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Breathing is controlled by complex interactions between the central and peripheral nervous systems in conjunction with the respiratory system. Neurological diseases predispose patients to nocturnal desaturation and pneumonia due to respiratory dysfunction, which increases mortality, daytime sleepiness and fatigue, and reduces the quality of life. Respiratory function tests are required to identify respiratory function decline and to consider compensatory management. This review summarizes the characteristics of several respiratory function tests and their applications to neurological diseases.

The current status of antidepressant use in patients with amyotrophic lateral sclerosis (ALS), such as the prevalence and factors associated with it, has not been systematically investigated. We aimed to analyze the prevalence and patterns of antidepressant prescriptions in patients with ALS and depression, and to identify factors associated with antidepressant prescriptions after the diagnosis of ALS.The data of patients with ALS and the prescription of antidepressants were retrieved from the Korean National Health Insurance claims data. A multivariate logistic regression model was used to identify factors associated with antidepressant prescriptions.In total, 533 of 2955 patients had depressive disorders, and 426 were prescribed antidepressants. Selective serotonin reuptake inhibitors and tricyclic antidepressants were the most frequently prescribed drugs. Adjusted odds ratios (ORs) were 1.379 for the prescription of antidepressants in females. For various age groups, compared with those aged 80 years and older, adjusted ORs were 1.889 for those in their 70s, 2.319 for those in their 60s, 2.872 for those in their 50s, 2.854 for those in their 40s, and 3.363 for those under 40 years of age. Adjusted ORs were 1.662 for patients with a history of a psychiatric disorder and 1.861 for those with a history of psychiatric pharmacotherapy (all P .05).Most patients with ALS who had depression received antidepressant prescriptions. In young females with a previous psychiatric disorder or pharmacotherapy, an in-depth evaluation for a depressive disorder should be performed.

Dysregulation of microRNAs (miRNA) in small extracellular vesicles (sEV) such as exosomes have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Although circulating cell-free miRNA have been extensively investigated in ALS, sEV-derived miRNAs have not been systemically explored yet. Here, we performed small RNA sequencing analysis of serum sEV and identified 5 differentially expressed miRNA in a discovery cohort of 12 patients and 11 age- and sex-matched healthy controls (fold change > 2, p

iObjective:/iThere is accumulating evidence about an association between amyotrophic lateral sclerosis (ALS) and psychiatric disorders. We aimed to investigate the prevalence of previous psychiatric disorders before ALS onset and evaluate the contribution of psychiatric disorders to the number of steps toward developing ALS.iMethods:/iWe analyzed the National Health Insurance claims data from 2011 to 2017 and calculated the incidence of ALS. We created a multistep model using the linear least squares method with regression of the log incidence against the log age.iResults:/iThe mean annual incidence of ALS was 0.95/100,000 and frequency of familial ALS (fALS) was 5.89%. The proportions of patients who had psychiatric disorders before ALS diagnosis were 36.8% and 47.0% in fALS and sporadic ALS (sALS), respectively (ip/i = 0.009). In both fALS and sALS, depressive disorders and anxiety and stress disorders were relatively frequent, whereas psychotic disorders and bipolar disorders were rare. Further, the slope estimates for regression analyses were 3.50 (Rsup2/sup= 0.94) and 3.56 (Rsup2/sup= 0.99) for fALS and sALS, respectively, suggesting a 4-5-step process to ALS onset. However, slope estimates did not differ between sALS patients withipre-symptomatic/ipsychiatric disorders and those without.iConclusions:/iThe incidence of ALS is relatively low in Korea and fewer steps are required to develop ALS compared to Western populations (all 6 steps). Although the prevalence of previous depression or anxiety is seemingly high, the multistep model provides no evidence that these conditions modify the risk of developing ALS in our cohort.

Background We aimed to evaluate the diagnostic accuracy of enzyme-linked immunosorbent assay (ELISA) for anti-muscle specific tyrosine kinase (MuSK) antibody (Ab) in a large cohort of anti-acetylcholine receptor (AChR) Ab-negative generalized myasthenia gravis (MG), and also to investigate clinical contexts for the diagnosis of MuSK MG. Methods A retrospective study of 160 patients with a clinical suspicion of AChR Ab-negative generalized MG was performed. The serum samples were tested for anti-clustered AChR Ab by cell-based assay (CBA), anti-MuSK Ab by ELISA, CBA and/or radioimmunoprecipitation assay (RIPA). Clinical data were compared between anti-MuSK Ab-positive MG and double seronegative (AChR and MuSK) MG groups. Results After excluding non-MG and clustered AChR Ab-positive patients, we identified 89 patients as a cohort of AChR Ab-negative generalized MG. Anti-MuSK Ab was positive by ELISA in 22 (24.7%) patients. While CBA identified five additional anti-MuSK Ab-positive patients, the results of ELISA were mostly consistent with CBA and RIPA with Cohen’s kappa of 0.80 and 0.90, respectively (p Conclusion While confirming the highest sensitivity of CBA for detecting anti-MuSK Ab, our results highlight the clinical pitfalls in making a diagnosis of MuSK MG and may support a diagnostic utility of MuSK-ELISA in clinical practice.

STUDY OBJECTIVES: To assess the seasonality of restless legs syndrome (RLS) using data from the Korean national health insurance database. METHODS: We retrospectively reviewed a randomly selected sample representing 3% of the national health insurance claims database in South Korea. From this sample, we obtained the monthly numbers of patients with RLS and diagnoses from 2009 to 2016, along with prescriptions for monthly dopamine agonists and clonazepam for patients with RLS from 2009 to 2013. Total dopamine agonist and clonazepam doses were converted to levodopa-equivalent doses, and the monthly cumulative prescription dose was calculated. Cosinor analysis was used to evaluate the seasonal pattern of each variable. RESULTS: This study included 11,466 patients with RLS and their diagnoses and 4,887 prescriptions for dopamine agonists and clonazepam. There were significant seasonal patterns in the numbers of patients with RLS (P < .001) and diagnoses (P < .001), both of which peaked in August. The magnitude of the greatest difference in the number of patients with RLS between August (highest) and February (lowest) was 29.96% (95% confidence interval, 24.03–100.80), and that of the number of RLS diagnoses was 39.56% (95% confidence interval, 31.24–47.89). The cumulative prescription dose of medication showed no significant seasonality. CONCLUSIONS: Our findings suggest that the prevalence of RLS is seasonally affected, with an increase during summer. CITATION: Oh SM, Son K-L, Choi S-J, Lee MH, Yoon SY, Lee YJ. The seasonal pattern of restless legs syndrome in a sample from the Korean health insurance review and assessment service national database. J Clin Sleep Med. 2021;17(5):1051–1056.

BACKGROUND Thymectomy is required for the treatment of thymoma-associated myasthenia gravis (MG). However, MG may develop only after thymectomy, a condition known as post-thymectomy MG. This study aimed to investigate the risk factors for post-thymectomy MG in patients with thymoma. METHODS We retrospectively identified 235 patients with thymoma who underwent thymectomy at a single hospital from January 2008 to December 2017: 44 with preoperatively diagnosed MG were excluded, leaving 191 patients in the final analysis. Univariable survival analyses using Cox proportional hazards regression model and Kaplan-Meier estimate were conducted to identify risk factors for post-thymectomy MG. RESULTS Post-thymectomy MG developed in 4.2% (8/191) of the patients with thymoma between 18 days and 108 mo after surgery. Hazard ratios (HRs) of pre- and postoperative anti-acetylcholine receptor antibody (AChR-Ab) titers were 2.267 (P = .002) and 1.506 (P

The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing.We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis.Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P0.001), lower lobe location (P0.001), prone position (P = 0.004), and visible motion artifact (P0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P0.001) were risk factors for hemoptysis.Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

123I-Metaiodobenzylguanidine (MIBG) scintigraphy is a widely used functional imaging tool with a high degree of sensitivity and specificity in diagnosis of pheochromocytoma. However, rare cases of false positive reactions have been reported. A 67-year-old male patient was admitted with epigastric pain. Abdominal computed tomography (CT) revealed a heterogeneous left adrenal mass 6 cm in diameter; following hormone testing, 123I-MIBG scintigraphy was performed to determine the presence of pheochromocytoma, which confirmed eccentric uptake by a large left adrenal gland mass. Chest CT and PET-CT confirmed metastatic lymphadenopathy; therefore, endobronchial ultrasound transbronchial needle aspiration was performed. Metastatic carcinoma of unknown origin was suspected from a lymph node biopsy and surgical resection was performed for definitive diagnosis and correction of excess hormonal secretion. A final diagnosis of undifferentiated adrenal malignant tumor was rendered, instead of histologically malignant pheochromocytoma, despite the uptake of MIBG demonstrated by scintigraphy. When the degree of MIBG uptake is low-grade in relationship to a large tumor mass, then a false-positive result should be entertained, particularly in the absence of typical clinical and biochemical features of pheochromocytoma.

A common cause of drug hypersensitivity reactions is iodinated contrast media (ICM). ICM-induced hypersensitivity had been considered to be a non-immunological reaction, but evidence for an immunological mechanism has increased recently. Thus, we evaluated whether HLA-A, -B, and -C alleles were associated with ICM-induced hypersensitivity. In total, 126 patients who underwent contrast-enhanced computed tomography studies through outpatient clinics at a tertiary referral hospital between 2008 and 2012 were assessed. Sixty-one patients experienced ICM-induced hypersensitivity and the remainder, 65, were ICM-tolerant patients (control). ICM-induced hypersensitivity patients showed 51 with immediate, 7 with non-immediate, 3 with both or mixed type. HLA-A, -B, and -C genotyping was performed using a PCR sequence-based typing method. Four kinds of ICM were used: iopromide, iohexol, iobitridol, and iodixanol. The most used ICM among the hypersensitivity patients was iopromide. Significant difference in the frequency of HLA-B*58:01 (odds ratios [OR], 3.90; p = 0.0200, 95% confidence interval [CI], 1.16-13.07) was observed between ICM-induced immediate hypersensitivity and control. There were statistically significant differences in the frequencies of the HLA-B*38:02 (OR, 10.24; p = 0.0145; 95% CI, 1.09-96.14) and HLA-B*58:01 (OR, 3.98; p = 0.0348; 95% CI, 1.03-15.39) between iopromide-induced immediate hypersensitivity and control. The mechanism of ICM-induced hypersensitivity remains unknown, but this study showed associations, although weak, with HLA-B*58:01 alleles for ICM-induced immediate hypersensitivity and HLA-B*38:02 and HLA-B*58:01 for iopromide-induced immediate hypersensitivity as risk predictors. Further studies are needed to validate the associations in larger samples and to identify the functional mechanism behind these results.

Epstein-Barr virus-induced G-protein coupled receptor 2 (EBI2) is important in regulating B cell activation. We investigated whether EBI2 expression on B cells is associated with acute attacks in neuromyelitis optica spectrum disorder with aquaporin-4 IgG (AQP4-IgG(+) NMOSD). Blood samples were collected from patients with AQP4-IgG(+) NMOSD, multiple sclerosis (MS), and patients without inflammatory demyelinating diseases (non-IDD controls). CD19+ B cells and CD4+ T cells were analyzed for surface expression of EBI2. Serum cytokine levels were also analyzed. The EBI2+CD19+ to EBI2–CD19+ cell ratio was significantly higher in patients with AQP4-IgG(+) NMOSD enrolled within 2 months of an attack than in those with non-IDDs (p = 0.007) and MS (p = 0.003). Patients with AQP4-IgG(+) NMOSD enrolled within 2 months of an attack had a higher EBI2+CD19+ cell frequency than patients with AQP4-IgG(+) NMOSD enrolled 2 months after a recent attack (p = 0.001). The EBI2+CD19+ cell frequency was positively correlated with interleukin (IL)-6 and IL-10. EBI2 expression on B cells could be associated with acute attacks of AQP4-IgG(+) NMOSD, possibly through IL-6- or IL-10-related pathways.

Background Minor adverse events of intravenous immunoglobulin (IVIg) include flu-like symptoms, eczematous skin reaction, electrolyte disturbance, and transient leukopenia. On rare occasions, serious complications such as aseptic meningitis, arrhythmia, decrease in blood pressure, and thromboembolic complications (TEC) have been described. The current study aimed to understand the frequency and clinical features of TEC related to IVIg administration in patients with immune-mediated neurological disorders. Methods We conducted a retrospective chart review of hospitalized patients with immune-mediated neuromuscular or neuroimmunological disorders treated with IVIg from January 2018 to March 2020 in a single tertiary hospital. Results During the study period, 61 patients were treated with a total of 364 IVIg infusions over 84 treatment courses. Among them, we identified 3 TEC cases that occurred during or after the completion of IVIg therapy: two patients with myasthenia gravis (F/60 and F/80) and one patient with Guillain-Barre syndrome (F/79) had undergone arterial TEC (two for ischemic stroke and one for pulmonary thromboembolism). The rates of TEC per patient, per treatment course, and per infusion were 4.91% (3/61), 3.57% (3/84), and 0.82% (3/364), respectively. Conclusion The risk of developing TEC upon receiving IVIg infusions is generally low in patients with immune-mediated neurological disorders; however, IVIg-related TEC should be cautiously monitored for in critically ill elderly patients with vascular risk factors, especially those suffering from myasthenic crisis.

Background Antibodies to the aquaporin-4 (AQP4) water channel in neuromyelitis optica spectrum disorder (NMOSD) are reported to trigger the complement cascade, which is implicated in astrocyte damage and subsequent neuronal injury. The PREVENT study demonstrated that the terminal complement inhibitor eculizumab reduces adjudicated relapse risk in patients with anti-AQP4 immunoglobulin G-positive (AQP4+) NMOSD. The objective of this analysis was to evaluate the efficacy of eculizumab in reducing relapse risk and its safety in AQP4+ NMOSD across clinically relevant subgroups in PREVENT. Methods In the randomized, double-blind, time-to-event, phase 3 PREVENT trial, 143 adults received eculizumab (maintenance dose, 1200 mg/2 weeks) or placebo (2:1), with stable-dose concomitant immunosuppressive therapy (IST) permitted (except rituximab and mitoxantrone). Post hoc analyses of relapses and adverse events were performed for prespecified and post hoc subgroups based on concomitant IST and prior rituximab use, demographic and disease characteristics, and autoimmune comorbidity. Results The significant reduction in relapse risk observed for eculizumab versus placebo in the overall PREVENT population was consistently maintained across subgroups based on concomitant IST and previous rituximab use, age, sex, region, race, time since clinical onset of NMOSD, historical annualized relapse rate, baseline Expanded Disability Status Scale score, and history of another autoimmune disorder. The serious infection rate was lower with eculizumab than placebo regardless of rituximab use in the previous year, concomitant IST use, or history of another autoimmune disorder. Conclusion Across a wide range of clinically relevant AQP4+ NMOSD patient subgroups in PREVENT, eculizumab therapy was consistently effective versus placebo in reducing relapse risk, with no apparent increase in serious infection rate. Trial registration NCT01892345 (ClinicalTrials.gov).

The aim of the present study was to investigate the frequency and clinical features of Guillain-Barré syndrome (GBS) with hyperCKemia. We retrospectively identified 139 patients with GBS at 2 teaching hospitals in South Korea. We excluded patients with Miller-Fisher syndrome (n = 19), acute bulbar palsy (n = 3), and those whose serum creatine kinase (CK) levels were not measured (n = 45). Twelve of 72 patients (16.7%) had transient hyperCKemia, defined as serum CK ≥300 IU/L. The frequency of male sex and non-demyelinating electrodiagnostic features were higher in patients with hyperCKemia than those without. Transient hyperCKemia, occasionally seen in patients with GBS may be associated with the non-demyelinating subtype.

The present study aimed to investigate the prognostic importance of the neutrophil-to-lymphocyte ratio (NLR) in patients with amyotrophic lateral sclerosis (ALS). Among 322 patients diagnosed as having definite, probable, or possible ALS at a single tertiary hospital, 194 patients were included in the final analysis. Patients were divided into three groups (T1, T2, and T3) according to the tertile of their NLR. Survival rate was significantly lower in T3 compared to the other groups (log-rank test; T1 vs. T3, p = 0.009; T2 vs. T3, p = 0.008). Median survival duration was 37.0 (24.0–56.0), 32.5 (19.5–51.2), and 22.0 (17.0–38.0) months in T1, T2, and T3, respectively. In a multivariable Cox proportional hazards regression analysis, the hazard ratio of age at onset, bulbar-onset, and NLR (T3/T1) was 1.04 (1.02–1.06, p

There is a lack of research on the effects of physical activity (PA) on the progression of Alzheimer's disease (AD).We investigated whether PA is associated with progression of dementia and mortality in AD.In the present study, 934 patients with mild-to-moderate AD were included. PA was evaluated using a questionnaire written by the caregiver. The outcome measures were the Clinical Dementia Rating-Sum of Boxes (CDR-SB), Seoul-Instrumental Activities of Daily Living (S-IADL), Caregiver-Administered Neuropsychiatric Inventory (CGA-NPI), a global composite score of neuropsychological subtests, and mortality. They were evaluated annually and received a maximum of three follow-up examinations.Between-group differences compared with the no PA group in the change of CDR-SB scores were -0.431 (95% CI = -0.824∼-0.039; p = 0.031) for the moderate PA group (150-750 minutes per week of moderate intensity PA), and -1.148 (-1.656∼-0.639; p 0.001) for the high PA group (750 minutes per week). As PA increased, there was a significant trend to slow the rate of increase in the CDR-SB, S-IADL, and CGA-NPI scores. The patients with ≥150 minutes per week for each of non-recreational and recreational PAs had a lower risk of mortality compared to those with150 minutes per week for each of the PAs (hazard ratio 0.22, 95% CI = 0.05∼0.88; p = 0.033).More PA is associated with slower progression of dementia severity, functional decline, and abnormal behavior, and with a lower risk of mortality in AD.

Objective To investigate the frequency, features, and prognosis of takotsubo cardiomyopathy (TTC) in patients with amyotrophic lateral sclerosis (ALS). Methods We reviewed detailed clinical, laboratory, and cardiovascular data from 64 ALS patients (38 men and 26 women) who underwent echocardiographic evaluation for various reasons at a single referral center between January 2011 and December 2015. Results TTC was diagnosed in 9 ALS patients (4 men and 5 women). Mean age was 61.3 years (range 55–71 years), and median disease duration was 51.5 months (range 18–134 months). All patients were bulbar or cervical onset, and were at advanced stages of ALS when TTC was diagnosed. Acute exacerbation of dyspnea was an invariable presentation, and chest discomfort mimicking acute coronary syndrome was present in 2 patients. Six patients had significant hypotension requiring intravenous fluid challenge and inotropic support. Three patients showed altered mentality, and 2 of them suffered cardiopulmonary arrest. Conclusions TTC should be suspected in ALS patients presenting with acute exacerbation of dyspnea and chest discomfort, particularly at advanced stages of the disease. This study highlights the need for proper evaluation and management of cardiac dysfunction in ALS.

Spinobulbar muscular atrophy (SBMA) is an X-linked recessive disease, presenting motor weakness and wasting of facial, bulbar and limb muscles. Hereditary neuropathy with liability to pressure palsy (HNPP) is autosomal dominant disorder characterized by recurrent neuropathies at common entrapment sites. We report a case of co-existence of SBMA and atypical HNPP with genetic confirmation of CAG expansion in the androgen receptor (AR) gene and deletion of the peripheral myelin protein 22 (PMP22) gene. A 62-year-old man presented with progressive muscle weakness, fasciculations in upper and lower limbs and dysesthesia predominantly in the distal regions. No family members, including his children, experienced similar symptoms. The electrodiagnostic examination was compatible with demyelinating sensorimotor polyneuropathy. Simultaneous hereditary polyneuropathy and motor neuron disease were suspected and relevant genetic testing was confirmed HNPP and SBMA. This case presented with 2 rare genetic neuromuscular disorders and the atypical HNPP phenotype. This case highlight the importance of detailed patient histories, as well as neurological and electrophysiological examinations for diagnosis of atypical and combination of rare genetic disorders.

Purpose This study aimed to explore students’ cognitive patterns while solving clinical problems in 3 different types of assessments—clinical performance examination (CPX), multimedia case-based assessment (CBA), and modified essay question (MEQ)—and thereby to understand how different types of assessments stimulate different patterns of thinking. Methods A total of 6 test-performance cases from 2 fourth-year medical students were used in this cross-case study. Data were collected through one-on-one interviews using a stimulated recall protocol where students were shown videos of themselves taking each assessment and asked to elaborate on what they were thinking. The unit of analysis was the smallest phrases or sentences in the participants’ narratives that represented a meaningful cognitive occurrence. The narrative data were reorganized chronologically and then analyzed according to the hypothetico-deductive reasoning framework for clinical reasoning. Results Both participants demonstrated similar proportional frequencies of clinical reasoning patterns on the same clinical assessments. The results also revealed that the three different assessment types may stimulate different patterns of clinical reasoning. For example, the CPX strongly promoted the participants’ reasoning related to inquiry strategy, while the MEQ strongly promoted hypothesis generation. Similarly, data analysis and synthesis by the participants were more strongly stimulated by the CBA than by the other assessment types. Conclusion This study found that different assessment designs stimulated different patterns of thinking during problem-solving. This finding can contribute to the search for ways to improve current clinical assessments. Importantly, the research method used in this study can be utilized as an alternative way to examine the validity of clinical assessments.

Background Myelin oligodendrocyte glycoprotein immunoglobulin G1 (MOG-IgG1)-associated disease is suggested as a separate disease entity distinct from multiple sclerosis and neuromyelitis optica spectrum disorder. Nonetheless, the optimal treatment regimen for preventing relapses in MOG-IgG1-associated disease remains unclear. Case presentation We describe the case of a 45-year-old man with MOG-IgG1-positive highly relapsing optic neuritis who had experienced 5 attacks over 21 months and had monocular blindness despite prednisolone and azathioprine therapy. He began treatment with rituximab, which reduced the rate of relapse markedly. Following discontinuation of rituximab, however, the patient experienced two successive optic neuritis attacks 2 and 4 months after B-lymphocyte restoration. Conclusions Highly relapsing MOG-IgG1-associated disease can be prevented with rituximab even when the MOG-IgG1 titers are relatively stationary. Discontinuation of rituximab and restoration of B-lymphocytes may be associated with the rebound of disease activity.

Purpose The quality of problem representation is critical for developing students' problem-solving abilities in problem-based learning (PBL). This study investigates preclinical students' experience with standardized patients (SPs) as a problem representation method compared to using video cases in PBL. Methods A cohort of 99 second-year preclinical students from Inje University College of Medicine (IUCM) responded to a Likert scale questionnaire on their learning experiences after they had experienced both video cases and SPs in PBL. The questionnaire consisted of 14 items with eight subcategories: problem identification, hypothesis generation, motivation, collaborative learning, reflective thinking, authenticity, patient-doctor communication, and attitude toward patients. Results The results reveal that using SPs led to the preclinical students having significantly positive experiences in boosting patient-doctor communication skills; the perceived authenticity of their clinical situations; development of proper attitudes toward patients; and motivation, reflective thinking, and collaborative learning when compared to using video cases. The SPs also provided more challenges than the video cases during problem identification and hypotheses generation. Conclusion SPs are more effective than video cases in delivering higher levels of authenticity in clinical problems for PBL. The interaction with SPs engages preclinical students in deeper thinking and discussion; growth of communication skills; development of proper attitudes toward patients; and motivation. Considering the higher cost of SPs compared with video cases, SPs could be used most advantageously during the preclinical period in the IUCM curriculum.

Rheumatoid meningitis is a rare complication of rheumatoid arthritis that requires a meningeal biopsy for diagnosis. The authors thank Drs. YoonJin Kwak and Kyu Sang Lee of the Department of Pathology at Seoul National University Bundang Hospital for comments and technical assistance in preparing the figures.

ObjectiveThis study aimed to explore the correlations between electrodiagnostic (EDX) features in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and to investigate whether EDX data-driven clustering can identify a distinct subgroup regarding clinical phenotype and treatment response.MethodsWe reviewed clinical and EDX data of 56 patients with definite CIDP fulfilling the 2010 European Federation of Neurological Societies and Peripheral Nerve Society criteria at two teaching hospitals. A hierarchical agglomerative clustering algorithm with complete linkage was used to partition the patients into subgroups with similar EDX features. A stepwise logistic regression analysis was performed to evaluate predictors of the long-term outcome.ResultsEDX data-driven clustering partitioned the patients into two clusters, identifying a distinct subgroup characterised by coexistence of prominent conduction slowing and markedly reduced distally evoked compound muscle action potential (CMAP) amplitudes. This cluster of patients was significantly over-represented by an atypical subtype (distal acquired demyelinating symmetric polyneuropathy) compared with the other cluster (70% vs 26.1%, p=0.042). Furthermore, patients in this cluster invariably showed favourable long-term treatment outcome (100% vs 63%, p=0.023). In logistic regression analyses, the initial disability (OR 6.1, 95% CI 2.4 to 25.4), F-wave latency (OR 0.93, 95% CI 0.86 to 0.98) and distal CMAP duration (OR 0.96, 95% CI 0.91 to 0.99) were significant predictors of the poor long-term outcome.ConclusionOur results show that EDX data-driven clustering could differentiate a pattern of EDX features with prognostic implication in patients with CIDP. Reduced distally evoked CMAPs may not necessarily predict poor responses to treatment, and active treatment is warranted when prominent slowing of conduction is accompanied in the distal segments.

In this study, we investigated whether IFN-γ has a role in contrast-medium-induced adverse reactions. Iopromide, a nonionic iodinated contrast agent, slightly induced mast cell proliferation and significantly increased the expression of IL-4 and MCP-1 at low doses. The pretreatment of cells with IFN-γ dramatically increased the expression of iopromide-induced IL-4 and MCP-1. An evaluation of mast cell activator secretion revealed that IFN-γ- or IL-4-pretreated HMC-1 cells released dramatically increased levels of β-hexosaminidase and histamine when stimulated with iopromide. We also found that the migration of EoL-1 and THP-1 cells was significantly increased in culture conditions with iopromide-stimulated IL-4-pretreated HMC-1 cells. Taken together, our findings suggest that measuring IFN-γ or IL-4 levels in serum would be helpful as a potential biomarker of adverse patient reactions and that blocking IFN-γ or IL-4 may be crucial in preventing the delayed allergy-like reaction induced by contrast medium in patients with various diseases.

123I-Metaiodobenzylguanidine (123I-MIBG) scintigraphy is a widely used functional imaging tool with a high degree of sensitivity and specificity in diagnosis of pheochromocytoma. However, rare cases of false positive reactions have been reported. A 67-year-old male patient was admitted with epigastric pain. Abdominal computed tomography (CT) revealed a heterogeneous left adrenal mass 6 cm in diameter; following hormone testing,123I-MIBG scintigraphy was performed to determine the presence of pheochromocytoma, which confirmed eccentric uptake by a large left adrenal gland mass. Chest CT and PET-CT confirmed metastatic lymphadenopathy; therefore, endobronchial ultrasound transbronchial needle aspiration was performed. Metastatic carcinoma of unknown origin was suspected from a lymph node biopsy, and surgical resection was performed for definitive diagnosis and correction of excess hormonal secretion. A final diagnosis of undifferentiated adrenal malignant tumor was rendered, instead of histologically malignant pheochromocytoma, despite the uptake of123I-MIBG demonstrated by scintigraphy.

OBJECTIVE: The aim of this study was to compare the predictive value of the VitalPAC Early Warning Score-lactate (ViEWS-L) score with that of the trauma and injury severity score (TRISS), which is a pre-existing risk scoring system used in trauma patients. METHODS: The patients were blunt trauma victims admitted consecutively to the study hospital between 1 April 2010 and 31 March 2011, who were 15 years or older and had an injury severity score of 9 or higher. The lactate level, the ViEWS and revised trauma score upon arrival at the emergency department, and the injury severity score and TRISS were evaluated. The ViEWS-L score was calculated according to the formula: ViEWS-L=ViEWS+lactate (mmol/l). The ability to predict mortality was assessed by area under the receiver operating characteristic curve (AUC) analysis and calibration analysis. RESULTS: A total of 299 patients were available for analysis, of whom 33 died (11.0%). The median ViEWS-L score was 3.7 (interquartile range:1.8-6.4) and the median TRISS was 96.8 (interquartile range: 93.4-98.6). The ViEWS-L score was better than TRISS at predicting hospital mortality (AUC, 0.838; 95% confidence interval, 0.771-0.906 vs. AUC, 0.734; 95% confidence interval, 0.635-0.833, P=0.031). Calibration of the ViEWS-L score (χ=11.13, P=0.194) was good but that of TRISS was not (χ=16.97, P=0.018). CONCLUSION: The prognostic value of the ViEWS-L score in terms of discrimination was better than that of TRISS in the blunt trauma patients admitted to the emergency department with an injury severity score of 9 or higher, and the ViEWS-L score showed good calibration. Language: en

본 연구에서는 PC/ABS 블렌드를 고속전단성형법을 사용하여 제조하였고 스크류 회전속도와 전단부하시간을 공정변수로 하여 이에 따른 블렌드의 모폴로지 변화를 분석하였다. 블렌드의 모폴로지 및 ABS 분산상의 크기를 주사전자현미경으로 관찰하여 안정한 상 구조와 최적의 물성을 가지는 고속전단성형조건을 확립하였고, 전단응력에 의한 블렌드의 열화 현상을 알아보기 위해 기계적 물성의 변화를 측정하였다. 이 때, 스크류 회전속도는 500 rpm에서 3000 rpm까지 변화시켰으며 전단부하시간은 10초에서 40초까지 주었다. 고속전단성형법을 사용하여 제조한 PC/ABS 블렌드 및고속전단성형을 가하지 않은PC/ABS 컴파운드의 분산상 크기를 명확하게 관찰하기 위하여 블렌드의 단면에 크롬산 수용액을 이용한 에칭공정을 시행하였고 공정 전후의 모폴로지를 비교 분석하였다. 에칭으로 생긴 블렌드 내의 ABS 홀을 이미지 측정 프로그램인 Image J를 이용하여 측정한 결과, 스크류 회전속도에 따라 그 크기가 감소하였으며 특히1000 rpm 이상의 스크류 회전속도 하에서 제조된 PC/ABS 블렌드의 경우, 기계적 물성이 급격하게 감소하여 블렌드의분해가 일어났음을 알 수 있었다. 결과적으로 PC/ABS 블렌드에 1000 rpm의 스크류 회전속도를 가한 경우, 나노미터단위의 분산상을 가지며 가장 안정한 상구조를 관찰할 수 있었고 인장강도 및 신율도 상대적으로 높아서 PC/ABS 블렌드의 최적 고속전단성형조건이라 할 수 있다.

The effects of high shear rate processing on the thermal properties of PC/ABS blends were studied. It was executed by the high shear processing machine (NHSS2-28) at the varied conditions of screw speeds and loaded duration. After the samples were processed with NHSS2-28, the Tgs were shifted from 143 to 133 C, and the behavior of degradation determined by TGA showed two distinct steps before high shear rate processing, while it showed a straight line after the processing. In order to provide the reasons of the properties, it was showen by SEM and UTM that the droplet sizes morphologically decreased after the processing, and the elongations decreased slightly until 1000 rpm of screw speed and then sharply decreased, according to the conditions of high shear rate processing. Therefore, it can be confirmed that Tg,s of PC/ABS blends were considerably shifted under an appropriate high shear rate condition, and rapidly dropped, so that blends degraded above the condition, due to stress-induced degradation.

Miliary tuberculosis (TB) is a rare extrapulmonary form of TB, and there have been only two reports of miliary TB associated with infection with multidrug-resistant (MDR)-TB pathogen in an immunocompetent host. A 32-year-old woman was referred to our hospital because of abnormal findings on chest X-ray. The patient was diagnosed with MDR-TB by a line probe assay and was administered proper antituberculous drugs. After eight weeks, a solid-media drug sensitivity test revealed that the pathogen was resistant to ethambutol and streptomycin in addition to isoniazid and rifampicin. The patient was then treated with effective antituberculous drugs without delay after diagnosis of MDR-TB. To the best of our knowledge, this is the first case of miliary TB caused by MDR-TB pathogen in Korea.

Polycarbonate/Acrylonitrile-Butadiene-Styrene(PC/ABS) 블렌드의 분해효과를 조사하기 위해 고전단 압출 성형기의스크류 회전속도와 전단시간의 함수로 PC/ABS의 물성변화에 영향을 미치는 산화방지제의 효과를 연구하였다. 인산계산화방지제로 Tris-(2,4-di-tert-butyl-phenyl phosphate) (이후 A1로 명명) and Bis(2,4-dicumylphenyl) pentaerythritoldiphosphite(이후 A3로 명명)가 사용되었고, 페놀계 산화방지제는 Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate(이후 A2로 명명)가 사용되었다. 열적 물성은 TGA를 통해 측정되었고 고속 전단 가공 후 크게 감소하였다. 산화방지제 A3가 포함된 PC/ABS 블렌드는 다른 산화방지제에 비해 스트레스로 유발된 degradation과, 열적 degradation이지연되었다. 고속 전단 가공 후 UTM을 사용한 기계적 물성 또한 산화방지제 종류에 따라 각각 감소하였고, 특히, 신율의 경우 크게 감소하는 거동이 나타난 것에 비해 인장강도의 변화는 매우 적었다. 스크류 회전속도 1000 rpm, 전단부하 시간 20초 조건에서의 신율로 예를 들면, 고속 전단 가공하기 전 신율인 148%에서 A1은 91.6%, A2는 63%, A3은 131%로 감소하였다. 형태학적 물성을 알기 위해 SEM을 사용하여 PC/ABS의 분산상을 조사하였고, 스크류 회전속도와 하중이 작용한 기간이 증가함에 따라 그 크기 분포가 감소하였다. 따라서, 세 종류 산화방지제 모두 고속 전단 가공에서 스트레스로 유발되는 PC/ABS 블렌드의 degradation을 억제하고, 그 효과는 A3가 가장 뛰어난 것을 확인하였다.

Purpose: This study aimed to explore students’ cognitive patterns while solving clinical problems in 3 different types of assessments—clinical performance examination (CPX), multimedia case-based assessment (CBA), and modified essay question (MEQ)—and thereby to understand how different types of assessments stimulate different patterns of thinking.Methods: A total of 6 test-performance cases from 2 fourth-year medical students were used in this cross-case study. Data were collected through one-on-one interviews using a stimulated recall protocol where students were shown videos of themselves taking each assessment and asked to elaborate on what they were thinking. The unit of analysis was the smallest phrases or sentences in the participants’ narratives that represented meaningful cognitive occurrences. The narrative data were reorganized chronologically and then analyzed according to the hypothetico-deductive reasoning framework for clinical reasoning.Results: Both participants demonstrated similar proportional frequencies of clinical reasoning patterns on the same clinical assessments. The results also revealed that the three different assessment types may stimulate different patterns of clinical reasoning. For example, the CPX strongly promoted the participants’ reasoning related to inquiry strategy, while the MEQ strongly promoted hypothesis generation. Similarly, data analysis and synthesis by the participants were more strongly stimulated by the CBA than by the other assessment types.Conclusion: This study found that different assessment designs stimulated different patterns of thinking during problem-solving. This finding can contribute to the search for ways to improve current clinical assessments. Importantly, the research method used in this study can be utilized as an alternative way to examine the validity of clinical assessments.

The objective of this study was to prospectively evaluate whether intraarticular anesthesia can reduce pain after MR or CT arthrography of the shoulder.This study included 120 patients who underwent CT or MR arthrography of the shoulder. The patients were randomized into two groups: the study group (n = 60), each administered an intraarticular injection of the contrast agent mixed with a local anesthetic (2% mepivacaine); and the control group (n = 60), each injected with the contrast agent only. Each patient's pain level was assessed at five phases-baseline and immediately, 2 hours, 1 day, and 2 days after injection-by using a visual analog scale or a verbal rating scale. The net pain score at each phase was also calculated. The pain course and net pain score were compared between study and control groups by repeated-measures analysis of variance. After the patients were divided into subgroups according to patient- or procedure-related factors, the efficacy of the intraarticular local anesthetic in each subgroup was evaluated.The pain course showed a quadratic trend and was not significantly different between study and control groups. The net pain score also was not significantly different between the two groups. No subgroup showed a significantly different efficacy of the intraarticular local anesthetic between the two groups.Intraarticular local anesthesia did not reduce arthrography-related pain.

A patient who has multiple lung masses with a history of malignancy in organs other than the lung is more likely to be diagnosed with metastatic rather than primary lung cancer. Rarely, metastatic cancer can coexist with primary. We experienced a case of concurrent diagnosis of primary small cell lung cancer and pulmonary metastasis of uterine malignant mixed Mullerian tumor (MMMT). The patient was a 52-year-old female with femur fracture and multiple lung masses with a history of an operation for uterine MMMT. The small cell lung cancer was diagnosed by bronchoscopic biopsy. The central lung mass decreased after chemotherapy for small cell lung cancer but multiple peripheral masses increased. A percutaneous biopsy for one of peripheral masses revealed metastatic uterine MMMT. We suggest that we have to consider the possible presence of concomitant malignancies of different origins in one organ especially with patients who had a history of malignancy in another organ.