Along with Graves’ disease, thyroid autonomy is the most common cause of hyperthyroidism (overactive thyroid) and is characterized by autonomous areas in the thyroid gland that produce thyroid hormones independently of hormonal control by the pituitary gland (appendage gland). Approximately 5 percent of the Central European population is affected by thyroid autonomy, and women are more likely to develop the disease than men, with a ratio of 5:1.
What is thyroid autonomy?
Thyroid autonomy is a disease of the thyroid gland in which demarcated areas of tissue (adenomas) or the entire tissue have diffusely escaped control by the pituitary gland, resulting in uninhibited production of thyroid hormones. If this autonomous hormone production exceeds the requirements of the human organism, depending on the mass and activity of the autonomous areas as well as the individual iodine intake, first a subclinical (latent) and later a manifest hyperthyroidism develops, which can manifest itself, among other things, by weight loss, tachycardia, psychomotor restlessness as well as diarrhea and menstrual disorders. In this case, multiple areas are affected in about 50 percent of cases (multifocal autonomy), an isolated area is affected in more than 30 percent (unifocal autonomy), and the entire thyroid tissue is affected by diffusely distributed cell islets in about one-sixth (disseminated autonomy).
Causes
Thyroid autonomy is most commonly due to iodine deficiency. Due to this deficiency, the thyroid gland can no longer produce sufficient hormones and attempts to compensate by increasing in size (goiter or goiter formation). As the size of the goiter increases, so does the risk for the development of nodules, which may escape pituitary control and develop autonomous areas. In addition, unifocal thyroid autonomy can be associated with a mutation of the TSH receptor gene in about 80 percent of cases, leading to increased growth as well as increased hormone production on the part of thyrocytes (hormone-producing follicular epithelial cells). In general, about 30 point mutations are now associated with the development of thyroid autonomy. The autonomy efforts of the affected thyroid tissue are probably additionally catalyzed by exogenous intake of high-dose iodine in the form of iodine-containing contrast or disinfectant agents and drugs (including amiodarone), which may also cause the development of hyperthyroidism (hyperthyroidism).
Symptoms, complaints, and signs
Thyroid autonomy develops extremely slowly and over a long period of time. Symptoms are often not noticed until older age. Typical in this case is the formation of a nodular goiter, which may also lead to breathing and swallowing difficulties due to the narrowing of the trachea and esophagus. Depending on the functional status of the thyroid gland, symptoms of hyperthyroidism may occur. Thus, thyroid autonomy may be asymptomatic or may present with significant symptoms. Thyroid hormones are critical for normal cell function. In excess, they negatively affect metabolism, which aggravates the action of the sympathetic nervous system. As a result, various body processes are accelerated and an overdose of adrenaline can be detected in the blood. Some of these symptoms include nervousness, irritability, increased sweating, palpitations, trembling hands, anxiety, sleep disturbances, thinning of the skin, fine, brittle hair, and muscle weakness – especially in the upper arms and thighs. Frequent bowel movements associated with diarrhea may also occur. Weight loss, sometimes significant, may occur despite a high appetite. Although ten percent of people with hyperthyroidism experience weight gain, vomiting may occur. For women, menstrual flow may vary in frequency and menstrual periods, less frequent or with longer cycles than usual.
Diagnosis and course
In many cases, the diagnosis of thyroid autonomy begins with a determination of serum TSH levels to rule out hyperthyroidism and assess thyroid function. In the case of a decreased TSH value, the parameters of the peripheral thyroid hormones thyroxine (T4) and triiodothyronine (T3) are usually also determined.In addition, the thyroid volume and morphological or nodular changes can be detected during sonography. Finally, the diagnosis of thyroid autonomy is confirmed by scintigraphy, in which iodine-131 or Tc99m-pertechnetate is administered, which accumulates in the affected thyroid areas and makes the affected areas visible in the scintigram. Differentially, thyroid autonomy should be differentiated from Graves’ disease by an autoantibody test. Thyroid autonomy is not curable, but has a favorable prognosis if diagnosed early and therapy is started early. If left untreated, thyroid autonomy with latent hyperthyroidism can lead to thyrotoxic crisis (life-threatening metabolic derailment) if iodine intake is excessive.
Complications
Thyroid autonomy can cause a variety of complications. The breathing and swallowing difficulties that typically occur can lead to respiratory distress and aspiration-both of which are associated with further complications. Weight loss can cause dehydration and deficiencies. This results in a decrease in physical and mental performance, and often mental distress. Inner restlessness contributes to the formation of depressive moods and anxiety disorders. If thyroid autonomy remains untreated, chronic gastrointestinal complaints may develop. Rarely, intestinal cysts form or even stomach cancer develops. Accompanying cardiac arrhythmias can occur, which can lead to heart attack and possibly death of the patient if the patient has the corresponding pre-existing conditions. The bones can also be damaged in a chronic course – osteoporosis and inflammatory bone diseases develop. Depending on the type of therapy, complications can also occur during treatment. Radioiodine therapy is associated with gastrointestinal discomfort and often also causes circulatory problems, dehydration and fatigue. If the thyroid gland is removed, it can result in allergic reactions, infections, hoarseness, and difficulty swallowing, among other symptoms. Very rarely, cardiac arrest occurs.
When should you see a doctor?
Thyroid autonomy must always be treated by a doctor. It is a serious condition that cannot heal itself. Therefore, to prevent further complications and discomfort, a doctor should always be consulted for thyroid autonomy. Early diagnosis and treatment always have a positive effect on the further course of the disease. A doctor can be consulted if the affected person suffers from severe swallowing difficulties. Breathing difficulties may also occur. In most cases, these symptoms occur without any particular reason and do not disappear on their own. Furthermore, it is not uncommon for hyperthyroidism to indicate thyroid autonomy and should be investigated. Often there is also diarrhea, sleep problems or even anxiety. These complaints also often indicate thyroid autonomy and must be treated by a physician. A general practitioner can be consulted for this. Further treatment is then carried out by a specialist.
Treatment and therapy
Various therapeutic measures are available for the treatment of thyroid autonomy, depending on the severity and progress of the disease. In the presence of a euthyroid metabolic state (normal hormone production) and the absence of clinical symptoms, thyroid autonomy can often be simply observed, although prophylactic therapy with levothyroxine or a combination of levothyroxine and iodide should be considered, particularly in the presence of struma formation. Therapeutic measures are definitely initiated as soon as latent hyperthyroidism is detected, as this can have long-term unfavorable effects on the heart (atrial fibrillation) and bones (osteoporosis). For this purpose, thyrostatic drugs (carbimazole, propylthiouracil, thiamazole) adapted to the individual functional situation are used to inhibit hormone production and normalize thyroid function.Since thyroid autonomy does not show any remissions and there is an increased risk of thyrotoxic crises, thyrostatic therapy is in most cases only used as a temporary bridging measure until the definitive form of therapy (radioiodine therapy, thyroid resection) is chosen, in which the autonomous tissue areas are eradicated. Whereas in the context of resection, the autonomous tissue areas are surgically removed via an approach through the neck, orally applied radioactive iodine-131 usually induces death of the affected tissue in radioiodine therapy, which is particularly recommended in multifocal or disseminated thyroid autonomy forms and in goiter formation.
Prevention
Because thyroid autonomy can be attributed to a permanent iodine deficiency in most cases, the disease or growth of the organ and nodule as well as struma formation can be prevented by adequate iodine intake. A daily iodine intake of 180 to 200 micrograms is recommended to prevent long-term deficiency and thus thyroid autonomy.
Follow-up
Thyroid autonomy favors hyperthyroidism. The production of the body’s own hormones is disturbed. Physical complaints are the result. Early administration of iodine supplements counteracts autonomy. Follow-up care is advisable to counteract hyperthyroidism. In addition, the cold nodules must be checked regularly. Noticeably enlarged tissue or development into hot nodules require surgical intervention. The degenerated parts are removed from the thyroid gland. The aim is to stabilize the hormone balance. Thyroid levels should return to normal. Thyroid autonomies lead to weight loss, heart palpitations as well as psychological complaints. Difficulties in swallowing and breathing are caused by thyroid nodules. Many patients also complain of a feeling of pressure in the neck. The physician treats the symptoms with medication. As part of follow-up care, he checks the effect. If necessary, he prescribes more suitable medication or modifies the dosage. In the case of thyroid surgery, the familiar postoperative follow-up controls take effect. The patient remains in the clinic until discharge. This is also the end of the follow-up care. Even after a successful operation, the general practitioner checks the size of the thyroid gland. Blood samples provide information on hormone levels. Treatment and aftercare start again if the symptoms return. Conspicuous findings require further surgery. Alternatively, iodine therapy provides relief.
What you can do yourself
In the case of thyroid autonomy, the affected person can strengthen his organism through iodine-containing food intake. To reduce the prevailing iodine deficiency in a natural way, the consumption of seaweed, cod, haddock or pollock is advisable. In addition, the diet should include regular consumption of herring, mushrooms or broccoli. Peanuts and pumpkin seeds also help to provide the organism with increased iodine. Meals should also be regularly seasoned with salt containing iodine. Foods such as spinach and a fatty cow’s milk also contain an increased amount of iodine, which can have a positive influence on the course of the disease in the case of thyroid autonomy. However, any intolerances should be checked before consumption to avoid triggering complications or side effects. To reduce swallowing difficulties, care should be taken to ensure adequate grinding of the food during the chewing process. The grinding process of the teeth should be optimized and improved. Care should be taken to control weight so that no unwanted weight loss occurs and possible deficiency symptoms can be reduced. Mental techniques are recommended to reduce inner restlessness. Autogenic training, meditation or yoga have a strengthening effect on the mental power of the affected person. They also reduce stressors and promote well-being.
