低顱壓綜合癥 Intracranial hypotension

1、低顱壓綜合癥 Intracranial hypotension 病史：The patient is a 22-year-old woman complaining of a headache that is exacerbated while standing and while coughing, but relieved in the recumbent position since the birth of her first child 1 month ago. The delivery was uncomplicated except for difficulty establish

2、ing epidural anesthesia.影像改變：There is diffuse linear enhancement of the pachymeninges involving both the supratentorial and infratentorial compartments (arrows in Figure 1 and Figure 2).硬腦膜可見彌漫性線樣強(qiáng)化,累及幕上及幕下The sagittal T1-weighted image demonstrates low-lying cerebellar tonsils (yellow arrow Figure

3、3), a slightly elongated fourth ventricle, and slight effacement of the prepontine cistern. Slight AP elongation of the mesencephalon is demonstrated on the axial T2-weighted image (yellow arrow in Figure 4).矢狀位Ti顯示扁桃體低位,四腦室輕度狹長,橋前池輕微狹窄,軸位T2顯示中腦向前后方向輕度延伸.診斷：Intracranial hypotension低顱壓綜合癥要點(diǎn)：· Me

4、ningeal enhancement should be categorized as pachymeningeal or leptomeningeal to aid in the formulation of a differential diagnosis.腦膜強(qiáng)化應(yīng)該被分為硬腦膜或軟腦膜強(qiáng)化,以幫助鑒別診斷· The typical imaging findings of intracranial hypotension are: sagging of posterior fossa structures and diffuse pachymeningeal enhancem

5、ent.顱內(nèi)低壓綜合征的典型影像表現(xiàn)為:后顱窩結(jié)構(gòu)下垂和彌漫性硬腦膜強(qiáng)化.討論：Intracranial hypotension (ICH) is a rare cause of orthostatic headache that worsens in the upright position. ICH is thought to result from a persistent CSF leak, usually after dural compromise following a diagnostic lumbar puncture, spinal anesthesia, or myelo

6、graphy. Other etiologies include prior craniotomy, craniectomy, spinal surgery, or trauma. ICH may also occur spontaneously secondary to rupture of a Tarlov cyst, dehydration, hyperpnea, uremia, or diabetic coma.低顱壓綜合癥（ICH）是體位性頭痛的一種少見病因，在直立位的時(shí)候更明顯，ICH被被認(rèn)為是腦脊液持續(xù)性滲漏的結(jié)果，通常發(fā)生在診斷性腰穿、脊椎麻醉或脊髓造影術(shù)后。其他的病因包括既往

7、的開顱術(shù)后、顱骨切除術(shù)、脊椎外科手術(shù)或創(chuàng)傷。ICH也可以繼發(fā)于Tarloy囊腫破裂、脫水、深快呼吸、尿毒癥或糖尿病昏迷Imaging characteristic can be subtle and nonspecific in the absence of an appropriate history. The imaging findings are characterized by sagging of the posterior fossa with low-lying cerebellar tonsils (which may be mistaken for a Chiari I m

8、alformation), elongation of the fourth ventricle, and effacement of the prepontine cistern. Additionally, diffuse smooth linear pachymeningeal enhancement is present involving both the supratentorial and infratentorial compartments. The diffuse pachymeningeal enhancement is felt to result from incre

9、ased intracranial blood flow to compensate for the CSF loss in accordance with the Monro-Kellie hypothesis, particularly on the venous side of the dura. Other imaging signs of venous congestion that may be present include bilateral subdural effusions and an enlarged pituitary gland.在缺乏明確的病史時(shí)，影像表現(xiàn)可以是

10、輕微的，且無特異性。其特征性的影像表現(xiàn)是顱后窩的下降，表現(xiàn)為小腦扁桃體的低位（可能被誤以為是Chiari型畸形），四腦室的延長、橋前池的消失。另外，彌漫性的硬腦膜線樣強(qiáng)化，同時(shí)累及幕上/下。依據(jù)假設(shè)，彌漫性的硬腦膜強(qiáng)化被認(rèn)為是由于顱內(nèi)血流增加以補(bǔ)償腦脊液的丟失，特別是硬膜靜脈。其他的靜脈性充血的影像表現(xiàn)包括雙側(cè)硬膜下積液和增大的腦垂體。The diagnosis can be confirmed with a low CSF opening pressure, nuclear radioisotope cisternography, or myelography. Symptoms will

11、often resolve spontaneously with conservative therapy and bed rest. If symptoms persist, an autologous epidural blood patch is a safe, effective treatment.通過降低的腦脊髓開放壓、核素顯像、脊髓造影可以確診，通過保守治療及臥床休息，臨床癥狀可以自發(fā)的消退。假如癥狀持續(xù)，硬膜外腔注射自體靜脈血是一種安全有效的治療方式。 另一段資料顱內(nèi)低壓綜合征疾病概述：正常顱內(nèi)壓的范圍，由腰椎穿刺測(cè)定應(yīng)在7.8411.8kPa（80120mmH2O）之間。一般

12、顱腦損傷后的顱內(nèi)壓，常有不同程度的升高，而表現(xiàn)為低顱壓者較少，間或有些病人傷后早期曾經(jīng)有過顱內(nèi)壓升高，嗣后又出現(xiàn)顱內(nèi)低壓，其發(fā)生率約為5。所謂顱內(nèi)低壓綜合征，系指病人側(cè)臥腰穿壓力在7.84kPa以下所產(chǎn)生的綜合性癥候群，臨床表現(xiàn)與顱內(nèi)壓增高相類似，只因處理方法各異，必須慎加區(qū)別。造成顱內(nèi)低壓的原因，可能原發(fā)于傷后腦血管痙攣，使脈絡(luò)叢分泌腦脊液的功能受到抑制，亦可能繼發(fā)于腦脊液漏、休克、嚴(yán)重脫水、低血鈉癥、過度換氣以及手術(shù)或腰穿放出過多的腦脊液等。腰穿后頭疼已為人們所熟知，其機(jī)理一是腰穿本身所引起的脈絡(luò)叢反射性抑制或因丘腦下部腦脊液分泌中樞發(fā)生功能紊亂；二是腦脊液容量的減少。Franksson曾

13、指出，當(dāng)顱內(nèi)壓為100200mmH2O時(shí)，自腰穿針孔漏入硬脊膜外間隙的腦脊液，1天就可達(dá)240ml之多，而正常情況下腦脊液總量為100160ml，分泌速率約為0.3ml/min，每天可產(chǎn)生400500ml，故健康人一次快速放出腦脊液20ml，即可引起頭疼。Grant等（1991）認(rèn)為頭疼可能是因代償性動(dòng)脈擴(kuò)張所致。另外，因外傷時(shí)腦脊液向椎管強(qiáng)力沖擊，造成腰神經(jīng)根袖囊撕裂亦有可能使腦脊液漏入硬脊膜外間隙，從而導(dǎo)致低顱壓（Bell,1960）。疾病描述正常顱內(nèi)壓的范圍，由腰椎穿刺測(cè)定應(yīng)在7.8411.8kPa（80120mmH2O）之間。一般顱腦損傷后的顱內(nèi)壓，常有不同程度的升高，而表現(xiàn)為低顱壓者較少，間或有些病人傷后早期曾經(jīng)有過顱內(nèi)壓升高，嗣后又出現(xiàn)顱內(nèi)低壓，其發(fā)生率約為5。所謂顱內(nèi)低壓綜合征，系指病人側(cè)臥腰穿壓力在7.84kPa以下所產(chǎn)生的綜合性癥候群，臨床表現(xiàn)與顱內(nèi)壓增高相類似，只因處理方法各異，必須慎加區(qū)別。癥狀體征昏迷和近事遺忘、昏迷時(shí)程長短，有無中間好轉(zhuǎn)或清醒期，有無嘔吐及其次數(shù)，大小便失禁，抽搐、癲