SEVERE HYPOTHYROIDISM IN CHRONIC HEPATITIS C INFECTION

A QUANDARY OF AUTOIMMUNITY VERSUS ANTIVIRAL THERAPY

Abstract

INTRODUCTION/BACKGROUND
Chronic Hepatitis C virus infection (HCV) may have extrahepatic manifestations, mainly related to autoimmune and malignant disorders. Autoimmune thyroid disease (AITD) may present in up to 10% of cases as influenced by the presence of autoantibodies as well as direct virus invasion that promotes T-cell mediated cytotoxicity Besides host factor, interferon previously used as a standard treatment in HCV, is known to cause thyroid dysfunction either by direct inhibitory effect on the thyroid gland or immune activation particularly in those with genetic predisposition to autoimmune disease Direct-acting Antivirals (DAA) targeting specific nonstructural proteins of the virus, hinders viral replication. Since it was introduced, there are few studies demonstrating the effect of DAA on thyroid dysfunction. We report a case of new-onset hypothyroidism in a patient with HCV soon after commencement of DAA.

CASE
A 53-year-old male, former intravenous drug user with Chronic Hepatitis C Child Pugh A, was treated with DAAs (sofosbuvir and daclatasvir) and ribavirin based on viral load and genotyping. He denied preceding hypothyroid symptoms or family history of thyroid disorder. Two months into treatment, he complained of facial puffiness, weight gain and was eventually admitted for heart failure. Biochemical investigations revealed overt hypothyroidism with FT4 <3.2 pmol/L (7.86 - 14.41) and TSH >300 uIU/mL (0.38 - 5.33) with positive thyroid peroxidase antibody. Levothyroxine was started subsequently, however due to poor compliance, he showed poor clinical and biochemical response in HCV viral suppression and thyroid disorder.

CONCLUSION
Hypothyroidism related to HCV infection is a relatively uncommon association but an important one to diagnose, nonetheless. The condition can be part of the extrahepatic viral manifestation or may be treatment related. Supported by previous study that demonstrated similar effect of DAA on the thyroid gland, further larger RCTs are needed to substantiate this association.