ICU; you see me

A 50-year-old woman presented with mild exercise-induced shortness of breath; she reported being otherwise healthy. Her family history was notable for her mother's having the Osler–Weber–Rendu syndrome, also calledhereditary hemorrhagic telangiectasia . Physical examination revealed a reduced arterial oxygen saturation level (80%) and telangiectasias of the lips and the tongue (Panel A). Chest radiography showed a tubular opacity in the right lower pulmonary lobe (Panel B, left side, white box, and right side [magnified view], arrows). A gadolinium-enhanced four-dimensional magnetic resonance angiogram revealed a complex vascular structure in the right lower lobe immediately posterior to the left atrium. The posterior view (Panel C) revealed an arteriovenous fistula with two feeding arteries (arrows) and one draining vein (arrowhead). Selective pulmonary angiography confirmed this diagnosis, and the feeding arteries were occluded. Subsequently, the patient's arterial oxygen saturation level returned to normal (98%). The diagnosis ofhereditary hemorrhagic telangiectasia was later confirmed by means of genetic examination.

Information

Figure . Hemodynamic determinants of mean pulmonary arterial
pressure (mPAP). A. Raised mPAP due to high flow through large
arteriovenous malformations (AVMs) leading to raised cardiac output
(CO) but typically normal pulmonary vascular resistance (PVR) and
pulmonary capillary wedge pressure (PCWP). B. Contrast to raised
mPAP due to raised PVR from obstructive pulmonary vascular lesions
in HHT-related pulmonary arterial hypertension.
 

原始血管和血细胞均是起源于中胚层的间充质，早期胚胎体节尚未形成时，在卵黄囊及体蒂的外中胚里，部分细胞集中形成大小不等的细胞群，称为血岛。血 岛渐渐 伸展并相互连接形成原始的毛细血管丛。动脉和静脉起源于时间同一的毛细血管丛。血管的胚胎发育过程，大致可分为丛状期、网状期和管干形成期三个阶段。在网 状期，如果扩大的血管交通集聚，并趋向于融合一起就可产生动静脉瘘。在组织学上可见到无数平行的血管融合不全，并多处互相交通，这些交通往往极其细小称为 微小动静脉瘘。在管干形成期，大体循环动静脉之间继续保留异常广泛的交通称为大动静脉瘘。分三型：①干状动静脉瘘，在周围动静脉主干之间在横轴方向有交通 支。多数的瘘口稍大，所以动静脉之间分流也多。在病变部位可出现杂音、震颤、静脉曲张和蜿 蜒状动脉瘤。②瘤样动静脉瘘：在周围动静脉主干之间，横轴方向有细小众多的交通支，而且累及局部软组织和骨骼，局部组织伴瘤样的篾宾主张。一般血液分流量 较少，局部无杂音和震颤。③混合型：有干状和瘤样的多发性动、静脉交通。

case 1

三维重建片

case 2

病史简介:
患者24岁，男性，活动后有心慌气短10余年，而且常有流鼻血病史。杵状指明显，左侧背部查体时可闻及血管搏动音。并且以吸气时较为明显，这种“心外音”是本病在临床上较为典型的体征。
肺动静脉瘘的相关临床问题：
肺动脉与肺静脉之间的异常交通而不经过肺泡毛细血管可造成以下三个临床后果：
（1）紫绀：肺血的右向左分流可造成低氧血症，活动后症状更加明显，稍剧烈运动即有心慌气短。
（2）脑卒中：由于绕过肺泡毛细血管床的过滤作用，微粒物质（气泡或栓子等）可直接到达体循环（异位栓塞），可造成脑部并发症（TIA，卒中，脑脓肿等），
（3）咯血：这些异常血管可以破入支气管（咯血）或胸腔（血胸），常见于妊娠妇女。
（4）鼻钮：鼻粘膜存在动静脉瘘时，患者常常有鼻出血的病史，而且每次出血量较大。
治疗：
经导管栓塞治疗是目前避免肺动静脉畸形神经系统并发症和治疗肺动静脉畸形引起的咯血的首选方法，经导管栓塞治疗亦用于减轻弥漫型患者的低氧症状。
手术切除病变的肺组织也是治疗肺部动静脉瘘的方法之一，尤其对于范围较大的肺动静脉瘘。

杵状指和正常手指比较

case 3

患者,男,34岁,嘴唇紫绀史14年,近两周胸闷.入院查体:杵状指，嘴唇紫绀，血气PO2 47mmHg。今天我随他去做DSA。大家瞧瞧~

case 4

hereditary hemorrhagic telangiectasia

Line diagram of classic components of TGF-beta mediated cell signaling pathway, illustrating the potential cross-talk between the type II receptor BMPR2 and the type I receptor ALK1, modulated by the accessory receptor endoglin. The balance between activation of these pathways is considered to regulate progression or resolution of angiogenesis, which may contribute to the clinical features of vascular remodeling.
 

遗传性出血性毛细血管扩张症是一种以血管发育异常为特征的常染色体显性遗传病（HHT）。HHT目前主要分为两型：HHT-1和HHT-2。HHT-2是 由于12号染色体上ALK-1基因突变所致。TGF-β具有调节细胞的增殖和分化、血管新生等功能，并且ALK-1介导的血管新生的过程中，需要TGF- β配体参与。ALK-1突变导致了TGF-β在ALK-1信号传导异常，从而HHT患者血管发育异常。

Figure 4. Family A reported in detail in Trembath et al.9 Pedigree shows diversity of vascular phenotypes consequent upon mutation of ALK1 segregating within the kindred.	Figure 5. Diagram of ALK1 cDNA with exons encoding protein functional domains. Location of previously reported mutations in classic HHT (above) and all ALK1 mutations reported to date in HHT-related pulmonary arterial hypertension (below). Note potential clustering within the so-called NANDOR box, a region from codons 479 to 489 apparently necessary for TGF-beta signaling regulation.10

遗传性出血性毛细血管扩张症(Rendu-Osler-Weber病)，是多个部位存在毛细血管扩张病变的综合症。
病变多存在于面部,唇部,口鼻粘膜,手指和脚趾尖端，同时伴有鼻出血，消化道出血，脑出血等。此病可以累计肝脏，但是也可以不累及。

Reference

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