Hyperthyroidism is a syndrome caused by hyperfunction of the thyroid gland, manifested by hypersecretion of triiodothyronine (T3) and thyroxin (T4).
Depending on the level of occurrence of the disorder, hyperthyroidism is distinguished as follows: primary – the thyroid gland, secondary – the pituitary gland, and sometimes tertiary – hypothalamus;
In secondary (pituitary) hyperthyroidism, the cause of the syndrome is hyperproduction of thyroid stimulating hormone (TSH) by pituitary adenoma (thyrotropinoma) or hypertrophy of thyrotrophs.

Symptoms of hyperthyroidism

The symptoms of hyperthyroidism include disorders of:
• Nervous system (sleep disturbance; increased excitability, irritability; anxiety; emotional lability)
• Cardiovascular system (tachycardia; increased systolic and decreased diastolic pressure; atrial fibrillation)
• Gastrointestinal system (increased appetite; impaired stool; liver function);
• Hyperhidrosis;
Distinctive signs of secondary hyperthyroidism can be considered the absence of autoimmune syndromes:
• Acropathy;
• Pretibial myxedema;
• Endocrine ophthalmopathy;
Most patients with thyrotropinoma-induced secondary hyperthyroidism received inadequate therapy aimed at suppressing thyroid function. Some patients underwent thyroidectomy or therapy with radioactive iodine, which could lead to a progression of tumor growth, in the same way as in Nelson syndrome and corticotropinoma.
There are also mixed TSH-producing pituitary adenomas with hypersecretion of both somatotropic hormone (STH) with symptoms of acromegaly, and prolactin with the clinic of hyperprolactinemia.

Treatment of hyperthyroidism

The main methods of thyrotropin-based treatment that cause secondary hyperthyroidism are surgical and radiation therapy. Drug treatment is used as an adjunct therapy.