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Background@#and Purpose Anti-neurofascin-155 (NF155) antibody is one of the autoantibodies associated with autoimmune nodopathy. We aimed to determine the clinical features of South Korean patients with anti-NF155-antibody-positive autoimmune nodopathy. @*Methods@#The sera of 68 patients who fulfilled the diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) were tested for anti-NF155 antibodies using a cellbased assay (CBA) and enzyme-linked immunosorbent assay (ELISA). The anti-NF155-positive sera were also assayed for NF155 immunoglobulin G (IgG) subclasses, and for antiNF186 and NF140 antibodies. The clinical features of the patients were reviewed retrospectively. @*Results@#Among the 68 patients, 6 (8.8%) were positive for anti-NF155 antibodies in both the CBA and ELISA. One of those six patients was also positive for anti-NF186 and anti-NF140 antibodies. IgG4 was the predominant subclass in four patients. The mean age at onset was 32.2 years. All six positive patients presented with progressive sensory ataxia. Five patients treated using corticosteroids presented a partial or no response. All six patients were treated using intravenous immunoglobulin (IVIg). Among them, five exhibited a partial or poor response and the other exhibited a good response. All three patients treated using rituximab showed a good response. @*Conclusions@#The clinical characteristics of the patients were consistent with those in previous studies. Anti-NF155 antibody assay is necessary for diagnosing autoimmune nodopathy and its appropriate treatment, especially in young patients with CIDP who present with sensory ataxia and poor therapeutic responses to corticosteroids and IVIg.
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Background@#During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general population. This study aimed to investigate the clinical course and prognosis of COVID-19 in patients with MG and to compare these parameters between vaccinated and unvaccinated patients in South Korea. @*Methods@#This multicenter, retrospective study, which was conducted at 14 tertiary hospitals in South Korea, reviewed the medical records and identified MG patients who contracted COVID-19 between February 2022 and April 2022. The demographic and clinical characteristics associated with MG and vaccination status were collected. The clinical outcomes of COVID-19 infection and MG were investigated and compared between the vaccinated and unvaccinated patients. @*Results@#Ninety-two patients with MG contracted COVID-19 during the study. Nine (9.8%) patients required hospitalization, 4 (4.3%) of whom were admitted to the intensive care unit. Seventy-five of 92 patients were vaccinated before contracting COVID-19 infection, and 17 were not. During the COVID-19 infection, 6 of 17 (35.3%) unvaccinated patients were hospitalized, whereas 3 of 75 (4.0%) vaccinated patients were hospitalized (P < 0.001). The frequencies of ICU admission and mechanical ventilation were significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.019 and P = 0.032, respectively). The rate of MG deterioration was significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.041). Logistic regression after weighting revealed that the risk of hospitalization and MG deterioration after COVID-19 infection was significantly lower in the vaccinated patients than in the unvaccinated patients. @*Conclusion@#This study suggests that the clinical course and prognosis of patients with MG who contracted COVID-19 during the dominance of the omicron variant of COVID-19 may be milder than those at the early phase of the COVID-19 pandemic when vaccination was unavailable. Vaccination may reduce the morbidity of COVID-19 in patients with MG and effectively prevent MG deterioration induced by COVID-19 infection.
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Neuropathic pain is defined as pain caused by lesions or diseases of the somatosensory system. Management of neuropathic pain is difficult owing to the heterogeneity of underlying causes and absence of objective standards for diagnosis and assessment of neuropathic pain. In this review, we reviewed the recently published guidelines regarding the pharmacological management of neuropathic pain including the French recommendations and the German Neurological Association guidelines, and the American Neurological Association's guidelines for the management of diabetic polyneuropathy. In general, drugs recommended as the first-line treatment for neuropathic pain include gabapentinoid, serotonin–norepinephrine reuptake inhibitor (SNRI), and tricyclic antidepressants. As the second-line treatment, combination of SNRI or tricyclic antidepressant with gabapentinoid could be recommended. Although tramadol and tapentadol are recommended as the second- or third-line treatment, caution is required in long-term use of these medications due to the side effects including dependence and abuse. Besides efficacy, it is necessary to consider the side effects of the medication and underlying disease of the patient in selecting pharmacological treatment.
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Background@#and Purpose Myokines include cytokines secreted by muscle fibers, which are the final targets of myasthenia gravis (MG). This pilot study investigated whether myokine plasma concentrations are altered in patients with MG and assessed the association between the concentration of each myokine and disease severity. @*Methods@#We compared the plasma concentrations of 15 myokines in 63 patients with acetylcholine receptor antibody (Ab)-positive MG and 14 with muscle-specific tyrosine kinase Ab-positive MG (MuSK MG) with those in 15 healthy controls. Plasma myokine concentrations were measured using a Luminex multiplex assay kit with magnetic beads that contained Abs for 15 myokines. Correlations between myokine concentration and clinical scale results were analyzed. @*Results@#The concentration of fractalkine in plasma was higher in MG (median [interquartile range]=419.6 [38.7–732.5] pg/mL) than in controls (158.5 [0.0–313.2] pg/mL, p=0.034).The leukemia inhibitory factor concentration was also found to be higher in MuSK MG (29.9 [8.7–40.1] pg/mL) than in healthy controls (7.6 [0.0–15.6] pg/mL, p=0.013). Fatty-acid-binding protein 3 (FABP3) concentrations in plasma were positively associated with clinical parameters for MG severity, including scores on the Quantitative Myasthenia Gravis score (p= 0.008), Myasthenia Gravis Activities of Daily Living (p=0.003), and Myasthenia Gravis Composite (p=0.024) scales. FABP3 concentration in plasma tended to decrease after treatment in patients without additional relapse but increased in those with further relapse. @*Conclusions@#The plasma myokine profile was significantly altered in patients with MG.FABP3 concentration may be useful in assessing disease severity and predicting the treatment response.
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Background@#and Purpose To understand the characteristics of Korean patients with anti-3-hydroxy-3-methylglutaryl-coenxyme A reductase (HMGCR) myopathy, we measured antiHMGCR antibodies and analyzed the clinical, radiological, and pathological features of patients with anti-HMGCR myopathy. @*Methods@#We measured titers of anti-HMGCR antibodies in the sera of 99 patients with inflammatory myopathy, 36 patients with genetic myopathy, and 63 healthy subjects using an enzyme-linked immunosorbent assay. We tested 16 myositis-specific autoantibodies (MSAs) in all patients with anti-HMGCR myopathy. @*Results@#Positivity for the anti-HMGCR antibody was observed in 17 (4 males and 13 females) of 99 patients with inflammatory myopathy. The median age at symptom onset was 60 years.Ten (59%) of the patients with anti-HMGCR positivity had taken statins. The titer of antiHMGCR antibodies was significantly higher in the statin-naïve group (median=230 U/mL, interquartile range=170–443 U/mL) than in the statin-exposed group (median=178 U/mL, interquartile range=105–210 U/mL, p=0.045). The most common symptom was proximal muscle weakness in 15 patients (88%), followed by myalgia in 9 (53%), neck weakness in 4 (24%), dysphagia in 3 (18%), and skin lesions in 2 (12%). The median titer of anti-HMGCR antibody was 202 U/mL. We found eight different MSAs in nine (53%) patients. The median disease duration from symptom onset to diagnosis was significantly shorter in the MSA-positive group than in the MSA-negative group (p=0.027). @*Conclusions@#Our study was the first to measure anti-HMGCR antibodies in inflammatory myopathy. It has provided new findings, including the suggestion of the coexistence of other MSAs in Korean patients.
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Background@#and Purpose Among patients with double-seronegative myasthenia gravis (dSN-MG) who do not have detectable antibodies against acetylcholine receptor or musclespecific tyrosine kinase, autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4-Ab) have been detected recently. The purpose of this study was to develop an in-house cell-based assay (CBA) to detect LRP4-Ab and to apply it to samples from patients with MG. @*Methods@#The complementary DNA of LRP4 fused into a vector plasmid containing GFP was transfected into human embryonic kidney 293 (HEK293) cells. LRP4 expression in the transfected HEK293 cells was assessed using the reverse-transcription polymerase chain reaction (RT-PCR), Western blotting, and immunocytochemistry. The CBA included 252 sera collected from 202 patients with MG and 38 with other neuromuscular diseases, and 12 healthy controls. The transfected HEK293 cells were incubated using sera and antihuman immunoglobulin G antibodies conjugated with Alexa Fluor 594. The presence of LRP4-Ab was determined based on the fluorescence intensity and the localization in fluorescence microscopy. @*Results@#The expressions of the mRNA and protein of LRP4 in the transfected HEK293 cells were confirmed using RT-PCR and Western blotting, respectively. Immunocytochemistry indicated LPR4 expression on the cell membrane. Among 202 patients with MG including 53 with dSN-MG, LRP4-Ab were positive in 3 patients who were all double seronegative. LRP4-Ab were not detected in the patients with other neuromuscular diseases or the healthy controls. @*Conclusions@#A CBA for detecting LRP4-Ab associated with MG has been developed, and was used to find LRP4-Ab in the sera of patients with MG.
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Schwannoma is a type of benign neurogenic tumor which may be derived from the nerve sheath. It is common in the head and neck region, but it occurs relatively rarely in the larynx. The laryngeal schwannoma can occur in the false vocal cord, aryepiglottic fold and epiglottis etc. The typical feature of it is a round submucosal well-encapsulated mass, and papillomatous appearance of its surface is extremely rare. A 76-year-old male came to our clinic with voice change and globus sense. The rigid laryngoscopy showed round papillomatous mass in the interarytenoid area. We performed laryngeal microsurgery, and he was pathologically diagnosed as schwannoma. We report an interesting and didactic case that has an atypical feature of laryngeal schwannoma with relevant literature review.
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Acute transverse myelitis (ATM) has been reported as rare complication of vaccination. Herein, we report 2 cases of ATM after the administration of an mRNA vaccine for coronavirus disease 2019 (COVID-19). The first one is an 81-year-old man who received the BNT162b2 vaccine. He presented with bilateral hand weakness. Spine magnetic resonance imaging (MRI) showed high signal intensity from the C1 to C3 vertebrae. The second is a 23-year-old woman who received the BNT162b2 vaccine and experienced tingling in her legs. Spine MRI showed a high signal intensity lesion at the conus medullaris. These patients were treated with intravenous methylprednisolone and their symptoms improved slightly. Careful follow-up is needed to identify adverse events after the administration of mRNA vaccines for COVID-19.
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Autoantibodies are present in many autoimmune disorders, including diseases impacting the peripheral nerve, neuromuscular junction, and muscle. Some of these autoantibodies play a vital role in pathogenesis, whereas others are unlikely to be directly pathogenic, but may be useful biomarkers. The identification of autoantibodies is valuable in diagnosis, as well as in establishing a treatment plan in antibody-mediated neuromuscular disorders. This review briefly summarizes antibody, autoantibody, and methods of autoantibody testing for clinicians who treat patients with neuromuscular disorders.
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The coronavirus disease (COVID-19) by severe acute syndrome coronavirus-2 (SARS-CoV-2) occurs the unprecedented pandemic during recent two years and the WHO declared a global pandemic of COVID-19 in March 2020. The most common sampling sites in COVID-19 test are the oropharynx and nasopharynx. We recently encountered a total laryngectomee who had a positivity COVID-19 diagnostic test from the tracheostoma, on the other hand, false negativity from the nasal cavity. The meaning of this case is that accurate screening test could be achieved by performing a test through the tracheostoma as well as nasal cavity or oropharynx. We also would like to discuss the accurate testing methods of patients whose airflow has distorted due to surgery, the management method of these patients, and the need of further research in the COVID-19 pandemic period with relevant literature reviews.
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Amyloidosis is defined as a deposit of amyloid substance. While it rarely occurs in the head and neck region, it is most commonly found in the larynx. Laryngeal amyloidosis can occur in the false vocal cord, ventricle, and glottis etc. The typical feature of laryngeal amyloidosis is a round yellowish submucosal mass. A 72-year-old male presented with voice change that began a couple of years ago. The rigid laryngoscopy showed a whitish patch in the medial and superior surfaces of the left true vocal fold. He was pathologically diagnosed with amyloidosis by laryngeal microsurgery. With a relevant review of literature, we report this case as it demonstrates rare, atypical features of laryngeal amyloidosis.
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Parathyroid carcinoma accounts for about 0.5%-5% of all parathyroid neoplasms. Very rarely, but if the intrathyroidal parathyroid gland is present, the carcinoma can arise in that developmental anomaly. It is very difficult to distinguish a thyroid nodule from an intrathyroidal parathyroid neoplasm with preoperative radiologic and cytologic evaluations. A 59-year-old male was initially evaluated as presenting a follicular thyroid neoplasm accompanied by hyperparathyroidism. He received hemi-thyroidectomy with central neck dissection and subtotal parathyroidectomy. The final pathology evaluation revealed intrathyroidal parathyroid carcinoma and hyperplasia of contralateral parathyroid glands. We report this very rare and unique clinical situation with a literature review.
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Background@#and Purpose A major concern with ocular myasthenia gravis (MG) is the potential conversion to generalized MG. This study was conducted to determine if the repetitive nerve stimulation (RNS) test could predict the conversion from ocular to generalized MG. @*Methods@#The RNS test was conducted in a consistent manner on five muscles in the face and limbs in every patient. Subjects were divided into those who remained as ocular MG (ROMG group) and those who experienced conversion to generalized MG during follow-up (GOMG group). @*Results@#Conversion to generalized MG occurred in 24 (21.4%) of 112 MG patients with ocular onset. The proportion of patients displaying abnormal decreases in responses in the trapezius, abductor digiti minimi, or flexor carpi ulnaris muscles on the RNS test was higher in the GOMG group (p<0.001,p=0.002, and p<0.001, respectively). The Cox proportional-hazards model revealed that an abnormal result on the RNS test was significantly associated with conversion to generalized MG [hazard ratio (HR)=3.13, 95% confidence interval (CI)=1.18– 8.32]. Notably, the HR was higher for abnormal results on the RNS test for the limb muscles, at 5.19 (95% CI=2.09–12.90). @*Conclusions@#An abnormal result on the RNS test, especially in the limb muscles, is an independent predictor of the conversion from ocular to generalized MG. Applying the RNS test to limb muscles could be useful for predicting the conversion to generalized MG in patients with ocular onset.
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Background@#and Purpose Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cellbased assay (CBA) to detect MuSK Abs. @*Methods@#A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). @*Results@#The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen’s kappa=0.880, p<0.001) and ELISA (Cohen’s kappa=0.982, p<0.001). @*Conclusions@#The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.
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The variable predominance of the affected muscle groups and the fluctuating severity and extent of myasthenia gravis (MG) makes it difficult to assess and classify these patients. With new treatments being developed and applied, it has become more important to properly classify MG patients and objectively evaluate the results of treatment. So far, a number of clinical classification and assessment systems have been proposed and used individually. However, for the comparative analysis, a uniform set of classifications and reliable measurement methods of muscle impairment are necessary. In this article, MG-clinical classification and several MG-specific assessment tools that are widely used are mentioned.
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The etiology of laryngeal hemangioma is unclear, and it is classified into infant and adult types. The former is capillary hemangioma and relatively common, the latter is cavernous type and very rare. The adult laryngeal hemangioma mainly occurs in supraglottis and glottis. A 75-year-old man came to our clinic with a voice change that started four months ago. The laryngoscopic finding showed that the surface of oval-shaped mass is covered with turbid exudates. We performed the laryngeal microsurgery with CO2 laser. The mass was pathologically proven as cavernous hemangioma. We report a very rare and didactic case with review of relevant literature.
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Mantle cell lymphoma (MCL) is a rare subtype of B-cell neoplasm and it accounts for about 3~6% of all non-Hodgkin's lymphomas. It occurs mainly in middle-aged or elderly man, involving the extra-nodal sites such as gastrointestinal tract, bone marrow and Waldeyer’s ring. The incidence of the MCL in salivary gland is about 3%. The blastoid MCL is a rare variant and it has a very aggressive clinical course. It is extremely rare to be arising from the parotid gland. To our knowledge, similar case has not been reported in domestic literature, one case has been described in English literature. We experienced a rare and unique disease entity and report it with brief literature review.
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Background@#and Purpose A major concern with ocular myasthenia gravis (MG) is the potential conversion to generalized MG. This study was conducted to determine if the repetitive nerve stimulation (RNS) test could predict the conversion from ocular to generalized MG. @*Methods@#The RNS test was conducted in a consistent manner on five muscles in the face and limbs in every patient. Subjects were divided into those who remained as ocular MG (ROMG group) and those who experienced conversion to generalized MG during follow-up (GOMG group). @*Results@#Conversion to generalized MG occurred in 24 (21.4%) of 112 MG patients with ocular onset. The proportion of patients displaying abnormal decreases in responses in the trapezius, abductor digiti minimi, or flexor carpi ulnaris muscles on the RNS test was higher in the GOMG group (p<0.001,p=0.002, and p<0.001, respectively). The Cox proportional-hazards model revealed that an abnormal result on the RNS test was significantly associated with conversion to generalized MG [hazard ratio (HR)=3.13, 95% confidence interval (CI)=1.18– 8.32]. Notably, the HR was higher for abnormal results on the RNS test for the limb muscles, at 5.19 (95% CI=2.09–12.90). @*Conclusions@#An abnormal result on the RNS test, especially in the limb muscles, is an independent predictor of the conversion from ocular to generalized MG. Applying the RNS test to limb muscles could be useful for predicting the conversion to generalized MG in patients with ocular onset.
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Background@#and Purpose Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cellbased assay (CBA) to detect MuSK Abs. @*Methods@#A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). @*Results@#The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen’s kappa=0.880, p<0.001) and ELISA (Cohen’s kappa=0.982, p<0.001). @*Conclusions@#The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.
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The variable predominance of the affected muscle groups and the fluctuating severity and extent of myasthenia gravis (MG) makes it difficult to assess and classify these patients. With new treatments being developed and applied, it has become more important to properly classify MG patients and objectively evaluate the results of treatment. So far, a number of clinical classification and assessment systems have been proposed and used individually. However, for the comparative analysis, a uniform set of classifications and reliable measurement methods of muscle impairment are necessary. In this article, MG-clinical classification and several MG-specific assessment tools that are widely used are mentioned.