Iodine Deficiency Disorders of Thyroid Gland
Iodine Deficiency Disorders of the Thyroid Gland( YDZ) is a group of pathological conditions.These thyroid pathologies are caused by a shortage in the body of an important trace element, such as iodine.This, in turn, is due to his low nutritional intake.
Important: daily requirement for iodine depends on the person's age( for adults - from 120 to 200 μg).It increases during the hormonal reconstruction of the body - in the puberty period, as well as with the carrying and breastfeeding of the child.In many regions of our country in drinking water, iodine content is below normal.Table of contents:
To YDZ not only pathologies of the thyroid gland proper, but also various abnormalities appearing against the background of a shortage of thyroid hormones, which are synthesized by this organ of the endocrine system.
Normally, an adult human body contains about 20 mg of iodine, most of which( up to 80%) is deposited in the thyroid gland.This microelement is needed to produce the so-called.Thyroid hormones.
Note: for thyroid hormones are T3 - triiodothyronine and T4 - thyroxine.They consist of about 65% iodine.
Causes of iodine deficiency
Iodine deficiency can be associated not only with the low content of this element in the external environment.
Possible causes of its deficiency include:
- parasitic diseases( helminthic infestations);
- pathology of infectious genesis;
- excess calcium;
- lack of cobalt, selenium, copper or manganese;
- malabsorption of iodine in gastrointestinal pathologies;
- low intake of vitamin A.
iodine deficiency disorders
Insufficient intake of iodine triggers a cascade of compensatory processes to preserve the production and release of thyroid-stimulating hormones at a sufficiently high level.
Continuous and prolonged iodine deficiency leads to the development of IDD - hypothyroidism, diffuse euthyroid or nodular goiter.Among the no less formidable consequences of the lack of this element are the child's physical and mental retardation, endemic cretinism, as well as miscarriage and high perinatal mortality .
It is accepted to distinguish two forms of diffuse goiter - endemic and sporadic. The first type of hyperplasia of the thyroid gland is typical for people living in areas where the presence of iodine in water is much lower than normal.The second - develops in the inhabitants of the regions, where this element is enough.
Note: according to the criteria adopted by the World Health Organization, the territory is considered endemic if diffuse goiter is diagnosed at least one in ten inhabitants.
In rare cases, the incidence of endemic goiter is due not to iodine deficiency, but to the negative effects of substances such as thiocyanic acid salts and flavonoids present in many plants.
The mechanism of development of sporadic diffuse goiter at a given time is unclear.According to one theory, pathology is a consequence of birth defects of enzyme systems responsible for the production of T3 and T4.
This pathology is the second most prevalent IDD.Nodular goiter is characterized by uneven hyperplasia of the thyroid gland with the formation of specific nodes.In the early phases of dysfunction of the gland does not arise, but against the background of taking iodine-containing drugs, thyrotoxicosis is not excluded.
Critical deficiency of iodine leads to hypothyroidism, characterized by a sharp drop in the level of thyroid-stimulating hormones.
Children and pregnant women are most susceptible to IDD.A significant iodine deficiency multiplies the likelihood of spontaneous abortions and intrauterine malformations.The children who are born have cases of hypothyroidism and cretinism.
The thyroid gland of the future child begins to synthesize thyroxine, only starting from the 4th-5th month of embryogenesis.At earlier terms, the thyroid hormones of the mother respond to the formation of the organs and systems of the fetus.Normally, in the first trimester, thyroxine production in women increases by 40%.
Iodine deficiency is divided into:
- is heavy.
The degree is set by the level of trace element in the urine.The mild degrees correspond to the numbers 50 to 99 μg / l, the average to 20-49, and the heavy <20 μg / l.
There are 4 degrees of hyperplasia of the thyroid against a background of iodine deficiency:
0 - the size of the organ within the anatomical norm( palpable it is not determined);
1 - the size of the gland corresponds to the phalange of the thumb;
2 - the organ is noticeable during visual inspection, when the patient throws back his head( palpation is determined by lobes and isthmus);
3 - euthyroid goiter.
Symptoms of iodine deficiency
Among the main symptoms of IDD are:
- Thyroid growth;
- constant fatigue and fatigue;
- fragility of nail plates;
- dry skin;
- violation of the swallowing act;
- weight gain( independent of the nature of the food).
Diffuse goiter is characterized by a prolonged asymptomatic course.Patients may complain of vague discomfort in the neck area. With severe hyperplasia, there are signs of compression of the esophagus - dysphagia and a feeling of "lump in the throat".Most often, for help to the endocrinologist, patients are treated when the thyroid gland increases so much that it is already a cosmetic defect.
Symptomatic of neurologic cretinism:
- dysplasia of bone and muscle tissue;
- low growth( no more than 150 cm);
- speech disorders;
- cranial deformation;
- the body's disproportion.
Symptoms of moderate iodine deficiency:
- decreased cognitive abilities( by 10% or more);
- decreased ability to remember( especially visual memory suffers);
- deterioration of the perception of information by ear;
- impaired concentration( absent-mindedness);
- frequent cephalalgia.
Patients with mild iodine deficiency have a feeling of constant lack of sleep.Due to metabolic disorders, weight increases, and restricting diets in this case are practically ineffective .In the blood, the level of cholesterol rises, so the risk of hypertension, IHD and atherosclerotic lesions of the main blood vessels increases.Many patients suffer from biliary tract motility( dyskinesia appears) and concrements( stones) in the gallbladder are formed. In patients with iodine deficiency, dysmenorrhea, mastopathy and uterine myomas are more often diagnosed.There are cases of female infertility.
Important: the greatest danger is the shortage of iodine during periods of development and growth - from intrauterine to pubertal.
How to determine the shortage of iodine?
Detection of pathologies of the thyroid gland is the task of an endocrinologist.The diagnosis is based on the history, physical examination and the results of laboratory tests at the level of TTG, T3 and T4.
During the interview, the endocrinologist needs to find out exactly if any of the relatives( blood relatives) of the patient suffered from these or other pathologies of the thyroid gland.
At the general inspection a visual assessment of the sizes and proportions of the cervical region is carried out.Symptoms such as swallowing disorders and changes in( hoarseness) of the voice associated with the pressure of the enlarged gland on nearby structures are also revealed.
During palpation, the density of the endocrine gland is assessed, as well as the possible presence and degree of node density.
The patient is necessarily subjected to ultrasound scanning "thyroid", which gives objective data on the degree of hyperplasia. An important method of investigation is fine-needle biopsy, during which the tissue samples of the organ are sampled for pathomorphological studies.
Normal volumes of the thyroid gland:
- for men - 25 ml;
- for women - 18 ml.
One of the most important diagnostic criteria is the level of thyroid-stimulating hormone.Diffuse goiter is characterized by hyperplasia of both lobes, and TSH indices do not exceed the limits of physiological values.If the numbers <0.5 mU / L, hyperthyroidism is not excluded;To verify this diagnosis, it is necessary to determine the levels of triiodothyronine and thyroxin .
How to make up iodine deficiency: treatment and prognosis
Pathological conditions in this category can be corrected by normalizing iodine intake.Therapy involves the appointment of a patient with a potassium iodide preparation( as a monotherapy) or in combination with L-thyroxine( combined treatment).
In elderly people, moderate hyperplasia in the absence of dysfunction of the gland, as a rule, does not require pharmacotherapy.
Treatment in full is required for young patients.Therapy( and prevention) of IDD in endemic regions presupposes the administration of iodine preparations in amounts not exceeding the normal daily requirement. Within six months or more, the dynamics of the state are assessed;Usually during this time the hyperplasia decreases or vanishes.
In case of treatment failure, levothyroxine is additionally prescribed( in some cases - in combination with potassium iodide). After reduction of the gland in size, they pass to "maintenance" monotherapy with iodine preparations.
Terminal stages of thyroid disease may require surgical intervention with resection of the lobe of the organ.
Congenital psychoneurological disorders are currently considered incurable, i.e., treatment is not amenable.
Acquired iodine deficiency states are reversible.Adequate therapy makes it possible to normalize the functional activity of the gland and reduce its size.
Among the possible consequences of the formation of nodal formations of an organ is its functional autonomy.It is characterized by hypersecretion of T3 and T4, independent of external stimulants and TSH.
Prevention of iodine deficiency thyroid diseases
Prevention of iodine deficiency and associated pathological conditions is divided into:
Individual and group measures for the prevention of iodine deficiency consist in prescribing the preparation of potassium iodide in the required doses.Especially important is the prevention among children, adolescents during puberty, as well as expectant mothers and lactating women.
Mass prophylaxis is reduced to the replacement in the endemic in the goiter regions of ordinary table salt by iodized salt.
Foods with a high iodine content:
- seaweed kelp( seaweed) and porphyry( nori);
- marine fish;
- squid and other seafood;
- fish oil( you can buy a drug).
Women who are planning to conceive are strongly advised to undergo a survey to determine the so-called.Thyroid status.Periodic monitoring of T3 and T4 levels is also needed during pregnancy.
Daily intake of iodine( in μg) according to WHO recommendations:
- From birth to 2 years - 50;
- 2-6 years - 90;
- 6-11 years old - 120;
- from 12 years - 150.
Important: it is advisable for women during pregnancy and lactation to increase the consumption of a microelement to 200 μg per day.
Prevention of IDD includes an annual visit to the endocrinologist as part of a medical examination.
Vladimir Plisov, medical reviewer