📖The interplay between thyroid and liver: implications for clinical practice

Abstract  抽象

A complex relationship exists between thyroid and liver in health and disease. Liver plays an essential physiological role in thyroid hormone activation and inactivation, transport, and metabolism. Conversely, thyroid hormones affect activities of hepatocytes and hepatic metabolism. Serum liver enzyme abnormalities observed in hypothyroidism may be related to impaired lipid metabolism, hepatic steatosis or hypothyroidism-induced myopathy. Severe hypothyroidism may have biochemical and clinical features, such as hyperammonemia and ascites, mimicking those of liver failure. Liver function tests are frequently abnormal also in hyperthyroidism, due to oxidative stress, cholestasis, or enhanced osteoblastic activity. Antithyroid drug-associated hepatotoxicity is a rare event, likely related mainly to an idiosyncratic mechanism, ranging from a mild hepatocellular damage to liver failure. Propylthiouracil-induced liver damage is usually more severe than that caused by methimazole. On the other hand, thyroid abnormalities can be found in liver diseases, such as chronic hepatitis C, liver cirrhosis, hepatocellular carcinoma, and cholangiocarcinoma. In particular, autoimmune thyroid diseases are frequently found in patients with hepatitis C virus infection. These patients, especially if thyroid autoimmunity preexists, are at risk of hypothyroidism or, less frequently, thyrotoxicosis, during and after treatment with interpheron-alpha alone or in combination with ribavirin, commonly used before the introduction of new antiviral drugs. The present review summarizes both liver abnormalities related to thyroid disorders and their treatment, and thyroid abnormalities related to liver diseases and their treatment.
甲状腺和肝脏在健康和疾病方面存在复杂的关系。肝脏在甲状腺激素的激活和失活、运输和代谢中起着重要的生理作用。相反，甲状腺激素影响肝细胞活性和肝脏代谢。在甲状腺功能减退症中观察到的血清肝酶异常可能与脂质代谢受损、肝脂肪变性或甲状腺功能减退症引起的肌病有关。重度甲状腺功能减退症可能具有生化和临床特征，例如高氨血症和腹水，与肝衰竭相似。由于氧化应激、胆汁淤积或成骨细胞活性增强，甲状腺功能亢进症患者的肝功能检查也经常异常。抗甲状腺药物相关的肝毒性是一种罕见事件，可能主要与一种特殊机制有关，范围从轻度肝细胞损伤到肝功能衰竭。丙硫氧嘧啶诱导的肝损伤通常比甲巯咪唑引起的肝损伤更严重。另一方面，甲状腺异常可见于肝脏疾病，如慢性丙型肝炎、肝硬化、肝细胞癌和胆管癌。特别是，自身免疫性甲状腺疾病常见于丙型肝炎病毒感染患者。这些患者，特别是如果甲状腺自身免疫已经存在，在单独使用 interpheron-α或与利巴韦林联合治疗期间和之后，有发生甲状腺功能减退症的风险，或者较少见的甲状腺毒症，通常在引入新的抗病毒药物之前使用。本文总结了甲状腺疾病及其治疗相关的肝脏异常和肝脏疾病及其治疗相关的甲状腺异常。