Materiały źródłowe

• #1 Hypothyroidism – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK519536/

  Hypothyroidism results from low levels of thyroid hormone with varied etiology and manifestations. Hypothyroidism is primarily categorized as primary and secondary (ie, central) hypothyroidism. In primary hypothyroidism, the thyroid gland cannot produce adequate amounts of thyroid hormone. The less commonly seen secondary or central hypothyroidism occurs when the thyroid gland functions normally; however, hypothyroidism results from the abnormal pituitary gland or hypothalamus function. Autoimmune thyroiditis and iodine deficiency are the most common causes of the disease. Central hypothyroidism is rare. […] The most common cause of hypothyroidism is the inability of the thyroid gland to produce a sufficient amount of thyroid hormone; however, less commonly, pituitary and hypothalamus impairment may also result in thyroid dysfunction. The hypothalamus secretes thyrotropin-releasing hormone (TRH) that stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH). Thyroid-stimulating hormones stimulate the thyroid gland to produce and secrete mainly T4, approximately 100 to 125 nmol daily, and smaller quantities of T3. The half-life of T4 is 7 to 10 days, and eventually, T4 is converted to T3 peripherally by 5′-deiodination. Negative feedback on the production of TRH and TSH is exerted primarily by T3 and, to some extent, T4. Alterations in the structure and function of any of these organs or pathways can result in hypothyroidism.

• #2 Hypothyroidism: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/122393-overview

  Hypothyroidism is a common endocrine disorder resulting from deficiency of thyroid hormone. In the United States and other areas of adequate iodine intake, autoimmune thyroid disease (Hashimoto disease) is the most common cause of hypothyroidism; worldwide, iodine deficiency remains the foremost cause. […] Although hypothalamic or pituitary disorders can affect thyroid function, localized disease of the thyroid gland that results in decreased thyroid hormone production is the most common cause of hypothyroidism. Under normal circumstances, the thyroid releases 100-125 nmol of T4 daily and small amounts of T3. The ratio of T4:T3 production varies between about 14:1 and 4:1, depending on iodine sufficiency and TSH stimulation. The half-life of T4 is approximately 7-10 days, whereas the half-life of T3 is about 24 hours. T4, a prohormone, is converted via the action of deiodinases to T3, the active form of thyroid hormone.

• #2 Hypothyroidism: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/122393-overview

  Deficiency of thyroid hormone has a wide range of effects. Systemic effects are the result of either derangements in metabolic processes or direct effects by myxedematous infiltration (ie, accumulation of glycosaminoglycans in the tissues). […] The hypothyroid changes in the heart result in decreased contractility, cardiac enlargement, pericardial effusion, decreased pulse, and decreased cardiac output. […] Decreased thyroid hormone effect can cause increased levels of total cholesterol and low-density-lipoprotein (LDL) cholesterol and a possible change in high-density-lipoprotein (HDL) cholesterol because of a change in metabolic clearance. In addition, hypothyroidism may result in an increase in insulin resistance. […] A study by Wopereis et al looked at the increased risk for anemia arising in hypothyroidism, reporting that for overt hypothyroidism, the pooled hazard ratio (HR) for anemia development was 1.38, while for subclinical hypothyroidism, it was 1.18. Although it is not clear how hypothyroidism leads to anemia, there is evidence that reduced thyroid function may interfere with the production of healthy erythrocytes. The possibility exists that T3, T4, and TSH are directly involved in erythropoiesis.

• #3 Hypothyroidism in Animals – Endocrine System – Merck Veterinary Manual

  https://www.merckvetmanual.com/endocrine-system/the-thyroid-gland/hypothyroidism-in-animals

  Hypothyroidism results from thyroid hormone deficiency and is most common in dogs but also develops rarely in other species, including cats, horses, and other large domestic animals. […] Although dysfunction anywhere in the hypothalamic-pituitary-thyroid axis may result in thyroid hormone deficiency, 95% of clinical cases of hypothyroidism in dogs appear to result from destruction of the thyroid gland itself (primary hypothyroidism). The two most common causes of adult-onset primary hypothyroidism in dogs are lymphocytic thyroiditis and idiopathic atrophy of the thyroid gland. […] Lymphocytic thyroiditis is likely immune-mediated and is characterized histologically by a diffuse infiltration of the gland by lymphocytes, plasma cells, and macrophages, resulting in progressive destruction of follicles and secondary fibrosis.

• #3 Hypothyroidism in Animals – Endocrine System – Merck Veterinary Manual

  https://www.merckvetmanual.com/endocrine-system/the-thyroid-gland/hypothyroidism-in-animals

  Idiopathic atrophy of the thyroid gland is characterized histologically by loss of thyroid parenchyma and replacement by adipose tissue. […] In dogs, secondary hypothyroidism is uncommon and usually results from destruction of pituitary thyrotrophs by an expanding, space-occupying tumor. […] Other rare forms of hypothyroidism in dogs include neoplastic destruction of thyroid tissue and congenital (or juvenile-onset) hypothyroidism. […] Congenital primary hypothyroidism may result from one of various forms of thyroid dysgenesis (eg, athyreosis, thyroid hypoplasia) or from dyshormonogenesis (usually an inherited inability to organify iodide). […] Congenital secondary hypothyroidism has been reported in Giant Schnauzers, Toy Fox Terriers, and Scottish Deerhounds. […] In cats, iatrogenic hypothyroidism is the most common form.

• #3 Hypothyroidism in Animals – Endocrine System – Merck Veterinary Manual

  https://www.merckvetmanual.com/endocrine-system/the-thyroid-gland/hypothyroidism-in-animals

  Recognized causes of congenital hypothyroidism in cats include dyshormonogenesis, an inability of the thyroid gland to respond to TSH, and thyroid dysgenesis. […] In foals, congenital hypothyroidism may develop when pregnant mares graze plants that contain goitrogens or are fed diets either deficient in or containing excessive amounts of iodine. […] A deficiency of thyroid hormone affects the function of all organ systems; as a result, clinical signs are diffuse, variable, often nonspecific, and rarely pathognomonic. […] Many of the clinical signs associated with canine hypothyroidism are directly related to slowing of cellular metabolism, which results in development of mental dullness, lethargy, exercise intolerance, and weight gain without a corresponding increase in appetite. […] Myxedema coma, a rare syndrome, is the extreme expression of severe hypothyroidism.

• #3 Hypothyroidism in Animals – Endocrine System – Merck Veterinary Manual

  https://www.merckvetmanual.com/endocrine-system/the-thyroid-gland/hypothyroidism-in-animals

  During the fetal period and in the first few months of postnatal life, thyroid hormones are crucial for growth and development of the skeleton and CNS. […] In primary congenital hypothyroidism, enlargement of the thyroid gland (goiter) may also be detected, depending on the cause of the hypothyroidism. […] Definitive diagnosis of canine hypothyroidism requires careful attention to clinical signs and results of routine laboratory testing. […] The classic hematologic finding associated with hypothyroidism, found in 40%-50% of cases, is normocytic, normochromic, nonregenerative anemia. […] The classic serum biochemical abnormality is hypercholesterolemia, which occurs in approximately 80% of dogs with hypothyroidism, and therefore can assist as a screening test for hypothyroidism. […] The standard treatment for hypothyroidism is daily oral administration of the synthetic thyroid hormone levothyroxine, which is the thyroid hormone replacement compound of choice in dogs and cats. […] With few exceptions, replacement therapy is necessary for the remainder of the animal’s life. […] The most important indicator of the success of treatment is clinical improvement. Improvements in lethargy and mentation occur within 2 weeks.

• #4 Hypothyroidism | American Thyroid Association

  https://www.thyroid.org/hypothyroidism/

  Hypothyroidism is an underactive thyroid gland. Hypothyroidism means that the thyroid gland cant make enough thyroid hormone to keep the body running normally. […] Common causes are autoimmune disease, such as Hashimotos thyroiditis, surgical removal of the thyroid, and radiation treatment. […] There can be many reasons why the cells in the thyroid gland cant make enough thyroid hormone. Here are the major causes, from the most to the least common. […] Autoimmune disease. In some peoples bodies, the immune system that protects the body from invading infections can mistake thyroid gland cells and their enzymes for invaders and can attack them. Then there arent enough thyroid cells and enzymes left to make enough thyroid hormone. […] Thyroiditis is an inflammation of the thyroid gland, usually caused by an autoimmune attack or by a viral infection. Thyroiditis can make the thyroid dump its whole supply of stored thyroid hormone into the blood at once, causing brief hyperthyroidism (too much thyroid activity); then the thyroid becomes underactive.

• #4 Hypothyroidism | American Thyroid Association

  https://www.thyroid.org/hypothyroidism/

  Medicines such as amiodarone, lithium, interferon alpha, and interleukin-2 can prevent the thyroid gland from being able to make hormone normally. […] The thyroid gland must have iodine to make thyroid hormone. […] The pituitary, the master gland, tells the thyroid how much hormone to make. When the pituitary is damaged by a tumor, radiation, or surgery, it may no longer be able to give the thyroid instructions, and the thyroid may stop making enough hormone. […] In a few people, diseases deposit abnormal substances in the thyroid and impair its ability to function.

• #5 Hypothyroidism – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/hypothyroidism

  Hypothyroidism is thyroid hormone deficiency. […] Primary hypothyroidism is due to decreased secretion of thyroxine (T4) and triiodothyronine (T3) from the thyroid. […] In the United States, the most common cause is autoimmune inflammation. […] The second most common cause is treatment for hyperthyroidism (post-therapeutic hypothyroidism), especially after radioactive iodine therapy or surgery for hyperthyroidism, goiter, or thyroid cancer. […] Iodine deficiency decreases thyroid hormonogenesis. […] Rare inherited enzymatic defects can alter the synthesis of thyroid hormone and cause goitrous hypothyroidism. […] Hypothyroidism may occur in patients taking lithium, perhaps because lithium inhibits hormone release by the thyroid. […] Hypothyroidism can result from radiation therapy for cancer of the larynx or Hodgkin lymphoma.

• #5 Hypothyroidism – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/hypothyroidism

  Secondary hypothyroidism occurs when the hypothalamus produces insufficient thyrotropin-releasing hormone (TRH) or the pituitary produces insufficient TSH. […] Subclinical hypothyroidism is elevated serum TSH in patients with absent or minimal symptoms of hypothyroidism and normal serum levels of free thyroxine (T4). […] In patients with serum TSH 10 mIU/L (10 microIU/mL), there is a high likelihood of progression to overt hypothyroidism with low serum levels of free T4 within the next 10 years. […] For patients with TSH levels between 4.5 and 10 mUI/L, a trial of levothyroxine is reasonable if symptoms of early hypothyroidism (eg, fatigue, depression) are present. […] Levothyroxine therapy is also indicated in pregnant women and in women who plan to become pregnant to avoid deleterious effects of hypothyroidism on the pregnancy and fetal development.

• #5 Hypothyroidism – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/hypothyroidism

  Myxedema coma is a life-threatening complication of hypothyroidism, usually occurring in patients with a long history of hypothyroidism. […] Serum thyroid-stimulating hormone measurement is the most sensitive test for diagnosing hypothyroidism. […] In primary hypothyroidism, there is decreased feedback inhibition of the intact pituitary, and serum TSH is always elevated, whereas serum free T4 is low. […] In secondary hypothyroidism, free T4 and serum TSH are low (sometimes TSH is normal but with decreased bioactivity). […] Myxedema coma is treated as follows: T4 given IV, corticosteroids, supportive care as needed, conversion to oral T4 when patient is stable. […] Check cortisol levels in patients with secondary hypothyroidism before starting thyroid replacement therapy, because of the serious risk of adrenal crisis.

• #6 Hypothyroidism – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK519536/

  Autoimmune thyroiditis causes an increase in the turnover of iodine and impaired organification. Chronic inflammation of the parenchyma leads to predominant T-cell lymphocytic infiltration. If this persists, the initial lymphocytic hyperplasia and vacuoles are replaced by dense fibrosis and atrophic thyroid follicles. Coexisting or associated malignancies, such as papillary thyroid cancer, can also be seen.

• #7 Hashimoto’s thyroiditis – Wikipedia

  https://en.wikipedia.org/wiki/Hashimoto%27s_thyroiditis

  Hashimoto’s thyroiditis is thought to be due to a combination of genetic and environmental factors. […] The pathophysiology of autoimmune thyroiditis is not well understood. However, once the disease is established, its core processes have been observed: Hashimoto’s thyroiditis is a T-lymphocyte mediated attack on the thyroid gland. […] The three major antibodies are: Thyroid peroxidase Antibodies (TPOAb), Thyroglobulin Antibodies (TgAb), and Thyroid stimulating hormone receptor Antibodies (TRAb), with TPOAb and TgAb being most commonly implicated in Hashimoto’s. […] They are hypothesized to develop as a result of thyroid damage, where T-lymphocytes are sensitized to residual thyroid peroxidase and thyroglobulin, rather than as the initial cause of thyroid damage. […] However, they may exacerbate further thyroid destruction by binding the complement system and triggering apoptosis of thyroid cells. […] Hypothyroidism is caused by replacement of follicular cells with parenchymatous tissue.

• #8 Hashimoto’s disease: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/hashimotos-disease/

  Hashimoto’s disease is a form of chronic inflammation that can damage the thyroid, reducing its ability to produce hormones. […] Hashimoto’s disease is the most common cause of thyroid underactivity (hypothyroidism) in the United States. […] In people with Hashimoto’s disease, white blood cells called lymphocytes accumulate abnormally in the thyroid, which can damage it. The lymphocytes make immune system proteins called antibodies that attack and destroy thyroid cells. When too many thyroid cells become damaged or die, the thyroid can no longer make enough hormones to regulate body functions. This shortage of thyroid hormones underlies the signs and symptoms of Hashimoto’s disease.

• #9 Hashimoto’s Disease – Creative Biolabs

  https://www.creative-biolabs.com/complement-therapeutics/hashimoto-disease.htm

  In patients with Hashimotos disease, B cells from thyroid tissue are activated to secrete antithyroid antibodies, the major pathogenic factors. It is acknowledged that excessively stimulated T cells CD4+ play the main role in the pathogenesis of Hashimotos disease. Moreover, T helper cells (Th1, Th2, and Th17) are also involved in the development of Hashimotos disease. Th2 cells lead to excessive stimulation and production of B cells, resulting in antithyroid antibodies accumulation. While Th1 cells activate cytotoxic lymphocytes and macrophages, leading to direct effects on thyroid tissue by destroying thyroid follicular cells. […] As an important parameter of Hashimotos disease, thyroperoxidase consists of a large N-terminal myeloperoxidase-like module followed by a complement control protein (CCP)-like module and an epidermal growth factor-like module. C4 may bind to thyroperoxidase and activate the complement pathway in autoimmune thyroiditis. Autoantibodies against complement C1q (anti-C1q) are correlated with parameters of thyroid function and anti-TPO, anti-Tg and TSBAb. The researches of C3 in the pathogenesis of Hashimotos disease shows that the severity and duration of the thyroid dysfunction correlate with the degree of complement activation.

• #9 Hashimoto’s Disease – Creative Biolabs

  https://www.creative-biolabs.com/complement-therapeutics/hashimoto-disease.htm

  Hashimotos disease, also known as Hashimoto’s thyroiditis, is a typification of autoimmune thyroiditis. Hashimotos disease is characterized by painless enlargement of the thyroid, which, in histopathological analysis, presents diffuse lymphocytic infiltrations, fibrosis, and atrophic changes. It is a diffuse process, a combination of epithelial cell damage, lymphocyte infiltrations, and fibrosis, finally leading to gradual destruction of thyroid gland. […] The antibodies against thyroperoxidase (anti-TPO), antithyroglobulin (anti-Tg) and more rarely TSH-stimulation blocking antibody (TSBAb), are positively correlated with an increased inflammatory reaction in the thyroid and with the development of Hashimotos disease. Antithyroid antibodies have an ability to fix complement and thus promote complement-dependent antibody-mediated cytotoxicity leading to more damage to thyroid tissue.

• #10

  https://link.springer.com/article/10.1007/s40618-020-01477-1

  The relationship between goitrous and atrophic forms of autoimmune thyroiditis has long been debated, particularly the question of whether the former simply progresses to the latter, as opposed to these being two discrete entities. […] Regulatory T cell (Treg) are now well established as having a critical role in preventing autoimmunity. […] In terms of thyroid cell injury, cytokines derived from the lymphocytic infiltrate play a key role, including their ability to stimulate the thyroid cells themselves to release proinflammatory mediators, thus amplifying and perpetuating the autoimmune response. […] A further proinflammatory cascade has been identified in HT with the finding of increased expression of multiple inflammasome components (NLRP1, NLRP3, NLRC4, AIM2, ASC, and caspase-1) and their associated cytokines (IL-18 and IL-1) in the thyroid of patients, as well as identification of inflammasome component release by thyroid cell stimulated in vitro with the IFN- and tumour necrosis factor-, which may in turn contribute to further cytokine release and cell death through pyroptosis. […] The PD-1/PD ligand-1 axis has also been investigated. This pathway plays a major role in suppressing adaptive immunity in a variety of settings, including the immune response by tumour cells, and as we have seen, blockade can result in autoimmune disease.

• #11 Thyroiditis: Evaluation and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2021/1200/p609.html

  The diagnosis of HT can be established by a combination of clinical features, thyroid function test results consistent with subclinical hypothyroidism (elevated serum TSH level, but normal serum levels of T4 and free triiodothyronine [T3]) or overt hypothyroidism (elevated TSH level with low T4 and T3 serum levels), and elevated thyroglobulin and thyroid peroxidase (TPO) antibodies. […] The thyroid gland is often diffusely enlarged and firm with an irregular surface on examination. […] The goal of treatment is to ameliorate the pain and thyrotoxicosis-related symptoms. […] The use of antithyroid drugs is not indicated. Treatment with beta blockers for control of severe symptoms during the thyrotoxic phase is recommended, although often no treatment is needed if symptoms are mild. […] Several drug therapies have been associated with the development of thyroiditis, including amiodarone, immune checkpoint inhibitors, interferon-alfa, interleukin-2, lithium, and tyrosine kinase inhibitors.

• #12 Hypothyroidism (Underactive Thyroid): Symptoms, Causes, Treatment

  https://www.healthline.com/health/hypothyroidism/symptoms-treatments-more

  Standard treatment for hyperthyroidism uses radioactive iodine to destroy thyroid cells. This may cause the levels of your thyroid hormone to remain low permanently. […] If your entire thyroid gland is removed as a result of thyroid problems, you’ll develop hypothyroidism. Using thyroid medication long term is the primary treatment. […] If you’ve received a diagnosis of cancer of the head or neck, lymphoma, or leukemia, you may have undergone radiation therapy. Radiation used for the treatment of these conditions may slow or halt the production of thyroid hormone, leading to hypothyroidism. […] Several medications may lower thyroid hormone production, resulting in hypothyroidism. […] Iodine deficiency occurs infrequently in the United States, but it is the most common cause of hypothyroidism in other parts of the world.

• #13 Thyroid dysfunction and drug interactions – The Pharmaceutical Journal

  https://pharmaceutical-journal.com/article/ld/thyroid-dysfunction-and-drug-interactions

  Hypothyroidism refers to any state when thyroid hormone production is inadequate. […] Disruption to this mechanism results in hypothyroidism or hyperthyroidism. […] Hypothyroidism is typically managed by administration of a synthetic form of T4, levothyroxine, or occasionally the synthetic form of T3, liothyronine. […] Amiodarone may inhibit the peripheral de-iodination of T4 to T3 resulting in a decreased concentration of active hormone, which can cause more overt symptoms in patients with existing hypothyroidism. […] Lithium may lead to clinical hypothyroidism due to a direct action on the thyroid gland, inhibiting the release of thyroid hormones. […] As thyroid status influences metabolic activity, thyroid disorders and their subsequent correction may have a wide range of implications on medicines.

• #14 Hypothyroidism (underactive thyroid) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284

  Hypothyroidism that isn’t treated can lead to other health problems, including: […] Hypothyroidism can lead to a higher risk of heart disease and heart failure. That’s mainly because people with an underactive thyroid tend to develop high levels of low-density lipoprotein (LDL) cholesterol the „bad” cholesterol. […] A relatively rare cause of hypothyroidism is the failure of the pituitary gland to make enough thyroid-stimulating hormone (TSH). This is usually because of a noncancerous tumor of the pituitary gland. […] Some people develop hypothyroidism during or after pregnancy. If hypothyroidism happens during pregnancy and isn’t treated, it raises the risk of pregnancy loss, premature delivery and preeclampsia. […] The thyroid gland needs the mineral iodine to make thyroid hormones. Iodine is found mainly in seafood, seaweed, plants grown in iodine-rich soil and iodized salt. Too little iodine can lead to hypothyroidism.

• #15 Central Hypothyroidism – Endocrinology Advisor

  https://www.endocrinologyadvisor.com/ddi/central-hypothyroidism/

  Hypothyroidism may be defined as primary, secondary, or tertiary hypothyroidism. […] Central hypothyroidism occurs when there is a problem with the pituitary gland (secondary) or hypothalamus (tertiary) rather than with the thyroid gland itself. […] Other causes of CeH include genetic factors, treating primary hypothyroidism with too much thyroid hormone, empty sella syndrome, inflammation, infiltrative causes, head injury, medication-related causes, Sheehan syndrome, thyroid-releasing hormone resistance or deficiency, pituitary macroadenomas, pituitary surgery, past radiation treatment, head trauma. […] A diagnosis of central hypothyroidism may be made when there is an abnormally low TSH along with below-normal thyroxine (T4) and triiodothyronine (T3). […] A thyroid-releasing hormone (TRH)-stimulation test may help identify pituitary or hypothalamic disease.

• #16 The Relationship Between Hypothyroidism and Your Reflexes | Paloma Health

  https://www.palomahealth.com/learn/hypothyroidism-reflexes?srsltid=AfmBOopJF5wzGzD4ZlmYYmU3X0aLsCw0mYXmrhnCJYrmV8JBvcWvgUCC

  Thyroid hormones regulate your metabolism, energy levels, and overall growth and development. When you’re hypothyroid, your underactive thyroid gland doesn’t produce enough thyroid hormones to support all your glands, organs, tissues, cells, and functions. […] One of the main reasons for slowed reflexes in hypothyroidism is the reduced metabolic rate caused by the lack of thyroid hormones. Metabolism refers to the body’s ability to convert food into energy and regulate body temperature. Without enough thyroid hormones, the metabolic rate decreases, resulting in a slower overall functioning of bodily processes. […] This decrease in metabolic rate also slows the speed at which nerve cells communicate with each other. Nerve cells rely on an electrical impulse called an action potential to transmit signals throughout the body. However, when the thyroid gland is underactive, and your metabolism is slowed, the generation and propagation of these action potentials are impaired.

• #16 The Relationship Between Hypothyroidism and Your Reflexes | Paloma Health

  https://www.palomahealth.com/learn/hypothyroidism-reflexes?srsltid=AfmBOopJF5wzGzD4ZlmYYmU3X0aLsCw0mYXmrhnCJYrmV8JBvcWvgUCC

  Furthermore, the lack of thyroid hormones affects the myelin sheath, a protective covering around nerve fibers. In hypothyroidism, the myelin sheath may become damaged or deteriorate, impairing the efficiency of nerve signal transmission. This damage can lead to delayed reflexes and a decrease in overall coordination. […] Finally, another factor contributing to slowed reflexes in hypothyroidism is the overall weakness and muscle stiffness often associated with an underactive thyroid. The decrease in thyroid hormones can lead to muscle wasting and decreased muscle tone, making it more challenging for muscles to respond promptly to reflex stimuli. […] In hypothyroidism, deep tendon reflexes are frequently slowed down or even absent. In fact, according to research, the delayed relaxation of deep tendon reflexes, also known as Woltmans sign, is seen in about 75% of patients with hypothyroidism, and the presence of Woltmans sign is considered to be 92% predictive in diagnosing hypothyroidism. […] The exact mechanism of hyperreflexia in hypothyroidism is not well understood, but it may be related to altered neurotransmitter function or changes in the excitability of the motor neurons.

• #17 Thyroid Disorders: Types, Signs, Symptoms, Treatment & Causes

  https://www.medicinenet.com/thyroid_disorders/article.htm

  Hypothyroidism increases the risk of heart disease and causes irregular heart rate and heart failure. […] Long-term untreated hypothyroidism can cause damage to your peripheral nerves (in the arms and legs). […] This is a rare, life-threatening complication of long-term, untreated hypothyroidism. […] Low levels of thyroid hormone can interfere with ovulation presenting with irregular periods. […] Babies born to women with untreated thyroid disease may have a higher risk of being born with birth defects. […] Untreated hypothyroidism during pregnancy increases the risk of miscarriage, premature delivery, preeclampsia, and birth defects in the developing baby.

• #18 Update on dyslipidemia in hypothyroidism: the mechanism of dyslipidemia in hypothyroidism in: Endocrine Connections Volume 11 Issue 2 (2022)

  https://ec.bioscientifica.com/view/journals/ec/11/2/EC-21-0002.xml

  Hypothyroidism is often associated with elevated serum levels of total cholesterol, LDL-C and triglycerides. […] Therefore, the mechanism of hypothyroidism-related dyslipidemia is associated with the decrease of TH and the increase of TSH levels. […] The current review focuses on the updated understanding of the mechanism of hypothyroidism-related dyslipidemia. […] The major effect of TH and TSH on lipid metabolism in hypothyroidism has been outlined in Fig. 1. […] The total effect of TSH on TC level includes the direct effect and the indirect effect (TH). […] TSH alone also can increase TC levels in CVD patients independent of TH. […] It has been reported that TSH regulates cholesterol metabolism through binding to TSH receptors (TSHRs) on the surface of hepatocytes and adipocytes.

• #18 Update on dyslipidemia in hypothyroidism: the mechanism of dyslipidemia in hypothyroidism in: Endocrine Connections Volume 11 Issue 2 (2022)

  https://ec.bioscientifica.com/view/journals/ec/11/2/EC-21-0002.xml

  The combined impact of TH on cholesterol production and clearance leads to a net accumulation of serum LDL-C in hypothyroidism. […] The decrease of TH and increase of TSH share similar pathogenic mechanisms of LDL-C accumulation in hypothyroidism, both of which could induce the cholesterol production and inhibit clearance. […] The effect of TH and TSH on LDL-C in hypothyroidism has been outlined in Fig. 2. […] The binding of TSH to TSHR of hepatocyte membrane upregulates the expression and activity of HMGCR through the cAMP/PKA/CREB signaling pathway. […] TSH could also stimulate the increase of ApoB. […] The decrease of TH leads to the attenuation of these effects, thus promoting the elevation of serum TG in hypothyroidism. […] The HDL clearance and transformation process decrease in hypothyroidism. […] Hypothyroidism could inhibit cholesterol clearance by decreasing scavenger receptor b1. […] The HDL-C level is not constant because regulating factors counteract each other; however, HDL function, a predictor of cardiovascular risk independent of HDL-C levels, is impaired in hypothyroidism.

• #19 Hypothyroidism and Joint Pain – Rheumatology Advisor

  https://www.rheumatologyadvisor.com/ddi/hypothyroidism-and-joint-pain/

  Hypothyroidism occurs when this hormone is in short supply, which causes body processes to slow down, resulting in a constellation of symptoms, including joint pain. […] This joint pain may stem from how the thyroid hormone affects the proliferation and differentiation of bone and cartilage at the cellular level. As such, hypothyroidism may lead to musculoskeletal conditions, including:1 Epiphyseal dysgenesis, Septic necrosis, Arthritis, crystal-induced arthritis, and erosive osteoarthritis, Arthralgias, Muscle weakness, Myalgias (with or without elevations in creatinine phosphokinase), Carpal tunnel syndrome, Highly viscous, noninflammatory joint effusions in the knees, wrists, and hands. […] Hypothyroid arthropathy, a joint disease that includes arthritis, most commonly strikes the knees and hands in adults and the hip and the epiphysis of the femoral head in children.

• #20 Hypothyroidism | PPT

  https://www.slideshare.net/slideshow/hypothyroidism-67205783/67205783

  Hypothyroidism is a clinical syndrome resulting from a deficiency of thyroid hormones. There is a generalized slowing down of metabolic processes. […] Pathogenesis of Hypothyroidism Characteristic finding: accumulation of glycosaminoglycans mostly hyaluronic acid in interstitial tissues The accumalation is due not to excessive synthesis but to decreased destruction of glycosaminoglycans. Accumulation of this hydrophilic substance and increased capillary permeability to albumin account for this interstitial edema that is particularly evident in the skin, heart muscle, and striated muscle. […] Hashimotos Thyroiditis Chronic lymphocytic thyroiditis Probably the most common cause of hypothyroidism With (younger patients) or without goiter (older patients atrophy gland after destruction by immunologic process) High titer of autoantibodies to thyroidal antigens (Thyroglobulin Ab, Thyroperoxidase Ab = TPO Ab = Antimicrosomal Ab = AMA)

• #21 Become a member

  https://www.btf-thyroid.org/thyroid-and-weight-the-science

  Since the BMR in a person with hypothyroidism is decreased, an underactive thyroid is generally associated with some weight gain. The weight gain is often greater in those individuals with more severe hypothyroidism. […] The cause of the weight gain in a hypothyroid person is also complex, and not always related to excess fat accumulation. Most of the extra weight gained in hypothyroid individuals is due to excess accumulation of salt and water. […] In general, 5-10 pounds of body weight may be attributable to the thyroid, depending on the severity of the hypothyroidism. […] Once hypothyroidism has been treated and thyroid hormone levels have returned to the normal range of thyroid hormone, the ability to gain or lose weight is the same as in individuals who do not have thyroid problems.

• #22 Hypothyroidism and Irregular Periods

  https://www.everydayhealth.com/hypothyroidism/irregular-periods/

  Hypothyroidism, a condition in which your thyroid gland doesn’t produce enough hormones, affects nearly 5 percent of Americans 12 and older, and women are more likely to develop it than men, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). […] Hypothyroidism can also affect your periods by setting off a cascade of hormonal changes that affect your reproductive system. […] High prolactin levels then suppress production of gonadotropin-releasing hormone (GnRH) in your hypothalamus. This is a problem, because you need GnRH to produce follicle-stimulating hormone and luteinizing hormone in your pituitary gland. These hormones are important for normal ovarian function, and when hypothyroidism leads to a decrease in their levels, menstrual irregularities may occur, says Dr. McConnell.

• #23 How Thyroid Function Affects Your Period

  https://www.verywellhealth.com/menstrual-problems-and-thyroid-disease-3231765

  Since a lack of thyroid hormone can prevent ovulation, having thyroid problems can make it difficult to get pregnant. Hyperthyroidism may also cause early menopause, or menopause that occurs before or around the age of 40. […] For people with hypothyroidism, treatment with levothyroxine may improve fertility and lower the risk of pregnancy loss.

• #24 How to Combat Dry Skin from Hypothyroidism

  https://npthyroid.com/tipsresource/combat-dry-skin-from-hypothyroidism/

  Hypothyroidism is characterized by an underactive thyroid gland. This gland is responsible for regulating the body’s metabolism, including the production and turnover of skin cells. […] When the thyroid hormone isn’t performing well, the skin may become flaky, dry, and itchy. […] With insufficient thyroid hormones, the body’s metabolism slows down, and this sluggishness affects not only moisture but reduced blood flow to the skin. The eccrine glands, responsible for sweat secretion, are also affected by low thyroid hormone levels. This further deprives the skin of essential nutrients and moisture. […] To combat dry skin caused by hypothyroidism, it is important to first address the underlying thyroid issues. Consult with a health care professional who can diagnose and provide appropriate treatment options, such as thyroid hormone replacement therapy.

• #25 Hypothyroidism and Bipolar Disorder: What Is the Link?

  https://www.healthline.com/health/hypothyroidism-and-bipolar-disorder

  Hypothyroidism isnt a direct cause of bipolar disorder, but research indicates that thyroid dysfunction may contribute to its progression and increase the severity of symptoms. […] However, some research shows that an underactive thyroid may contribute to the progression of certain types of bipolar disorder, especially if someone is predisposed to the condition. Thyroid function may also affect symptom severity. […] Researchers concluded that the findings may show that thyroid dysfunction disrupts mood and influences bipolar disorder progression in people already predisposed to the condition. […] The link between hypothyroidism and bipolar disorders is complex and misunderstood. Experts theorize thyroid hormone dysfunction could contribute to mood changes that influence bipolar disorder progression in people already predisposed to the condition. […] Bipolar disorder treatment with lithium may also increase the chance of developing hypothyroidism by reducing your thyroid gland function.

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