Ohyun Kwon

Risk Factors of Intracranial Cerebral Atherosclerosis among Asymptomatics

Background: Little information is available regarding the risk factors for intracranial cerebral atherosclerosis (ICAS), particularly among asymptomatics. Methods: Data from a consecutive series of 1,208 subjects aged ≧40 years, with no history of stroke, and who had undergone transcranial Doppler ultrasonography (TCD) were collected prospectively. The role of classic risk factors was assessed in the presence and severity of asymptomatic ICAS, which was determined by TCD. Results: Regarding the presence of ICAS, the adjusted odds ratios (95% confidence intervals) were as follows: 1.22 (1.08–1.37) for every 10-year increase in age, 1.44 (1.08–1.91) for hypertension and 1.86 (1.33–2.59) for diabetes mellitus. No significant association was observed with regard to male sex, smoking or hyperlipidemia. Conclusion: The findings suggest that age, hypertension and diabetes mellitus are significant risk factors for ICAS in asymptomatic populations.

In-Hospital Medical Complications and Long-Term Mortality After Ischemic Stroke

Background and Purpose— Inhospital medical complications account for a considerable portion of deaths during the early stage of stroke. However, relatively few studies have examined their long-term effects on mortality in stroke patients. Methods— We prospectively and consecutively collected data on 579 patients with acute ischemic stroke from November 1998 to February 2001. Mortality was confirmed using national death certificate data from 1999 to 2003. Results— During admission, one or more medical complications requiring intervention developed in 160 of these 579 patients (27.6%). For these 160 subjects, the 30-day, 90-day, 1-year, 2-year, 3-year, and 4-year mortalities were 16.3, 29.4, 46.9, 55.6, 61.3, and 70.7%, whereas the mortality figures for those without such complications (n=419) were 1.4, 3.8, 8.8, 15.0, 19.1, and 22.4 (P<0.001 with log-rank test). To eliminate the short-term effects of these complications and thus reveal their long-term effects, we investigated differences in mortality versus the presence of inhospital complications at more than 30 days, 90 days, 1 year, 2 years, and 3 years after stroke, respectively. Coxs proportional hazard regression analysis was applied at these times after stroke and showed that all hazard ratios of medical complications in terms of mortality were statistically larger than one, regardless of adjusting for effects of potential predictors on mortality. Conclusions— Our study shows that stroke patient mortality is influenced by inhospital medical complications significantly up to the chronic stage. This finding suggests that the appropriate prevention and management of inhospital complications could improve short-term and long-term prognoses after stroke.

Prevalence of Anti-Ganglioside Antibodies and Their Clinical Correlates with Guillain-Barré Syndrome in Korea: A Nationwide Multicenter Study

Background and Purpose No previous studies have investigated the relationship between various anti-ganglioside antibodies and the clinical characteristics of Guillain-Barré syndrome (GBS) in Korea. The aim of this study was to determine the prevalence and types of anti-ganglioside antibodies in Korean GBS patients, and to identify their clinical significance. Methods Serum was collected from patients during the acute phase of GBS at 20 university-based hospitals in Korea. The clinical and laboratory findings were reviewed and compared with the detected types of anti-ganglioside antibody. Results Among 119 patients, 60 were positive for immunoglobulin G (IgG) or immunoglobulin M antibodies against any type of ganglioside (50%). The most frequent type was IgG anti-GM1 antibody (47%), followed by IgG anti-GT1a (38%), IgG anti-GD1a (25%), and IgG anti-GQ1b (8%) antibodies. Anti-GM1-antibody positivity was strongly correlated with the presence of preceding gastrointestinal infection, absence of sensory symptoms or signs, and absence of cranial nerve involvement. Patients with anti-GD1a antibody were younger, predominantly male, and had more facial nerve involvement than the antibody-negative group. Anti-GT1a-antibody positivity was more frequently associated with bulbar weakness and was highly associated with ophthalmoplegia when coupled with the coexisting anti-GQ1b antibody. Despite the presence of clinical features of acute motor axonal neuropathy (AMAN), 68% of anti-GM1- or anti-GD1a-antibody-positive cases of GBS were diagnosed with acute inflammatory demyelinating polyradiculoneuropathy (AIDP) by a single electrophysiological study. Conclusions Anti-ganglioside antibodies were frequently found in the serum of Korean GBS patients, and each antibody was correlated strongly with the various clinical manifestations. Nevertheless, without an anti-ganglioside antibody assay, in Korea AMAN is frequently misdiagnosed as AIDP by single electrophysiological studies.

Reproducibility of statistical motor unit number estimates in amyotrophic lateral sclerosis: Comparisons between size- and number-weighted modifications

Motor unit number estimations (MUNEs) can directly assess motor unit populations in muscle and quantify the degree of physiological or pathological motor unit degeneration. A high degree of reproducibility and reliability is required of any effective quantitative tool. MUNE is being increasingly applied clinically, and statistical MUNE has several advantages over alternative techniques. Nevertheless, the optimal method of applying statistical MUNE with respect to its reproducibility has not been established. We performed statistical MUNE by selecting the most compensated compound muscle action potential (CMAP) area as a test area and modified the results obtained by using the weighted mean surface‐recorded motor unit potential (SMUP). MUNE measurements made in patients with amyotrophic lateral sclerosis (ALS) showed better reproducibility after incorporating the size‐weighted modification. Therefore, we suggest that the size‐weighted MUNE in combination with the selection of testing “neurogenically compensated” CMAP areas is a more reliable method of statistical MUNE analysis in ALS patients. Muscle Nerve 29: 211–217, 2004

Vertebrobasilar dolichoectasia as a risk factor for cerebral microbleeds.

Both vertebrobasilar dolichoectasia (VBD) and cerebral microbleeds (CMBs) are related with the risk of intracerebral hemorrhage. We aimed to examine the relationship between the VBD and CMB in ischaemic stroke patients.

Seizures Related to Vitamin B6 Deficiency in Adults

Vitamin B6 is closely associated with functions of the nervous, immune, and endocrine systems. Its deficiency may result in neurological disorders including convulsions and epileptic encephalopathy. Until today, this has only been reported in infants, children, and critically ill adult patients. We report a case of a 36year-old man with chronic alcoholism who presented with seizures after gastrointestinal disturbance. His seizures persisted even after treatment with antiepileptic drugs, but eventually disappeared after administration of pyridoxine. Hence, vitamin B6 deficiency may cause seizures in adult patients with chronic alcoholism.

Aggressive Glucose Control for Acute Ischemic Stroke Patients by Insulin Infusion

Background and Purpose Hyperglycemia after acute ischemic stroke (AIS) is associated with poor outcomes. However, there is no consensus as to the optimal method for glycemic control. We designed an insulin infusion protocol for aggressive glucose control and investigated its efficacy and safety. Methods We applied our protocol to patients within 48 hours after AIS or transient ischemic attack (TIA) with an initial capillary glucose level of between 100 and 399 mg/dL (5.6-22.2 mmol/L). An insulin solution comprising 40 or 50 U of human regular insulin in 500 mL of 5% dextrose was administered for 24 hours. Capillary glucose was measured every 2 hours and the infusion rate was adjusted according to a nomogram with a target range of 80-129 mg/dL (4.4-7.2 mmol/L). Changes in glucose and overall glucose levels during insulin infusion were analyzed according to the presence of diabetes or admission hyperglycemia (admission glucose >139 mg/dL or 7.7 mmol/L) by the generalized estimating equation method. Results The study cohort comprised 115 consecutive patients. Glucose was significantly lowered from 160±57 mg/dL (8.9±3.2 mmol/L) at admission to 93±28 mg/dL (5.2±1.6 mmol/L) during insulin infusion (p<0.05). Laboratory hypoglycemia (capillary glucose <80 mg/dL or 4.4 mmol/L) occurred in 91 (71%) patients, 11 (10%) of whom had symptomatic hypoglycemia. Although glucose levels were significantly lowered and maintained within the target range in all patients, overall glucose levels were significantly higher in patients with diabetes or hyperglycemia (p<0.05). Conclusions Our insulin-infusion protocol was effective in glycemic control for patients with AIS or TIA. Further modification is needed to improve the efficacy and safety of this procedure, and tailored intervention should be considered according to glycemic status.

Clinical characteristics of late-onset neuromyelitis optica spectrum disorder: A multicenter retrospective study in Korea:

Background: There are currently few studies regarding late-onset neuromyelitis optica spectrum disorder (LO-NMOSD). Objective: We aimed to describe the characteristic features of patients with LO-NMOSD in Korea. Methods: Anti-aquaporin-4 antibody-positive patients with neuromyelitis optica spectrum disorder (NMOSD) from nine tertiary hospitals were reviewed retrospectively. The patients were divided into two groups based on age of onset: LO-NMOSD (⩾50 years of age at onset) versus early-onset neuromyelitis optica spectrum disorder (EO-NMOSD) (<50 years of age at onset). Clinical, laboratory, and magnetic resonance imaging (MRI) parameters were investigated. Results: Among a total of 147 patients (125 female; age of onset, 39.4 ± 15.2 years), 45 patients (30.6%) had an age of onset of more than 50 years. Compared to patients with EO-NMOSD, patients with LO-NMOSD had more frequent isolated spinal cord involvement at onset (64.4% vs 37.2%, p = 0.002), less frequent involvement of the optic nerve (40.0% vs 67.7%, p = 0.002), and less frequent brain MRI lesions (31.1% vs 50.0%, p = 0.034). Furthermore, there was a significant positive correlation between age of onset and Expanded Disability Status Scale (EDSS) score at last follow-up (r = 0.246, p = 0.003). Conclusion: Age of onset could be an important predictor of lesion location and clinical course of patients with NMOSD.

Comparison of body mass index, waist circumference, and waist-height ratio in predicting functional outcome following ischemic stroke

Although a positive association between body mass index (BMI) and stroke incidence has been reported, having a higher BMI is known to be advantageous in surviving and recovering from stroke. The association between adiposity and stroke incidence is more evident for measures of abdominal obesity than for general obesity. The aim of our study was to compare BMI, waist circumference, and waist-height ratio (WHR) as predictors of 3-month functional outcome in stroke patients. The BMI, waist circumference, and WHR of acute stroke patients were divided into sex-specific quartiles. A total of 605 female and 727 male patients were included. For BMI, male patients in the second quartile were more likely to have a favorable functional outcome compared with those in the lowest quartile (adjusted OR 1.64, 95% CI 1.02–2.62). For waist circumference (adjusted OR for top quartile vs. lowest quartile 1.79, 95% CI 1.14–2.82) and WHR (adjusted OR for second quartile vs. lowest quartile 1.99, 95% CI 1.22–3.25), male patients in the two top quartiles were more likely to have a favorable functional outcome compared with those in the respective lowest quartile. BMI and WHR showed similar relationships to a favorable functional outcome, with a favorable functional outcome occurring most often among male patients in the second quartiles. In women, however, obesity was not related to functional outcome. In conclusion, general obesity measured by BMI and abdominal obesity measured by WHR showed similar effects on the functional outcome after stroke in men.

Progression of Opalski syndrome to the hemimedullary and contralateral medial medullary infarct

Opalski syndrome is a rare variant of the lateral medullary syndrome of Wallenberg accompanied by an ispilateral hemiparesis (1). However, the anatomic basis for this syndrome is not clear. In addition, hemimedullary infarct or bilateral medial medullary infarct is a rare disease and a combination of both is even rarer (2). We report a case of Opalski syndrome that progressed to hemimedullary infarct and contralateral medial medullary infarct and suggest a possible pathologic mechanism for Opalski syndrome. Previous reports have described the progression of lateral medullary to total hemimedullary infarct (3) or the progression of unilateral medial to bilateral medial medullary infarct (4), but to our knowledge no report described the pattern observed in this patient. A 63-year-old man with a history of hypertension, diabetes, dyslipidemia, and coronary heart disease developed dizziness, left-beating nystagmus, right ptosis, hoarseness, dysphagia, and deteriorating right hemiparesis. Two decades previously, he had suffered a stroke and had recovered with a stable deficit of mild right hemiparesis. Deep tendon reflexes were more active on the right than the left. Diffusion-weighted imaging (DWI) obtained 90 min after onset revealed right lateral medullary infarct (Fig. 1a). Oneday later, he developed left hemiparesis and hypalgesia of the right side of the body, but a repeat DWI showed no additional lesion (Fig. 1b). Three days later, vibration and joint position senses were diminished in the right hemibody and the left leg. T2-weighted MRI demonstrated progression of the initial right lateral medullary infarction to hemimedullary infarction extending to the cervical spinal cord and occurrence of the left medial medullary infarction (Fig. 1c and d). Magnetic resonance angiography showed absent right vertebral artery flow (Fig. 1e). This patient is of interest for two reasons. First, he developed hemimedullary infarct and contralateral medial medullary infarct, which is a rare combination. Second, he had right hemiparesis although the initial DWI revealed Correspondence: Kyusik Kang*, Department of Neurology, Eulji General Hospital, 68 Hangeulbiseok-ro, Nowon-gu, Seoul 139-711, Korea. E-mail: cobnut1@gmail.com