Georgia Regents University, Augusta, GA 30912, USA.
Am Fam Physician. 2013 Jul 1;88(1):35-42.
Nonalcoholic fatty liver disease is characterized by excessive fat accumulation in the liver (hepatic steatosis). Nonalcoholic steatohepatitis is characterized by steatosis, liver cell injury, and inflammation. The mechanism of nonalcoholic fatty liver disease is unknown but involves the development of insulin resistance, steatosis, inflammatory cytokines, and oxidative stress. Nonalcoholic fatty liver disease is associated with physical inactivity, obesity, and metabolic syndrome. Screening is not recommended in the general population. The diagnosis is usually made after an incidental discovery of unexplained elevation of liver enzyme levels or when steatosis is noted on imaging (e.g., ultrasonography). Patients are often asymptomatic and the physical examination is often unremarkable. No single laboratory test is diagnostic, but tests of liver function, tests for metabolic syndrome, and tests to exclude other causes of abnormal liver enzyme levels are routinely performed. Imaging studies, such as ultrasonography, computed tomography, and magnetic resonance imaging, can assess hepatic fat, measure liver and spleen size, and exclude other diseases. Liver biopsy remains the criterion standard for the diagnosis of nonalcoholic steatohepatitis. Noninvasive tests are available and may reduce the need for liver biopsy. A healthy diet, weight loss, and exercise are first-line therapeutic measures to reduce insulin resistance. There is insufficient evidence to support bariatric surgery, metformin, thiazolidinediones, bile acids, or antioxidant supplements for the treatment of nonalcoholic fatty liver disease. The long-term prognosis is not associated with an increased risk of all-cause mortality, cardiovascular disease, cancer, or liver disease.
非酒精性脂肪性肝病的特征是肝脏（肝细胞）中脂肪堆积过多（肝脂肪变性）。非酒精性脂肪性肝炎的特征是脂肪变性、肝细胞损伤和炎症。非酒精性脂肪性肝病的发病机制尚不清楚，但涉及胰岛素抵抗、脂肪变性、炎症细胞因子和氧化应激的发展。非酒精性脂肪性肝病与身体活动不足、肥胖和代谢综合征有关。不建议在一般人群中进行筛查。通常在意外发现不明原因的肝酶水平升高或在影像学（例如超声检查）上发现脂肪变性时诊断该病。患者通常无症状，体检通常无异常。没有单一的实验室检查是诊断性的，但通常会进行肝功能检查、代谢综合征检查以及排除其他异常肝酶水平原因的检查。影像学研究，如超声、计算机断层扫描和磁共振成像，可评估肝脂肪、测量肝脾大小，并排除其他疾病。肝活检仍然是非酒精性脂肪性肝炎的诊断标准。有非侵入性检查方法，可能会减少肝活检的需要。健康饮食、减肥和运动是非酒精性脂肪性肝病治疗中减少胰岛素抵抗的一线治疗措施。没有足够的证据支持使用减重手术、二甲双胍、噻唑烷二酮类药物、胆酸或抗氧化剂补充剂来治疗非酒精性脂肪性肝病。长期预后与全因死亡率、心血管疾病、癌症或肝病的风险增加无关。
