEMS and DM are uncommon conditions that can present similarly and are often associated with autoantibodies. Concomitant LEMS and DM have only been reported a few times, and most of those cases were paraneoplastic. We present the first reported case of a patient with antivoltage gated calcium channel antibody positive LEMS who subsequently developed DM with antitranscription intermediary factor 1-gamma (anti-TIF1-γ) antibodies. Interestingly, both conditions occurred without evidence of malignancy. This diagnosis of LEMS and DM with characteristic clinical, electrodiagnostic, and histopathological evidence led to a beneficial modification of the patient's therapeutic regimen. Due to the fact that overlapping concurrent neuromuscular conditions are rare, a high clinical suspicion is needed to identify, evaluate (including appropriate cancer screenings), and appropriately treat these patients.

Immunosuppression in chronic autoimmune neurological disorders during the COVID-19 pandemic

Objective

To study the risk of acquiring Corona Virus Disease 2019 (COVID-19) and its outcomes in patients on immunosuppressive therapy (IST) for chronic autoimmune neuromuscular disorders (aNMD) and multiple sclerosis (MS).

Methods

We used TriNetX, a global health collaborative clinical research platform collecting real-time electronic medical records data, which has one of the largest known global COVID-19 database. We included patients with chronic autoimmune neuromuscular disorders (aNMD) [myasthenia gravis (MG), inflammatory myositis, and chronic inflammatory neuropathies (CIN)] and MS, based on the International Classification of Disease-10 (ICD-10) coding for one year before January 20th, 2020. We examined the use of IST, rate of COVID- 19, hospitalization, intubation, and mortality among the patients with aNMD and MS.

Results

A total of 33,451 patients with aNMD and 42,899 patients with MS were included. Among them, 111 (0.33%) patients with aNMD and 115 patients (0.27%) with MS had COVID-19. About one third of them required hospitalization. IST did not appear to have a significant impact on overall infection risk in either group; however, risk of hospitalization for immunosuppressed patients with aNMD was higher (Odds ratio 2.86, p-value 0.011).

Conclusions

IST use does not appear to make patients with aNMD and MS more vulnerable to COVID-19. IST may be continued during the pandemic, as previously suggested by expert opinion guidelines. However, it is important to consider individualizing immunotherapy regimens in some cases. Additional physician reported registry-based data is needed to further confirm these findings.

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Majority of patients with chronic autoimmune neurological disorders(cAND’s) likely have mild-to-moderate COVID-19.

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Patients with cAND’s who had COVID-19, 33% were hospitalized 12.1% required intensive care unit stay and 8.5% died.

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Immunosuppressive therapies did not appear to have a significant impact on overall infection risk.

Use of therapeutic plasma exchange for pediatric neurological diseases

Therapeutic plasma exchange is used to treat neurological diseases in the pediatric population. Since its first use in pediatric patients with hepatic coma in the form of manual whole blood exchange, therapeutic plasma exchange has been increasingly used to treat these disorders of the nervous system. This expansion is a result of improved techniques and apheresis instruments suitable for small children, as well as the recognition of its applicability to many diseases in the pediatric population. This review provides a historical overview of the use of therapeutic apheresis in children and highlights the most common applications for therapeutic plasma exchange to treat neurological disorders in children.

Aminopiridines in the treatment of multiple sclerosis and other neurological disorders

Symptomatic treatment has a great relevance for the management of patients with neurologic diseases, since it reduces disease burden and improves quality of life. Aminopyridines (APs) are a group of potassium (K+) channel blocking agents that exert their activity both at central nervous system level and on neuromuscular junction. This review describes the use of APs for the symptomatic treatment of neurological conditions. We will describe trials leading to the approval of the extended-release 4-aminopyridine for MS and evidence in support of the use in other neurological diseases.

Sudomotor Dysfunction

Disorders of sudomotor function are common and diverse in their presentations. Hyperhidrosis or hypohidrosis in generalized or regional neuroanatomical patterns can provide clues to neurologic localization and inform neurologic diagnosis. Conditions that impair sudomotor function include small fiber peripheral neuropathy, sudomotor neuropathy, myelopathy, α-synucleinopathies, autoimmune autonomic ganglionopathy, antibody-mediated hyperexcitability syndromes, and a host of medications. Particularly relevant to neurologic practice is the detection of postganglionic sudomotor deficits as a diagnostic marker of small fiber neuropathies. Extensive anhidrosis is important to recognize, as it not only correlates with symptoms of heat intolerance but may also place the patient at risk for heat stroke when under conditions of heat stress. Methods for assessing sudomotor dysfunction include the thermoregulatory sweat test, the quantitative sudomotor axon reflex test, silicone impressions, and the sympathetic skin response.

Gender issues of antibody-mediated diseases in neurology: (NMOSD/autoimmune encephalitis/MG)

Neuromyelitis optica spectrum disorder (NMOSD), autoimmune encephalitis (AE), myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) are antibody-mediated neurological diseases. They have mostly female predominance, affecting many women during childbearing age. Interactions between the underlying disease (or necessary treatment) and pregnancy can occur in every of these illnesses. Herein, we present the characteristics of NMOSD, AE, MG and LEMS in general, and review published data regarding the influence of the different diseases on fertility, pregnancy, puerperium, treatment strategy during pregnancy and post-partum period, and menopause but also male factors. We summarise key elements that should be borne in mind when confronted with such cases.

Approach to Muscle and Neuromuscular Junction Disorders

PURPOSE OF REVIEW

Muscle and neuromuscular junction disorders are a diverse group of disorders that can be difficult to diagnose. This article provides a diagnostic approach based on clinical history and neurologic examination leading to a narrow set of diagnostic tests.

RECENT FINDINGS

Numerous discoveries in recent years have facilitated clinician access to more advanced laboratory and genetic testing to pinpoint the exact diagnosis in patients with muscle or neuromuscular junction disorders. Large-scale genetic testing has become much less expensive, and free testing has become available for many of the rare conditions because of increased research and the availability of effective therapies for these rare disorders.

SUMMARY

The approach to muscle and neuromuscular junction disorders depends on the clinical pattern of muscle weakness. By classifying patients into one of 10 muscle patterns, diagnostic testing can be targeted and gene testing yield will be optimized. With the increased accessibility and reduced cost of genetic testing (eg, gene panels, whole-exome sequencing, whole-genome sequencing, and chromosomal microarray), this clinical approach to muscle weakness and targeted gene testing will ensure a cost-effective investigational plan. This clinical approach should also assist clinicians in making a timely and accurate diagnosis.

Aetiology and pathogenesis of paraneoplastic autoimmune disorders

Paraneoplastic autoimmune disorders (PAD) represent a group of autoimmune diseases associated with neoplasms. As a consequence of a remote autoimmunity-mediated effect, PAD are found in multiple organs or tissues, including the skin, blood and nervous system. Compared with non-paraneoplastic autoimmune diseases, PAD have different aetiologies, pathologies, disease symptoms and treatment responses. There are two main origins of autoimmunity in PAD: neoplasm-mediated dysregulated homeostasis in immune cells/organs and in autoantigens. Pathologically, PAD are mediated predominantly by either autoantibodies or autoreactive T-cells. In the past decade, significant progress has been achieved in increasing our understanding of the aetiology and pathology of PAD. In this review article, we aim to provide a comprehensive overview of the recent advances in this field.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Thyrotoxic Periodic Paralysis: A Spine Consultation

As a consultant, the orthopaedic spine surgeon is often asked to evaluate patients with acute-onset extremity weakness. In some cases, patient's deficits can be attributed to nonspinal pathology; therefore, it is important to be aware of nonorthopaedic diagnoses when evaluating these patients. We report a case of thyrotoxic periodic paralysis that was initially confused by the consulting service with spinal pathology. A 32-year-old Hispanic man presented to our emergency department with rapid onset of lower extremity weakness. The consulting team ordered CT of the cervical and lumbar spine, as well as MRI of the lumbar spine which was aborted due to the patient's worsening tachycardia and chest pain. The spine service was subsequently consulted to evaluate the patient. Review of the metabolic panel revealed a low potassium, and additional testing led to the eventual diagnosis of thyrotoxic periodic paralysis. After correction of the patient's potassium, his weakness rapidly resolved, and no additional spinal workup was pursued. We describe this patient's presentation and outline the differential diagnosis for acute, nontraumatic extremity weakness, including both orthopaedic and other medical causes, that the spine surgeon should be aware of when evaluating patients with extremity weakness.

Amifampridine tablets for the treatment of Lambert-Eaton myasthenic syndrome

Introduction: Lambert-Eaton myasthenic syndrome is an autoimmune disease of the neuromuscular junction characterized by a presynaptic defect of neuromuscular transmission resulting in muscle weakness and fatigability. Diagnostic features are specific neurophysiological alterations and autoantibody detection. The present review is focused on the use of Amifampridine Phosphate to treat LEMS patients.Areas covered: Medline search from 1990 to 2019 was examined using the free subject terms: Lambert-Eaton myasthenic syndrome, LEMS, Amifampridine, 3,4-diaminopyridine, which were then combined with Treatment, Therapy, Clinical Trial, Controlled Clinical Trial, Randomized Clinical Trial and Cochrane Review. The author has done a supervised analysis of the retrieved articles and focused on those subjectively evaluated as most relevant.Expert commentary: Data from randomized clinical trials and case series have demonstrated that Lambert-Eaton myasthenic syndrome symptoms were successfully treated by Amifampridine Phosphate. Hence, the drug represents a substantial step forward in the symptomatic treatment of the disease due to its efficacy, safety and reliable GMP formulation. As Amifampridine Phosphate works by enhancing the release of acetylcholine at the neuromuscular junction by blocking K+ efflux at the pre-synaptic membrane, it is also conceivable to use it for other diseases of the neuromuscular junction in which such an effect is searched for.

Paraneoplastic Syndromes in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses the varied types of paraneoplastic syndromes that commonly have neuro-ophthalmologic manifestations. Diagnostic considerations and therapeutic options for individual diseases are also discussed.

RECENT FINDINGS

Paraneoplastic syndromes can affect the afferent and efferent visual systems. Paraneoplastic syndromes may result in reduced visual acuity from retinal degeneration, alterations in melanocyte proliferation and uveal thickening, or acquired nystagmus. Ocular motor abnormalities related to paraneoplastic syndromes may present with symptoms from opsoclonus or from neuromuscular junction disease. Diagnosis remains challenging, but serologic identification of some specific antibodies may be helpful or confirmatory. Treatment, in addition to directed therapies against the underlying cancer, often requires systemic corticosteroids, plasma exchange, or immunosuppression, but some specific syndromes improve with use of targeted pharmacologic therapy.

SUMMARY

Diagnosis and therapy of paraneoplastic syndromes presenting with neuro-ophthalmic symptoms remain a challenge, but strategies are evolving and new approaches are on the horizon.

Critical Care of Neuromuscular Disorders

PURPOSE OF REVIEW

Weakness is a common reason patients are seen in neurologic consultation. This article reviews the differential diagnosis of neuromuscular disorders in the intensive care unit (ICU), discusses the intensive care needs and evaluation of respiratory failure in patients with neuromuscular disorders, and provides a practical guide for management.

RECENT FINDINGS

Although primary neuromuscular disorders used to be the most common cause for weakness from peripheral nervous system disease in the ICU, a shift toward ICU-acquired weakness is observed in today's clinical practice. Therefore, determining the cause of weakness is important and may have significant prognostic implications. Guillain-Barré syndrome and myasthenia gravis remain the most common primary neuromuscular disorders in the ICU. In patients with myasthenia gravis, it is important to be vigilant with the airway and institute noninvasive ventilation early in the course of the disease to attempt to avoid the need for intubation. On the other hand, patients with Guillain-Barré syndrome should be intubated without delay if the airway is at risk to avoid further complications. In patients with ICU-acquired weakness, failure to wean from the ventilator is usually the challenge. Early mobility, glucose control, minimizing sedation, and avoiding neuromuscular blocking agents remain the only therapeutic regimen available for ICU-acquired weakness.

SUMMARY

Critical care management of neuromuscular disorders requires a multidisciplinary approach engaging members of the ICU and consultative teams. Developing an airway management protocol could have implications on outcome and length of stay for patients with neuromuscular disorders in the ICU. Tending to the appropriate nuances of each patient who is critically ill with a neuromuscular disorder through evidence-based medicine can also have implications on length of stay and outcome.

Amifampridine for the Management of Lambert-Eaton Myasthenic Syndrome: A New Take on an Old Drug

Objective: The purpose of this article is to review the literature for both 3,4-diaminopyridine (3,4-DAP) and amifampridine for the treatment of Lambert-Eaton myasthenic syndrome (LEMS). Amifampridine (Firdapse) is the salt form of 3,4-DAP and was approved by the Food and Drug Administration for the treatment of LEMS. Data Sources: PubMed, TRIP database, and EMBASE searches were conducted without a back date (current to June 2019) utilizing the following search terms: amifampridine, 3,4-diaminopyridine, and Lambert-Eaton myasthenic syndrome. Completed trials were also reviewed at clinicaltrials.gov. Study Selection and Data Extraction: Criteria for article inclusion consisted of human subjects, age ≥18 years, phase II or III clinical trials, and English language for both drugs. Observational and pharmacokinetic studies for amifampridine were also included. Data Synthesis: Prior to the approval of amifampridine, 3,4-DAP was first-line for the management of LEMS symptoms. Two phase III trials have evaluated amifampridine to confirm efficacy, both showing superiority over placebo in the management of LEMS symptoms, with minimal adverse effects. A significant improvement in both quantitative myasthenia gravis scores and Subjective Global Impression scores was established at days 4 and 14. Relevance to Patient Care and Clinical Practice: With an improved stability profile and decreased dose variability, amifampridine will likely assume the role of first-line management of LEMS. Conclusions: Amifampridine has been shown to improve symptoms of LEMS and is generally well tolerated.

Therapeutic apheresis in neurological, nephrological and gastrointestinal diseases

Therapeutic plasma exchange (TPE) is a process in which plasma containing antibodies, immune complexes, inflammatory moderators, paraproteins and other toxins which are believed to be the cause of disease is removed from a patient. TPE is the first-line treatment (category I, level 1A) in all forms of Acute inflammatory demyelinating polyradiculoneuropathy disease (axonal, demyelinating and miller-fisher variant) as well as in acute myasthenic crisis, chronic inflammatory demyelinating polyradiculoneuropathy and Paraproteinemic neuropathies (category I, level 1B). Moreover, TPE in kidney diseases, for instance: desensitization in renal transplantation(ABO compatible) (living donor)and desensitization in deceased donor, desensitization in renal transplantation(ABO incompatible) (living donor), thrombotic microangiopathy complement Mediated (Factor H autoantibodies), Focal segmental glomerulosclerosis(recurrent in transplanted kidney), ANCA-associated rapidly progressive glomerulonephritis(Dialysis dependence, DAH), Anti-Glomerular basement membrane disease Goodpasture's syndrome)(DAH,Dialysis-independence,) has been utilized as an initial treatment. (category I) TPE has been used as the key therapeutic modality to reduce anti-A or anti-B antibody titers in the liver peri-transplant period with the goal of preventing rejection and facilitating graft survival. Also, plasma exchange is the first-line therapy in Wilson's disease (category I, level1C).

Stimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome

Objective

To report the clinical features and the neurophysiological approach of a patient with Lambert-Eaton myasthenic syndrome (LEMS), highlighting the diagnostic role of the stimulated single fiber electromyography (sSFEMG).

Case report

A 60-year-old woman presenting with the LEMS triad (proximal and axial weakness, autonomic dysfunction and areflexia) was evaluated by neurophysiological tests (electroneuromyography, repetitive stimulation test (TSR), voluntary and stimulated SFEMG). We reported: 1) increase of compound muscle action potential (CMAP) amplitude (>60%) following brief isometric exercise compared to the rest (baseline); 2) decremental/incremental response of CMAP amplitude at low- (3 Hz) and high-frequency (30 Hz) repetitive stimulation test (RST), respectively; 3) increased neuromuscular jitter and blocking at voluntary single-fiber electromyography (vSFEMG); 4) stimulation rate-dependent reduction of the neuromuscular jitter and blocking at sSFEMG. Diagnosis was confirmed by serological demonstration of circulating voltage gated calcium channels (VGCC) antibodies.

Significance

The present case highlights the role of the sSFEMG in the diagnosis of LEMS, underling the stimulation rate-dependency of both neuromuscular jitter and blocks.

Lambert-Eaton Myasthenic Syndrome Associated with Synchronous Double Cancer: A Combination of Small Cell Carcinoma of the Cervix and Breast Carcinoma

Lambert-Eaton myasthenic syndrome (LEMS) is most commonly associated with small cell lung carcinoma, while it is rarely associated with gynecological and breast carcinoma. We herein report a case of LEMS associated with synchronous double cancer, which was a combination of small cell carcinoma of the cervix and breast carcinoma. The early diagnosis and treatment of LEMS are important for achieving a good outcome. The possibility of accompanying paraneoplastic neurological syndrome must be sufficiently considered in gynecology and breast cancer patients. To our knowledge, this is the first report of LEMS associated with synchronous double cancer.

Acetylcholine receptor antibody-positive myasthenia gravis associated with small-cell lung cancer: A case report

RATIONALE

Only few cases of myasthenia gravis (MG) associated with small-cell lung cancer (SCLC) have been reported, and cases positive for acetylcholine receptor antibody (AChR-ab) are even rarer. The efficacy of standard MG treatment, such as cholinesterase inhibitor therapy, immunosuppressive therapy using steroids and immunosuppressive drugs, plasma exchange, and intravenous immune globulin (IVIg), for these cases is unclear.

PATIENT CONCERNS AND DIAGNOSES

A 71-year-old man complained of bilateral eyelid ptosis. He also presented with dysphagia and masticatory muscle fatigue after chewing. The edrophonium test was positive, and the serum AChR-ab level was increased; therefore, the patient was diagnosed with MG. Computed tomography scan showed a nodule on the left upper lobe of the lung and mediastinal lymphadenopathy. Further examination revealed the lesion as SCLC. Finally, he was diagnosed with AChR-ab-positive MG associated with SCLC.

INTERVENTIONS AND OUTCOMES

Oral pyridostigmine and tacrolimus were administered to treat MG; however, his symptoms worsened. Therefore, methylprednisolone and IVIg were administrated, which temporarily improved his symptoms. However, they remained uncontrolled. Meanwhile, chemotherapy with carboplatin and etoposide was administered to treat his SCLC. The lesions shrunk, and the MG symptoms and serum AChR-ab level also improved.

LESSONS

AChR-ab-positive MG may develop as a comorbidity of SCLC. In such cases, management might require treatment for SCLC in addition to the standard MG treatment to stabilize the MG symptoms.