Frequency of Pathological Types of Hyperthyroidism in Thyroid Scan Patients.

BACKGROUND Hyperthyroidism is a common systemic disorder where Graves' disease is known as the leading cause of the disease. Thyroid stimulating hormone, T4 and T3 antibody assay are usually performed for the diagnosis of the pathology. However, with uncertainty in the results and in order to estimate the magnitude and the exact cause of the disease, radioactive iodine uptake (RAIU) test is recommended. The aim of this study is to evaluate underlying pathology in the patients presenting hyperthyroidism using RAIU test results. METHODS This is a cross-sectional retrospective study conducted on the patients with hyperthyroidism referred to Shahid Madani Hospital in Khorramabad. Data regarding the biochemical analysis and RAIU test was collected from the records and a questionnaire based on demographic and clinical information was completed for each patient. RESULTS Of 137 patients presenting hyperthyroidism, 62.04% were presented with Graves' disease, 24.08% with toxic multinodular goiter and 13.86% with toxic adenoma. 24-hour RAIU test showed that the percent of radioiodine uptake was most in toxic adenoma 67.7%, Graves' disease 53.5% and multinodular goiter 39%, respectively. From the age-based analysis, we found that Graves' was most common in 20-30 years old individuals 34%, multinodular goiter in 50+ aged individuals 36.3% and toxic adenoma was most prevalent in 30-40 and 50+ aged patients, 26.3% each. In our population of interest, 81.8% toxic multinodular goiter patients were females. CONCLUSIONS Our study presents the outcome of RAIU tests in hyperthyroidism based on the underlying pathologies. We also conclude, in light of other findings, Graves' disease is the most common cause of hyperthyroidism in our population.