The thyroid gland is an endocrine gland located in front of the trachea, at the level of the Adam's apple in men, and is responsible for the synthesis of various hormones. It continues to work under the control of TRH (Thyrotropin-releasing hormone) from the hypothalamus and then TSH (Thyroid stimulating hormone) secreted from the pituitary. Inability to function is called hypothyroidism. Hypothyroidism may also occur if the hormones TSH and TRH, which regulate the functioning of the gland and have a stimulating effect by being secreted from the upper centers, are insufficiently secreted or fail to show any effect.
As a result of insufficient amount of thyroid hormones, a decrease in the metabolic activity of the cells and a slowdown in their basal metabolism occur. In cases of hypothyroidism, there may be no obvious symptoms at first, but later on, it may manifest itself with other disorders such as obesity, joint problems, problems with having a child, or heart diseases.
What are the Causes of Hypothyroidism?
Among the causes of hypothyroidism, radiation (radiation) therapy, thyroid surgery, autoimmune diseases that express the attack of the defense system on its own cells and tissues, or hyperthyroidism treatment can be counted as examples.
Hypothyroidism is classified as primary (primary) if the cause of hypothyroidism is due to dysfunction of the gland itself, and secondary (secondary) hypothyroidism if it originates from the stimulating upper centers. The cause of the disease is usually the gland itself.
The most common cause of primary hypothyroidism is insufficient iodine intake. Hashimoto's disease ranks first among autoimmune diseases that cause hypothyroidism. Treatment practices related to other health conditions can cause hypothyroidism. In particular, some drugs used in the treatment of rhythm disorders, drugs used in the treatment of diseases with seizures, and some antibiotics may cause hypothyroidism. Having a history of radiation therapy to the head and neck region can be considered as the cause of hypothyroidism, as the gland was destroyed during radiation therapy.
Discomfort that may occur in the pituitary and hypothalamus Caused by hypothyroidism is classified as secondary hypothyroidism. They may not be able to function because a tumor formed in the pituitary gland or a tumor formed in another part of the brain presses on these tissues. At the same time, resistance to the stimulating hormones they secrete is among the causes of secondary hypothyroidism.
Hypothyroidism develops due to iodine deficiency. Nutritional habits often play a role in its development. Frequent consumption of cabbage, broccoli, cauliflower, soy and soy-based products, which are called goitrogenic foods, causes hypothyroidism (goiter).
Causes of hypothyroidism in addition to iodine deficiency:
Hashimoto's thyroiditis is the most common cause of hypothyroidism. The immune system attacks its own thyroid tissue (autoimmune) and damages it and thyroid hormone production decreases.
If the entire gland is removed during thyroid surgery, the patient has to use thyroid hormone for life.
Radioactive iodine or drug used for the treatment of hyperthyroidism treatment may cause excessive pressure on the thyroid gland after a while. Some patients develop hypothyroidism. These diseases are;
- Pregnancy,
- Pituitary gland (brain) disorders,
- Non-normal development or absence of the thyroid gland (congenital hypothyroidism),
- Some drugs,
- Radiation therapy applied in head and neck cancers.
What are the causes of hypothyroidism in pregnant women?
Iodine deficiency is the most important cause of hypothyroidism. Some changes in the mother's body during pregnancy pave the way for the development of hypothyroidism. During pregnancy, renal clearance increases and urinary iodine loss develops.
While the baby is developing in the womb, in the second half of pregnancy, it draws iodine from the mother through the placenta. In this case, the mother's iodine requirement increases. If enough iodine is taken, these changes do not cause any problems in the mother's body.
The most common cause of hypothyroidism in pregnancy is autoimmune based Hashimoto's thyroiditis. Detailed information about Hashimoto's thyroiditis What is Hashimoto's thyroiditis?
What are the Symptoms of Hypothyroidism?
Fatigue, muscle fatigue, loss of motivation, cold intolerance, constipation, hoarseness, dry skin, hair loss/ sparse nails Weakness of the abdomen and decrease in sweating can be counted as examples of symptoms. In addition, patients experience swelling in the body (especially the face), water retention, and weight gain.
As the disease progresses, psychiatric conditions such as depression, worsening memory and anxiety may be added to the symptoms. Neuropathies caused by nerve compression, such as carpal tunnel syndrome, and a decrease in heart rate (slowing of the pulse, bradycardia) may also occur in hypothyroid patients. At the same time, the tongue of hypothyroid patients may enlarge over time, and the blood values of some substances may change due to the effect of metabolism in hypothyroid patients. Especially hyponatremia (decrease in sodium) and high cholesterol level are examples of these biochemical changes.
Changes may occur in menstrual periods in female patients. At the same time, loss of libido (sexual reluctance) may occur in both sexes during the course of the disease.
What is Subclinical Hypothyroidism?
Free thyroid hormone levels in the serum are normal and thyroid-releasing hormone (TSH) level is normal. slightly elevated. It is more common in women (7.5%) compared to men (2.8%).
Among the causes, autoimmune thyroiditis (attacking the body's own tissues due to hypersensitivity in the immune system), Graves' disease, surgical or radioactive iodine treatment of autonomous adenomas (adenomas that cause hyperthyroidism by secreting thyroid hormone), treatment incompatibilities or deficiencies, iodinated drugs, lithium use and non-thyroid Type 1 DM, adrenal insufficiency, interferon alpha use, dopamine antagonist use can be counted.
How to Diagnose Hypothyroidism?
Blood levels of thyroid hormones and stimulating hormones can be counted. It is diagnostically important to determine the levels of the disease with the help of biochemical methods. In the problems caused by the gland itself, the stimulating hormone TSH increases in order to stimulate the non-functioning gland. High TSH is accompanied by low T4, the hormone of the thyroid gland. In cases where autoimmune diseases are suspected, the presence of antibodies formed by defense cells in the blood circulation can be investigated. it can be eliminated. This condition is called subclinical hypothyroidism. In this form of the disease, the signs and symptoms of the disease may not have appeared yet due to the normal level of thyroid hormones.
Examining the levels of other pituitary gland hormones may be beneficial in cases with secondary hypothyroidism. While the levels of thyroid gland hormones are low in secondary hypothyroidism, the TSH level is not as high as in patients with primary hypothyroidism.
How is Hypothyroidism Treated?
TSH level is used as the determining parameter for drug use in treatment. In patients with high TSH levels, drug therapy can be started if the doctor deems it appropriate. Since the symptoms of hypothyroidism occur due to the deficiency of thyroid gland hormones, it is necessary to give the deficient hormones externally in the treatment.
T3 and T4 hormones are produced in a normally functioning thyroid gland and released into the blood circulation. The active form of thyroid hormones is T3 and it is formed by converting T4 hormone to T3 hormone. To mimic this physiological mechanism, synthetic thyroid hormone called levothyroxine (LT4) is used as a hypothyroidism drug. In order to increase the absorption of the drug, it is recommended to take it in the morning on an empty stomach.
The age, gender and weight of the person are important in determining the dose to be used daily. In patients with hypothyroidism, which is expressed as subclinical, treatment with lower doses of the drug can be started.
There are some differences in the treatment approach in pregnant women. In order to prevent undesirable conditions such as miscarriage and stillbirths during pregnancy at lower TSH levels compared to other hypothyroid cases, drug treatment can be started after the physician's evaluation, if deemed appropriate. It is recommended for individuals who want pregnancy and who also have hypothyroidism to be treated during the pre-pregnancy period.
Regular observation is necessary to evaluate the effectiveness of hypothyroidism treatment. Physicians evaluate whether the blood TSH level can be kept within normal limits with drug therapy. During the follow-up, if the doctor deems it necessary, the treatment n dose can be changed. In addition to the use of thyroid hormone in women during pregnancy and lactation, iodine support can also be given.
While the target TSH level is between 0.4-2.5 mU/mL in the young and middle age group, a physiological increase in TSH level occurs with age. Target TSH level may rise up to 3-6mU/mL in the treatment of advanced age group. The effectiveness of the treatment is monitored at times determined by the physician, with an average of 1.5-2 months. However, one should be careful about the side effects that may occur due to the drug. The incidence of side effects increases with higher doses. In addition to excessive appetite and excessive insomnia, palpitation and shaking-shaking sensation can be given as examples of undesirable effects that may occur during treatment.
In hypothyroid patients with cardiovascular disorders, treatment should be approached more carefully. People with symptoms such as chest pain or atrial fibrillation may need closer follow-up to prevent these symptoms from recurring. In people with a history of disorders in the coronary vessels that feed the heart, the physician may start drug therapy at lower doses. At the same time, in a long-term treatment of hypothyroidism, the patient should be careful in terms of osteoporosis, that is, the development of bone resorption.
How Should Nutrition Be in Hypothyroidism?
Supplementary nutrition is recommended in addition to drug treatment. Diet alone does not provide treatment. First of all, iodized table salt can be preferred to increase dietary iodine intake. With a balanced diet, the necessary iodine can be taken into the body. Food groups rich in iodine include milk, cheese, yoghurt, and seafood. These foods are:
- Walnuts,
- Soybean meal,
- Additional iron products or multivitamins containing iron,
- Additional calcium products ,
- Antacids containing aluminum, magnesium or calcium (a group of drugs taken for heartburn),
- Some ulcer drugs such as sucralfate,
- Some cholesterol drug groups
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