Virus C genotype predisposes to primary hypothyroidism during interferon-α treatment for chronic hepatitis C

OBJECTIVE: The treatment of the chronic hepatitis C (HCV) with α-interferon is associated with thyroid dysfunction (TD). The aim of this study was to evaluate thyroid function outcome among patients with chronic HCV under treatment with conventional interferon (IFN) or peguilated interferon (PEG-IFN) in association with ribavirin. PATIENTS AND METHODS: We studied 293 patients with chronic HCV, submitted to drug therapy for 24 or 48 weeks. Initially, we evaluated FT4, TSH, TPOAb, TgAb, and continued to monitor FT4 and TSH every three months during therapy and six months thereafter. RESULTS: At baseline, TD prevalence was 6.82 percent (n = 20); 6.14 percent hypothyroidism; 0.68 percent hyperthyroidism. TPOAb was present in 5.46 percent of euthyroid patients. Out of 273 euthyroid patients at baseline, 19 percent developed TD: 17.2 percent hypothyroidism; 1.8 percent hyperthyroidism; 5.1 percent destructive thyroiditis (DT). 90 percent of TPOAb-positive patients at baseline developed hypothyroidism vs 14.5 percent of TPOAb-negative patients (p < 0.001). On average, TD occurred after 25.8 ± 15.5 weeks of treatment. 87.2 percent of patients who developed hypothyroidism did so during the first therapeutic cycle (p = 0.004; OR = 3.52; 95 percent CI = 1.36-9.65). Patients infected with genotype 1 virus were 2.13 times more likely to develop hypothyroidism (p = 0.036; 95 percent CI = 1.04-4.38). Hypothyroid and DT patients presented higher TSH levels before-treatment than patients who had remained euthyroid (p < 0.001; p = 0.002, respectively). DT patients presented lower qALT (p = 0.012) than euthyroid patients. CONCLUSION: Hypothyroidism was the most frequent TD, especially during the first cycle of α-interferon. Genotype 1 virus was associated with a risk two times higher for developing the illness. There was no need to interrupt or to change HCV treatment. Therefore, approximately 34 percent of TD was transient.

Thyroid uptake and scintigraphy using 99mTc pertechnetate: standardization in normal individuals

CONTEXT: Thyroid uptake and scintigraphy using 99mTc-pertechnetate has proven to be more advantageous than with 131I-iodide, since the images have better quality, the procedure is faster and the patient is submitted to a lower radiation dose. OBJECTIVE: The purpose of this study was to standardize a simple and fast methodology for performing thyroid uptake and scintigraphy and to determine the normal values for 99mTc- pertechnetate uptake. TYPE OF STUDY: Prospective, non-randomized. SETTING: Division of Nuclear Medicine, Department of Radiology, School of Medical Sciences, Campinas State University. PARTICIPANTS: The study consisted of 47 normal individuals, 30 women and 17 men, with ages ranging from 19 to 61 years (mean of 33 years). PROCEDURES: The laboratory assessment of thyroid function consisted of serum dosages of ultra-sensitive thyroxin and thyrotrophin. Twenty minutes after an intravenous injection of 10 mCi (370 MBq) of 99mTc-pertechnetate, the images were obtained on a computerized scintillation camera equipped with a low-energy high-resolution parallel hole collimator. RESULTS: All the individuals were euthyroid both on clinical and laboratory evaluation. The baseline thyroid 99mTc-pertechnetate uptake ranged from 0.4 to 1.7 percent. The uptake values obtained in these normal individuals showed that 95 percent presented a thyroid uptake that ranged from 0.4 to 1.5 percent of the injected dose. CONCLUSION: The assessment of thyroid structure and function using 99mTc-pertechnetate is a simple, fast and efficient method, which could easily become a part of the routine studies in nuclear medicine laboratories