INTRODUCTION  介紹 — 

Intestinal ischemia, which can affect the small or large intestine, can be caused by any process that reduces intestinal blood flow, such as arterial occlusion, venous occlusion, or arterial vasospasm. For patients with acute symptoms, a rapid diagnosis is imperative since the clinical consequences can be catastrophic, including sepsis, bowel infarction, and death.
腸缺血可影響小腸或大腸，可由任何減少腸道血流量的過程引起，例如動脈閉塞、靜脈閉塞或動脈血管痙攣。對於有急性癥狀的患者，快速診斷勢在必行，因為臨床後果可能是災難性的，包括敗血症、腸梗死和死亡。

An overview of intestinal ischemia and differentiation of the various forms of intestinal ischemia are reviewed. Specific etiologies of intestinal ischemia are reviewed in more detail elsewhere.
本文將總結腸缺血的概述和各種形式的腸缺血的鑒別。腸缺血的具體病因詳見其他專題。

●(See "Acute mesenteric arterial occlusion".)
（參見 “急性腸系膜動脈閉塞”）

●(See "Chronic mesenteric ischemia".)
（參見 “慢性腸系膜缺血”）

●(See "Nonocclusive mesenteric ischemia".)
（參見 “非閉塞性腸系膜缺血”）

●(See "Mesenteric venous thrombosis in adults".)
（參見 “成人腸系膜靜脈血栓形成”）

●(See "Colonic ischemia".)
（參見 “結腸缺血”）

CLASSIFICATION  分類 — 

Intestinal ischemia can be classified according to the time course of onset and quality of symptoms, the degree to which blood flow is compromised, and the segment of the bowel that is affected. Ischemia affecting the small intestine is generally referred to as mesenteric ischemia, while ischemia affecting the large intestine is referred to as colonic ischemia. A broader term, splanchnic (visceral) ischemia, encompasses ischemia affecting the intestine, as well as other abdominal organs such as the liver, spleen, or kidneys.
腸缺血可根據發作的時間過程和癥狀品質、血流受損程度以及受累的腸段進行分類。影響小腸的缺血通常稱為腸系膜缺血，而影響大腸的缺血稱為結腸缺血。更廣泛的術語是內臟（內臟）缺血，包括影響腸道以及其他腹部器官（如肝臟、脾臟或腎臟）的缺血。

●Acute mesenteric ischemia – Acute mesenteric ischemia refers to the sudden onset of small intestinal hypoperfusion, which can be due to occlusive or nonocclusive obstruction of the arterial blood supply or obstruction of venous outflow. Occlusive arterial obstruction is due to an acute embolism or thrombosis and most commonly affects the superior mesenteric artery (SMA). Venous thrombosis is due to obstruction of the intestinal outflow tract, including the superior and inferior mesenteric veins and the splenic and portal veins. Nonocclusive mesenteric ischemia is a result of a low-flow state and is most commonly due to vasoconstriction from low cardiac output or the use of vasopressors.
急性腸系膜缺血 – 急性腸系膜缺血是指小腸灌注不足的突然發作，這可能是由於動脈供血的閉塞性或非閉塞性阻塞或靜脈流出受阻所致。閉塞性動脈梗阻是由急性栓塞或血栓形成引起的，最常影響腸系膜上動脈 （SMA）。靜脈血栓形成是由於腸流出道阻塞所致，包括腸系膜上靜脈和腸系膜下靜脈以及脾靜脈和門靜脈。非閉塞性腸系膜缺血是低流量狀態的結果，最常見的原因是低心輸出量或使用血管加壓藥導致血管收縮。

●Chronic mesenteric ischemia – Chronic mesenteric ischemia usually develops in patients with mesenteric atherosclerosis causing episodic intestinal hypoperfusion related to eating.
慢性腸系膜缺血 – 慢性腸系膜缺血通常發生在腸系膜動脈粥樣硬化患者中，導致與進食相關的發作性腸灌注不足。

INTESTINAL VASCULAR ANATOMY
腸血管解剖學 — 

The arterial supply to the intestines consists primarily of the superior mesenteric artery (SMA) and inferior mesenteric artery (IMA).
腸道的動脈供應主要由腸系膜上動脈 （SMA） 和腸系膜下動脈 （IMA） 組成。

●The SMA supplies the entire small intestine except for the proximal duodenum (figure 1).
SMA 供應除十二指腸近端以外的整個小腸 （ 圖 1）。

●The SMA and IMA both supply the colon (figure 1 and figure 2).
SMA 和 IMA 均供應結腸 （ 圖 1 和 圖 2）。

●The celiac artery, which provides blood flow to the liver, pancreas, and spleen (figure 3), also provides collateral blood flow to the intestines (figure 4).
腹腔動脈為肝臟、胰腺和脾臟提供血流 （ 圖 3），也為腸道提供側支血流 （ 圖 4）。

The venous drainage parallels the arterial circulation and drains into the portal venous system (figure 5 and figure 6).
靜脈引流與動脈迴圈平行，流入門靜脈系統 （ 圖 5 和 圖 6）。

Collateral circulation — An extensive collateral circulation protects the intestines from transient periods of inadequate perfusion. However, prolonged reduction in splanchnic blood flow leads to vasoconstriction in the affected vascular bed and eventually reduces collateral blood flow [1,2].
側支迴圈  —  廣泛的側支迴圈可保護腸道免受短暫灌注不足的影響。然而，內臟血流量的長期減少會導致受累血管床的血管收縮，並最終減少側支血流量[1,2]。

The major collateral pathways include (figure 4):
主要的側支途徑包括（ 圖 4）：

●The celiac axis and the SMA communicate principally through the junction of the superior and inferior pancreaticoduodenal arteries (figure 3). Several smaller conduits have also been described. Because of the rich collaterals around the stomach, gastric ischemia is rare.
腹腔軸和 SMA 主要通過胰十二指腸上動脈和胰下動脈的交界處進行交通 （ 圖 3）。還描述了幾種較小的管道。由於胃周圍有豐富的側支，胃缺血很少見。

●The SMA and IMA communicate via the marginal artery of Drummond and the meandering mesenteric artery. The marginal artery of Drummond represents the major collateral arcade and is composed of branches from the right, middle, and left colic arteries [1,2]. It is located within the mesentery of the colon lying adjacent to the colonic wall and runs the entire length of the colon. The meandering mesenteric artery is an inconstant communication between the SMA and IMA that is variably described and is also referred to as the central communicating artery, and historically referred to as the arc of Riolan [3,4].
SMA 和 IMA 通過德拉蒙德邊緣動脈和蜿蜒的腸系膜動脈進行通信。Drummond 邊緣動脈代表主要側支拱廊，由右絞痛動脈、中絞痛動脈和左絞痛動脈的分支組成[1,2]。它位於結腸腸系膜內，靠近結腸壁，貫穿結腸的整個長度。蜿蜒腸系膜動脈是 SMA 和 IMA 之間的不恆定連通，其描述多種多樣，也稱為中央連通動脈，歷史上稱為 Riolan 弧[3,4]。

●Collateralization between the IMA and systemic circulation occurs in the rectum as the superior rectal (hemorrhoidal) vessels merge with the middle rectal vessels from the internal iliac arteries.
IMA 和體循環之間的側支發生在直腸中，因為直腸上（痔）血管與髂內動脈的直腸中部血管合併。

Areas prone to ischemia — The watershed areas between the major vessels that supply the colon are at risk for ischemia. The narrow terminal branches of the SMA supply the splenic flexure, and the narrow terminal branches of the IMA supply the rectosigmoid junction.
易缺血  區域 —  供應結腸的主要血管之間的分水嶺區域有缺血的風險。SMA 的窄末端分支供應脾屈，IMA 的窄末端分支供應直腸乙狀結腸交界處。

●Splenic flexure – The marginal artery of Drummond is often very small, and in 11 percent of patients, it is devoid of vasa recta for a length of approximately 1 to 3 cm [5]. Griffiths' point is defined as the site of communication of the ascending left colic artery with the marginal artery of Drummond, and anastomotic bridging between the right and left terminal branches of the ascending left colic artery at the splenic flexure of the colon [5]. It is a critical area of weakness of the blood supply of the splenic flexure that is prone to ischemia.
脾屈–Drummond 邊緣動脈通常非常小，11%的患者無直腸血管，長度約為 1-3cm[5]。Griffiths 點定義為左疝氣升動脈與 Drummond 邊緣動脈的交通部位，以及結腸脾曲處左疝氣升動脈左右末端支之間的吻合口橋接[5]。它是脾屈血液供應無力的關鍵區域，容易缺血。

●Rectosigmoid junction – Another area of critical weakness in the blood supply occurs at Sudeck's point, where the descending branch of the left colic artery forms an anastomosis with the superior rectal artery [6,7].
直腸乙狀結腸交界處–另一個血供嚴重無力部位發生在 Sudeck 穴，左絞痛動脈的降支與直腸上動脈形成吻合口[6,7]。

PHYSIOLOGY AND MECHANISMS OF ISCHEMIA
缺血的生理學和機制

Normal physiology — Changes in the resistance of mesenteric arterioles account for wide fluctuations in splanchnic blood flow. The splanchnic circulation receives between 10 to 35 percent of cardiac output, depending upon whether it is in the fed or fasted state. Although the capillary density within the intestinal vasculature is high compared with other vascular beds, intestinal oxygen extraction is relatively low, thereby permitting sufficient oxygen to be delivered to the liver via the portal vein. As a result, intestinal blood flow must be reduced by at least 50 percent from the normal fasting level before oxygen delivery to the intestine becomes compromised [8].
正常生理  —  腸系膜小動脈阻力的變化是內臟血流量波動較大的原因。內臟迴圈接收心輸出量的 10% 到 35%，具體取決於它是處於進食狀態還是空腹狀態。雖然與其他血管床相比，腸脈管系統內的毛細血管密度較高，但腸道氧氣提取量相對較低，從而允許足夠的氧氣通過門靜脈輸送到肝臟。因此，腸道血流量必須比正常空腹水準減少至少 50%，然後腸道的氧氣輸送才會受到損害[8]。

Numerous control mechanisms contribute to the regulation of mesenteric vascular tone and are responsive to varying conditions such as the postprandial state or systemic hypotension [9]. Intrinsic autoregulation of blood flow is an adaptation that helps redirect blood from the gut to the brain during periods of systemic hypotension [10]. Proposed mechanisms that preserve tissue perfusion include direct arteriolar smooth muscle relaxation and a metabolic response to adenosine and other metabolites of mucosal ischemia [10].
許多控制機制有助於腸系膜血管張力的調節，並對餐后狀態或全身性低血壓等不同情況做出反應[9]。血流的內在自動調節是一種適應，有助於在全身性低血壓期間將血液從腸道重新引導至大腦[10]。所提出的保留組織灌注的機制包括直接小動脈平滑肌鬆弛以及對腺苷和其他粘膜缺血代謝物的代謝反應[10]。

Neural and hormonal mechanisms also contribute to the extrinsic control of intestinal blood flow. These include the sympathetic nervous system, the renin-angiotensin axis, and the release of vasopressin from the pituitary gland.
神經和激素機制也有助於腸道血流的外在控制。這些包括交感神經系統、腎素-血管緊張素軸以及垂體加壓素的釋放。

Response to ischemia — The likelihood of developing intestinal ischemia depends upon the adequacy of systemic perfusion and collateral circulation, the number and caliber of the vessels that are affected, and the duration of the ischemic insult. Ischemic injury to the intestine develops when there is insufficient delivery of oxygen and nutrients required for cellular metabolism. However, intestinal injury is caused both by tissue hypoxia and reperfusion. Reperfusion injury occurs following restoration of blood flow after a period of ischemia [11]. It is a complex response characterized by the release of free oxygen radicals, toxic byproducts of ischemic injury, and neutrophil activation, which can lead to multisystem organ failure [12].
缺血  的反應 —  發生腸缺血的可能性取決於全身灌注和側支迴圈的充分性、受累血管的數量和口徑以及缺血性損傷的持續時間。當細胞代謝所需的氧氣和營養物質輸送不足時，就會發生腸道缺血性損傷。然而，腸損傷是由組織缺氧和再灌注引起的。再灌注損傷發生在缺血一段時間后血流恢復后[11]。這是一種複雜的反應，其特徵是釋放自由基、缺血性損傷的有毒副產物和中性粒細胞活化，可導致多系統器官衰竭[12]。

Under experimental conditions, ischemic injury of the mesenteric circulation does not occur until perfusion pressure is reduced to approximately 30 mmHg or the mean mesenteric arterial pressure is reduced to 45 mmHg [13]. The intestine is able to compensate for an approximately 75 percent reduction in mesenteric blood flow for up to 12 hours without substantial injury, in part because of increased oxygen extraction and vasodilation of collateral circulation [14]. However, after a prolonged period of ischemia, progressive vasoconstriction develops in the obstructed vascular bed, increasing its pressure and reducing collateral flow [15,16]. Vasoconstriction may persist even after blood flow has been restored. Persistent ischemia can lead to full-thickness necrosis of the bowel wall and subsequent perforation.
在實驗條件下，直到灌注壓降至約 30mmHg 或平均腸系膜動脈壓降至 45mmHg 后，腸系膜迴圈缺血性損傷才會發生[13]。腸道能夠補償腸系膜血流量減少約 75%，持續長達 12 小時，而不會造成重大損傷，部分原因是氧氣提取增加和側支迴圈血管舒張[14]。然而，在長時間缺血后，阻塞的血管床會出現進行性血管收縮，增加其壓力並減少側支血流[15,16]。即使在血流恢復后，血管收縮也可能持續存在。持續缺血可導致腸壁全層壞死和隨後的穿孔。

The colonic circulation is vulnerable to hypoperfusion since it receives relatively less blood flow compared with the rest of the gastrointestinal tract. However, an observational human study performed during intestinal surgery suggested that the colonic epithelium may be more resistant to ischemia compared with the jejunum [17]. In addition, the microvasculature plexus of the colon is less developed and is embedded in a relatively thick wall as compared with the small bowel. In the majority of patients with colonic ischemia, a specific occlusive vascular lesion cannot be identified on angiography. Approximately 85 percent of these patients develop nongangrenous ischemia, which is usually transient and resolves without surgery or further complications [18].
結腸迴圈容易受到灌注不足的影響，因為與胃腸道的其他部分相比，結腸迴圈接收的血流量相對較少。然而，一項在腸道手術期間進行的人體觀察性研究表明，與空腸相比，結腸上皮對缺血的抵抗力可能更強[17]。此外，與小腸相比，結腸的微血管叢不太發達，嵌入相對較厚的壁中。在大多數結腸缺血患者中，血管造影無法識別特定的閉塞性血管病變。這些患者中約 85%發生非壞疽性缺血，通常為一過性，無需手術或進一步併發症即可消退[18]。

Etiologies of ischemia — The major etiologies of mesenteric ischemia are mesenteric arterial embolism (50 percent), mesenteric arterial thrombosis (15 to 25 percent), mesenteric venous thrombosis (5 percent), and nonocclusive mesenteric ischemia due to intestinal hypoperfusion (20 to 30 percent) [16,19].
缺血  的病因 —  腸系膜缺血的主要病因是腸系膜動脈栓塞（50%）、腸系膜動脈血栓形成（15%-25%）、腸系膜靜脈血栓形成（5%）和腸灌注不足所致的非閉塞性腸系膜缺血（20%-30%）[16,19]。

Both arterial and venous occlusion can lead to intestinal ischemia from twisting of the bowel (ie, volvulus) around a fixed attachment (ie, adhesion, mesenteric defect) or incarceration and strangulation of intestinal contents within a hernia. Patients with excessive bowel distention from bowel obstruction can get hypoperfusion from increased venous pressure and/or venous thrombosis of the involved segment of the intestine. (See "Management of small bowel obstruction in adults" and "Large bowel obstruction".)
動脈和靜脈閉塞均可導致腸缺血，原因是腸扭轉（即腸扭轉）圍繞固定附著物（即粘連、腸系膜缺損）或疝氣內腸內容物的嵌頓和勒死。腸梗阻導致腸過度擴張的患者可因靜脈壓升高和/或腸受累部分靜脈血栓形成而出現灌注不足。（參見 “成人小腸梗阻的治療” 和 “大腸梗阻”）

Less frequently, acute mesenteric ischemia may also be observed in the setting of an underlying vasculitis (eg, polyarteritis nodosa) most commonly affecting the small- and medium-diameter arteries; however, it may be difficult to determine whether arterial occlusion or spasm (ie, nonocclusive ischemia) is the cause of segmental intestinal infarction from vasculitis.
不太常見的是，急性腸系膜缺血也可能出現在基礎血管炎（如結節性多動脈炎）的情況下，最常累及小徑和中徑動脈;然而，可能難以確定動脈閉塞或痙攣（即非閉塞性缺血）是否是血管炎節段性腸梗死的病因。

Mesenteric arterial occlusion
腸系膜動脈閉塞

Arterial embolism — Embolism to the mesenteric arteries is most frequently due to a dislodged thrombus from the left atrium, left ventricle, cardiac valves, or proximal aorta. (See "Acute mesenteric arterial occlusion".)
動脈栓塞  —  腸系膜動脈栓塞最常見的原因是左心房、左心室、心臟瓣膜或近端主動脈的血栓脫落。（參見 “急性腸系膜動脈閉塞”）

Arterial thrombosis — Acute thrombosis of the mesenteric circulation usually occurs as a superimposed phenomenon in patients with a history of chronic intestinal ischemia from atherosclerotic disease. It can also occur in the setting of abdominal trauma, infection, thrombosed mesenteric aneurysm, and aortic or mesenteric artery dissection. (See "Acute mesenteric arterial occlusion" and "Chronic mesenteric ischemia".)
動脈血栓形成  —  腸系膜迴圈急性血栓形成通常表現為疊加現象，見於有動脈粥樣硬化性疾病慢性腸缺血病史的患者。它也可能發生在腹部外傷、感染、血栓性腸系膜動脈瘤以及主動脈或腸系膜動脈夾層的情況下。（參見 “急性腸系膜動脈閉塞” 和 “慢性腸系膜缺血”）

Venous thrombosis — Mesenteric venous thrombosis can be either idiopathic (eg, hypercoagulable states) or from secondary causes (eg, malignancy or prior abdominal surgery). Increases in the resistance of mesenteric venous blood flow lead to bowel wall edema, and the extent of ischemia is related to the extent of venous involvement. Mesenteric venous thrombosis rarely involves the colon. (See "Mesenteric venous thrombosis in adults".)
靜脈血栓形成  —  腸系膜靜脈血栓形成可是特發性（如高凝狀態），也可由繼發性（如惡性腫瘤或既往腹部手術）引起。腸系膜靜脈血流阻力增加導致腸壁水腫，缺血程度與靜脈受累程度有關。腸系膜靜脈血栓形成很少累及結腸。（參見 “成人腸系膜靜脈血栓形成”）

Nonocclusive mesenteric ischemia — Nonocclusive mesenteric ischemia (NOMI) is thought to occur as a result of splanchnic hypoperfusion and vasoconstriction [20]. Nonocclusive colonic ischemia or ischemic colitis most commonly affects the "watershed" areas of the colon that have limited collateralization, such as the splenic flexure and rectosigmoid junction. (See "Nonocclusive mesenteric ischemia".)
非閉塞性腸系膜缺血  —  非閉塞性腸系膜缺血（nonocclusive mesenteric ischeme， NOMI）被認為是由內臟灌注不足和血管收縮所致[20]。非閉塞性結腸缺血或缺血性結腸炎最常影響結腸側支有限的“分水嶺”區域，例如脾屈和直腸乙狀結腸交界處。（參見 “非閉塞性腸系膜缺血”）

EPIDEMIOLOGY AND RISK FACTORS
流行病學和危險因素 — 

Acute insufficiency of mesenteric arterial blood flow accounts for 60 to 70 percent of cases of mesenteric ischemia [15]. The remainder is related to chronic mesenteric and colonic ischemia.
腸系膜動脈血流量急性不足佔腸系膜缺血病例的 60%-70%[15]。其餘的與慢性腸系膜和結腸缺血有關。

The incidence of acute mesenteric ischemia appears to be rising, which may be due, in part, to an increased awareness among clinicians and an aging population with severe cardiovascular and/or systemic disease. Another contributing factor may be due to the prolonged survival of critically ill patients.
急性腸系膜缺血的發病率似乎在上升，這可能部分是由於臨床醫生意識的提高以及患有嚴重心血管和/或全身疾病的人口老齡化。另一個促成因素可能是危重患者的存留期延長。

In younger patients without cardiovascular disease, mesenteric venous thrombosis is the major cause of acute ischemia of the small bowel.
在沒有心血管疾病的年輕患者中，腸系膜靜脈血栓形成是小腸急性缺血的主要原因。

Risk factors — Risk factors for intestinal ischemia include any condition that reduces perfusion to the intestine, or that predisposes to mesenteric arterial embolism, arterial thrombosis, venous thrombosis, or vasoconstriction.
危險因素  —  腸缺血的危險因素包括腸道灌注減少，或易患腸系膜動脈栓塞、動脈血栓形成、靜脈血栓形成或血管收縮的疾病。

Risk factors for intestinal ischemia are listed below but vary according to the specific etiology.
腸缺血的危險因素如下，但因具體病因而異。

●(See "Acute mesenteric arterial occlusion", section on 'Etiologies'.)
（參見 “急性腸系膜動脈閉塞”，關於'病因'一節 ）

●(See "Chronic mesenteric ischemia", section on 'Etiology and associations'.)
（參見 “慢性腸系膜缺血”，關於'病因和關聯'一節 ）

●(See "Nonocclusive mesenteric ischemia", section on 'Risk factors'.)
（參見 “非閉塞性腸系膜缺血”，關於'危險因素'一節 ）

●(See "Mesenteric venous thrombosis in adults", section on 'Risk factors'.)
（參見 “成人腸系膜靜脈血栓形成”，關於'危險因素'一節 ）

●(See "Colonic ischemia", section on 'Risk factors'.)
（參見 “結腸缺血”，關於'危險因素'一節 ）

The following conditions put the patient at risk for intestinal ischemia:
以下情況使患者面臨腸缺血的風險：

●Cardiac disease – The majority of arterial emboli originate from the heart. Cardiac embolism can be related to arrhythmia, valvular disease, ventricular aneurysm, or poor cardiac function. Cardiac dysfunction can lead to peripheral hypoperfusion, and the treatment of certain conditions may involve the use of medications that cause vasoconstriction, leading to nonocclusive ischemia. Cardiopulmonary bypass during cardiac surgery can lead to underperfusion of the intestines, showering of microemboli, release of vasoactive substances, and alterations in coagulation [21-23]. (See "Thromboembolism from aortic plaque" and "Atrial fibrillation in adults: Selection of candidates for long-term anticoagulation".)
心臟病 – 大多數動脈栓塞起源於心臟。心臟栓塞可能與心律失常、瓣膜病、心室動脈瘤或心功能差有關。心功能不全可導致外周灌注不足，某些病症的治療可能涉及使用引起血管收縮的藥物，導致非閉塞性缺血。心臟手術期間體外迴圈可導致腸道灌注不足、微栓子淋浴、血管活性物質釋放和凝血改變[21-23]。（參見 “主動脈斑塊引起的血栓栓塞” 和 “成人心房顫動：長期抗凝治療的候選者選擇”）

●Aortic surgery or instrumentation – Atheroembolism can complicate cardiac catheterization, aortography, or endovascular aortic intervention. Similarly, aortic manipulation during aortic surgery can dislodge intraluminal thrombus or atherosclerotic debris, which can embolize distally into the intestinal circulation. (See "Postoperative complications among patients undergoing cardiac surgery", section on 'Physiologic complications' and "Complications of endovascular abdominal aortic repair", section on 'Ischemic complications' and "Procedure-specific and late complications of open aortic surgery in adults", section on 'Intestinal ischemia'.)
主動脈手術或器械 – 動脈粥樣硬化栓塞會使心導管插入術、主動脈造影或血管內主動脈介入治療複雜化。同樣，主動脈手術期間的主動脈作可以清除腔內血栓或動脈粥樣硬化碎片，這些碎片可以栓塞到遠端進入腸道迴圈。（參見 “心臟手術患者的術后併發症”，關於'生理併發症'一節和 “血管內腹主動脈修復術的併發症”，關於'缺血性併發症'一節和 “成人開放性主動脈手術的手術特異性併發症和晚期併發症”，關於'腸缺血'一節 ）

●Peripheral artery disease – Patients with atherosclerotic occlusive disease of the celiac artery, superior mesenteric artery, or inferior mesenteric artery are at risk for intestinal ischemia. (See "Chronic mesenteric ischemia", section on 'Clinical presentations'.)
外周動脈疾病 –患有腹腔動脈、腸系膜上動脈或腸系膜下動脈的動脈粥樣硬化性閉塞性疾病患者有腸缺血的風險。（參見 “慢性腸系膜缺血”，關於'臨床表現'一節 ）

●Hemodialysis – Low flow to the intestinal circulation can lead to nonocclusive intestinal ischemia [24] or intestinal infarction [25-29]. (See "Unique aspects of gastrointestinal disease in patients on dialysis".)
血液透析 –腸道迴圈流量低可導致非閉塞性腸缺血[24]或腸梗死[25-29]。（參見 “透析患者胃腸道疾病的獨特表現”）

●Vasoconstrictive medications – Many medications, as well as illicit drugs, have been implicated in the development of nonocclusive intestinal ischemia [30].
血管收縮藥物 –許多藥物以及違禁藥物都與非閉塞性腸缺血的發生有關[30]。

●Acquired and hereditary thrombotic conditions – To what extent acquired or hereditary hypercoagulable states contribute to the pathogenesis of intestinal ischemia is not well known. Up to 75 percent of patients with mesenteric venous thrombosis have an inherited thrombotic disorder [31-33]. Individuals with COVID-19 may have several complex and varied coagulation abnormalities that create a hypercoagulable state, and intestinal ischemia has been reported. (See "Overview of the causes of venous thrombosis in adults", section on 'Acquired risk factors' and "COVID-19: Hypercoagulability" and "Acute mesenteric arterial occlusion", section on 'Etiologies' and "Mesenteric venous thrombosis in adults", section on 'Risk factors' and "Overview of the causes of venous thrombosis in adults", section on 'Inherited thrombophilia'.)
獲得性和遺傳性血栓性疾病 – 獲得性或遺傳性高凝狀態在多大程度上促成腸缺血的發病機制尚不清楚。高達 75%的腸系膜靜脈血栓形成患者存在遺傳性血栓性疾病[31-33]。COVID-19 患者可能有幾種複雜多樣的凝血異常，從而產生高凝狀態，並且已有腸缺血的報導。（參見 “成人靜脈血栓形成的病因概述”，關於'獲得性危險因素'一節和 “COVID-19 的高凝狀態” 和 “急性腸系膜動脈閉塞”，關於'病因'一節和 “成人腸系膜靜脈血栓形成”，關於'危險因素'一節和 “成人靜脈血栓形成的病因概述”，關於'遺傳性血栓形成傾向'一節 ）

●Inflammation/infection – Inflammation affecting the small or large intestines can lead to mesenteric venous thrombosis. Arterial infection can lead to the formation of aneurysms, which can lead to thrombosis. Underlying vascular disorders, such as vasculitis, may also predispose the patient to intestinal ischemia. (See "Overview of gastrointestinal manifestations of vasculitis".)
炎症/感染 – 影響小腸或大腸的炎症可導致腸系膜靜脈血栓形成。動脈感染可導致動脈瘤的形成，從而導致血栓形成。潛在的血管疾病，如血管炎，也可能使患者易患腸缺血。（參見 “血管炎的胃腸道表現概述”）

●Hypovolemia – Hypovolemia reduces the circulating blood volume, leading to vasoconstriction and shunting of blood flow away from the intestines. Extreme exercise (as occurs in marathon running or triathlon competition) accompanied by dehydration can lead to intestinal ischemia.
血容量不足 – 血容量不足會減少迴圈血容量，導致血管收縮和血流分流離開腸道。伴有脫水的極端運動（如馬拉松跑步或鐵人三項比賽中發生）會導致腸缺血。

●Segmental ischemia – Segmental ischemia from bowel strangulation can be due to external or internal hernias, bowel volvulus, or overdistention of the bowel (eg, bowel obstruction, superior mesenteric artery syndrome). Ischemia may also be the etiology of pain in patients with median arcuate ligament syndrome. (See "Etiologies, clinical manifestations, and diagnosis of mechanical small bowel obstruction in adults", section on 'Etiologies' and "Superior mesenteric artery syndrome" and "Median arcuate ligament syndrome".)
節段性缺血 –腸絞窄引起的節段性缺血可由外疝或內疝、腸扭轉或腸過度擴張（如腸梗阻、腸系膜上動脈綜合征）引起。缺血也可能是正中弓狀韌帶綜合征患者疼痛的病因。（參見 “成人機械性小腸梗阻的病因、臨床表現和診斷”，關於'病因'一節和 “腸系膜上動脈綜合征” 和 “正中弓狀韌帶綜合征”）

●Vascular compression – Patients with retroperitoneal fibrosis or other tumors can present with abdominal symptoms due to mesenteric artery compression. (See "Clinical manifestations and diagnosis of retroperitoneal fibrosis".)
血管壓迫 – 腹膜后纖維化或其他腫瘤患者可因腸系膜動脈壓迫而出現腹部癥狀。（參見 “腹膜后纖維化的臨床表現和診斷”）

CLINICAL FEATURES  臨床特徵

History — A careful review of the patient's personal and family history is important. A history of a prior embolic event is present in approximately one-third of patients with acute embolic mesenteric ischemia. A personal or familial history of a deep vein thrombosis or pulmonary embolism is present in approximately one-half of patients with acute mesenteric venous thrombosis [34]. Patients with acute mesenteric arterial thrombosis frequently have antecedent symptoms of chronic mesenteric ischemia, including postprandial abdominal pain, an aversion to eating, and unintentional weight loss.
病史  —  仔細回顧患者的個人史和家族史很重要。大約三分之一的急性栓塞性腸系膜缺血患者有既往栓塞事件史。約 1/2 的急性腸系膜靜脈血栓形成患者有深靜脈血栓形成或肺栓塞的個人史或家族史[34]。急性腸系膜動脈血栓形成患者常有慢性腸系膜缺血的既往癥狀，包括餐后腹痛、厭惡進食和無意中體重減輕。

Abdominal pain — Abdominal pain is the most common presenting symptom in patients with intestinal ischemia. The general evaluation of the patient with abdominal pain is discussed in detail elsewhere. (See "Evaluation of the adult with nontraumatic abdominal or flank pain in the emergency department".)
腹痛  —  腹痛是腸缺血患者最常見的主訴癥狀。腹痛患者的一般評估詳見其他專題。（參見 “急診科成人非創傷性腹痛或腰痛的評估”）

The classic clinical description for acute intestinal ischemia is "abdominal pain out of proportion to the physical examination." The onset and severity of pain depend upon the duration of occlusion and the effectiveness of the collateral circulation. Several features of the pain and its presentation may provide clues to the etiology of the ischemia and help distinguish small intestinal from colonic ischemia (table 1):
急性腸缺血的經典臨床描述是「腹痛與體格檢查不成比例」。。疼痛的發作和嚴重程度取決於閉塞的持續時間和側支迴圈的有效性。疼痛的幾個特徵及其表現可能為缺血的病因提供線索，並有助於區分小腸缺血和結腸缺血 （ 表 1）：

●Pain associated with arterial embolism to the proximal superior mesenteric artery is typically sudden, severe, periumbilical, and often accompanied by nausea and vomiting. (See "Acute mesenteric arterial occlusion".)
腸系膜上動脈近端動脈栓塞相關的疼痛通常是突然的、嚴重的、臍周的，並且通常伴有噁心和嘔吐。（參見 “急性腸系膜動脈閉塞”）

●Patients with underlying peripheral artery disease who have a thrombotic mesenteric arterial occlusion may report worsened postprandial pain or have symptoms indistinguishable from mesenteric arterial embolism. (See "Chronic mesenteric ischemia", section on 'Clinical presentations'.)
患有血栓性腸系膜動脈閉塞的基礎外周動脈疾病患者可能會報告餐后疼痛加重或出現與腸系膜動脈栓塞無法區分的癥狀。（參見 “慢性腸系膜缺血”，關於'臨床表現'一節 ）

●Patients with mesenteric venous thrombosis are more likely to present with a more insidious onset of abdominal pain that can wax and wane for a period of time before a diagnosis is established [15,35]. (See "Mesenteric venous thrombosis in adults", section on 'Anticoagulation'.)
腸系膜靜脈血栓形成患者更易出現更隱匿的腹痛發作，在確診前會在一段時間內起伏不定[15,35]。（參見 “成人腸系膜靜脈血栓形成”，關於'抗凝'一節 ）

●The severity and location of the abdominal pain that accompanies nonocclusive mesenteric ischemia (NOMI) is usually more variable than the classic severe pain of acute occlusive mesenteric ischemia. Symptoms may be overshadowed by precipitating disorders including hypotension, heart failure, hypovolemia, and cardiac arrhythmias. Thus, a high index of suspicion in older patients with risk factors for NOMI is imperative for making a prompt diagnosis. (See "Nonocclusive mesenteric ischemia", section on 'Clinical features'.)
伴隨非閉塞性腸系膜缺血 （NOMI） 的腹痛的嚴重程度和位置通常比急性閉塞性腸系膜缺血的典型劇烈疼痛更具變化性。癥狀可能會被低血壓、心力衰竭、低血容量和心律失常等誘發性疾病所掩蓋。因此，對於有 NOMI 危險因素的老年患者，高度懷疑對於及時診斷至關重要。（參見 “非閉塞性腸系膜缺血”，關於'臨床特徵'一節 ）

●Patients with acute colonic ischemia usually present with rapid onset of mild abdominal pain and tenderness over the affected bowel, commonly on the left side of the abdomen. Mild to moderate amounts of rectal bleeding or bloody diarrhea typically develop within 24 hours of the onset of abdominal pain. (See "Colonic ischemia", section on 'Clinical features'.)
急性結腸缺血患者通常表現為受累腸道（通常位於腹部左側）出現輕度腹痛和壓痛。輕度至中度直腸出血或血性腹瀉通常在腹痛發作后 24 小時內出現。（參見 “結腸缺血”，關於'臨床特徵'一節 ）

Patients with chronic mesenteric ischemia complain of recurrent abdominal pain after eating, which is due to an inability to increase blood flow to meet the demand of the intestine postprandially. Consequently, these patients develop food fear and can lose a considerable amount of weight. (See "Chronic mesenteric ischemia", section on 'Clinical presentations'.)
慢性腸系膜缺血患者主訴飯後反覆腹痛，這是由於餐后無法增加血流量以滿足腸道的需求。因此，這些患者會出現食物恐懼症，並且可以減輕相當多的體重。（參見 “慢性腸系膜缺血”，關於'臨床表現'一節 ）

Physical examination — The abdominal examination may be normal initially or show only mild abdominal distension with no signs of peritoneal inflammation, such as rebound tenderness and guarding. Occult blood may be present in the stool. However, as bowel ischemia progresses and transmural bowel infarction develops, the abdomen becomes grossly distended, bowel sounds become absent, and peritoneal signs develop. A feculent odor to the breath may also be appreciated. Signs consistent with dehydration and shock indicate a deteriorating clinical course.
體格檢查  —  腹部檢查最初可能正常，也可能僅顯示輕度腹脹，無腹膜炎症征象，如反彈性壓痛和保護。糞便中可能存在潛血。然而，隨著腸缺血的進展和透壁性腸梗死的發展，腹部變得嚴重膨脹，腸鳴音消失，並出現腹膜體征。呼吸中的糞便氣味也可能受到讚賞。與脫水和休克一致的體征表明臨床病程惡化。

Laboratory studies — Laboratory studies are nonspecific; while abnormal laboratory values may be helpful in bolstering suspicion for acute mesenteric ischemia, normal laboratory values do not exclude acute mesenteric ischemia and do not justify delaying urgent radiologic evaluation when clinical suspicion for acute mesenteric ischemia exists.
實驗室檢查  —  實驗室檢查是非特異性的;雖然實驗室值異常可能有助於加強對急性腸系膜缺血的懷疑，但實驗室值正常並不能排除急性腸系膜缺血，也不能證明在臨床懷疑急性腸系膜缺血時延遲緊急影像學評估的合理性。

Findings may include a marked leukocytosis with a predominance of immature white blood cells, an elevated hematocrit consistent with hemoconcentration, and metabolic acidosis. A useful clinical guideline is that any patient with acute abdominal pain and metabolic acidosis has intestinal ischemia until proven otherwise.
發現可能包括以未成熟白細胞為主的明顯白細胞增多、與血液濃縮一致的血細胞比容升高以及代謝性酸中毒。一個有用的臨床指南是，任何患有急性腹痛和代謝性酸中毒的患者都患有腸缺血，除非另有證明。

Many individual laboratory values have been examined to ascertain their utility in diagnosing mesenteric ischemia or infarction [36]. Unfortunately, most abnormalities arise only after the ischemic insult has progressed to bowel necrosis.
已經檢查了許多單獨的實驗室值，以確定其在診斷腸系膜缺血或梗死中的效用[36]。不幸的是，大多數異常只有在缺血性損傷發展為腸壞死後才會出現。

●A systematic review reported a pooled sensitivity for l-lactate for acute mesenteric ischemia of 86 percent (95% CI 73 to 94 percent) and a pooled specificity of 44 percent (95% CI 32 to 55 percent) [37]. The specificity of an elevated serum lactate level does improve significantly when conditions such as shock, diabetic ketoacidosis, and renal and hepatic failure can be excluded [38].
一項系統評價報導，L-乳酸對急性腸系膜缺血的匯總敏感性為 86%（95%CI 73-94%），匯總特異性為 44%（95%CI 32-55%）[37]。當可以排除休克、糖尿病酮症酸中毒以及腎衰竭和肝功能衰竭等疾病時，血清乳酸水準升高的特異性確實會顯著提高[38]。

●Elevated serum amylase levels have been observed in approximately one-half of patients with intestinal ischemia [39,40], while phosphate elevations have been found in 80 percent [41].
約 1/2 的腸缺血患者血清澱粉酶水準升高[39,40]，80%的腸缺血患者血清澱粉酶水準升高[41]。

●Normal D-dimer levels may help to exclude acute intestinal ischemia, but elevated levels are less useful for making a diagnosis [42]. Animal models of acute intestinal ischemia have demonstrated an increase in D-dimer levels beginning 30 minutes after the ischemic event [43]. However, elevated levels can also be seen in a variety of conditions, such as in patients with acute pancreatitis and those with an abdominal aortic aneurysm [44,45]. In a systematic review, the pooled sensitivity for D-dimer for acute mesenteric ischemia was 96 percent (95% CI 89 to 99 percent) with a pooled specificity of 40 percent (95% CI 33 to 47 percent) [37].
正常的 D-二聚體水準可能有助於排除急性腸缺血，但水準升高對診斷的用處較差[42]。急性腸缺血的動物模型顯示，缺血事件發生后 30 分鐘開始，D-二聚體水準升高[43]。然而，在多種情況下也可見水準升高，例如急性胰腺炎患者和腹主動脈瘤患者[44,45]。一項系統評價顯示，D-二聚體對急性腸系膜缺血的匯總敏感性為 96%（95%CI 89-99%），匯總特異性為 40%（95%CI 33-47%）[37]。

Experimental tests — Measurement of serum alpha-glutathione S-transferase (alpha-GST) intestinal fatty acid-binding protein (I-FABP) and others have been evaluated as markers of intestinal ischemia [40,46-53]. None are widely available, and they are rarely used in clinical practice.
實驗性檢查  —  血清α-谷胱甘肽 S 轉移酶（alpha-glutathione S-transferase， alpha-GST）腸道脂肪酸結合蛋白（intestary fatty acid-binding protein， I-FABP）等的檢測被評估為腸缺血的標誌物[40,46-53]。沒有一種是廣泛使用的，也很少在臨床實踐中使用。

Plain radiographs — Plain abdominal radiography is relatively nonspecific and may be completely normal in more than 25 percent of patients [15]. Findings suggestive of mesenteric ischemia include the presence of an ileus with distended loops of bowel, bowel wall thickening (particularly prominent in acute mesenteric venous thrombosis) (image 1), and/or pneumatosis intestinalis (image 2 and image 3). The latter may be observed in patients with advanced ischemia. Obvious findings, such as free intraperitoneal air, indicate the need for immediate abdominal exploration.
X 線  平片 —  腹部 X 線平片相對非特異性，超過 25%的患者可能完全正常[15]。提示腸系膜缺血的表現包括腸梗阻伴腸袢擴張、腸壁增厚（在急性腸系膜靜脈血栓形成中尤為突出）（ 影像 1）和/或腸充氣（ 影像 2 和影像 3）。後者可能在晚期缺血患者中觀察到。明顯的發現，例如腹膜內自由空氣，表明需要立即進行腹部探查。

DIAGNOSIS  診斷 — 

Our diagnostic approach is given in the algorithm (algorithm 1).
我們的診斷方法在演算法中給出（ 流程圖 1）。

Rapid diagnosis is essential among patients with clinical features and risk factors suggestive of intestinal ischemia to reduce the potential for intestinal infarction, although these are generally nonspecific [54]. Intestinal ischemia should be considered a potential diagnosis in any critically ill patient who is deteriorating without adequate explanation.
對於有提示腸缺血的臨床特徵和危險因素的患者，快速診斷對於降低腸梗死的可能性至關重要，儘管這些通常是非特異性的[54]。對於任何在沒有充分解釋的情況下病情惡化的危重患者，腸缺血都應被視為一種潛在的診斷。

●For patients who present with peritonitis or obvious bowel perforation, the diagnosis will necessarily be made in the operating room.
對於出現腹膜炎或明顯腸穿孔的患者，必須在手術室進行診斷。

●For those without indications for immediate abdominal exploration, a definitive diagnosis requires advanced abdominal imaging. We recommend computed tomographic (CT) angiography as the initial test for most patients with clinical features consistent with intestinal ischemia.
對於那些沒有立即腹部探查指征的患者，明確診斷需要先進的腹部影像學檢查。對於大多數臨床特徵與腸缺血一致的患者，我們建議將計算機斷層掃描 （CT） 血管造影作為初始檢查。

●Although duplex ultrasound can identify arterial stenosis or occlusion of the celiac or superior mesenteric arteries, the test is often technically limited by the presence of air-filled loops of distended bowel. In addition, the sensitivity of duplex is limited for detecting more distal emboli or in the assessment of nonocclusive mesenteric ischemia.
儘管雙工超聲可以識別腹腔動脈或腸系膜上動脈的動脈狹窄或閉塞，但該測試在技術上通常受到擴張腸充氣袢的存在的限制。此外，雙工的靈敏度在檢測更多遠端栓子或評估非閉塞性腸系膜缺血方面受到限制。

●Colonoscopy or sigmoidoscopy is often required to establish or confirm the diagnosis of ischemic colitis.
通常需要進行結腸鏡檢查或乙狀結腸鏡檢查來確定或確認缺血性結腸炎的診斷。

In cases of vasculitis, which typically affects the small- and medium-diameter arteries, stenoses and/or microaneurysms may be detected on arteriography typically without evidence of obstruction of the main mesenteric arteries. However, the bowel wall changes associated with vasculitis are nonspecific and simply reflect the changes one sees with varying degrees of ischemia, including mural edema and/or hemorrhage. If vasculitis-associated aneurysms are large enough, they may be detectable on ultrasound. (See "Overview of visceral artery aneurysm and pseudoaneurysm".)
對於通常影響中小直徑動脈的血管炎病例，動脈造影可能會檢測到狹窄和/或微動脈瘤，通常沒有腸系膜主動脈阻塞的證據。然而，與血管炎相關的腸壁變化是非特異性的，只是反映了人們在不同程度的缺血中看到的變化，包括壁水腫和/或出血。如果血管炎相關動脈瘤足夠大，則可以通過超聲波檢測到它們。（參見 “內臟動脈瘤和假性動脈瘤概述”）

Advanced abdominal imaging — Abdominal CT is commonly used to screen hemodynamically stable patients with acute abdominal pain [55-63].
晚期腹部影像學檢查  —  腹部 CT 常用於篩查血流動力學穩定的急性腹痛患者[55-63]。

For patients in whom the index of suspicion for intestinal ischemia is high, multidetector CT angiography and magnetic resonance (MR) angiography have improved the ability to diagnose acute mesenteric ischemia [55-63]. The CT scan should be performed without oral contrast, which can obscure the mesenteric vessels, obscure bowel wall enhancement, and can lead to a delay of the diagnosis. The origins of the celiac axis and superior mesenteric artery should also be evaluated for the presence of calcification that indicates an underlying atherosclerotic process as a possible etiology for mesenteric ischemia.
對於疑似腸缺血指數較高的患者，多探測器 CT 血管造影和 MR 血管造影提高了急性腸系膜缺血的診斷能力[55-63]。CT 掃描應在不使用口腔造影劑的情況下進行， 這會遮擋腸系膜血管，遮擋腸壁增強，並可能導致診斷延誤 。還應評估腹腔軸和腸系膜上動脈的起源，以確定是否存在鈣化，這表明潛在的動脈粥樣硬化過程是腸系膜缺血的可能病因。

CT is preferred over MR because of its lower costs, speed, and wide availability [57,59]. However, MR angiography may be more sensitive for the diagnosis of mesenteric venous thrombosis and may be necessary for those with an allergy to iodinated contrast. CT can demonstrate findings consistent with acute ischemia, such as focal or segmental bowel wall thickening, intestinal pneumatosis with portal vein gas (image 4), bowel dilation, mesenteric stranding, portomesenteric thrombosis, or solid organ infarction, in addition to ruling out other causes of acute abdominal pain [64,65]. It is important to note that the bowel wall changes of acute mesenteric ischemia, while sensitive, are not specific [64,65]. The presence of pneumatosis intestinalis on CT does not necessarily indicate that transmural infarction has occurred, but transmural infarction is more likely in patients with pneumatosis and portomesenteric venous gas [66]. Mesenteric arterial occlusions can be identified as a lack of enhancement of the arterial vasculature with timed intravenous contrast injections. When present, thromboembolic occlusion is specific for the diagnosis; however, the absence of a filling defect is not sufficiently sensitive to rule out acute mesenteric ischemia [64,65,67].
CT 比 MR 更受青睞，因為它成本低、速度快、可用性廣[57,59]。然而，MR 血管造影可能對腸系膜靜脈血栓形成的診斷更敏感，並且對於對碘造影劑過敏的患者可能是必要的。CT 可顯示與急性缺血一致的表現，如局灶性或節段性腸壁增厚、腸氣腫伴門靜脈氣體 （ 影像 4）、腸擴張、腸系膜擱淺、門膜血栓形成或實體器官梗死，此外還可排除急性腹痛的其他病因[64,65]。需要注意的是，急性腸系膜缺血的腸壁變化雖然敏感，但並不具有特異性[64,65]。CT 顯示腸充氣並不一定表明發生了透壁性梗死，但透壁性梗死在氣腫和門膜腸靜脈氣體患者中更易發生[66]。腸系膜動脈閉塞可確定為動脈脈管系統缺乏通過定時靜脈注射造影劑增強。如果存在血栓栓塞性閉塞，則對診斷具有特異性;然而，沒有充盈缺損不足以排除急性腸系膜缺血[64,65,67]。

The accuracy of CT was evaluated in a review that identified six studies involving 619 patients, 142 of whom had acute mesenteric ischemia based upon surgical findings or clinical outcome [68]; the pooled sensitivity for CT was 93.3 percent (95% CI 83 to 98 percent), and pooled specificity was 96 percent (95% CI 91 to 98 percent). Another study compared CT findings in 39 patients who had surgically proven acute mesenteric ischemia with 24 controls in whom suspected acute mesenteric ischemia was disproved at surgery [67]. A single finding of either arterial or venous thrombosis, intramural gas, portal venous gas, focal lack of bowel-wall enhancement, or liver or splenic infarcts had a sensitivity and specificity of 64 and 92 percent, respectively. In another review, the sensitivity of CT for the diagnosis of mesenteric venous thrombosis was approximately 90 percent [32]. In a later prospective study of 79 patients with suspected acute mesenteric ischemia evaluated using multidetector CT angiography, a positive predictive value of 100 percent and a negative predictive value of 94 percent were found using criteria that required the presence of visualized arterial occlusion, intestinal pneumatosis, portomesenteric venous gas, or bowel wall thickening, in combination with portomesenteric thrombosis or solid organ infarction [65]. The diagnosis was made by the failure to opacify the mesenteric veins with intravenous contrast. Similarly, multidetector CT angiography was used to evaluate 91 patients with suspected acute mesenteric ischemia in another retrospective review [64]. It correctly diagnosed acute mesenteric ischemia in 16 of 18 patients with confirmed acute mesenteric ischemia, while supporting another diagnosis in an additional 38 patients. There were two false negative and two false positive examinations.
一項綜述評估了 CT 的準確性，該綜述確定了 6 項研究，涉及 619 例患者，其中 142 例為急性腸系膜缺血，基於手術表現或臨床結局[68];CT 的匯總敏感性為 93.3%（95%CI 83-98%），匯總特異性為 96%（95%CI 91-98%）。另一項研究比較了 39 例手術證實為急性腸系膜缺血的患者與 24 例手術證實疑似急性腸系膜缺血的對照組的 CT 結果[67]。單次發現動脈或靜脈血栓形成、壁內氣體、門靜脈氣體、局灶性腸壁增強不足或肝臟或脾臟梗死的敏感性和特異性分別為 64%和 92%。另一項綜述顯示，CT 診斷腸系膜靜脈血栓形成的敏感性約為 90%[32]。後來的一項前瞻性研究納入了 79 例疑似急性腸系膜缺血患者，採用多探測器 CT 血管造影評估，結果發現陽性預測值為 100%，陰性預測值為 94%，這些標準要求存在可見動脈閉塞、腸氣腫、腸腔靜脈氣體或腸壁增厚，並伴有門腸內血栓形成或實體器官梗死[65].診斷是通過靜脈造影劑未能使腸系膜靜脈混濁而做出的。同樣，在另一項回顧性綜述中，多檢測器 CT 血管造影評估了 91 例疑似急性腸系膜缺血患者[64]。 在確診急性腸系膜缺血的18例患者中，有16例正確診斷了急性腸系膜缺血，同時支援另外38例患者的另一種診斷。有兩次假陰性和兩次假陽性檢查。

More data comparing these modalities to conventional arteriography are needed, particularly to understand whether CT and MR can accurately detect the presence of small thromboemboli; early, reversible ischemia; or nonocclusive ischemia [62]. Anteroposterior and lateral views are needed to adequately assess the mesenteric vasculature. The origins of the celiac axis and SMA are visualized only with the lateral view, while the distal celiac axis and remainder of the SMA are assessed best with anteroposterior projections. One systematic review that evaluated CT angiography for acute mesenteric ischemia reported a pooled sensitivity of 94 percent (95% CI 90 to 97 percent) with a specificity of 95 percent (95% CI 93 to 97 percent) [37]. Conventional catheter-based arteriography is still recommended if the diagnosis of mesenteric ischemia remains in question (image 5) [69].
需要更多數據將這些方式與傳統動脈造影進行比較，特別是瞭解 CT 和 MR 是否可以準確檢測小血栓栓塞的存在;早期可逆性缺血;或非閉塞性缺血[62]。需要前後檢視和側視圖來充分評估腸系膜脈管系統。腹腔軸和 SMA 的起源只能通過側視圖可視化，而遠端腹腔軸和 SMA 的其餘部分最好通過前後投影進行評估。一項評估 CT 血管造影治療急性腸系膜缺血的系統評價報告稱，合併敏感性為 94%（95%CI 90-97%），特異性為 95%（95%CI 93-97%）[37]。如果腸系膜缺血的診斷仍有疑問，仍建議進行常規導管動脈造影 （ 影像 5）[69]。

Mesenteric venous thrombosis may be diagnosed with CT angiography or conventional arteriography by performing delayed imaging to allow for contrasted filling of the mesenteric venous system. The diagnosis is made by the presence of venous filling defects or the absence of flow. Reflux of contrast into the aorta on selective arteriography may indicate a highly resistant venous system with resultant low arterial flow. Contrast extravasation into the bowel lumen indicates active bleeding. In patients with nonocclusive mesenteric ischemia (NOMI), angiography can demonstrate areas of segmental narrowing in major branches with a string-of-beads appearance, decreased or absent flow in the smaller vessels, and an absent submucosal "blush."
腸系膜靜脈血栓形成可以通過 CT 血管造影或常規動脈造影來診斷，方法是進行延遲成像，以允許腸系膜靜脈系統的對比填充。診斷是通過靜脈充盈缺陷的存在或沒有血流來做出的。在選擇性動脈造影中造影劑回流到主動脈可能表明靜脈系統具有高度抵抗力，導致動脈流量低。造影劑外滲到腸腔內表明活動性出血。在非閉塞性腸系膜缺血 （NOMI） 患者中，血管造影可顯示主要分支的節段性狹窄區域，呈串珠狀外觀，較小血管中的血流減少或消失，粘膜下“腮紅”消失。

Differential diagnosis — Intestinal ischemia needs to be differentiated from other causes of abdominal pain. (See "Evaluation of the adult with abdominal pain" and "Causes of abdominal pain in adults".)
鑒別診斷  —  腸缺血需要與其他腹痛病因相鑒別。（參見 “成人腹痛的評估” 和 “成人腹痛的病因”）

INITIAL MANAGEMENT  初始管理 — 

Initial management includes gastrointestinal decompression, fluid resuscitation, hemodynamic monitoring and support, correction of electrolyte abnormalities, pain control, anticoagulation under most circumstances, and initiation of broad-spectrum antibiotics [70].
初始治療包括胃腸道減壓、液體復甦、血流動力學監測和支援、電解質異常糾正、疼痛控制、大多數情況下抗凝以及開始使用廣譜抗生素[70]。

Vasoconstricting agents and digitalis should be avoided since they can exacerbate mesenteric ischemia. If vasopressors are needed, dobutamine, low-dose dopamine, or milrinone are preferred since they have less of an effect on mesenteric perfusion as compared with other vasopressors.
應避免使用血管收縮劑和洋地黃，因為它們會加劇腸系膜缺血。如果需要血管加壓藥，首選多巴酚丁胺 、低劑量多巴胺或米力農 ，因為與其他血管加壓藥相比，它們對腸系膜灌注的影響較小。

Pain control — The patient's pain should be judiciously controlled, typically using parenteral opioids. (See "Use of opioids for acute pain in hospitalized patients".)
疼痛控制  —  應謹慎控制患者的疼痛，通常使用腸外阿片類藥物。（參見 “阿片類藥物治療住院患者急性疼痛的使用”）

Anticoagulation — For patients with acute intestinal ischemia due to mesenteric arterial or venous occlusion, or nonocclusive mesenteric ischemia, we recommend systemic anticoagulation to prevent thrombus formation and propagation, unless patients are actively bleeding, as in ischemic colitis related to nonocclusive ischemia. For those who require abdominal exploration, anticoagulation is typically continued after surgery to prevent new thrombus formation [16].
抗凝  —  對於腸系膜動脈或靜脈閉塞所致急性腸缺血，或非閉塞性腸系膜缺血患者，我們建議全身抗凝以防止血栓形成和擴散，除非患者正在活動性出血，如非閉塞性缺血相關的缺血性結腸炎。對於需要腹部探查的患者，通常在手術後繼續進行抗凝治療，以防止新血栓形成[16]。

Antibiotics — Broad-spectrum antibiotic therapy is recommended for patients with acute mesenteric and colonic ischemia. Antibiotic regimens that provide coverage for gastrointestinal pathogens are outlined in depth separately. (See "Antimicrobial approach to intra-abdominal infections in adults".)
抗生素  —  急性腸系膜和結腸缺血患者推薦採用廣譜抗生素治療。覆蓋胃腸道病原體的抗生素方案詳見其他專題。（參見 “成人腹腔內感染的抗菌方法”）

ABDOMINAL EXPLORATION  腹部探查 — 

Intestinal ischemia develops as a consequence of severe hypoperfusion leading to transmural necrosis of the bowel wall, which can progress to sepsis, peritonitis, free intra-abdominal air, or extensive gangrene. Surgery should not be delayed in patients suspected of having intestinal infarction or perforation based upon clinical, radiographic, or laboratory parameters, regardless of etiology. For patients with nonocclusive mesenteric ischemia, surgical exploration should be limited to patients with peritoneal signs.
腸缺血是由於嚴重灌注不足導致腸壁透壁壞死而發展起來的，可發展為膿毒症、腹膜炎、腹腔內遊離空氣或廣泛壞疽。對於根據臨床、影像學或實驗室參數懷疑患有腸梗死或穿孔的患者，無論病因如何，都不應延遲手術。對於非閉塞性腸系膜缺血患者，手術探查應僅限於有腹膜體征的患者。

TREATMENT OF SPECIFIC ETIOLOGIES
特定病因的治療 — 

The management of intestinal ischemia may require any number of treatment options. The management of specific etiologies of intestinal ischemia due to arterial occlusion or thrombosis, mesenteric venous thrombosis, and nonocclusive mesenteric ischemia are summarized briefly below and reviewed in detail elsewhere.
腸缺血的治療可能需要任意數量的治療方案。動脈閉塞或血栓形成、腸系膜靜脈血栓形成和非閉塞性腸系膜缺血所致腸缺血的具體病因的治療詳見下文，詳見其他專題。

●Mesenteric arterial occlusion – The traditional treatment of acute mesenteric arterial embolism is early surgical laparotomy with embolectomy, which may be the preferred treatment for patients with a solitary, proximal superior mesenteric embolus, since it provides rapid treatment and allows direct inspection of the bowel. An alternative but less established approach for acute embolus, particularly in those with severe comorbidities, is local infusion of a thrombolytic agent; however, this option is reserved for patients with a shorter duration of symptoms and without signs of peritonitis. Thrombolysis risks possible catheter-related embolism to the more distal arterial mesenteric branches. For mesenteric arterial thrombosis, choices include surgical revascularization, or thrombolysis with endovascular angioplasty and stenting [71-73]. The choice depends on the time course, severity of ischemia, and medical comorbidities of the patient. (See "Acute mesenteric arterial occlusion" and "Chronic mesenteric ischemia".)
腸系膜動脈阻塞 – 急性腸系膜動脈栓塞的傳統治療方法是早期手術剖腹手術和取栓術，這可能是孤立性近端腸系膜上塞患者的首選治療方法，因為它提供快速治療並允許直接檢查腸道。對於急性栓子，特別是對於患有嚴重合併症的患者，一種替代但不太成熟的方法是局部輸注溶栓劑;然而，此選項僅適用於癥狀持續時間較短且沒有腹膜炎跡象的患者。溶栓有可能使導管相關栓塞發生至更遠端的動脈腸系膜分支。對於腸系膜動脈血栓形成，可選擇手術血運重建，或溶栓聯合血管內血管成形術和支架置入術[71-73]。選擇取決於患者的時程、缺血嚴重程度和軀體合併症。（參見 “急性腸系膜動脈閉塞” 和 “慢性腸系膜缺血”）

●Mesenteric venous thrombosis – Anticoagulation may be all that is needed in the treatment of patients with mesenteric venous thrombosis (algorithm 2). However, for those with persistent symptoms, venous thrombolysis has been reported in small case series. If symptoms progress, abdominal exploration may be needed to evaluate for nonviable bowel. (See "Mesenteric venous thrombosis in adults".)
腸系膜靜脈血栓形成 –腸系膜靜脈血栓形成患者的治療可能只需要抗凝 （ 流程圖 2）。然而，對於癥狀持續的患者，靜脈溶栓已在小病例系列中報導。如果癥狀進展，可能需要進行腹部探查以評估腸道是否存活。（參見 “成人腸系膜靜脈血栓形成”）

●Nonocclusive mesenteric ischemia – The treatment of nonocclusive mesenteric ischemia focuses on removing inciting factors (vasoconstrictive medications), treating underlying causes (heart failure, sepsis), hemodynamic support and monitoring, and intra-arterial infusion of vasodilators, if necessary (algorithm 3). (See "Nonocclusive mesenteric ischemia" and "Colonic ischemia".)
非閉塞性腸系膜缺血 –非閉塞性腸系膜缺血的治療重點是清除誘導因數（血管收縮藥物）、治療根本原因（心力衰竭、膿毒症）、血流動力學支援和監測，以及必要時動脈內輸注血管擴張劑 （ 流程圖 3）。（參見 “非閉塞性腸系膜缺血” 和 “結腸缺血”）

OUTCOMES  結果 — 

The outcomes related to the treatment of intestinal ischemia depend upon the mechanism. Survival of an acute ischemic event is worse for patients with an arterial etiology compared with a venous etiology. For acute mesenteric ischemia, mortality rates exceed 60 percent [15]. In one systematic review, the pooled operative mortality rate for acute mesenteric ischemia was 47 percent [37]. Patients who survive an acute event are likely to die of complications related to the underlying condition that predisposed them to intestinal ischemia.
與腸缺血治療相關的結果取決於機制。與靜脈病因相比，動脈病因患者的急性缺血事件生存率更差。急性腸系膜缺血的死亡率超過 60%[15]。一項系統評價顯示，急性腸系膜缺血的合併手術死亡率為 47%[37]。在急性事件中倖存下來的患者可能會死於與易患腸缺血的潛在疾病相關的併發症。

SOCIETY GUIDELINE LINKS  學會指南連結 — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Intestinal ischemia".)
來自世界各地選定國家和地區的社會和政府贊助指南的連結另行提供。（參見 “學會指南鏈接：腸缺血”）

INFORMATION FOR PATIENTS
患者資訊 — 

UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
UpToDate 提供兩種類型的患者教育材料，「基礎知識」和“超越基礎知識”。基礎知識患者教育文章是用通俗易懂的語言編寫的，處於 ^{5 至 6 年級}的閱讀水準，它們回答了患者可能對特定病症提出的四到五個關鍵問題。這些文章最適合想要總體概述並喜歡簡短、易於閱讀的材料的患者。超越基礎知識的患者教育文章更長、更複雜、更詳細。這些文章是在 10 ^至 12 ^年級的閱讀水準上寫的，最適合想要深入了解資訊並熟悉一些醫學術語的患者。

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
以下是與此主題相關的患者教育文章。我們鼓勵您將這些主題列印或通過電子郵件發送給您的患者。（您還可以透過搜索“患者資訊”和感興趣的關鍵字來查找有關各種主題的患者教育文章。

●Basics topic (see "Patient education: Ischemic bowel disease (The Basics)")
基礎專題（參見 “缺血性腸病患者教育（基礎篇）”）

SUMMARY AND RECOMMENDATIONS
總結和建議

●Intestinal ischemia – Intestinal ischemia, which can affect the small or large intestine, can be caused by any process that reduces intestinal blood flow, such as arterial occlusion, venous occlusion, or vasoconstriction. Intestinal ischemia can be classified according to the time course of onset and quality of symptoms (acute or chronic), the degree to which blood flow is compromised, and the segment of bowel that is affected. Ischemia affecting the small intestine is generally referred to as mesenteric ischemia, while ischemia affecting the large intestine is referred to as colonic ischemia. Acute intestinal ischemia accounts for 60 to 70 percent of cases of mesenteric ischemia and results in high mortality rates that can exceed 60 percent. The remainder is due to chronic intestinal ischemia. (See 'Physiology and mechanisms of ischemia' above.)
腸缺血 – 腸缺血可影響小腸或大腸，可由任何減少腸道血流量的過程引起，例如動脈閉塞、靜脈閉塞或血管收縮。腸缺血可根據發病的時間過程和癥狀品質（急性或慢性）、血流受損程度以及受影響的腸段進行分類。影響小腸的缺血通常稱為腸系膜缺血，而影響大腸的缺血稱為結腸缺血。急性腸缺血佔腸系膜缺血病例的 60% 至 70%，死亡率高達 60%。其餘是由於慢性腸缺血。（參見上文 '缺血的生理學和機制'）

●Risk factors – Risk factors for intestinal ischemia include any condition that reduces perfusion of the intestines or predisposes to mesenteric arterial embolism, arterial thrombosis, venous thrombosis, or vasoconstriction. The likelihood of developing intestinal ischemia depends upon the adequacy of systemic perfusion and collateral circulation, the number and caliber of the vessels that are affected, and the duration of the ischemic insult. (See 'Risk factors' above.)
危險因素– 腸缺血的危險因素包括任何減少腸道灌注或易患腸系膜動脈栓塞、動脈血栓形成、靜脈血栓形成或血管收縮的疾病。發生腸缺血的可能性取決於全身灌注和側支迴圈的充分性、受累血管的數量和口徑以及缺血性損傷的持續時間。（參見上文 '危險因素'）

●Clinical features – Abdominal pain is the most common presenting symptom in patients with intestinal ischemia. The classic clinical description for acute intestinal ischemia is "abdominal pain out of proportion to the physical examination." The onset of pain depends upon the time course of occlusion and the effectiveness of the collateral circulation. Patients with chronic mesenteric ischemia complain of recurrent abdominal pain after eating. Specific features of the pain and its presentation may provide clues to the etiology of the ischemia and for distinguishing small intestinal from colonic ischemia (table 1). (See 'Clinical features' above.)
臨床特徵 – 腹痛是腸缺血患者最常見的主訴癥狀。急性腸缺血的經典臨床描述是「腹痛與體格檢查不成比例」。。疼痛的發作取決於閉塞的時間過程和側支迴圈的有效性。慢性腸系膜缺血患者主訴進食后反覆腹痛。疼痛的具體特徵及其表現可能為缺血的病因和鑒別小腸缺血和結腸缺血提供線索 （ 表 1）。（參見上文 '臨床特徵'）

●Diagnosis – The diagnosis of mesenteric ischemia depends upon a high level of clinical suspicion, especially in patients with known risk factors. Rapid diagnosis is essential among patients with clinical features and risk factors suggestive of acute intestinal ischemia to reduce the potential for intestinal infarction. However, early signs and symptoms of acute mesenteric ischemia are nonspecific, and definitive diagnosis often requires invasive testing. We obtain CT angiography without oral contrast as an initial test for patients suspected of having mesenteric ischemia. CT angiography has a high degree of accuracy for diagnosing mesenteric ischemia and is useful in excluding other causes of acute abdominal pain. Arteriography may still be necessary if the diagnosis of mesenteric ischemia remains in question. Colonoscopy or sigmoidoscopy is used to establish the diagnosis of colonic ischemia. (See 'Diagnosis' above.)
診斷 –腸系膜缺血的診斷取決於高度的臨床懷疑，尤其是對於具有已知危險因素的患者。對於具有提示急性腸缺血的臨床特徵和危險因素的患者，快速診斷對於降低腸梗死的可能性至關重要。然而，急性腸系膜缺血的早期體征和癥狀是非特異性的，明確診斷通常需要侵入性檢查。我們獲得無口腔造影劑的 CT 血管造影，作為疑似腸系膜缺血患者的初步檢查。CT 血管造影診斷腸系膜缺血的準確度很高，有助於排除急性腹痛的其他原因。如果腸系膜缺血的診斷仍然存在問題，可能仍需要進行動脈造影。結腸鏡檢查或乙狀結腸鏡檢查用於確定結腸缺血的診斷。（參見上文 '診斷'）

●Treatment – The goal of treatment for patients with acute intestinal ischemia is to restore intestinal blood flow as rapidly as possible after initial supportive management. Patients with acute intestinal ischemia should be anticoagulated to prevent thrombus formation or propagation, provided there are no contraindications. The management of specific etiologies of acute or chronic intestinal ischemia depends on the specific etiology (ie, arterial occlusion or thrombosis, mesenteric venous thrombosis, and nonocclusive mesenteric ischemia). Treatment options include arterial embolectomy, arterial bypass, arterial stenting, arterial or venous thrombolysis, and intra-arterial vasodilator infusion. (See 'Initial management' above and 'Treatment of specific etiologies' above.)
治療 – 急性腸缺血患者的治療目標是在初始支持治療后儘快恢復腸道血流。急性腸缺血患者應進行抗凝治療，以防止血栓形成或擴散，前提是沒有禁忌症。急性或慢性腸缺血特定病因的治療取決於具體病因（即動脈閉塞或血栓形成、腸系膜靜脈血栓形成和非閉塞性腸系膜缺血）。治療選擇包括動脈栓塞切除術、動脈旁路術、動脈支架置入術、動脈或靜脈溶栓以及動脈內血管擴張劑輸注。（參見上文 '初始治療' 和 '特定病因的治療'）