Endocrine Abstracts

Goal: Study thyroid function in patients with acromegaly. Materials and method: 88 patients with acromegaly, age 54.6±13.2 years, mediana diagnosis acromegaly 4 years, IGF1 528 (265; 701.3 ng/ml, HG 10.4 (3.7; 30.1) μE/ml, only 12 patients had a remission of disease. All patients were taken TSH, fT₄, TPO antibodies, revealed anamnesis of thyroid diseases.

Results: 19 from 88 patients (21.6%) had hypothyreosis and 2 (2.3%) had subclinical thyrotoxicosis, that higher average prevalence these disease (2 and 1% correspondently). The causes of hypothyreosis were different: eight paitents (9.1%) had central hypothyreosis mainly due surgical ttreatment of acromegaly (seven from eight patients); 12 patients (13.6%) had hypothyreosis due thyroidectomy (six patients) or autoimmune thyroidit (six patients). Thyroidectomy was performed for thyroid cancer in five from six patients. There is interesting combination of different thyroid dysfunction at two patients. One patient 53 years old had acromegaly for 1year. She had hypothyreosis due thyroidectomia 5 years ago and took 75 μg L-thyroxine. But then central hypothyreosis was added after surgical treatment of acromegaly: TSH 0.53 μE/ml, fT₄ 8.5 pmol/l on the same dose of L-thyroxine. Doctor has to consider this combination dysfunction because TSH is not informative at patients with central hypothyreosis. The cause of subclinical thyrotoxicosis was toxic polynodular goiter. One patient had combination subclinical thyrotoxicosis with central hypothyreosis. At first, central hypothyreosis was appeared after surgical treatment of acromegaly and the patient took L-thyroxine for 6 years. Then fT₄ was increased up to 24 pmol/l, L-thyroxine was stopped but fT₄ remained high (fT₄ 22 pmol/l, TSH 0.01 μE/ml). Scintigraphy revealed ‘hot’ nodule. In this case there are two causes of suppressed TSH: central hypothyreosis and subclinical thyreotoxicosis.

Conclusion: The patients with acromegaly have high prevalence of hypothyreosis (21.6%) and subclinical thyrotoxicosis (2.3%). Thyroid dysfunction develops as a result of impact of IGF1 and GH to thyroid and TSH falls after surgical treatment of acromegaly. This simultaneously impact to thyroid function leads to combination of some thyroid diseases and makes the treatment of patients difficult.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.