In hyperthyroidism (synonyms: Hyperthyroidism; Hyperthyroidism; Thyroid hormone toxicity; Hyperthyroidism; Thyrotoxicosis; ICD-10-GM E05.9: Hyperthyroidism, unspecified) is hyperthyroidism due to multiple causes. The most important cause is Graves’ disease, which is responsible for 60-80% of all hyperthyroidism. Other causes include thyroid autonomy (independent thyroid hormone production) and iodine-induced hyperthyroidism (exogenous intake of iodine in high amounts). Hyperthyroidism is classified by symptomatology into:
- Subclinical (latent) hyperthyroidism – asymptomatic (with no apparent symptoms).
- Clinical hyperthyroidism – hyperthyroidism associated with symptoms.
Hyperthyroidism is classified according to the location of the disorder into:
- Primary hyperthyroidism – “true” hyperthyroidism.
- Manifest form – elevation of free triiodothyronine (fT3) and/or free thyrosine (fT4) above the upper normal range and concomitant TSH decrease (= suppressed basal thyroid-stimulating hormone (TSH)).
- Subclinical (latent) form – isolated TSH depression.
- Secondary hyperthyroidism – this is an excessive stimulation by increased TSH activity (eg, in hormone-forming tumors of the pituitary gland (pituitary gland)).
Furthermore, there is an amiodarone-induced hyperthyroidism (AIH) – see this under “Causes”. Gender ratio: women are significantly more often affected by hyperthyroidism than men. In Graves’ disease, which is the most common cause of hyperthyroidism, the sex ratio of males to females is 1: 5. In thyroid autonomy, the sex ratio of males to females is 1: 4. Peak incidence: The peak incidence of hyperthyroidism is between the ages of 20 and 50. The prevalence (disease frequency) in women is 1-2%, in men it is much lower (in Germany).In pregnancy the prevalence is 0.1-1.0%. The main cause is Graves’ disease. The incidence (frequency of new cases) for Graves’ disease is 10-40 cases per 100,000 inhabitants per year (in Germany). Course and prognosis: The symptoms of hyperthyroidism such as heavy sweat production, tachycardia (heartbeat too fast: > 100 beats per minute), weight loss, nervousness as well as tremor (shaking) are unpleasant and are not always associated with hyperthyroidism at first, since the complaints mentioned can also be symptoms caused by everyday life or stress. Only laboratory diagnostics (TSH, fT3, fT4), thyroid sonography (ultrasound examination) and, if necessary, a scintigraphy (imaging procedure in nuclear medicine diagnostics) of the thyroid gland provide certainty. The prognosis of hyperthyroidism is largely determined by the cause. In about half of the cases, the disease may resolve spontaneously (on its own). Just as well, the disease can be recurrent (recurring). In cases of underlying thyroid autonomy, the prognosis is rather unfavorable. In the course of hyperthyroidism, regardless of the cause, there is always a risk of thyrotoxic crisis (life-threatening exacerbation of hyperthyroidism), especially if therapy is inadequate. This is accompanied by high fever, tachycardia (excessively fast heartbeat: > 100 beats per minute), agitation, vomiting (vomiting), diarrhea (diarrhea), confusion, and impaired consciousness. In such cases, intensive medical treatment is vital.The lethality (mortality related to the total number of people suffering from the disease) of patients with thyrotoxic crisis is 8-25%. Comorbidities (concomitant diseases):Hyperthyroidism is associated (linked) with a 1.4-fold risk of gout in men and 2.1-fold risk in women. Furthermore, untreated hyperthyroidism is associated with depression.
