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Fulltext Results of long-term follow-up after compensated fixed-dose therapy for thyrotoxicosis

Zaini A, Khir A, Doi SA, Chan SP, Paramsothy M, Khoo BH

J Int Med Res, 1992 Jun;20(3):279-88.
PMID: 1397673

To evaluate the effects of simple compensated fixed-dose iodine-131 therapy for thyrotoxicosis, the long-term results for 74 patients treated with a fixed dose of iodine-131 ranging from 5 to 12 mCi (185 to 444 MBq) were evaluated in the first 2 years of a trial. The dose selected was loosely based on the gross size of the thyroid gland. Routine antithyroid drug therapy was given for a minimum of 3 months after iodine-131 therapy. The mean (+/- SD) duration of follow-up was 74.5 +/- 42 months. The results indicated that roughly 25% of patients treated in this way will become hypothyroid after 5 years and that 85% are cured (need no further therapy during the follow-up period) using a single dose of iodine-131. Of those cured using a single iodine-131 dose, 81% were no longer receiving drugs after 6 months and 85% after 1 year. Such a regimen seems currently to be among the best available where prolonged periods of medication-free euthyroidism after therapy are sought.

Matched MeSH terms: Thyrotoxicosis/radiotherapy*
Fulltext Psychoses associated with thyrotoxicosis: a retrospective study of twenty cases

Tan CK

Med J Malaysia, 1985 Sep;40(3):247-51.
PMID: 3842721

A total of 23 patients with psychoses associated with thyrotoxicosis were admitted to the psychiatric unit of a University Hospital over a 13-year period, of which 20 patients were included in this retrospective study. It was found that a parallel relationship between thyrotoxicosis and psychosis appears to exist in six patients, while in the remaining 14 patients, the course of the two disease processes were largely independent of each other. Paranoid delusions and auditory hallucinations were the most prominent psychiatric symptoms. Depression was commonly seen even in patients who were not having an affective illness. In four patients, a mixed schizo-affective psychosis was seen, suggesting that the diagnostic distinction between the affective and schizophrenic reactions are often blurred in psychosis associated with thyrotoxicosis.

Matched MeSH terms: Thyrotoxicosis/complications*
Fulltext Transient hypothyroidism following I131 treatment for thyrotoxicosis

Zaini A, Ngan A, Paramsothy M, Khoo BH, Ch'ng SL

Med J Malaysia, 1983 Dec;38(4):331-3.
PMID: 6599994
Matched MeSH terms: Thyrotoxicosis/radiotherapy*
Slow carbamazepine clearance in a nonadherent Malay woman with epilepsy and thyrotoxicosis

Yeap LL, Lim KS, Ng CC, Hui-Ping Khor A, Lo YL

Ther Drug Monit, 2014 Feb;36(1):3-9.
PMID: 24342894 DOI: 10.1097/FTD.0000000000000024

The authors describe a case of a 37-year-old Malay lady with an unusually slow carbamazepine clearance, which may be related to genetic polymorphisms of drug metabolizing enzymes and transporters. When given a small daily dose of 200 mg immediate-release carbamazepine, this patient experienced drowsiness. Subsequently, she reduced her carbamazepine dose to 200 mg twice a week (on Mondays and Fridays), resulting in poor seizure control. At the same time, the patient was diagnosed with hyperthyroidism and was given carbimazole and propranolol. Hyperthyroidism and the concurrent use of these antihyperthyroid agents may have further slowed down the metabolism of carbamazepine. Therapeutic drug monitoring of carbamazepine was carried out, and a slow carbamazepine clearance of 1.45 L·h⁻¹ per 70 kg was observed. Genotyping of selected genetic variants in CYP3A4, CYP3A5, EPHX1, ABCB1, and ABCC2 revealed that she has CYP3A5*3/*3 and ABCB1 3435-CC genotypes. Both genotypes have been shown to be associated with higher adjusted mean serum carbamazepine concentration in Chinese and Korean patients with epilepsy. Physicians should be vigilant about the risk of adverse effects among patients with a slow carbamazepine clearance, especially in Malays. Simulations of carbamazepine dosing regimen based on the pharmacokinetic parameters of this patient were performed to allow individualization of drug therapy.

Matched MeSH terms: Thyrotoxicosis/drug therapy; Thyrotoxicosis/physiopathology*
Hyperthyroidism in pregnancy

Zainuddin Z, Shaker AAH

Family Physician, 2005;13(3):2-4.
MyJurnal

Thyroid diseases are common in women, including at the time of pregnancies. Many typical features of hyperthyroidism are common in normal pregnancies and this may delay or mask the diagnosis. Uncontrolled thyrotoxicosis increases the rate of miscarriage, intrauterine growth restriction (IUGR), premature labour and perinatal mortality. Multi-disciplinary efforts are required to achieve optimal control of thyrotoxicosis. Anti-thyroid drugs are safe and should be used with the lowest possible doses. Radioiodine treatment is contraindicated during pregnancy and lactation. Indications of surgery include: compression symptoms, thyroid malignancy, non-compliance to medications or when the patient develop drugs side effects

Matched MeSH terms: Thyrotoxicosis
Fulltext Weathering the Crisis: A Case of Thyroid Crisis with Propranolol-Induced Circulatory Collapse Successfully Treated with Therapeutic Plasma Exchange

Cheah JM, Ng D, Low MY, Foo SH

J ASEAN Fed Endocr Soc, 2019;34(2):206-209.
PMID: 33442157 DOI: 10.15605/jafes.034.02.12

Thyroid crisis is a life-threatening form of thyrotoxicosis characterized by multi-system dysfunction. Therapeutic plasma exchange has been reported to be effective in removing excessive circulating thyroid hormones. We present a 46-year-old female with recently diagnosed Graves' disease associated with thyrotoxic cardiomyopathy admitted for thyroid crisis complicated by propranolol-induced circulatory collapse, acute kidney injury and ischemic hepatitis. The tachyarrhythmia was refractory to conventional therapy. Initiation of TPE resulted in rapid clinical and biochemical stabilization.

Matched MeSH terms: Thyrotoxicosis
Conduction abnormalities in thyrotoxicosis--a report of three cases

Yusoff K, Khalid BA

Ann Acad Med Singap, 1993 Jul;22(4):609-12.
PMID: 8257070

Cardiac arrhythmias are common in patients with thyrotoxicosis. Conduction abnormalities have been seen in a few thyrotoxic patients, but these, in particular high grade atrioventricular (AV) block, often occur in the presence of other conditions. Three thyrotoxic patients with conduction abnormalities are described: two were associated with severe hypokalaemia and the third had congestive cardiac failure. Conditions predisposing to conduction abnormality should be identified when this occurs in a thyrotoxic patient as their correction may help resolve or explain the conduction abnormality.

Matched MeSH terms: Thyrotoxicosis/physiopathology*
Plasma renin and aldosterone in thyroid diseases

Asmah BJ, Wan Nazaimoon WM, Norazmi K, Tan TT, Khalid BA

Horm Metab Res, 1997 Nov;29(11):580-3.
PMID: 9479560 DOI: 10.1055/s-2007-979105

The effect of thyroid hormones on the renin-angiotensin-aldosterone system has not been fully resolved. Highly specific immunoassays for measurement of renin, aldosterone, free T4 (fT4), free T3 (fT3) and ultrasensitive TSH enables a direct and more accurate measurement of these hormones. We investigated the relationship between plasma renin, aldosterone and thyroid hormones in the basal state and after intravenous frusemide. This is a cross-sectional study involving 37 patients with thyrotoxicosis, 42 rendered euthyroid with normal fT4, fT3 and TSH levels, 17 with euthyroid levels of fT4 and fT3 but suppressed TSH, and 11 with hypothyroidism. Basal plasma renin was significantly higher in thyrotoxicosis (63.4 +/- 9.8 microU/ml, mean +/- SEM) compared to euthyroid (32.7 +/- 4.4 microU/ml) and hypothyroid (26.7 +/- 9.8 microU/ml). Basal plasma renin for euthyroid with suppressed TSH (41.0 +/- 7.4 microU/ml) was significantly higher than hypothyroid (p = 0.02). Basal plasma aldosterones were not significantly different except for suppressed TSH (157.7 +/- 13 pg/ml), which was higher than normal (109.9 +/- 10.4 pg/ml; p = 0.04). Following frusemide, plasma renin and aldosterone were significantly increased in all groups. Plasma renin was highly correlated to fT3 (r = 0.405, p < 0.001), total T3 (r = 0.359, p < 0.001), fT4 (r = 0.331, p < 0.001) and TSH (r = 0.300, p < 0.001) in the basal state, but less to total T4 (r = 0.248, p < 0.01). Plasma renin correlated poorly to serum aldosterone (r = 0.212, p < 0.03). This study clearly showed that regulation of renin was mainly influenced by fT3, and that aldosterone response to frusemide was blunted in thyrotoxicosis despite normal electrolytes.

Matched MeSH terms: Thyrotoxicosis/blood
Prolonged Exercise Test in Patients With History of Thyrotoxicosis

Tan HT, Tan CY, Teong CS, Ratnasingam J, Goh KJ

J Clin Neurophysiol, 2020 Aug 05.
PMID: 32773648 DOI: 10.1097/WNP.0000000000000766

PURPOSE: Thyrotoxic periodic paralysis is characterized by recurrent episodes of reversible, severe proximal muscle weakness associated with hypokalemia and hyperthyroidism. Prolonged exercise test is an easy, noninvasive method of demonstrating abnormal muscle membrane excitability in periodic paralyses. Although abnormal in thyrotoxic periodic paralysis patients, the effects thyroid hormone levels in non-thyrotoxic periodic paralysis thyrotoxicosis patients have not been well studied. The study aims to evaluate thyrotoxicosis patients (regardless of thyrotoxic periodic paralysis history) with prolonged exercise test and correlate it with their thyroid status.
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.

Matched MeSH terms: Thyrotoxicosis
Right ventricular dysfunction and pulmonary hypertension: a neglected presentation of thyrotoxicosis

Singarayar CS, Siew Hui F, Cheong N, Swee En G

Endocrinol Diabetes Metab Case Rep, 2018;2018.
PMID: 29785271 DOI: 10.1530/EDM-18-0012

Thyrotoxicosis is associated with cardiac dysfunction; more commonly, left ventricular dysfunction. However, in recent years, there have been more cases reported on right ventricular dysfunction, often associated with pulmonary hypertension in patients with thyrotoxicosis. Three cases of thyrotoxicosis associated with right ventricular dysfunction were presented. A total of 25 other cases of thyrotoxicosis associated with right ventricular dysfunction published from 1994 to 2017 were reviewed along with the present 3 cases. The mean age was 45 years. Most (82%) of the cases were newly diagnosed thyrotoxicosis. There was a preponderance of female gender (71%) and Graves' disease (86%) as the underlying aetiology. Common presenting features included dyspnoea, fatigue and ankle oedema. Atrial fibrillation was reported in 50% of the cases. The echocardiography for almost all cases revealed dilated right atrial and or ventricular chambers with elevated pulmonary artery pressure. The abnormal echocardiographic parameters were resolved in most cases after rendering the patients euthyroid. Right ventricular dysfunction and pulmonary hypertension are not well-recognized complications of thyrotoxicosis. They are life-threatening conditions that can be reversed with early recognition and treatment of thyrotoxicosis. Signs and symptoms of right ventricular dysfunction should be sought in all patients with newly diagnosed thyrotoxicosis, and prompt restoration of euthyroidism is warranted in affected patients before the development of overt right heart failure.
Learning points: Thyrotoxicosis is associated with right ventricular dysfunction and pulmonary hypertension apart from left ventricular dysfunction described in typical thyrotoxic cardiomyopathy.Symptoms and signs of right ventricular dysfunction and pulmonary hypertension should be sought in all patients with newly diagnosed thyrotoxicosis.Thyrotoxicosis should be considered in all cases of right ventricular dysfunction or pulmonary hypertension not readily explained by other causes.Prompt restoration of euthyroidism is warranted in patients with thyrotoxicosis complicated by right ventricular dysfunction with or without pulmonary hypertension to allow timely resolution of the abnormal cardiac parameters before development of overt right heart failure.

Matched MeSH terms: Thyrotoxicosis