High prevalence of thyroid dysfunction in adult patients with β-thalassemia major submitted to amiodarone treatment

Abstract

Amiodarone may induce hyper- or hypothyroidism. Patients with beta-Thalassemia Major (beta-Thal) have an increased prevalence of primary hypothyroidism and often require amiodarone for hemosyderotic cardiomyopathy. Aim of this study was to retrospectively evaluate thyroid function in beta-Thal adult patients on long-term amiodarone. The study group consisted of twenty-two (21 males, 1 female; age: 23-36 yr) beta-Thal patients submitted to long-term (3-48 months) amiodarone therapy from January 1991 to July 1996. Controls included 73 beta-Thal patients (23 males and 50 females aged 25-35 yr) not treated with amiodarone. In all cases serum free thyroid hormones, thyrotropin and thyroid autoantibodies were evaluated. A higher prevalence of overt hypothyroidism (5/22 [22.7%]) as compared to controls (3/73 [4.1%], p=0.02) was found in beta-Thal patients < or = 3 months after starting amiodarone, while the prevalence of subclinical hypothyroidism was similar in amiodarone-treated (18.2%) and untreated (15%) beta-Thal patients. Overt hypothyroidism resolved spontaneously after amiodarone withdrawal in 1 case, while the remaining patients were maintained euthyroid on amiodarone by L-thyroxine administration. After 21-47 months of amiodarone therapy, 3 patients (13.6%) developed thyrotoxicosis (2 overt and 1 subclinical), which remitted shortly after amiodarone withdrawal. No case of hyperthyroidism was observed in beta-Thal controls (p=0.012 vs amiodarone-treated patients). In conclusion, amiodarone administration is often associated in adult beta-Thal patients to a rapid progression of the pre-existing subclinical hypothyroidism, but transient thyrotoxicosis may also be observed after a longer period of therapy. These findings should be carefully considered in the management of these patients.

Urinary Iodine in Egyptian Patients with Thalassemia Major: A Focus on its Potential Contributing Impact on Consequent Hypothyroidism

“…Mariotti et al [32] found no significant difference in the incidence of hypothyroidism and type of chelation, resembling the results of Gamberini et al [33] who denoted that the incidence of hypothyroidism is not different in patients on oral or sc chelators on a long term treatment. However, in our study, the group of sc chelation of 3 cases only were not hypothyroid, however, the number is too small to be able to draw a conclusion.…”

Efficacy of the Surgical Management of Amiodarone-induced Thyrotoxicosis

“…Secondly, there is a variable duration of amiodarone use before onset of symptoms, which has also been previously documented. 5 Mariotti et al 5 stated the duration of time before onset ranged between 2 and 47 months and, as shown in Table 1, all the values from this study fall within that range. Thirdly, the time between diagnosis and surgery is also highly variable.…”

“…The onset of AIT is variable and can occur anytime from 2 to 47 months after use of amiodarone. 5 Thyrotoxicosis is diagnosed by clinical signs and symptoms and thyroid function tests (TFTs). The signs and symptoms can include relapse and/or worsening of an arrhythmia with cardiac insufficiency, nervousness, tremor, fatigue, muscle weakness, and weight loss.…”

A Review of Endocrine Disorders in Thalassaemia

“…Elevated levels of TSH and reduction in T4 and T3 result from increased sensitivity of the gland to pharmacological doses of Iodine [76] which may result in rapid progression of subclinical hypothyroidism into a severe disease [77]. This is more detrimental in those with concomitant cardiomyopathy and thus caution is required with co-prescription of Iodine based anti-arrhythmic agents such as amiodarone.…”