编者按：美国东部时间11月11日08:00，位于波士顿的John B. Hynes退伍军人纪念会议中心迎来了“第67届美国肝病研究学会（AASLD）年会（The 67th Annual Meeting of the American Association for the Study of Liver Diseases）”。随着“Hepatic Encephalopathy as a Complication of ACLF: A Clearer Path Ahead?”专题的的正式开讲，AASLD2016学术之旅正式起航。《国际肝病》前方记者，在会场内静候专题主持、美国弗吉尼亚大学及McGuire VA医学中心胃肠病、肝病和营养科Jasmohan S. Bajaj教授。

 

　　在美国药物性肝衰竭最为常见，我国的药物性肝衰竭，尤其是不当应用传统中药所致肝衰竭也呈逐年增高趋势。除外肝移植，目前临床上并无有效的治疗肝衰竭的方法。但是现有的考察肝衰竭患者是否需要接受肝移植及优先程度分级标准还需要进一步改进，以使患者更好地获益，同时节约有限的器官来源。肝衰竭是临床上导致肝性脑病的重要原因，营养支持是治疗的重要组成部分，也容易在临床中被忽略。Bajaj教授是慢性肝病及肝硬化，尤其是大脑与肝脏功能紊乱相关性研究的专家，在现场，他为我们解答了肝衰竭病因、肝移植时机，并分享了肝性脑病的营养管理经验。

 

　　一、急性肝衰竭的病因变化

 

　　Bajaj教授指出，急性肝衰竭的病因变化是个非常值得关注的问题。在北美地区，药物性肝衰竭、急性肝衰竭及急性肝损伤相当常见。急性肝衰竭研究小组（ALSFG）认为，在美国对乙酰氨基酚（扑热息痛）仍是导致肝衰竭的重要原因，这与中国的情况一致。

 

　　对于药物过量诱导的肝衰竭，S. Bajaj教授认为：“需要提醒大家的是，无论在美国还是中国，不仅应重视工业化成品药物，同时应关注传统中医药，因为部分传统中医药可导致肝衰竭。”

 

　　Prof. Bajaj: This is an important question. Drug-induced liver failure, acute liver failure and acute liver injury are quite common conditions in North America as well. The Acute Liver Failure Study Group (ALSFG) has consistently found that acetaminophen (paracetamol) still remains a significant cause of acute liver failure in the United States and that is consistent with the Chinese experience. They are seeing a lot more supplement-induced liver failure and some of that is due to medications that are Traditional Chinese Medicine based. It is very important for us in the United States and for China to be cognizant not only of the manufactured drugs but also the traditional medicine induced liver failures as they are important to both of our populations.

 

　　二、肝衰竭患者的肝移植时机

 

　　肝移植是肝衰竭患者治疗的重要治疗手段，其时机的选择视两种情况而定：

 

　　第一，对于急性肝衰竭发生于（损害发生前）肝功能正常，且随后出现完全肝脏衰竭的患者。治疗时间十分关键，应当尽快进行肝移植。在美国，这些患者应当设置为“Status 1”，并有最高的移植优先权。但同时，我们也应十分谨慎，因为这些患者的病情并未完全不可逆，关于这方面我们有相应的评价标准。

 

　　第二，对于慢性肝衰竭患者包括代偿性肝硬化，有多种方法可以实施。一方面，当患者罹患肝癌（在中国也很流行）时，可以列入移植队列，如果不进行移植，癌症将会扩散。另一方面，可以使用传统方法，即MELD评分（该评分基于血液检测指标，可反应肝病严重程度），其有助于决定随后的90天内患者的病死及生存情况，是广泛认可的确定需要肝移植患者的方法。但Bajaj教授同时指出：“MELD评分标准相对严苛，患者必须十分虚弱才能达到大部分纳入标准（包括社会支持），但同时患者除肝脏外的其他器官功能还必须健康，因此这类患者往往不能从肝移植中获益。”

 

　　Prof. Bajaj: They are two very different conditions. Acute liver failure occurs in patients who had normal liver function before a massive insult occurs after which the liver fails completely. Time is of the essence and the liver transplant has to be performed as soon as possible. In the United States, these subjects are placed at Status 1 and have the highest priority. We have to careful that these people are not sick to the point of irreversibility and there are certain criteria for that.

 

　　In chronic liver failure, there is decompensated cirrhosis and there are a couple of ways to approach it. One is when patients have liver cancer (which is also epidemic in China), this can promote the patient up the transplant list because without the transplant, the cancer will spread. The alternative traditional method is to follow the MELD score, which is a validated score from blood tests telling us how badly the liver is doing to help us decide who is going to live or die within the next 90 days. These are validated ways of receiving liver transplants but, in short, the patient has to be very sick to qualify and fill a lot of criteria including social support and that the rest of their organs are healthy. But they shouldn’t be too sick to the point that they are too sick for a liver transplant or that the injury to other organs associated with the liver failure is so severe that a liver transplant won’t help them.

 

　　三、肝衰竭患者营养管理的经验？

 

　　在通常的临床医疗中，营养支持常被忽视。Bajaj教授指出，通常应由营养师实施针对患者的个体化营养支持，尤其是在饮食习惯存在差异极大的美国、印度或中国。不同的人群甚至个体都有其自己的饮食习惯，营养摄入需要完全具体到每位患者正在吃的、希望吃的以及将要吃的。

 

　　Bajaj教授指出，包括肝昏迷在内的肝衰竭患者应当严格限制蛋白质摄入，“但是患者饥饿时会出现肌力降低，肌肉纤维被机体分解，对于这部分患者，需要摄入更多的蛋白质来维持肌肉，即使存在肝性脑病及肝昏迷，也不应当限制蛋白质摄入。”训练营养师及患者十分重要，包括限制盐分摄入及让患者戒酒，特别针对晚期肝病患者。这虽然十分重要，但是作为医生我们经常没有告诉患者。

 

　　Prof. Bajaj: Nutrition is something that is often ignored in mainstream medicine. This is usually managed by dieticians and is very specific to each person, especially when we consider the wide range of dietary practices in the United States or India or China. Each population group and individual has their own dietary practices, and nutritional intake needs to be completely tailored to what a particular patient is eating, wants to eat, and will eat. Protein should not be restricted in patients with liver failure including those with hepatic coma. These patients have reduced muscle mass and these muscles are further drawn upon by the body when it is starving. These patients require a lot more protein to maintain their muscle, so even in hepatic encephalopathy and hepatic coma, there should be no protein restriction. It is important for us to train our dieticians and patients to restrict salt, especially in advanced liver disease, and for patients to avoid alcohol. These are important things that, as doctors, we often do not tell our patients.