Hyperthyroidism impacts about 2% of ladies and 0.2% of males.1 It's a hypermetabolic state characterised by elevated ranges of free thyroxine (fT4) and/or free triiodothyronine (fT3) and a low stage of serum thyroid stimulating hormone (TSH).2 Weight reduction, osteoporosis, atrial fibrillation, and embolic occasions are a few of the problems related to hyperthyroidism. Essentially the most profound impact of hyperthyroidism is on the cardiovascular system.three The causes of hyperthyroidism embrace poisonous multinodular goitre (TMNG), poisonous adenoma, and thyroiditis. Nevertheless, the commonest explanation for hyperthyroidism is Graves' illness and the annual incidence of Graves’ illness was discovered to be 0.5 circumstances per 1000 individuals, with a peak incidence amongst individuals aged 20–40 years.4, 5
The correct remedy for hyperthyroidism relies on the identification of the signs and indicators of the illness and its aetiologies. Antithyroid medicine, radioactive iodine (RAI) remedy and surgical procedure are the principle remedy modalities identified to be efficient. In 1941, RAI remedy was launched and have become fashionable as a result of its robust efficacy and security profile.6, 7 The nuclide used on this remedy is iodine-131 (131I).8 131I is a beta-emitting radionuclide with a median power of 0.192 MeV (most power of 0.61 MeV) and tissue vary of 0.8 mm.9 Though 131I could trigger cell mutation and cell loss of life, all of the iodine isotopes are quickly taken up into the thyroid follicles; thus, solely thyroid follicles endure organification. The absorption and organification of 131I beta radiation by the thyroid follicles end result within the extremely localised destruction of these follicles. 131I disrupts thyroid hormone biosynthesis and causes the necrosis of the follicles and blood vessels. The half-life of 131I is roughly Eight days and ends in euthyroidism inside 6–18 weeks.9
RAI remedy is indicated when antithyroid drug remedy fails to deal with hyperthyroidism or when there may be recurrent hyperthyroidism. Remedy of Graves’ illness with treatment is related to 50–70% recurrence after finishing a normal course of 1–2 years of antithyroid medicine.10 Sufferers who're allergic to antithyroid medicine and who've neither TMNG nor thyroid most cancers are the very best candidates for RAI remedy. RAI remedy destroys the thyroid tissue and renders sufferers both euthyroid or hypothyroid.9 Most frequently, hypothyroidism is a long-term impact of RAI that necessitates life-long thyroxine supplementation.Eight Hypothyroidism incessantly develops within the first yr after remedy. Nevertheless, hypothyroidism may manifest a number of years publish RAI remedy.11 Thus, sufferers who've undergone RAI require long-term comply with up.
In Malaysia, RAI has develop into one of many foremost therapeutic providers obtainable at a number of tertiary hospitals and establishments with nuclear medication amenities. Hospital Universiti Sains Malaysia (HUSM) positioned in Kelantan, is the one facility that gives RAI within the Northeast Coast of Peninsular Malaysia the place it serves as a referral centre for the 2 neighbouring states, i.e., Terengganu and Kedah. The RAI administration observe varies from centre to centre as regards to the choice of circumstances, preparation for RAI, dosage of radioiodine, and protocol for the usage of antithyroid medicine pre- and publish RAI. Though there are customary worldwide tips for RAI remedy, the totally different practices might result in totally different outcomes of RAI remedy from centre to centre, particularly within the incidence of hypothyroidism publish RAI remedy.
A research in Bangladesh confirmed that the incidence of hypothyroidism one yr publish RAI was 35.6%.12 A retrospective research of 360 sufferers by Ghabhan et al. revealed that the incidence of hypothyroidism publish RAI at 6 months and one yr was 55.8% and 67.9%, respectively.13 Ahmad et al. confirmed that the cumulative incidence of hypothyroidism was 55.8% at one yr and 86.1% at 10 years.14 There are a lot of elements related to the event of hypothyroidism publish RAI remedy, reminiscent of historical past of Graves’ illness, presence of thyroid autoantibodies, utilization of antithyroid remedy previous to RAI and absence of a palpable goitre.13 These conflicting outcomes mandate additional research relating to this difficulty. Thus, the target of this research was to find out the incidence of hypothyroidism and its related elements inside one-year publish RAI amongst sufferers with hyperthyroidism within the Northeast Coast Area of Malaysia.