Renal artery embolism

　　First, etiology

　　The occurrence of renal artery embolism is often due to emboli originating from the heart or aorta, such as the detachment of rheumatic disease pannus or blood clot embolism after surgery. More than half of the patients have simultaneous embolism in other visceral arteries. The main causes of renal artery thrombosis and embolism include:

　　1. Thrombosis

　　(1) Spontaneous occurrence:Renal arteriosclerosis; aortic or renal artery aneurysm; renal artery fibromuscular dysplasia; renal artery inflammation (nodal polyarteritis, multinodular giant cell arteritis, occlusive thrombotic arteritis, and syphilis); blood diseases (deficiency of antithrombin III, sickle cell disease); metabolic diseases (familial hypercholesterolemia, cystinuria).

　　(2)创伤继发：肾蒂部钝伤；主动脉或肾动脉造影；经皮经腔肾动脉球囊扩张；肾动脉重建术；肾移植栓塞。

　　2、栓塞

　　(1)心脏栓子：心房纤颤；人工心脏瓣膜；心肌梗死后附壁血栓；左心房黏液瘤。

　　(2)心外栓子：脂肪栓子；肿瘤栓子；静脉栓子经房或室间隔缺损进入动脉。

　　二、发病机制

　　肾动脉血栓可因血管病变或血液凝固性增高而自发产生，也可由血管创伤而继发形成。

　　在某些特定条件下，肾动脉或其分支可局部形成血栓或被循环栓子栓塞，较大动脉被血栓或栓子堵塞后将造成肾缺血，甚至诱发肾梗死。

　　肾功能不全：双侧肾脏同时发生梗死时，可因肾脏的缺血性坏死导致急性肾功能衰竭。最常见并发症是肾实质坏死，其次栓塞常常影响其他腹部器官（如胰腺，胃肠道）。为纤维斑块发生出血、坏死、溃疡、钙化季会壁血栓所形成。粥样斑块可因内膜表面破溃而形成所谓粥样溃疡；破溃后粥样物质进入血流成为栓子，破溃处可引起出血，溃疡表面粗糙易产生血栓，附壁血栓形成又加重管腔的狭窄甚至使之闭塞。

　　1、急性肾梗死的病人一般先前有冠状动脉心脏病，瓣膜性疾病，心律不齐，心房纤维性颤动，周围血管病的病史。

　　2、急性肾绞痛可无明显诱因地突然出现剧烈的腰痛，疼痛呈持续性，伴有低热，恶心，呕吐及全身不适，有些病人有创伤史，医源性肾动脉操作，可卡因注射史等。

　　3、病人常可以有高热。

　　4、血尿可为肉眼血尿，也可为镜下血尿，这是由于肾梗死时红细胞进入集合系统所致。

　　5、高血压一般在发病后数天内发生，数周后可恢复正常。

　　1、控制热量：摄入的热量必须与消耗的热量相平衡，要通过合理平衡膳食和加强体力活动，把这种平衡保持在标准体重范围内。

　　2、低脂饮食：少食动物油，代之以植物油，如豆油，花生油，玉米油等，用量为每人每日25号，每月在750克以内为宜，要限制食物中的胆固醇量，每日每人应在300毫克以内，蛋黄以及肝，肾等动物内脏中脂肪含量较高，应少食用。

　　3、低盐饮食：动脉粥样硬化病人往往合并高血压，因而要采用低盐饮食，每日食盐不要超过5克。

　　1、尿液检查：镜检可发现红细胞及少量蛋白，尿LD(乳酸脱氢酶)H1，LDH2及碱性磷酸酶活性会升高。

　　2. Blood tests:Blood routine examination shows an increase in white blood cell count and neutrophils, LDH (can increase to more than 2000U/ml and last for 14 days), alanine aminotransferase and alkaline phosphatase increase.

　　3. Renal function tests:A few patients may experience acute renal failure.

　　4. Urinary tract plain film:When calcium salts accumulate in the renal infarction area 3 to 4 weeks after onset, calcified shadows can be seen on the plain film, and the renal shadow has shrunk.

　　1. Dietary therapy for renal artery embolism:

　　Irregular diet has a certain impact on the occurrence of the disease (such as malnutrition and alcohol consumption causing disharmony between the spleen and kidney), and the diet should be light and avoid spicy, cold, and raw foods to prevent the formation of phlegm.

　　2. Foods to avoid in renal artery embolism:

　　During the remission period, dietary therapy usually focuses on tonifying the lung, spleen, and kidney, and it is not advisable to eat foods such as crucian carp, shrimp, crab, and chicken that cause 'disease'. During the acute infection period, the diet should be light and nutritious, and spicy, hot, and燥热 should be avoided.

　　I. Treatment

　　Acute renal artery obstruction: Once the diagnosis is confirmed, immediate surgery should be performed. Under the guidance of dual-function Doppler ultrasound, PTA percutaneous transluminal angioplasty can be used to catheterize the renal artery occlusion site and inject antithrombotic agents (antithrombotic drugs) or fibrinolytic agents such as sodium alginate, alteplase (recombinant tissue plasminogen activator), or urokinase, etc., diluted and directly injected, hoping to dissolve the thrombus. If it fails, surgery should be performed immediately to incise the arterial wall and remove the thrombus. Postoperative aspirin and other anticoagulant drugs should be taken.

　　II. Prognosis

　　The prognosis is related to the etiology of the disease, the extent of renal artery occlusion, and the timing of effective treatment. Generally, if the renal artery thrombosis after young trauma is not removed in a timely manner, it is difficult to recover kidney function; while renal artery thrombosis occurring on the basis of elderly arteriosclerosis has a better prognosis, the kidney function can recover to varying degrees spontaneously, the reason being that many collateral circulation has been formed before the thrombosis due to arteriosclerosis and stenosis, which alleviates renal ischemia after thrombosis.