Tendencia de la nutrición de yodo durante las últimas décadas en escolares chilenos y sus consecuencias / Trend of iodine nutrition in recent decades and its consequences in Chilean schoolchildren

The endemic goiter, nutritional collective problem due to iodine deficience, constitutes a chronic disease with easy prevention and control, nevertheless still it constitutes a serious problem of public world health, being thought that about 650 million persons have goiter, 43 millions suffer from endemic cretinism and 1570 millions are in risk of suffering this disease for living in areas that present a deficit of iodine. Both patterns, deficit and the excess of iodine can conducted to a thyroid disease. The relation between the ingestion of iodine and the risk of disease corresponds to a U curve, where both, the low one and high ingestion of iodine it is associate to high risk of thyroid disease. To have a program of iodine supplementation, it should imply a constant vigilance of iodine nutrition to see its effect on the goiter prevalence in the population, to control his degree of fulfillment, to avoid a possible excess of ingestion of iodine it might help to correct any precocious alteration. Endemic goiter is not longer a problem in Chile. Salt iodination is in agreement with present legislation, but it is very important to have a continuous surveillance of iodine nutrition in Chile to control if salt fortification is appropiate.

Tiroiditis autoinmune inducida por interferón en pacientes con infección por virus de la hepatitis C. / Interferon-induced autoimmune thyroiditis in a patient with hepatitis C virus infection

Se reporta el caso de un varón de 43 años de edad, sin antecedentes patológicos de importancia, que acudió por elevación asintomática de la alanino aminotransferasa (ALT). El paciente negó ser bebedor crónico de alcohol. Se hizo el diagnóstico serológico de infección activa por hepatitis C y la biopsia de hígado reveló inflamación crónica activa. Con estos resultados, se inició tratamiento con interferón-alfa y ribavirina. Durante el tratamiento de 48 semanas, el paciente presentó anticuerpos antitiroideos positivos con variaciones en sus niveles de tirotropina (TSH) y hormonas tiroideas. En el seguimiento postratamiento, el paciente continuó con hipertiroidismo por enfermedad de Graves. La tiroiditis autoinmune es una complicación frecuente del uso de interferón en pacientes con hepatitis C. En algunos casos se presenta como hipertiroidismo por enfermedad de Graves. Se debe evaluar la función tiroidea y los anticuerpos antitiroideos antes y durante el tratamiento con interferón.

A 43 year old man presented with asymptomatic elevation of alanine aminotransferase (ALT) and no relevant past history. The patient denied being a chronic alcohol drinker. Work-up revealed an active hepatitis C, and liver biopsy showed active inflammation. Treatment was started with interferon-alfa and ribavirin. During the 48 weeks of treatment, the patient developed positive thyroid antibodies with varying level of thyrotropin (TSH) and thyroid hormones. At follow-up after treatment, the patient continued with hyperthyroidism due to Graves’ disease. Autoimmune thyroiditis is a common complication of using interferon in patients with hepatitis C. In some cases, it is presented as hyperthyroidism because of Graves’ disease. Thyroid function and thyroid antibodies should be evaluated before and during treatment with interferon.

Thyroid hormonal disturbances related to treatment of hepatitis C with interferon-alpha and ribavirin

OBJECTIVE: To characterize thyroid disturbances induced by interferon-alpha and ribavirin therapy in patients with chronic hepatitis C. INTRODUCTION: Interferon-alpha is used to treat chronic hepatitis C infections. This compound commonly induces both autoimmune and non-autoimmune thyroiditis. METHODS: We prospectively selected 26 patients with chronic hepatitis C infections. Clinical examinations, hormonal evaluations, and color-flow Doppler ultrasonography of the thyroid were performed before and during antiviral therapy. RESULTS: Of the patients in our study, 54 percent had no thyroid disorders associated with the interferon-alpha therapy but showed reduced levels of total T3 along with a decrease in serum alanine aminotransferase. Total T4 levels were also reduced at 3 and 12 months, but free T4 and thyroid stimulating hormone (TSH) levels remained stable. A total of 19 percent of the subjects had autoimmune interferon-induced thyroiditis, which is characterized by an emerge of antithyroid antibodies or overt hypothyroidism. Additionally, 16 percent had non-autoimmune thyroiditis, which presents as destructive thyroiditis or subclinical hypothyroidism, and 11 percent remained in a state of euthyroidism despite the prior existence of antithyroidal antibodies. Thyrotoxicosis with destructive thyroiditis was diagnosed within three months of therapy, and ultrasonography of these patients revealed thyroid shrinkage and discordant change in the vascular patterns. DISCUSSION: Decreases in the total T3 and total T4 levels may be related to improvements in the hepatocellular lesions or inflammatory changes similar to those associated with nonthyroidal illnesses. The immune mechanisms and direct effects of interferon-alpha can be associated with thyroiditis. CONCLUSION: Interferon-alpha and ribavirin induce autoimmune and non-autoimmune thyroiditis and hormonal changes (such as decreased total T3 and total T4 levels), which occur despite stable free T4 and TSH levels. A thyroid hormonal evaluation, including the analysis of the free T4, TSH, and antithyroid antibody levels, should be mandatory before therapy, and an early re-evaluation within three months of treatment is necessary as an appropriate follow-up.

Thyroiditis induced by interferon in dialysis

We describe a dialysis patient who acquired acute Hepatitis C infection. Her primary renal disease was systemic lupus erythromatosis. She was having goitre but clinically euthyroid and her thyroid function test was normal. To avoid long term complications of Hepatitis C we elected to treat her with Interferon 3 million units subcutaneously 3 times a week. During treatment she developed some transient side effects initially which subsided but later she felt pressure symptoms around her neck. When we checked her TSH and thyroid antibodies these were elevated. Though this could be related to HCV, rarely, but we think the thyroid change is mostly related to Interferon. Some possible explanation of the effect of Interferon on thyroid have been reviewed and we think patients getting such drugs should be under close monitoring to avoid permanent thyroid dysfunction