第141例后循环白质脑病综合征.docx

1、第141例后循环白质脑病综合征第141例 后循环白质脑病综合征流星飞雪战友：后循环白质脑病综合征（Posterior leukoencephalopathy syndrome）短述：后循环白质脑病综合征（Posterior leukoencephalopathy syndrome，PLS）是一种潜在的可逆性疾病，在临床特点及影像学特点比较相似。以下三个病例被误诊为卒中，并遵循指南治疗，没有一例满足现在的高血压治疗标准（卒中急性期），诊断未明确之前，当然没有给予降压治疗。当然诊断明确之后，应该迅速降压治疗，三位患者临床症状迅速好转。由于在预后和治疗方面的差异，快速和正确的诊断是基本且是重要的。如

2、果患者的临床和影像学特点主要影响枕叶，应该考虑到后循环白质脑病综合征（PLS）。这三个病例表明PLS从自发性后循环梗死（病因如基底动脉血栓形成或血管炎）中鉴别开来的重要性。病例1：一位48岁右利手女性患者，持续5天频繁发作性排尿困难、僵直及下腹部疼痛。一个月前放置避孕环治疗月经过多。体格检查：血压正常（BP 120/60 mm Hg)，耻骨弓上明显触痛。实验室检查：白细胞 24109/L，Hgb 7.9g/dL。诊断为子宫积脓，处理：去除避孕环、手术引流。剖腹后的起初过程是满意的，但是在第8天，血压波动在175/95 mm Hg.，考虑手术后疼痛引起的血压升高，并给予止痛。两天后患者易激惹、躁

3、动不安，时间及地点定向力差，血压持续升高（190/117 mm Hg）。神经系统检查：皮质盲（常视盘）。急诊头CT发现双侧枕叶广泛性脑梗死改变，明显的基底池消失，核磁Flair和T2序列双侧枕叶异常的高信号。诊断为双侧枕叶卒中。随后几天患者反应迟钝，血压持续在215/118 mm Hg，双侧瞳孔对光反射消失及去大脑僵直。给予气管插管、过度换气及静脉给予甘露醇。依据急性缺血性卒中治疗指南，血压未给予治疗。对病史、体格及影像学回顾，诊断为PLS。静脉给予拉贝洛尔使平均动脉压降至100-110 mm Hg，在降血压治疗的24小时内神经体征得到了改善，两周后定向力恢复正常并出院。病例2一位56岁的女性

4、患者持续性头痛10天，到急诊就诊。4个月前诊断为结肠腺癌浸润性转移（网膜和肝脏），行乙状结肠切除术，并给予药物化疗（伊立替康、5-氟尿嘧啶及甲酚四氢叶酸）。入院前3周，给予红细胞生成素治疗贫血。入院时患者主诉持续性枕部疼痛，起初的头痛与第二次给予红细胞生成素相关，第三次给予红细胞生成素头痛加重。此时，血压和神经系统评价均正常，但是正常红细胞性贫血。增强头CT显示枕叶脑室旁梗塞。后来的5天，患者意识错乱且诉双眼模糊及剧烈头痛，血压升至165/85 mm Hg，神经系统检查无定位体征。增强头核磁显示双侧枕叶广泛地皮层下白质异常信号且小脑轻度受累，且灰质相对不足(图a,b)，未见转移灶或软脑膜增强，

5、这些发现优先考虑血管炎或白质脑病。诊断：继发于红细胞生成素的后循环白质脑病。治疗：停止红细胞生成素，开始口服尼莫地平。10天后，患者症状完全消失，复查头核磁枕叶异常信号基本完全消失(图c,d)a：核磁Flair像b：核磁T2像c：3周后复查核磁，FLAIR像d：3周后复查核磁，T2像病例3一位35岁右利手男性患者继发于右基底肺炎的脓毒血症。既往系统性红斑狼疮，伴发慢性肾衰且10年前住院时需要肾移植。规律口服红细胞生成素、环孢菌素、泼尼松龙、麦考酚酯（免疫抑制剂）。起初此患者对抗生素反应良好，入院后10天出现癫痫大发作，发作后患者诉视觉模糊，体格检查无局灶性神经体征，血压升高为172/114 m

6、m Hg (入院时BP 128/73 mm Hg).血环孢菌素浓度高（400 ng/ml）。头CT显示双侧枕叶梗死样低密度，头核磁显示双侧枕叶Flair像高信号，MRV正常。上述表现感觉像血管炎或中毒性脑病。停止环孢菌素，并给予络活喜降压治疗。诊断为PLS，是继发于红细胞生成素和/或环孢菌素，此患者恢复较好。介绍：PLS近来被描述为神经综合征，主要累及顶枕白质，此病多发生在惊厥、肾衰、高血压脑病、免疫抑制治疗的患者。此病数天后可迅速进展，其综合征包括头痛、意识错乱、视觉模糊。大部分高血压患者可有可无神经系统局灶性体征如皮质盲即巴林特综合征(双侧顶-枕区损伤)。核磁显示双侧顶枕白质水肿，这些改变

7、与动脉或静脉梗塞相似。快速识别及合适地迅速降压可阻止其进展。流星飞雪战友：讨论：Three cases of PLS are presented which had been diagnosed as cerebral infarction. The aetiologies of PLS in these cases is diverse; abdominal sepsis (case one), erythropoietin (cases two and three) and cyclosporin (case three). All patients had common clinical

8、 findings characteristic of PLS2: subacute onset of symptoms; insidious rise in blood pressure correlating with the onset of neurological symptoms; headache with visual disturbances; and seizure. In particular, the patient in case one then progressed clinically to show all the common features of PLS

9、 such as confusion, decreased level of conscious and cortical blindness. Suggestive radiological findings were present in all patients involving the white matter in the parietio-occipital regions, which were apparent to varying degreesion CT and, in particular, MR imaging. In all three cases there w

10、as rapid and complete resolution of symptoms following treatment/withdrawal of the predisposing factor combined with aggressive management of hypertension.PLS, as these cases illustrate, is completely reversible with timely diagnosis and appropriate management4. Delay in diagnosis leads to permanent

11、 brain injury and possibly death5. The primary differential diagnoses that need to be excluded are cerebral venous thrombosis and simultaneous bilateral posterior artery territory infarction (top of the basilar syndrome). Clinicoradiologically, cerebral venous thrombosis may be differentiated from P

12、LS. Clinically focal motor defects are common in cerebral venous thrombosis while hypertension is uncommon in the initial stages. Radiologically, subcortical haemorrhagic infarcts and the delta sign may be seen in cerebral venous thrombosis6.In contrast to the sub acute onset of PLS, basilar artery

13、territory infarction presents acutely and evolves over hours. There is usually a clinical background of atrial fibrillation, bacterial endocarditis, coagulopathy or other stroke risk factors. Cortical blindness, hemianopia and brainstem signs are prominent, while seizures are initially uncommon6. In

14、 addition, MRI with diffusion weighted sequences may be used reliably to distinguish PLS from posterior circulation infarction7.The management and prognosis of basilar artery territory stroke differs considerably from PLS. Recent guidelines from the American Stroke Association on management of strok

15、e and a systematic review of stroke literature recommend that anti hypertensives be withheld during the acute period unless the systolic blood pressure exceeds 220mmHg, or the diastolic blood pressure exceeds 120mmHg. In addition the guidelines advocate that thrombolysis with recombinant tissue-plas

16、minogen activator (rtPA) be administered to selected patients within three hours of onset of symptoms3,8. Specifically, treatment of basilar artery occlusion by intra-arterial administration of rtPA may benefit patients treated at longer time period after symptom onset9. These cases emphasise the im

17、portance of accurately distinguishing early PLS from stroke due the basilar artery occlusion. Initial diagnoses of bilateral occipital infarction were made in these patients and the treating physicians then appropriately followed the current guidelines on treatment of acute stroke and withheld anti

18、hypertensive treatment. Prompt recognition of PLS allows removal of the precipitant and control of hypertension and avoids potentially hazardous administration of anticoagulant or thrombolytic agents. In addition it appears from our clinical experience that the prevalence of PLS may be underestimate

19、d. We feel that PLS needs to be considered a in the differential diagnosis of patients presenting with clinicoradiological features predominantly affecting the posterior circulation.参考文献：Hinchey J, Chaves C, Appignani B, Breen J, Pao L, Wang A, Pessin MS, Lamy C, Mas J, Caplan LR. A reversible poste

20、rior leuokencephalopathy syndrome. N Engl J Med. 1996;334:494-500 Minagar A, Detoledo JC, Falcone S. Cortical-subcortical lesions in reversible posterior leukoencephalopathy syndrome. Encephalopathy or seizures? J Neurol 2001;248:537-540 Adams HP, Adams RJ, Brott T, del Zoppo GJ, Furlan A, Goldstein

21、 LB, Grubb RL, Higashida R, Kidwell C, Kwiatkowski TG, Marler JR, Hademenoa GJ. Guidelines for the early management of patients with ischemic stroke. Stroke. 2003;34:1056-1083 Vaughan CJ, Delanty N. Hypertensive emergencies. Lancet. 2000;356: 411-417 Ay H, Buonanno FS, Schaefer PW, Le DA, Wang B, Go

22、nzalez RG, Koroshetz WJ. Posterior leukoencephalopathy without severe hypertension utility of diffusion-weighted MRI. Neurology. 1998;51:1369-1376 Garg RK. Posterior leukoencephalophy syndrome. Postgrad med J. 2001;77:24-28 Lamy C, Oppenheim C, Meder JF, Mas JL. Neuroimaging in Posterior Reversible

23、Encephalopathy Syndrome. J. Neuroimaging 2004;14:89-96 Warlow C, Sudlow C, Dennis M, Wardlaw J, Sandercock P. Stroke. Lancet. 2003;362:1211-24 Lin DDM, Gailloud P, Beauchamp NJ, Aldrich EM, Wityk RJ, Murphy KJ. Combined stent placement and thrombolysis in acute vertebrobasilar ischemic stroke. Am. J

24、. Neuroradiol. 2003;24:1827-1833 Yyzzhh战友：RPLS可发生在多种临床情况下，如高血压脑病，妊娠毒血症，化疗，免疫球蛋白治疗，血栓形成性血小板减少性紫癜、卟啉病，器官移植后，胶原性血管如SLE、结节性动脉炎，Behcets病和获得性免疫缺陷综合征，肾病综合征等引起高凝状态的系统性疾病。可逆性后部白质脑病 的影像学表现：RPLS的CT和MRI颅脑影像学改变具有鲜明的特征性，主要累及大脑半球顶枕区，表现为以皮质下白质为主的弥漫性对称性大片脑水肿，小脑、额颞叶白质以及基底节均偶有受累，经适当治疗，上述部位的异常信号多可在数月内恢复。近年来随着认识的不断深入，也出

25、现了越来越多关于不典型RPLE影像学特征的报道，病灶部位包括：双侧丘脑、内囊、脑干、额顶叶白质等。头颅CT常显示为大脑半球后部以白质为主的大片脑水肿，可以对称或不对称分布，灰质一般不受累；MRI的分辨率较高，除上述部位的病灶外，还可以清晰显示累及小脑、脑干、额颞叶白质以及基底节的病灶，表现为T1加权等或低信号，T2加权高信号，FLAIR序列更为敏感，能显示早期微小的局部异常。还有学者进行DWI以及表观弥散成像（apparent diffusion coefficient, ADC）的测定，不仅进一步提高了微小病灶的检出率，而且能与其他性质的疾病进行鉴别，因为细胞毒性脑水肿在DWI上呈现高信号，

26、在ADC上呈低信号，而RPLS为血管源性的脑水肿在DWI上呈现等或低信号，在ADC上呈现高信号。借助这两种检测序列可区别缺血性脑损伤的细胞毒性水肿与RPLE的血管性水肿，对疾病的鉴别诊断具有重要的意义Yyzzhh战友：Quote:因为细胞毒性脑水肿在DWI上呈现高信号，在ADC上呈低信号，而RPLS为血管源性的脑水肿在DWI上呈现等或低信号，在ADC上呈现高信号。借助这两种检测序列可区别缺血性脑损伤的细胞毒性水肿与RPLE的血管性水肿，对疾病的鉴别诊断具有重要的意义以上关于RPLS ADC和DWI的论述是否完全正确呢？看下图：a-flair b-DWI c-ADC d-flair：DWI高信号

27、，ADC低信号，和上述影像表现完全相反，图片到底是不是RPLS呢，答案是肯定的。Yyzzhh战友：DISCUSSIONRecently, several studies have been trying to predict the evolution of RPLS8,11,12. Increased signal intensity on diffusion-weighted images (D-WI) with a decreased ADC, configure the illness as a result of cytotoxic edema, which can course w

28、ith possible neurological sequela8,12. In our cases, four patients showed increased signal intensity on D-WI; two of them did not show any reduction of the ADC and had a good outcome and the other two showed reduced ADC and had adverse outcomes. In the last two cases, persistent lesions were observe

29、d on control examinations. One suffered from partial loss of vision and the other suffered upper left limb motor deficit. The poor clinical prognosis related to the reduction of ADC, may be explained by the cytotoxic edema theory, characterized by an abrupt elevation of the blood pressure that induc

30、es a reflex vasoconstriction, leading to low blood flow and consequently cytotoxic edema and ischemia1,13. The reversibility of RPLS in the majority of cases diverges from cytotoxic edema theory2,10.Another acceptable theory is sustained by the abrupt elevation of the blood pressure with loss of aut

31、oregulation of the cerebral vessels, leading to a cerebral vasodilatation and vasogenic edema. When the average blood pressure (which normally ranges from 60 to 120 mmHg) increases, there is a tendency of vasoconstriction limiting the high blood flow and protecting the cerebral parenchyma, but somet

32、imes the arterial blood pressure rises so high that regulation fails and plasma and cell extravasation occurs into the interstitial space both in the cortex and the white matter, which may explain the reversibility of some lesions and the vasogenic edema theory2,13.Besides conventional MRI, proton spectroscopy and perfusion have been used to predict the evolution of RPLS7,13,14. Eicheler et al.14 analyzed proton spectroscopy in two patients with RPLS and showed rises of the choline level and a decrease in the N-acetyl aspartate. Despite of