Hyperthyroidism (overactive thyroid)
What is hyperthyroidism?
Hyperthyroidism means increased thyroid function with the finding of excessive production of thyroid hormones T4 and/or T3. It is a chronic disease prone to recurrence. As with hypothyroidism, the disorder can be in the thyroid itself or in the control structures (pituitary gland and hypothalamus) or outside of them.
What are the causes of hyperthyroidism?
Increased thyroid hormone synthesis is most often caused by Basedow-Graves disease (about 60% of cases), Hashimoto's disease and TSH receptor disease (due to TSHR (Thyroid Stimulating Hormone Receptor) gene mutations). This is followed by autonomous thyroid disorders (toxic adenoma, multinodular goiter), increased release of hormones due to destruction of thyroid tissue (infectious thyroiditis, thyroid cancer, metastases, storage diseases, radiation in the head and neck area), use of drugs, paraneoplastic syndromes (ovarian tumors formed partly from thyroid tissue) and thyroid cancer that produces T4.
By the term subclinical (latent) hyperthyroidism, it is considered a condition in which we find a reduced TSH value with still normal T4 and/or T3 values.
The special form of the disease in which we find an increase in the level of T3 with a normal value of T4 and a reduced value of TSH is called isolated T3 hyperthyroidism. It occurs rarely and often represents a laboratory introduction to the definitive clinical form of hyperthyroidism. Symptomatology varies from mild forms to extremely striking presentation (thyrotoxic crisis or storm).
What are the symptoms of hyperthyroidism?
Patients usually complain about symptoms of accelerated metabolism (sweating, increased appetite with weight loss, intolerance to heat). Other complaints include general weakness, restlessness and hyperreactivity, irritability and nervousness, frequent urination and diarrhea, sleep disturbance, bulging of the eyeballs (exophthalmus), rapid heart rate with palpitations, increased blood pressure, heart rhythm disorders, neurological symptoms (muscular weakness, hand tremors, loss of consciousness), eye irritation and skin changes.
Thyrotoxic crisis (thyrotoxic storm) is an extreme form of hyperthyroidism characterized by the sudden onset of symptoms with high body temperature, restlessness, malaise, loss of muscle mass and rapid heart rate, often accompanied by heart rhythm disturbances, liver enlargement and jaundice. Untreated, it leads to serious complications, such as cardiac arrest and death.
Diagnostics and treatment
The diagnostic procedure includes specialist and ultrasound examination of the thyroid, laboratory determination of TSH, thyroid hormone, antibodies and sometimes thyroid scintigraphy. Genetic testing is also possible.
Treatment is carried out using drugs that reduce the production of thyroid hormones, the so-called. thyrostatics. It is associated with the possible development of side effects (impairment of bone marrow, liver and kidney function, allergic reactions, damage to the development of the child in pregnant women). Other measures include symptomatic control of rapid heart rate. In case of protrusion of the eyeballs, eye protection is required by wearing sunglasses with the use of protective drops and specific medications are also applied. The definitive form of treatment aims to remove the thyroid tissue, which is carried out surgically or using radioactive iodine.