NB. More detailed information about the endocrine glands can be found in the article “Endocrine system. Norm and pathology “, and about the thyroid gland – in the material” Thyroid gland. Hypothyroidism Hyperthyroidism “.
According to the tradition established on our website, we will begin the consideration of the problem with the analysis of terminology. First of all, remember: all medical terms containing the root ” thyro -” refer to the thyroid gland. Note further that the diagnoses “hyperthyroidism” and “thyrotoxicosis” are often used interchangeably; it is generally not accepted in Western literature to ask the question of why two names for the same seemingly pathology appeared in the medical vocabulary. Domestic experts see and emphasize the semantic difference between “hyperthyroidism” and “thyrotoxicosis”, although this difference can be interpreted with some insignificant discrepancies. Let’s try to figure it out.
it is an abnormal condition of the thyroid gland in which an excess of thyroid hormones ( triiodothyronine , tetraiodothyronine, and calcitonin ) are produced .
this is a pathological condition of the body caused by an excess of thyroid hormones; as follows from the translation, this is thyroid hormone poisoning . Thus, thyrotoxicosis can be caused by hyperthyroidism, but not vice versa. And not always.
The most common cause of thyrotoxicosis is an increased secretory activity of the thyroid gland in Graves ‘disease (diffuse toxic goiter, Graves’ disease ). A number of other diseases lead to the same consequences, for example, Plummer’s disease (a hormone-producing benign tumor of the thyroid gland) and various inflammatory processes in the gland ( thyroiditis ). In some cases, there is a transient (transient, temporary) thyrotoxicosis during pregnancy.
However, the reason, as indicated above, does not always lie in the gland itself, in the excessive secretion of its hormones. 10-15% of cases of thyrotoxicosis develop against the background of normal or even reduced thyroid function. In these cases , the simultaneous release of all accumulated hormone reserves leads to thyrohormonal intoxication; a change in the reactivity of receptors that are sensitive to thyroid-stimulating hormone (which is produced by the pituitary gland and controls the activity of the thyroid gland); excess iodine in the body; taking drugs based on thyrohormones (iatrogenic thyrotoxicosis), autoimmune reactions. Similar situations are also found in neoplastic processes in the ovaries, hypothalamic-pituitary system, etc.
The main risk factor is being female: in women, thyrotoxic syndrome is detected up to ten times more often than in men.
Since the thyroid gland simultaneously affects several body systems, the clinical picture of thyrotoxicosis is very polymorphic. Violations of cardiovascular activity are observed: tachycardia, increased blood pressure, certain types of arrhythmias; atrial fibrillation may occur. With prolonged thyrotoxicosis, there is a tendency to pathological enlargement of the heart muscle ( cardiomegaly ), and heart failure syndrome is formed.
On the part of the central and peripheral nervous system, thyrotoxicosis is manifested by increased excitability, affective instability, hyperhidrosis and hyperthermia, finger tremors, cognitive disorders (difficulty concentrating, memory dysfunction), dyssomnia (various sleep disorders), often depression and anxiety stress, in the most severe crisis cases – thyrotoxic psychosis.
In the musculoskeletal system, typical disorders are muscle weakness and a tendency to atrophy (so-called thyrotoxic myopathy).
On the part of the gastrointestinal tract, a combination of increased appetite and decreased BMI (body mass index), increased frequency of bowel movements is characteristic.
One of the most famous and obvious symptoms of thyrotoxicosis is exophthalmos – bulging, i.e. pathological expansion of the palpebral fissure with exposure of the sclera area between the iris and the eyelid, rare blinking.
The reproductive sphere suffers: libido decreases, the ability to conceive (in representatives of any sex) and carry pregnancy by women. Dis – and oligomenorrhea is also noted in women ; in men, spermatogenesis is inhibited, potency decreases.
In addition, thyrotoxicosis is often accompanied by brittle nails and hair, liver dysfunction, metabolic disorders (up to diabetes mellitus), breast pathology and many other disorders.
In general, many variants of thyrotoxicosis are distinguished – in particular, according to the severity, the type of course (from slowly progressive to comatose), according to the dominant symptom complex (gastrointestinal, cardiovascular, subfebrile and other forms).
If thyrotoxicosis is suspected, the diagnosis is verified and clarified by laboratory blood tests: a number of tests are performed (concentration of thyrohormones , thyrotropin , antibodies). As needed, tests for the absorption of iodine isotopes , scintigraphy , ultrasound, MRI, biopsy, stimulating and suppressive tests are prescribed .
Depending on the diagnostic results, the patient’s age, immunoallergic status and a number of other individual characteristics, a therapeutic scheme is selected. Treatment can be medication (including therapy with radioactive iodine drugs ), surgical or combined.
Of the drugs, inhibitors of thyrohormone secretion are most often used , however, if these measures are ineffective (or in the presence of a tumor process), the issue of surgical intervention is considered. In some cases, such as a single node of hyperplasia, partial thyroid resection is the method of choice.