Methods: A retrospective study was conducted among patients with hyperthyroidism who received RAI therapy at Nuclear Medicine Clinic, Hospital Universiti Sains Malaysia (HUSM), Kelantan. Data regarding patients' demographics, gender, aetiology of hyperthyroidism, presence of autoantibodies, dose of RAI used and usage of antithyroid drug post RAI therapy were included in the analysis.
Results: Of a total of 167 screened patients, 137 subjects were eligible for this study. The incidence of hypothyroidism within one year of RAI therapy was 32.9%. Women were found to be less likely to develop hypothyroidism post RAI therapy (adjusted odds ratio, 0.406; 95% confidence interval: 0.181-0.908; p = 0.028). The usage of antithyroid drug post RAI was significantly associated with a lower incidence of hypothyroidism post RAI therapy (adjusted odds ratio, 0.188; 95% confidence interval: 0.081-0.438; p<0.001).
Conclusion: This study showed a high incidence of hypothyroidism within one-year post RAI therapy. Gender and usage of antithyroid drug post RAI therapy are significantly associated with the development of hypothyroidism.
Case presentation: A 29-year-old female with incomplete paraplegia secondary to tuberculosis (TB) spondylodiscitis presented with asymptomatic sinus tachycardia. The related medical conditions, including anaemia, acute coronary syndrome, hyperthyroidism and other infective causes had been ruled out. Deep venous thrombosis was not on the list of differentials as she showed improvements in neurological and mobility functions with no clinical signs of calf pain or swelling. She had moderate risk of acute PE based on Wells' criteria with positive D-dimer testing and computed tomography pulmonary angiography (CTPA) showing thrombus formation in the left-ascending pulmonary artery.
Discussion: Acute PE may present solely with asymptomatic sinus tachycardia in TB spondylodiscitis. This caveat should provide a high index of suspicion to prevent delay in diagnosis and prevention of more sinister complications. Early stratification based on Wells' criteria for a possible diagnosis of acute PE is proven to be a useful approach in conjunction with clinical features.
METHODS: This is a prospective, cross-sectional study of consecutive thyrotoxicosis patients seen at the endocrine clinic of a tertiary medical center. Thyroid status was determined biochemically before prolonged exercise test. Compound muscle action potential (CMAP) amplitudes postexercise were compared against pre-exercise amplitudes and recorded as percentage of mean baseline CMAP amplitude. Comparisons of time-dependent postexercise CMAP amplitudes and mean CMAP amplitude decrement were made between hyperthyroid and nonhyperthyroid groups.
RESULTS: Seventy-four patients were recruited, 23 (31%) men, 30 (41%) Chinese, and the mean age was 48.5 ± 16.8 years. Of 74 patients, 32 (43%) were hyperthyroid and 42 (57%) were nonhyperthyroid viz. euthyroid and hypothyroid. Time-dependent CMAP amplitudes from 10 to 45 minutes after exercise were significantly lower in hyperthyroid patients compared with nonhyperthyroid patients (P < 0.01). Mean CMAP amplitude decrement postexercise was significantly greater in hyperthyroid than nonhyperthyroid patients (23.4% ± 11.4% vs. 17.3% ± 10.5%; P = 0.02).
CONCLUSIONS: Compound muscle action potential amplitude declines on prolonged exercise test were significantly greater in hyperthyroid patients compared with nonhyperthyroid patients. Muscle membrane excitability is highly influenced by thyroid hormone level. Thyrotoxic periodic paralysis occurs from increased levels of thyroid hormone activity in susceptible patients.