Endocrine Abstracts

Radioiodine therapy is non-invasive, safe and cost effective method of therapy for reduction of goitre. We aimed to determine whether radioiodine therapy has benefit effect on the symptoms mimicking hyperthyroidism in nontoxic goitre patients.

Material and methods: We studied 20 patients with non toxic nodular goitre, aged 42–79 years, 12 females and 8 males. All the patients complained of some symptoms of hyperthyroidism (palpitation, hot intolerance, sweating, tiredness and tachycardia). In all the patients serum TSH was in the lower normal range, serum levels of fT₃, and fT₄ were in the normal range, initial RAIU after 24 h was ranged between 23 and 47%, and thyroid volume ranged between 40 and 80 ml. The serum fT₄, fT₃, and TSH were evaluated before and monthly up to 12 months after RIT. Thyroid ultrasound, and thyroid scan with thyroid RAIU were done before and after 12 months of radioiodine therapy. The activity dose was calculated by Marinelli’s formula and was ranged between 280 and 800 MBq. The absorbed dose ranged between 180 and 260 Gy and was proportional to thyroid volume.

Results: After 12 months of radioiodine therapy a mean thyroid volume reduction of 46% was achieved in all the patients, euthyroidism persist in 95% of patients, and hypothyroidism develop in one patient (5%). All patients were highly satisfied; all the symptoms relieved and exercise tolerance improved.

Conclusions: The hot nodules may contribute to the symptoms complained by the patients, and this was confirmed when all the symptoms relieved after radioiodine therapy. Radioiodine is non-invasive, safe and cost effective method of therapy for reduction of goitre and should be used as first choice in every patient with non-toxic nodular goitre (>40 ml) with and without symptoms. The reduction of thyroid volume with low percent of hypothyroidism were due to accurate measurement of administered activity, and relatively high effective half-life.