Evidence for the effect of antibodies to TSH receptors on the thyroid ultrasonographic volume in patients with Graves' disease

Should radioiodine be the first-line treatment for paediatric Graves' disease?

BACKGROUND

Debate exists regarding the optimal treatment strategy for paediatric Graves' disease with radioiodine (RAI), and surgery, usually reserved for failure of medical therapy. We present our own experience to introduce a review of the published literature focussing on the predictors of remission after antithyroid drug (ATD) therapy from diagnosis, and discuss whether RAI should be considered as a first-line therapy.

METHOD

A retrospective analysis of all diagnosed cases of paediatric Graves' disease presenting to a large District General Hospital.

RESULTS

Thirteen patients were diagnosed with Graves' disease between February 2004 and May 2013. The median age at diagnosis was 13.7 years (range 7.2-17.1 years) with a female:male ratio of 11:2. Some nine patients completed a 2-year course of carbimazole out of which 8 relapsed after a mean duration of 0.82 years (range 0.08-1.42 years); the ninth currently remains in remission. Of the eight patients who relapsed, three have undergone RAI treatment. Two patients failed to tolerate carbimazole treatment, one of whom received RAI treatment because surgery was contraindicated and one patient with severe autism proceeded to RAI treatment due to poor compliance and persistent hyperthyroidism.

LITERATURE REVIEW

Prognostic factors at presentation predicting a low likelihood of remission following ATD treatment include younger age, non-Caucasian ethnicity, and severe clinical and/or biochemical markers of hyperthyroidism. Psycho-social factors including compliance also influence management decisions.

CONCLUSION

In specifically selected patients presenting with paediatric Graves' disease, the benefits and risks of radioactive iodine as a potential first-line therapy should be communicated allowing families to make informed decisions.

Volume changes in remnant thyroid tissue after thyroidectomy in Graves disease

BACKGROUND/PURPOSE

Surgery is one of the treatment choices for Graves disease. The residual thyroid tissue may shrink or become larger. The object of this study was trying to find out what factors affect the residual thyroid gland volume change after thyroidectomy in Graves disease.

METHODS

We followed thyroid volume changes by ultrasonography in 101 patients with Graves disease who underwent one side lobectomy and another side subtotal thyroidectomy from 1996 to 2006. These patients were divided into three groups according to the residual thyroid size increasing, no change in size, and shrinking. We checked the factors as follows: age, body weight, thyroid-stimulating hormone (TSH) level, TSH-receptor antibody level, anti-thyroid peroxidase (TPO) antibody level, total thyroid volume before and after thyroidectomy, and degree of lymphocyte infiltration.

RESULTS

We found that young age and lower residual volume ratio were the most powerful two factors affecting remnant thyroid gland volume changing. We also found that there is no significant correlation between TSH levels and thyroid volume change, nor TSH-receptor antibody titer or thyroid volume change.

CONCLUSION

Age and residual volume ratio were the most powerful two factors in this study.

Association Between Autoantibodies Against Thyroid Stimulating Hormone Receptor and Thyroid Diseases

Aim:

The aim of this study is to determine the relationship between TRAb and different diseases. The highest percentage of increased TRAb levels can be found at patients with Graves’ diseases.

Material and methods:

Study was performed in 70 patients, grouped in three groups, and 14 persons who based on the clinical status and the levels of thyroid hormones do not have any thyroid disease. The TRAb levels has been determined in patients with Graves’ disease (N=40), Hashimoto’s disease (N=15), Plummer’s disease (N=15) and the control group (N=14).

Results:

The highest mean TRAb levels exist in patients with Graves’ disease. There exists a positive correlation between TRAb levels and T3, and T4, while there is no correlation between TSH and TRAb levels in patients with Graves’ disease,. On the other hand, the correlation between TRAb and T3 and T4 in patients with Hashimoto’s diseases and Plummers disease was shown to be positive, but of a low levels.

Reduction of the risk of relapse after withdrawal of medical therapy for Graves' disease

It has been a continuing challenge to try and identify those patients with hyperthyroid Graves' disease likely to remain in remission after an antithyroid drug course or to manage the medical treatment so as to increase the chance of remission. On average, the overall relapse rate is approximately 50% and any significant reduction of this figure would be of practical as well as theoretical value. The numerous controlled prospective studies performed in many parts of the world, with varying iodine intakes, have all confirmed that the main initial features related to the subsequent risk of relapse are: young age, male gender, goiter larger than 40 mL, hypoechogenic and hypervascular gland, high level of anti-thyrotropin receptor antibody (TRAb), detected either with radioreceptor assay (TBII: >40 U/L) or the biologic stimulation assay (thyroid-stimulating antibodies [TSAb]; >300%), severity of hyperthyroidism, and possibly the presence of ophthalmopathy. Alone, each of these has a low predictive value, but together they allow evaluation of the risk of relapse, thus helping treatment choice. As to the modalities of antithyroid drug treatment, dose of the drug or addition of levothyroxine does not affect posttreatment outcome. In contrast, significantly fewer relapses occur for drug courses longer than at least 1 year. Persistence of high levels of TRAb after medical treatment is strongly predictive of relapse but this is of limited value because in most patients, TRAb levels are low or even undetectable at the end of treatment, which does not indicate for further outcome. Smoking is a significant independent risk factor for relapse. In conclusion, reduction of the risk of relapse in patients with medically treated hyperthyroid Graves' disease relies on clinical competence and appropriate management taking into account an array of factors none of which alone has definite predictive value.

Anti-TSH receptor antibodies in clinical practice

Anti-thyroid stimulating hormone receptor antibodies are pathophysiologic and clinical indicators in autoimmune thyroid diseases, not only in Graves' disease. The detection of these antibodies is useful for diagnostic and management purposes. The presence and titers of anti-TSH receptor antibodies, however, have to be interpreted in light of the clinical and other biological characteristics of each patient. Newer, more sensitive assays of anti-TSH receptor antibodies may increase their significance in the diagnosis and management of autoimmune thyroid diseases and Graves' disease.

Prevalence of sporadic medullary thyroid carcinoma: the importance of routine measurement of serum calcitonin in the diagnostic evaluation of thyroid nodules

OBJECTIVE

The prevalence of sporadic forms of medullary thyroid carcinoma (MTC) has been studied in patients living in an area of moderate iodine deficiency. Such forms of MTC are usually diagnosed after surgery and have little chance of definitive cure. Using the measurement of basal serum calcitonin (CT) levels in a large series of patients with both thyroid disease and normal 24-hour urinary iodine excretion, we assessed the prevalence of MTC and, in patients affected with the disease, we also evaluated the stage of the disease according to surgical findings and post surgical plasma CT levels.

PATIENTS

A prospective study of 657 patients with thyroid disease (469 with nodular and 188 with non-nodular thyroid disease). As controls, 40 normal subjects were also studied.

MEASUREMENTS

In all patients: (1) measurement of basal serum CT, free T4, total T3, TSH levels and serum TSH-receptor, peroxidase and thyroglobulin (Tg) antibody concentrations, (2) thyroid ultrasonography, (3) fine needle aspiration cytology (FNAC). In patients with increased basal CT levels: (1) measurement of serum CT levels during pentagastrin test prior to surgery, (2) histological examination and immunostaining with both anti-CT and anti-Tg antibodies of all the nodular thyroid tissue surgically removed, (3) measurement of basal and pentagastrin stimulated serum CT values after surgery.

RESULTS

All the patients with non-nodular thyroid disease had normal basal CT levels. Four patients (0.84%) with nodular thyroid disease (2 with uninodular and 2 with multinodular goitre) had both elevated basal and pentagastrin stimulated CT levels. In the two patients with uninodular goitre, FNAC was suggestive of MTC in 1 (nodular diameter 8.0 cm) and of follicular carcinoma in 1 (nodular diameter 2.5 cm). Histological examination of the nodules confirmed these histotypes. Immunostaining with anti-CT antibodies was positive in the former patient but also in the latter. FNAC was suggestive of benign adenomatous tissues in the two patients with multinodular goitre. Histological examination of all the thyroid nodules confirmed the cytological findings. However, serial sections through the gland in each of these two patients showed an occult follicular carcinoma which had, however, positive staining with anti-CT antibodies. Furthermore, immunostaining with anti-Tg antibodies was negative in the patient with MTC but positive in the 3 patients with follicular carcinoma. Finally, both basal and pentagastrin stimulated CT levels remained elevated after total thyroidectomy only in the patient with FNAC suggesting MTC.

CONCLUSIONS

This study demonstrates a surprisingly high prevalence of sporadic forms of medullary thyroid carcinoma in patients with nodular thyroid disease. Such forms of medullary thyroid carcinoma seem to be unrelated to iodine intake and may be pure or mixed with a follicular carcinoma. In these mixed thyroid carcinomas, only the neoplastic follicular pattern was seen on both cytological and histological examination. Routine measurements of serum calcitonin levels should therefore be considered an integral part of the diagnostic evaluation of thyroid nodules. Indeed, increasing the accuracy of diagnosis of medullary thyroid carcinoma encourages the surgeon to perform more radical treatment, thus achieving more frequent normalization of post-operative serum calcitonin levels.