Hypothyroidism

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(Myxedema)

Hypothyroidism is a thyroid hormone deficiency. Diagnosis is by clinical symptoms such. B. made a typical facial expression, coarse, slow speech and dry skin as well as by the low values ??for thyroid hormones. The treatment involves the treatment of the underlying disease and the administration of thyroxine.

Hypothyroidism is a thyroid hormone deficiency. Diagnosis is by clinical symptoms such. B. made a typical facial expression, coarse, slow speech and dry skin as well as by the low values ??for thyroid hormones. The treatment involves the treatment of the underlying disease and the administration of thyroxine.

(See illustration of the thyroid function.) Hypothyroidism is a thyroid hormone deficiency. Diagnosis is by clinical symptoms such. B. made a typical facial expression, coarse, slow speech and dry skin as well as by the low values ??for thyroid hormones. The treatment involves the treatment of the underlying disease and the administration of thyroxine. Hypothyroidism can occur at any age but is more common among the elderly, where it occurs subtle and difficult to diagnose. Hypothyroidism can be primary: by a disease in the thyroid caused Secondary: by a disease in the hypothalamus or pituitary gland causes Primary hypothyroidism a primary hypothyroidism is caused by a disease of the thyroid gland itself; the thyroid-stimulating hormone (TSH) is increased. The most common cause is an autoimmune disease. Mostly it is a Hashimoto’s thyroiditis, which is initially associated with a goiter and later in a Atrophic-fibrotic thyroid gland, which has little or no function. The second most common reason is an iatrogenic hypothyroidism, especially after radiation or surgical treatment of hyperthyroidism or a goiter. Hypothyroidism during treatment with antithyroid drugs disappear after cessation of treatment. Most patients with non-Hashimoto’s goiters are euthyroid or have hyperthyroidism, but hypothyroidism with goiter may occur in endemic goiter. Iodine deficiency decreases thyroid hormone production then there is an increase of TSH and an enlargement of the thyroid, so to goiter. If the iodine deficiency is severe, the patient is hypothyroid, which only rarely in the United States since the advent of iodized salt. Iodine deficiency can cause congenital hypothyroidism. In highly iodine-deficient regions congenital hypothyroidism (formerly endemic cretinism called) worldwide a major cause of mental retardation. Rare congenital enzyme deficiencies can lead to changes in hormone production and to a hypothyroid goiter (Congenital goiter). Hypothyroidism can also occur in patients taking lithium, because lithium probably inhibits the release of hormones from the thyroid gland. Likewise, hypothyroidism can occur in patients taking amiodarone or other iodine-containing drugs or interferon alfa and taking in patients checkpoint inhibitors or certain tyrosine kinase inhibitors for cancer. A radiation therapy for laryngeal cancer or Hodgkin’s lymphoma (Hodgkin’s disease) can cause hypothyroidism. The incidence of permanent hypothyroidism after radiation is high. Therefore, thyroid function every 6-12 months should be checked by the measurement of serum TSH. Secondary hypothyroidism arises A secondary hypothyroidism, when the hypothalamus insufficient amounts of thyrotropin releasing hormone (TRH) or the pituitary gland will not produce sufficient amounts of TSH. Occasionally resulting from a deficiency TRH TSH deficiency is referred to as tertiary hypothyroidism. A subclinical hypothyroidism subclinical hypothyroidism is characterized by elevated serum TSH in patients with missing or minimal symptoms of hypothyroidism and normal values ??for free T4 in serum. A subclinical thyroid hormone deficiency is relatively common; it occurs in more than 15% of older women and 10% of older men, particularly those with underlying Hashimoto’s thyroiditis. Patients with a serum TSH> 10 mU / l have a high risk of developing over the next 10 years of overt hypothyroidism with low serum values ??for free T4. These patients also have an increased risk of hypercholesterolemia and atherosclerosis. You should, even if they are asymptomatic, are treated with L-thyroxine. treatment with L-thyroxine is reasonable for patients with TSH levels from 4.5 to 10 mU / l if early symptoms of hypothyroidism (z. B. fatigue, depression) are present. To harmful effects of hypothyroidism on pregnancy and fetal development to prevent a l-Thyroxintherapie is also in pregnant women and women who plan to become pregnant, indexed. Patients should annually determine serum TSH and free T4 to – if untreated – to assess the progress of the development, or to adjust the lThyroxin dose. Symptoms and signs The symptoms and discomfort primary hypothyroidism usually develop slowly. Various organ systems are affected. Metabolic manifestations: Cold intolerance, low weight gain (due to fluid retention and reduced metabolism), hypothermia Neurologic Manifestations: forgetfulness, paresthesias of the hands and feet (usually caused by carpal tunnel syndrome and thickening of the ligaments, as in the ligaments of the wrist and ankle a mucoproteinhaltige substance is deposited); slowing of relaxation phase of deep tendon reflexes psychiatric manifestations: personality changes, dull facial expressions, dementia or psychosis free (myxedema-disease) Dermatologic manifestations: swelling of the face; myxedema; sparse, coarse and dry hair; rough, dry, scaly and thick skin; Karotinämie, particularly remarkable on the palms and soles (by deposition of carotene caused in the lipid-rich epidermal layers); Macroglossia due to deposition of proteinaceous ground substance in the tongue ocular manifestations: periorbital puffiness due to the infiltration with mucopolysaccharide hyaluronic acid and chondroitin sulfate), drooping eyelids due to the decreased adrenergic drive gastrointestinal manifestations: constipation Gynecological manifestations: menorrhagia or secondary amenorrhea cardiovascular manifestations : slow heart rate (a decrease in both thyroid hormone and adrenergic stimulation, caused by bradycardia), enlarged heart in the investigation and imaging (partly because of the extension, but mainly because of pericardial effusion, pericardial effusions develop slowly and cause rarely hemodynamic Leiden) other manifestations: pleural or Abdomenergüsse (pleural effusions develop slowly and rarely cause respiratory or hämodynam ical problems), hotter voice and slow speech pretibial myxedema (Mild) © Springer Science + Business Media var model = {thumbnailUrl: ‘/ – / media / manual / professional / images / 497-pretibial-myxedema-slide-5-Springer high.jpg lang = en & thn = 0 & mw = 350? ‘, imageUrl:’ /-/media/manual/professional/images/497-pretibial-myxedema-slide-5-springer-high.jpg?la=de&thn=0 ‘ title: ‘pretibial myxedema (Mild)’ description: ” credits ‘© Springer Science + Business Media’, hideCredits: false, hideTitle: false, hideFigure: false, hideDescription: true}; var panel = $ (MManual.utils.getCurrentScript ()) Closest ( ‘image-element-panel.’). ko.applyBindings (model, panel.get (0)); Myxedema in hypothyroidism with permission of the publisher. From Burman K. Becker K., Cytryn A., et al. In Atlas of Clinical Endocrinology: Thyroid Diseases. Edited by S. G. Korenman (series editors) and M.I. Surks. Philadelphia, Current Medicine, 1999. var model = {thumbnailUrl: ‘/-/media/manual/professional/images/myxedema_in_hypothyroidism_high_de.jpg?la=de&thn=0&mw=350’ imageUrl: ‘/ – / media / manual / professional / images / myxedema_in_hypothyroidism_high_de.jpg lang = en & thn = 0 ‘, title:’? myxedema with hypothyroidism ‘description:’ ‘credits’ with permission of the publisher. From Burman K. Becker K., Cytryn A., et al. In Atlas of Clinical Endocrinology: Thyroid Diseases. Edited by S. G. Korenman (series editors) and M.I. Surks. Philadelphia, Current Medicine, 1999. ‘hideCredits: false, hideTitle: false, hideFigure: false, hideDescription: true}; var panel = $ (MManual.utils.getCurrentScript ()) Closest ( ‘image-element-panel.’). ko.applyBindings (model, panel.get (0)); Symptoms can be clearly distinguished in the elderly. A secondary hypothyroidism is rare. but its causes often affect other endocrine organs that are controlled by the hypothalamic-pituitary axis. Hypothyroid women have amenorrhea, and certain physical examination findings that may indicate a secondary hypothyroidism. A secondary hypothyroidism is characterized by skin and hair that are dry but not very rough, depigmentation of the skin, minimal macroglossia, atrophic breasts and low blood pressure. The heart is small, and serous pericardial not occur. are often hypoglycemia that may occur in connection with the accompanying adrenal insufficiency and of GH deficiency. Myxoedema coma Myxoedema coma is a life-threatening complication of hypothyroidism, which occurs frequently in patients with hypothyroidism is a long time. Characteristic features are a coma at a hypothermia and temperatures from 24 to 32.2 ° C, areflexia, seizures, and respiratory insufficiency with Carbondioxid retention. Severe hypothermia can be overlooked if not thermometers are used with very low measurement ranges. A quick diagnosis based on clinical experience, medical history and physical examination is very important because without immediate treatment, the mortality rate is high. Triggering factors are disease, infection, trauma, drugs that affect the central nervous system and exposure to cold. Diagnostics TSH free thyroxine (T4), the determination of serum TSH is the most sensitive test, and screening of selected groups is justified. In primary hypothyroidism, there is no feedback inhibition of the pituitary intact, and thus the serum TSH is always elevated, while the free serum T4 is low. In secondary hypothyroidism free T4 and serum TSH is low (sometimes TSH is normal, but shows a reduced bioactivity). Many patients with primary hypothyroidism have normal values ??for circulating triiodothyronine (T3), presumably because the continuing TSH stimulation of thyroid failing leads to a preferred synthesis and release of the biologically active hormone T3. Therefore, the determination of serum T3 for the exclusion of hypothyroidism is not suitable. There are often anemia, which is usually normocytic-normochromic and of unknown etiology. but it may be hypochromic also because of menorrhagia. Occasionally be found within an associated pernicious anemia or as a consequence of reduced folate intake macrocytic anemia. The anemia is rarely severe (Hb typically> 9 g / dl). If the hypo metabolic condition is corrected, the anemia, which can sometimes take 6-9 months disappears. Serum cholesterol is usually in primary hypothyroidism high, but in secondary hypothyroidism, the values ??are not as high. In addition to primary and secondary hypothyroidism other circumstances also may cause a decrease in total T4 levels such. As a lack of thyroxine-binding globulin (TBG), some drugs (primary hypothyroidism), Hashimoto thyroiditis and euthyroid sick syndrome. Therapy l-thyroxine is adjusted until the TSH values ??in the mid-normal range For a substitution therapy various thyroid preparations are available, including synthetic T4 preparations (L-thyroxine) and T3 preparations (liothyronine), combinations of the two synthetic hormones, and dried, animal thyroid extracts. L-thyroxine is preferred, the usual maintenance dose is 75-150 ug p.o. 1 time day, depending on age, body mass index and absorption (for pediatric doses, hypothyroidism in infants and children: therapeutic regimen). The starting dose in patients young or middle-aged, who are otherwise healthy, can po at 100 micrograms or 1.7 g / kg 1 time / day are. But in patients with heart disease, the therapy is started with low doses, typically 25 micrograms 1 times / day. The dose is adjusted every 6 weeks as long until the maintenance dose is reached. The maintenance dose may need to be increased in pregnant women. The dose may need u. U. are also increased when additional medication to be taken, which inhibit the T4 absorption (Editor’s note:., for example, proton pump inhibitors) or increase the biliary excretion. The dose used should be the lowest dose that remain under the serum TSH values ??in the mid-normal range. This criterion can not be used in patients with secondary hypothyroidism. In secondary hypothyroidism free T4 in the mid-normal range should be obtained with the dose of L-thyroxine. Liothyronine alone should not be given for long-term substitution because of its short half-life and high serum T3 peaks. The T3 levels return to normal within 24 hours. The transfer of the standard dose substitution (25-37.5 .mu.g 2 times daily) results, since it is almost completely absorbed within 4 h in rapidly rising serum T3 levels between 300 and 1000 ng / dL (4.62 to 15 , 4 nmol / l). So patients who are substituted with liothyronine are at least a few hours a day “hyperthyroid” which may increase cardiovascular risk. Similar patterns of serum T3 levels occur when a mixture of T3 and T4 is administered orally. Here are lower, the T3 peak values ??since less T3 is given. Substitution regimes with synthetic T4 -products show a different pattern of response T3. The increase in serum T3 is gradual, and normal values ??are achieved when the dose is sufficient T4. Dried preparations from animal thyroid tissues contain different amounts of T3 and T4 and should not be prescribed for the patient is already taking the preparation and has a normal TSH serum value. Patients with secondary hypothyroidism should receive no L-thyroxine, cortisol secretion is present until a sufficient (or treatment with cortisol occurs), since L-thyroxine can trigger a Addison crisis. Myxoedema coma A Myxoedema coma is treated as follows: iv Administration of corticosteroids T4 Supportive treatment as required conversion to oral administration of T4 when the patient is stable patients require initial high dose T4 (300-500 micrograms i.v.) or T3 (25-50 ug i.v.). The maintenance dose of T4 is 75-100 ug i.v. 1 times a day and T3 10-20 micrograms iv can be administered two times a day until T4 orally. It also be given corticosteroids, because the possibility of central hypothyroidism usually at the beginning can not be excluded. The patient should not be heated too quickly, as this may lead to hypotension and arrhythmias. Hypoxemia is often so that the PaO 2 value should be monitored. If breathing is affected, they should immediately be mechanically supported. Triggering factors should be immediately and effectively treated. The fluid therapy must be careful because hypothyroid patients excrete water inadequate. In addition, with each medication caution because all drugs compared with healthy people are metabolized more slowly. Geriatric Essentials Hypothyroidism is especially common among the elderly. The frequency is 10% of women and 6% of men in the age group of people> 65 years. In young patients, the diagnosis of overt disease is very easy to make, while the hypothyroidism can manifest oligosymptomatic and atypical in the elderly. Elderly patients have significantly fewer symptoms than younger adults, and the symptoms are often subtle and vague. Many elderly patients with hypothyroidism non-specific geriatric syndromes are -Verwirrung, loss of appetite, weight loss, falls, incontinence and decreased mobility. Musculoskeletal disorders often occur (especially joint pain), but arthritis is rare. There may be muscle pain and weakness, often mimic polymyalgia or polymyositis and elevated CK levels. In the elderly, hypothyroidism may show symptoms similar to dementia or Parkinson’s disease. In older people, the L-Thyroxine therapy is started with low doses, typically 25 micrograms 1 times / day. Maintenance doses should be lower possibly also in older patients. Conclusion A primary hypothyroidism is most common. It is caused by a disease of the thyroid gland itself and the TSH levels are elevated. A secondary hypothyroidism is less frequent. It is caused due to a disorder of the pituitary gland and the hypothalamus and TSH levels are low. The symptoms develop gradually and usually include sensitivity to cold, constipation, and cognitive and / or personality changes. Later, the face is puffy and the facial expression is dull. A Myxoedema coma is a life-threatening complication that requires rapid diagnosis and treatment. The levels of free thyroxine (T4) are always low, but T3 can remain normal in some disturbances in the early stages. The determination of serum TSH is the best diagnostic test and a screening of selected groups of people (eg. As the elderly) justified because the disease is subtle and insidious. Oral administration of T4 (L-thyroxine) is the preferred treatment. It is administered at the lowest dose, which brings the serum TSH values ??back to the mean normal range.

Health Life Media Team

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