Hyperthyroidism and jaundice

Transcriptome Profile of Thyroid Glands in Bile Duct Ligation Mouse Model

Thyroid hormone (TH) contributes to multiple cellular mechanisms in the liver, muscle cells, adipose tissue, and brain, etc. In particular, the liver is an important organ in TH metabolism for the conversion of thyronine (T4) into triiodothyronine (T3) by the deiodinase enzyme. TH levels were significantly decreased and thyroid-stimulating hormone (TSH) levels were significantly increased in patients with liver failure compared with normal subjects. Among liver failure diseases, hepatic encephalopathy (HE) deserves more attention because liver damage and neuropathologies occur simultaneously. Although there is numerous evidence of TH dysregulation in the HE model, specific mechanisms and genetic features of the thyroid glands in the HE model are not fully understood. Here, we investigated the significantly different genes in the thyroid glands of a bile duct ligation (BDL) mouse model as the HE model, compared to the thyroid glands of the control mouse using RNA sequencing. We also confirmed the alteration in mRNA levels of thyroid gland function-related genes in the BDL mouse model. Furthermore, we evaluated the increased level of free T4 and TSH in the BDL mouse blood. Thus, we emphasize the potential roles of TH in liver metabolism and suggest that thyroid dysfunction-related genes in the HE model should be highlighted for finding the appropriate solution for an impaired thyroid system in HE.

Hyperthyroidism and Liver Dysfunction: A Review of a Common Comorbidity

Deranged liver enzymes due to hyperthyroidism rather than intrinsic liver pathology are not uncommon. The reported prevalence of liver biochemical abnormalities in patients with untreated thyrotoxicosis varies widely ranging from 15% to 76%. The suggested causes of liver dysfunction include direct hepatocyte injury, co-morbid heart failure, associated autoimmune conditions (especially in the setting of Graves' Disease), preexisting liver disease and drugs including antithyroid medications. Although, some patients may have a pattern of mild liver injury, about 1% to 2% can have fulminant hepatitis. Liver enzymes can return to normalcy in as many as 77% to 83% of patients once the initiations of thionamides are started in a timely fashion, which can help forestall complications and prevent or minimize multi-organ dysfunction. Clinicians should maintain a high index of suspicion for underlying hyperthyroidism in patients presenting with unexplained liver dysfunction or unexplained jaundice.

Hyperthyroidism and hepatic dysfunction: Report of 17 cases

Aims

Hyperthyroidism has been known to be associated with abnormalities of serum liver chemistry. The objective of our study is to describe clinical, biochemical and therapeutic features of hepatic dysfunction in hyperthyroidism.

Methods and Results

This retrospective study was conducted on patients hospitalized in our endocrinology department over 20 years. We included patients with untreated and noniatrogenic hyperthyroidism among whom biochemical findings noted hepatic dysfunction and excluded those with concomitant liver disease. Our population is composed of 10 men and 7 women. The average age was 41.4 years. The mean serum level of free thyroxine was 83.8 pmol/L. The serum thyrotropin level was below the detection limit in 10/17 cases. Graves' disease was the most frequently found etiology of hyperthyroidism. Fourteen patients had hyperthyroidism's complications. Eleven patients manifested congestive heart failure. Hepatic dysfunction was moderate and severe in eight and two cases, respectively. Fifteen patients had cholestasis, associated with jaundice in five cases. Hepatocellular injury and synthetic liver dysfunction were noted in seven and five cases, respectively. Thyroid peroxidase antibodies were positively correlated with the serum level of bilirubin (ρ = 0.695; P = 0.038). A negative correlation was noted between alanine aminotransferase and left ventricular ejection fraction (ρ = −0.812; P = 0.05). Radioactive iodine was indicated in 15/17 cases. Follow‐up liver tests were performed in 11 cases. They all had normalized hepatic function once euthyroidism restored.

Conclusion

Liver injury in hyperthyroidism is relatively common, ranging from mild to severe. Therefore, patients presenting unexplained hepatic abnormalities require close examination and an evaluation of the thyroid function should be sought.