[Hepatitis C virus infection and thyroid diseases]

[Guest guest]

[Hepatitis C virus infection and thyroid diseases]

[Article in French]

Broussolle C, Steineur MP, Bailly F, Zoulim F, Trépo C.

Service de médecine interne, Hôtel-Dieu, Lyon, France.

INTRODUCTION: The combination of hepatitis C virus (HCV) infection

and thyroid diseases raises several issues that are the prevalence of

thyroid autoimmunity in patients with chronic hepatitis C, the

prevalence of HCV infection in patients with autoimmune thyroid

diseases, and the effects of interferon alpha treatment on thyroid

function in chronic HCV hepatitis. CURRENT KNOWLEDGE AND KEY POINTS:

The prevalence of anti-thyroid auto-antibodies ranges from 4.6 to 15%

in HCV infection, which is considered as significant by various

authors. Results have to be interpreted according to the following:

the type of auto-antibodies detected, the age, sex, ethnic origin of

the population studied, and characteristics of the control

population. Recent data are suggestive of a high prevalence of anti-

thyroid auto-antibodies in females with HCV infection. An increased

prevalence of HCV infection in patients with Hashimoto's thyroiditis

is not confirmed. During treatment of chronic hepatitis C, interferon

alpha induces thyroid dysfunctions (3 to 15% of the cases) with

various clinical presentations. Hypothyroidism is more common (two

out of three cases) than hyperthyroidism (one out of three cases).

Hyperthyroidism followed by hypothyroidism has also been described.

Clinical symptoms vary, ranging from subclinical to severe

manifestations. Thyroid dysfunction may be delayed after

discontinuation of the interferon treatment. Hypothyroidism is easily

cured by L-thyroxine replacement therapy when necessary, and

regression may be observed following discontinuation of interferon

treatment. Each case of hyperthyroidism has to be precisely

evaluated. Development of anti-thyroid antibodies or an increase in

anti-thyroid antibodies titers is often observed during interferon

alpha treatment, thus suggesting the existence of immunological

mechanisms at the origin of thyroid dysfunction. Furthermore,

interferon would directly act on iodine. FUTURE PROSPECTS AND

PROJECTS: Clinical studies are still necessary to better clarify the

links between HCV infection and thyroid autoimmunity, and to

determine risk factors for the development of thyroid dysfunction

during interferon alpha therapy. The effects of HCV and interferon

alpha on thyroid autoimmunity and function have to be investigated in

basic research.

PMID: 10522298 [PubMed - indexed for MEDLINE