Hyperthyroidism: advantages and disadvantages of medical therapy

Influence of Thyroid Peroxidase Antibodies Serum Levels in Graves' Disease: A Retrospective Cohort Study

Purpose Graves' disease (GD) is an autoimmune disorder caused by the presence of antibodies to the thyroid stimulating hormone (TSH) receptor (TRAbs), usually presenting with clinical signs of hyperthyroidism. Previous evidence suggests that higher serum levels of thyroid peroxidase antibodies (TPOAbs) may lead to more sustained remission of hyperthyroidism after treatment with antithyroid drugs (AT). However, doubts about the influence of TPOAbs in Graves' disease outcomes still remain. Methods A retrospective, unicenter cohort study was performed. All patients with GD (TRAbs > 1.58U/L), biochemical primary hyperthyroidism (TSH < 0.4 µUI/mL), and TPOAbs measurement at diagnosis, treated with AT between January 2008 and January 2021, were included for analysis. Results One hundred and forty-two patients (113 women) with a mean age of 52 ± 15 years old were included. They were followed up for 65.4 ± 43.8 months. TPOAbs positivity was present in 71.10% (n=101) of those patients. Patients were treated with AT for a median of 18 (IQR (12; 24)) months. Remission occurred in 47.2% of patients. Patients with remission presented with lower TRAbs and free thyroxine (FT4) levels at the diagnosis. (p-value <0.001, p-value 0.003, respectively). No association was found in the median TPOAbs serum levels of patients who remitted and those who maintained biochemical hyperthyroidism after the first course of AT. Relapse of hyperthyroidism occurred in 54 patients (57.4%). No difference was found in TPOAbs serum levels regarding the patient's relapse. Moreover, a time-based analysis revealed no differences in the relapse rate after 18 months of AT therapy between patients with and without TPOAbs positivity at the diagnosis (p-value 0.176). It was found a weak positive correlation (r=0.295; p-value <0.05) between TRAbs and TPOAbs titters at the moment of Graves' diagnosis. Conclusion In this study, a correlation between TRAbs measurements and TPOAbs titter was described, although no significant association was found between the presence of TPOAbs and the outcomes of patients with GD treated with AT. These results do not support the use of TPOAbs as a useful biomarker to predict remission or relapse of hyperthyroidism in GD patients.

Redistribution of body composition in patients with Graves' disease after iodine-131 treatment

OBJECTIVE

The objective of this study was to investigate body composition redistribution at 3 months after radioactive iodine therapy (RAI).

METHODS

Eighty patients with Graves' disease (GD) for RAI and 18 volunteers were recruited. All patients underwent thyroid status test and dual-energy x-ray absorptiometry at baseline and 3 months after RAI. According to the second thyroid status test, patients were divided into the following groups: A, with aggravated hyperthyroidism; B-1, with improved hyperthyroidism; B-2, with euthyroidism; and B-3, with hypothyroidism.

RESULTS

Total lean mass (LM) but fat mass (FM) and bone mineral content (BMC) of whole GD patients after RAI recovered to be not different with controls. Compared with baseline, in group A, FM in the left leg increased, and LM in left arm, right arm, trunk and total LM decreased (P<0.05). In B-2, FM in the head increased, and LM in the head, right arm, trunk and total LM increased (P<0.05). In B-3, FM in the right leg and total body fat percentage decreased, but FM in the head, android-to-gynoid fat ratio and body mass index increased (P<0.05); LM of all sites, weight and total mass increased (P<0.05); BMC in lumbar spine and left leg, and total BMC decreased (P<0.05). Body composition of unmentioned sites was retained after RAI in each group (P>0.05).

CONCLUSIONS

Replenishment of LM gets priority rather than FM and BMC during the first 3 months after RAI, and the increase in LM starts from the upper body; head is the regional site in which FM recovery occurs first.

Thyroid disorders

All forms of thyroid diseases are much more frequently observed in women than men, although the reasons are still not completely elucidated.Hyperthyroidism is defined by elevated circulating free thyroid hormones. The prevalence is about 2 % in women and 0.2 % in men. The most frequent causes are various forms of thyroid autonomy in elderly women and Graves' disease, which occurs mostly in younger women.Hypothyroidism is defined by a lack of thyroid hormones. It is a common endocrine disorder caused by autoimmune thyroiditis (Hashimoto thyroiditis), iodine deficiency or following surgery or radioiodine therapy. Thyroxine requirements depend on fat-free mass and are, therefore, somewhat higher in males who are more often undersubstituted. In pregnancy lower TSH-reference ranges have to be considered and thyroid function should be monitored throughout pregnancy to avoid harm to the foetus caused by maternal thyroid dysfunctions. If overtreated women more often feature fractures, whereas males more often develop atrial fibrillation.

Long-term immunological study in Graves' disease treated with thyroid arterial embolization

OBJECTIVE

The aim of this study was to investigate long-term immunological changes after the treatment of Graves' disease (GD) with thyroid arterial embolization and the effect of thyroid arterial embolization on the body's immunological functions.

MATERIALS AND METHODS

Forty-one patients with clinically and laboratorily ascertained GD were treated with thyroid arterial embolization and followed up for 3-54 months following embolization. Prior to embolization and at 1, 3, 6, 12, and 36 months following embolization, thyroid autoimmune antibodies were tested respectively, including thyroid stimulating antibody (TSAb), thyrotropin antibody (TRAb), thyroglobulin antibody (TGAb), and thyroid microsomal antibody (TMAb), as well as subgroup lymphocytes of CD16+CD56+, CD19+, CD3+, CD3+CD4+ and CD3+CD8+. The autoimmune status of GD patients prior to embolization and the dynamic changes of the immunological function after embolization were analyzed.

RESULTS

The therapy of thyroid arterial embolization could effectively decrease the activity/titer and positive rate of TRAb and the ratio of CD4+/ CD8+ to normal levels at 6 months following embolization, while the ratio of CD3+CD8+ increased gradually to normal level at 1 year following embolization. In patients with recurrence, TSAb and TRAb remained at a higher level, while the rate of CD3+CD8+ and the ratio of CD4+/CD8+ were not statistically significantly different from those before embolization.

CONCLUSION

Immunological functional disorder exists in GD patients. The treatment method of thyroid arterial embolization can effectively resume the basic immunological function to normal range while patients with recurrence have no significant improvement, suggesting that thyroid arterial embolization has an effective role in adjusting the immunological function.

Safety and efficacy of surgical management of hyperthyroidism: 15-year experience from a tertiary care center in a developing country

BACKGROUND

Ideal management of toxic goiter still remains elusive. Though surgical management of toxic multinodular goiter (MNG) is well accepted, surgical treatment of Graves' disease (GD) is still controversial in view of the presumed increased incidence of complications. In this paper, we discuss the experience of the surgical management of hyperthyroidism at a specialized tertiary care endocrine center in a developing country, highlighting the minimal morbidity and satisfactory outcome in experienced hands.

MATERIALS AND METHODS

We retrospectively reviewed 325 consecutive patients with hyperthyroidism managed surgically from 1990 to 2005. The etiologic diagnoses were Graves' disease (185), toxic MNG (105), and autonomously functioning thyroid nodules (AFTN) (n = 35). The indications for surgery in Graves' patients were large goiter, relapse after antithyroid drug therapy (ATD), Graves' ophthalmopathy, and presence of nodule. The indications for surgery in toxic MNG were retrosternal extension (n = 15), compressive symptoms (n = 20), and large size (grade II). Among the AFTN nodule size, those greater than 4 cm (85%) formed the major indication for surgery. Subjects with GD and toxic MNG were subjected to subtotal thyroidectomy (n = 93 prior to 1995) or total thyroidectomy (n = 205 post-1995). Hemithyroidectomy was the procedure of choice in patients with AFTN.

RESULTS

Patients with Graves' disease were younger in age, with shorter mean duration of goiter when compared with the other 2 groups. Eight percent of patients with Graves' disease without a clinically palpable nodule and 25% of those with nodules had associated differentiated carcinoma, including papillary, follicular, and medullary thyroid cancer. Four percent of patients with toxic MNG had malignancy. Complications included temporary hypocalcemia (24%), permanent hypocalcemia (3%), and permanent vocal-cord palsy (1%).

CONCLUSIONS

Surgery for hyperthyroidism has negligible mortality and acceptable morbidity in experienced hands. It is a definite option in selected cases. Immediate and permanent cure of hyperthyroidism is achieved, with no recurrences, after total thyroidectomy. The cosmetic outcome is good, with excellent patient satisfaction and acceptance.

Disposition of abouthiouzine: a novel antihyperthyroid drug

Abouthiouzine is a novel antithyroid agent with a profile of fewer reported adverse effects than other currently used drugs. The purpose of this current work was to explore, for the first time, the disposition of abouthiouzine following intravenous and oral administration using an animal model; also, to study its plasma protein binding properties. Abouthiouzine (2 mg/kg intravenously) was administered to healthy male Vole rabbits and Beagle dogs. A dose of 20 mg/kg of the drug was also given orally to another group of Beagle dogs. Abouthiouzine plasma concentrations were measured using an HPLC method, and its pharmacokinetic parameters were determined by non-compartmental analysis. Abouthiouzine plasma protein binding was determined using an ultrafiltration technique. The drug was quickly eliminated from the rabbit and dog systemic circulations with terminal half-lives (T(1/2 lambda)) of 0.7 h and 1.9 h, respectively. The calculated T(1/2 lambda) following the oral administration in dogs was 1.8 h. Total abouthiouzine clearance (CL) in rabbits was 7.84+/-0.87 ml/min/kg, and 4.03+/-0.83 ml/min/kg in dogs. The apparent volume of distribution at steady state (V(ss)) in rabbits and dogs was 360.09+/-63.41 ml/kg and 481.10+/-62.64 ml/kg, respectively. The absolute oral bioavailability in dogs was approximately 16%, which may indicate poor absorption characteristics of the pure drug and/or an extensive first past effect. Protein binding studies have demonstrated that abouthiouzine has moderate-to-high binding properties ( approximately 63%-86%). Further studies are needed to evaluate the route of elimination of abouthiouzine in these animal models including any metabolite formation and the role of enterohepatic recycling in this process.