Diffusion-weighted magnetic resonance imaging in Wernicke's encephalopathy

OBJECTIVE: To report diffusion-weighted imaging (DWI) findings and postulate the pathogenic mechanism of Wernicke's encephalopathy (WE). PATIENT: A 47-year-old-woman presented with altered consciousness, ophthalmoplegia, and ataxia. DWI revealed the abnormal signal changes in periaqueductal gray matter, mamillary bodies and bilateral medial thalami. Apparent diffusion coefficient (ADC) map revealed the high signal intensity lesions in bilateral medial thalami, suggestive of vasogenic edema. The abnormal signal intensity lesions disappeared on follow-up imaging with clinical improvement. CONCLUSIONS: Vasogenic edema plays an important role in the pathogenesis of WE and can be reversed by proper management. DWI findings in the early stage of WE may provide useful information about the prognosis.     

Reversible Cytotoxic Edema in TPN‐Related Hepatic Encephalopathy

Hepatic encephalopathy (HE) is an uncommon complication of total parenteral nutrition (TPN). Cytotoxic edema has not been reported in children with TPN‐related HE. We describe a case of TPN‐related HE presenting with diffuse cytotoxic edema which reversed after liver transplantation.     

Diagnostic Value of Apparent Diffusion Coefficient Hyperintensity in Selected Patients With Acute Neurologic Deficits

BACKGROUND AND PURPOSE: A pattern of decreased intensity on apparent diffusion coefficient (ADC) maps is useful in the early detection of ischemic brain injury. Less information exists with regard to patients with acute neurologic deficits in whom there is abnormal conventional magnetic resonance imaging (MRI) and increased ADC intensity. METHODS: The authors identified 13 patients with acute neurologic deficits who underwent diffusion MRI and had calculated ADC maps demonstrating hyper-intensity in regions characterized by computed tomography hypodensity and MRI T2 hyperintensity. The initial and follow-up imaging characteristics and clinical syndromes were recorded. RESULTS: Clinical syndromes included hypertensive encephalopathy, posterior leukoencephalopathy, hyperperfusion following carotid endarterectomy, venous sinus thrombosis, HIV encephalopathy, and brain tumor. Diffusion-weighted imaging (DWI) was hyperintense in 3 of 13 patients, isointense in 4 of 13 patients, heterogeneous in 3 of 13 patients, and hypointense in 3 of 13 patients. The ADC values in these regions were significantly higher than those in control regions (P < .0001). At early follow-up, MRI abnormalities resolved completely in 3 of 13 patients and partially in 9 of 13 patients. MRI abnormalities were unchanged in 1 patient. CONCLUSIONS: In the evaluation of patients with acute neurologic deficits, ADC hyperintensity may identify a subset of patients with vasogenic edema of nonischemic etiology. Frequently, these conditions are potentially reversible if appropriately managed. DWI and conventional images alone are not sufficient to identify these neurologic conditions.     

Corpus Callosum Atrophy in Wernicke's Encephalopathy

Background and Purpose. Neuropathologic changes in Wernicke's encephalopathy (WE) involve variable brain structures. Corpus callosum involvement in WE, however, is largely unknown. The authors investigated the degree and the pattern of corpus callosum changes in WE according to the etiologies. Methods. Nineteen patients with WE (between 34 and 81 years) and 19 age‐ and sex‐matched control participants were included. The total cross‐sectional callosal area and 5 callosal subregions (C1‐C5) were measured by tracing outer margins in the midsagittal sections. Subregions were determined by placing radial dividers with 10 rays. The pixel numbers for corpus callosums were calculated, and the values obtained were adjusted for head size variations. Results. The causes of WE were alcoholism (10), intestinal surgery (5), anorexia (3), and hyperemesis gravidarum (1). The mean size of the total corpus callosum was significantly reduced in alcoholic WE (P< .001; 527.8 ± 70.8 mm 2for alcoholic WE; 664.6 ± 58.1 mm 2for the corresponding controls), but not in nonalcoholic WE. In subregion analysis, prefrontal callosum (C2) atrophy was the most prominent in alcoholic WE. In contrast, only splenium (C5) was atrophied in nonalcoholic WE. The degree of atrophy did not change throughout the follow‐up period (mean 5.3 weeks). Conclusion. This study suggests that the extent and location of corpus callosum atrophy differs between alcoholic WE and nonalcoholic WE, implying separate contribution of alcohol neurotoxicity and nutritional deficiency.     

Acute necrotizing encephalopathy with widespread edematous lesions of symmetrical distribution

Summary A 67-year-old Japanese woman with liver cirrhosis was affected by an unusual acute progressive encephalopathy, presenting mental confusion and slurred speech as its initial symptoms. She died in profound coma, following the entire course of 17 days. Autopsy disclosed bilateral symmetrical, widespread, edematous and necrotic lesions, their centers being located in the basal ganglia, diencephalon and midbrain, and their peripheries expanding into the cerebral white matter, cerebellum, pons and medulla. Diapedesis of erythrocytes and serum plasma was conspicuous, in contrast to paucity of capillary proliferation. Although the lesions were somewhat similar to those of Wernicke's and Leigh's encephalopathies, they were considered to be representative of a more acute metabolic disorder distinct from the latter conditions.     

急性期脑出血灶周水肿的磁共振弥散加权成像临床初步研究

目的应用磁共振弥散加权成像(DWI)探讨急性期脑出血血肿周围水肿性质及形成机制。方法对满足检查条件的连续发病2周内的44例脑出血患者进行DWI成像,测量血肿周围1cm区域和水肿区表观弥散系数(ADC)的变化情况,对水肿区相对ADC与水肿体积做相关分析。结果44例脑出血患者血肿周围均存在水肿,40例患者血肿周围ADC升高,水肿区ADC较对侧对称区域升高58．6%差异有非常显著性意义(P＜0．001),血肿周围1 cm区域较对侧对称区域ADC升高24．1%;水肿区相对ADC与绝对水肿体积和相对水肿体积呈正相关(P=0．003)。另4例患者血肿周围水肿区ADC降低。结论急性期大部分血肿周围水肿ADC升高,血管源性水肿是其主要的发生机制;少数患者血肿周围水肿ADC下降,提示细胞毒性水肿占主导地位,患者病情多危重,预后不良。     

Wernicke脑病12例临床分析

目的探讨Wernicke脑病患者的临床特点。方法回顾性分析12例Wernicke脑病患者的临床表现、实验室检查及影像学检查等临床资料。结果 12例Wernicke脑病患者男性6例,女性6例;有明确病因的患者为9例,如禁食、饮食差;恶心、呕吐、嗜酒;临床以"三主征"中的2个主征最多,为7例,1个主征得为4例,"三主征"仅为1例;辅助检查以头颅MR检查最有意义,12例患者中有6例出现典型的头颅MRI信号改变即短或等T1、长T2异常信号,多位于丘脑、小脑及中脑导水管周围;经维生素B1补充治疗后患者的症状有不同程度的好转。结论禁食、饮酒等诱因、临床表现及典型的头颅MR表现可为临床上该病的早期诊断提供重要线索。早期进行维生素B1的补充治疗在临床上可达到显著的疗效。     

Diffusion-weighted MR findings in a reversible case of acute Wernicke encephalopathy

We report a case of acute Wernicke encephalopathy (WE) in which apparent diffusion coefficient maps showed areas of increased diffusion in the bilateral medial thalami that corresponded to the hyperintense lesions on T2-weighted imaging. The hyperintense lesions on T2-weighted imaging disappeared with full recovery from symptoms. These findings suggest that the hyperintense lesions of the acute changes of WE include reversible vasogenic edema and are not caused by acute ischemia.     

Altered global and regional brain mean diffusivity in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common and progressive disorder accompanied by severe cardiovascular and neuropsychological sequelae, presumably induced by brain injury resulting from the intermittent hypoxia and cardiovascular processes accompanying the syndrome. However, whether the predominant brain tissue pathology is acute or chronic in newly‐diagnosed, untreated OSA subjects is unclear; this assessment is essential for revealing pathological processes. Diffusion tensor imaging (DTI)‐based mean diffusivity (MD) procedures can detect and differentiate acute from chronic pathology and may be useful to reveal processes in the condition. We collected four DTI series from 23 newly‐diagnosed, treatment‐naïve OSA and 23 control subjects, using a 3.0‐Tesla magnetic resonance imaging scanner. Mean diffusivity maps were calculated from each series, realigned, averaged, normalized to a common space, and smoothed. Global brain MD values for each subject were calculated using normalized MD maps and a global brain mask. Mean global brain MD values and smoothed MD maps were compared between groups by using analysis of covariance (covariate: age). Mean global brain MD values were significantly reduced in OSA compared with controls (P = 0.01). Multiple brain sites in OSA, including medullary, cerebellar, basal ganglia, prefrontal and frontal, limbic, insular, cingulum bundle, external capsule, corpus callosum, temporal, occipital, and corona radiata regions showed reduced regional MD values compared with controls. The results suggest that global brain MD values are significantly reduced in OSA, with certain regional sites especially affected, presumably a consequence of axonal, glial, and other cell changes in those areas. The findings likely represent acute pathological processes in newly‐diagnosed OSA subjects. © 2012 Wiley Periodicals, Inc.     

MRI对非乙醇中毒性韦尼克脑病的诊断价值(附五例临床分析)

目的 分析非乙醇中毒性韦尼克脑病(WE)患者的临床和颅脑MRI成像特点,探讨颅脑MRI对其的诊断价值. 方法 深圳市第二人民医院放射科自2007年6月至2010年2月应用MRI检查非乙醇中毒性WE患者5例,回顾性分析患者的临床特征、颅脑MRI成像特点及治疗转归等资料. 结果 非乙醇中毒性WE患者缺乏特征性临床表现,颅脑MRI主要表现为丘脑内侧,侧脑室,第三脑室,中脑导水管周围脑组织对称性高信号,2例患者可见大脑皮层受累.增强扫描后部分病变可见强化.2例患者死亡,3例患者应用维生素B1治疗后预后良好. 结论 颅脑MRI对非乙醇中毒性WE具有诊断价值,其显示的损害范围可反映WE的疾病严重程度.

Abstract：

Objective To analyze the clinical features and MR imaging features of patients with nonalcoholic Wemicke's encephalopathy (WE). Methods A retrospective review of the data,consisting of clinical and cranial MRI features, and the treatment results, was conducted on 5 patients with nonalcoholic WE, who admitted to our hospital fiom June 2007 to February 2010. Results The clinical features of nonalcoholic WE were non-characterized and most of them had no specific value for diagnosis. MR imaging showed symmetrical high signal in the medial thalamus, lateral ventricle, third ventricle and surrounding area of the aqueduct of midbrain; involvement of the cerebral cortex was found in 2 patients. Enhancement in some of the lesions was noted after performing contrast-enhanced scan.Favorable prognosis was given to the 3 patients treated with vitamin B1; 2 patients died. Conclusion Cerebral MRI enjoys great value in diagnosing nonalcoholic WE and reflects appropriately the pathological severity of this disease by demonstrating the scope of the lesions.     

脑电图预测急性CO中毒后迟发性脑病研究

目的探讨急性CO中毒后迟发性脑病(DEACMP)的脑电图(EEG)演变规律与临床症状的关系。方法对136例急性CO中毒患者进行EEG跟踪检查,首次EEG检查均在中毒后48 h内完成。结果136例急性CO中毒患者共行EEG检查360次,其中异常EEG140例次(38.89%),EEG的异常程度与临床症状严重程度呈正相关。首次EEG有异常改变者43例,其中31例(72.09%)最终发生了DEACMP。第二次EEG仍有异常改变者30例,其中24例(80%)最终发生了DEACMP。结论EEG可预测DEACMP,急性CO中毒患者经抢救即使中毒症状已缓解或消失,只要EEG仍有异常改变就不应终止治疗。     

急性一氧化碳中毒后迟发性脑病的血液免疫学研究

本文采用单向琼脂扩散法、直接红细胞花环试验及微量ＮＡＧ酶释放法对３１例急性一氧化碳中毒后迟发性脑病患者外周血进行了免疫学研究。结果表明，该病患者血中ＩｇＧ、ＩｇＭ、Ｃ＿３、Ｃ＿４增高，总Ｔ细胞（Ｔｔ）、辅助性Ｔ细胞（Ｔｈ）、自然杀伤（ＮＫ）细胞、Ｔｈ／Ｔｓ比值下降，而ＩｇＡ、抑制性Ｔ细胞（Ｔｓ）正常，提示本病的发生与免疫病理损伤有关。     

MRI Findings of Hemolytic Uremic Syndrome With Encephalopathy: Widespread Symmetrical Distribution

The authors report the magnetic resonance imaging (MRI) findings in a 22-year-old woman with hemolytic uremic syndrome and encephalopathy secondary to verotoxin-producing Escherichia coli. Multiple lesions in the midbrain, cerebellum, occipital lobe, and basal ganglia showed high signal intensity on T2-weighted images with widespread symmetrical distribution. Most of these findings showed remarkable reduction on MRI images obtained 70 days after the onset. It is suggested that edema induced by local breakdown of blood-brain barrier might play an important role in the patient.     

Encephalopathy and Cerebral Edema in the Setting of Acute Liver Failure: Pathogenesis and Management

Cerebral edema is a potential life-threatening complication in patients with acute liver failure who progress to grade III/IV encephalopathy. The incidence is variably reported but appears to be most prevalent in those patients with hyperacute liver failure as opposed to subacute forms of liver failure. In those patients who are deemed at risk of cerebral edema and raised intracranial pressure, insertion of an intra-cranial pressure monitoring device may be considered to optimize treatment and interventions. The pathogenesis of cerebral edema in this setting remains controversial, although recent work suggests a pivotal role for arterial ammonia, whose effects appear to be potentiated by the presence of systemic inflammation. Recent work has also suggested the import of free radical formation occurring at a mitochondrial level as being the potential mediator of cellular dysfunction as opposed to ammonia per se. Treatment of such patients requires a multi-disciplinary approach incorporating both hepatology and critical care. In a significant proportion of such cases, consideration of liver transplantation may be required. Treatment should be focused at optimizing liver function and regenerative capacity and minimizing the inflammatory milieu. Controlled studies are lacking and much of the management has been extrapolated from neurocritical care. Sustained elevation of intracranial pressure may be responsive to mannitol or hypertonic saline bolus, and in those with hyperemia indomethacin has been reported as beneficial in case series. Recently, interest has developed into the use of cooling in the management of patients with acute liver failure and raised intracranial pressure. Animal studies support this treatment option as do case series, although randomized trials are still awaited.     

Acute Encephalopathy with Necrosis of Bilateral Thalami: Clinical Aspects

An unusual type of acute encephalopathy is prevalent among Japanese children. The disorder is characterized by the bilateral symmetrical, edematous and necrotic brain lesions. Clinical and pathological evidence indicates that the encephalopathy is a novel entity. Its pathomechanism remains to be solved.     

Encephalopathy in the course of Wegener vasculitis

A 44-year-old woman presenting first ear disease and then cranial nerve, lung and kidney lesions and ultimately central nervous system involvement was found on kidney biopsy to have Wegener granulomatosis (WG). It is unlikely that the vasculitic component of the illness was directly responsible for most of the neurological symptoms.

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Sommario Viene descritto il caso di una paziente di 44 anni la quale presentò, nell'ordine, una patologia dell'orecchio medio, di alcuni nervi cranici, dei polmoni, dei reni ed infine del sistema nervoso centrale. La diagnosi di Granulomatosi di Wegener venne formulata dopo biopsia renale. Gli autori ritengono che una relazione diretta fra le componenti vasculitiche della malattia ed i sintomi neurologici sia, almeno per quanto riguarda il SNC, improbabile.

     

Postictal Subcortical Restricted Diffusion in a Child With Focal Symptomatic Epilepsy

BackgroundDiffusion abnormalities on MRI are well described after prolonged seizures. However, isolated, focal, subcortical restricted diffusion is uncommon.PatientA girl of Kurdish descent experienced focal-onset epilepsy secondary to a left thalamic infarction at age 3 years. At age 6 years, she developed status epilepticus in the context of a febrile illness.ResultsFour days after the seizure, she had neurological deterioration including involuntary posturing movements and irritability. A brain MRI revealed left hemisphere subcortical restricted diffusion, predominantly in the frontal and occipital regions. She experienced persistent right hemiparesis for 2 months after the initial seizure.ConclusionsThis presentation is reminiscent of acute encephalopathy with biphasic seizures and late reduced diffusion, a syndrome thus far reported almost exclusively in Japan. This represents one of the few documented examples of acute encephalopathy with biphasic seizures and late reduced diffusion in an individual not of east Asian descent.     

急性一氧化碳中毒后迟发性脑病与自由基关系的初步研究

测定了３１例急性一氧化碳中毒后迟发性脑病患者血清过氧化脂质（ＬＰＯ）、水溶性脂质过氧化物（ＷＳＦＳ）、谷胱甘肽过氧化物酶（ＧＰＸ）、维生素Ｅ（ＶＥ）的含量，并与健康者作了比较。结果表明，患者血清中ＬＰＯ、ＷＳＦＳ含量明显增高，ＧＰＸ、ＶＥ含量明显降低，与对照组比较有显著性差异。患者组治疗１个月后复查，结果上述指标均有不同程度改变，且与病情变化基本一致。提示自由基可能在本病发病中起重要作用。