Signs and Symptoms

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Signs and symptoms

Hypothalamus - TRH

Early § Poor muscle tone (muscle hypotonia) § Fatigue § Any form of menstrual irregularity and fertility problems § Hyperprolactinemia and galactorrhea § Elevated serum cholesterol § Cold intolerance, increased sensitivity to cold § Constipation § Rapid thoughts § Depression § Muscle cramps and joint pain § Thin, brittle fingernails § Coarse hair § Paleness § Decreased sweating § Dry, itchy skin [10][11][12] § Weight gain and water retention § Bradycardia (low heart rate – fewer than sixty beats per minute) [edit]Late § Goiter § Slow speech and a hoarse, breaking voice – deepening of the voice can also be noticed, caused by Reinke's Edema. § Dry puffy skin, especially on the face § Thinning of the outer third of the eyebrows (sign of Hertoghe) § Abnormal menstrual cycles § Low basal body temperature § Thyroid-Related Depression hypothyroidism (pronounced /ˌhaɪpɵˈθaɪrɔɪ dɪzəm/) is a condition in which the thyroid gland does not make enough thyroid hormone. (a deficiency of thyroid hormone). Severe hypothyroidism in infants can result in cretinism. Thyroid hormone regulation- the chain of command The thyroid itself is regulated by another gland that is located in the brain, called the pituitary. In turn, the pituitary is regulated in part by the thyroid (via a "feedback" effect of thyroid hormone on the pituitary gland) and by another gland called the hypothalamus. The hypothalamus releases a hormone called thyrotropin releasing hormone (TRH), which sends a signal to the pituitary to release thyroid stimulating hormone (TSH). In turn, TSH sends a signal to the thyroid to release thyroid hormones. If a disruption occurs at any of these levels, a defect in thyroid hormone production may result in a deficiency of thyroid hormone (hypothyroidism).

Pituitary- TSH

Thyroid- T4 and T3 The rate of thyroid hormone production is controlled by the pituitary gland. If there is an insufficient amount of thyroid hormone circulating in the body to allow for normal functioning, the release of TSH is increased by the pituitary gland in an attempt to stimulate more thyroid hormone production. In contrast, when there is an excessive amount of circulating thyroid hormone, TSH levels fall as the pituitary attempts to decrease the production of thyroid hormone. In persons with hypothyroidism, there is a persistent low level of circulating thyroid hormones. causes hypothyroidism? 1.Hashimoto's Thyroiditis In this condition, the thyroid gland is usually enlarged (goiter) and has a decreased ability to make thyroid hormones. Hashimoto's is an autoimmune disease in which the body's immune system inappropriately attacks the thyroid tissue. 2. Lymphocytic thyroiditis following hyperthyroidism This condition is particularly common after pregnancy and can actually affect up to 8% of women after they deliver. In these cases, there is usually ahyperthyroid phase (in which excessive amounts of thyroid hormone leak out of the inflamed gland), which is followed by a hypothyroid phase that can last for up to six months. The majority of affected women eventually return to a state of normal thyroid function, although there is a possibility of remaining hypothyroid. 3. Thyroid destruction secondary to radioactive iodine or surgery Patients who have been treated for a hyperthyroid condition (such asGraves' disease) and received radioactive iodine may be left with little or no functioning thyroid tissue after treatment. The likelihood of this depends on a number of factors including the dose of iodine given, along with the size and the activity of the thyroid gland. If there is no significant activity of the thyroid gland six months after the radioactive iodine treatment, it is usually assumed that the thyroid will no longer function adequately. The result is hypothyroidism. Similarly, removal of the thyroid gland during surgery will be followed by hypothyroidism. 4. Pituitary or Hypothalamic disease If for some reason the pituitary gland or the hypothalamus are unable to signal the thyroid and instruct it to produce thyroid

hormones, a decreased level of circulating T4 and T3 may result, even if the thyroid gland itself is normal. If this defect is caused by pituitary disease, the condition is called "secondary hypothyroidism." If the defect is due to hypothalamic disease, it is called "tertiary hypothyroidism." 5.Pituitary injury A pituitary injury may result after brain surgery or if there has been a decrease of blood supply to the area. In these cases of pituitary injury, the TSH that is produced by the pituitary gland is deficient and blood levels of TSH are low. Hypothyroidism results because the thyroid gland is no longer stimulated by the pituitary TSH. This form of hypothyroidism can, therefore, be distinguished from hypothyroidism that is caused by thyroid gland disease, in which the TSH level becomes elevated as the pituitary gland attempts to encourage thyroid hormone production by stimulating the thyroid gland with more TSH. 6. Medications Medications that are used to treat an overactive thyroid (hyperthyroidism) may actually cause hypothyroidism. These drugs include methimazole(Tapazole) and propylthiouracil (PTU). The psychiatric medication, lithium(Eskalith, Lithobid), is also known to alter thyroid function and cause hypothyroidism. Interestingly, drugs containing a large amount of iodine such as amiodarone (Cordarone), potassium iodide (SSKI, Pima), and Lugol's solution can cause changes in thyroid function, which may result in low blood levels of thyroid hormone. 7. Iodine deficiency or excess: Worldwide, iodine deficiency is the most common cause of hypothyroidism. Excess iodine, as in radiocontrast dyes, amiodarone, health tonics, and seaweed, inhibits iodide organification and thyroid hormone synthesis. These include patients with autoimmune thyroiditis, surgically treated Graves hyperthyroidism (subtotal thyroidectomy) and prior radioiodine therapy. symptoms of hypothyroidism? ·

Fatigue

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Depression

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Modest weight gain

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Cold intolerance

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Excessive sleepiness

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Dry, coarse hair

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Constipation

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Dry skin

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Muscle cramps

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Increased cholesterol levels

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Decreased concentration

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Vague aches and pains

· Swelling of the legs As the disease becomes more severe, there may be puffiness around the eyes, a slowing of the heart rate, a drop in body temperature, and heart failure. In its most profound form, severe hypothyroidism may lead to a life-threatening coma (myxedema coma). In a severely hypothyroid individual, amyxedema coma tends to be triggered by severe illness, surgery, stress, or traumatic injury. hypothyroidism diagnosed? 1.blood test- When hypothyroidism is present, the blood levels of thyroid hormones can be measured directly and are usually decreased. However, in early hypothyroidism, the level of thyroid hormones (T3 and T4) may be normal. 2. TRH test- can help distinguish if the disease is caused by a defect in the pituitary or the hypothalamus. This test requires an injection of the TRH hormone and is performed by an endocrinologist (hormone specialist). 3. antibody screening and a thyroid scan can help diagnose the precise underlying thyroid problem more clearly. Exams and Tests A physical examination may reveal a smaller than normal thyroid gland, although sometimes the gland is normal size or even enlarged (goiter). The examination may also reveal:

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Brittle nails Coarse facial features Pale or dry skin, which may be cool to the touch Swelling of the arms and legs Thin and brittle hair A chest x-ray may show an enlarged heart. Laboratory tests to determine thyroid function include:

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TSH test T4 test http://www.nlm.nih.gov/medlineplus/ency /article/000353.htm Pathophysiology 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 100125 nmol of thyroxine (T4) daily and only small amounts of triiodothyronine (T3). The half-life of T4 is approximately 7-10 days. T4, a prohormone, is converted to T3, the active form of thyroid hormone, in the peripheral tissues by 5’-deiodination. Early in the disease process, compensatory mechanisms maintain T3 levels. Decreased production of T4 causes an increase in the secretion of TSH by the pituitary gland. TSH stimulates hypertrophy and hyperplasia of the thyroid gland and thyroid T4-5'deiodinase activity. This, in turn, causes the thyroid to release more T3.

forms are Hashimoto's disease, subacute granulomatous thyroiditis, postpartum thyroiditis, subacute lymphocytic thyroiditis and drug induced thyroiditis. What Causes It?: Immune disorders, viruses, and fever disorders can cause thyroiditis. Sometimes thyroiditis develops if you have Graves' disease (an autoimmune disorder that causes hyperthyroidism). Certain drugs, such as amiodarone, interferon-alpha, inter leukin-2, or lithium can also cause

Because all metabolically active cells require thyroid hormone, deficiency of the hormone has a wide range of effects. Systemic effects are due to either derangements in metabolic processes or direct effects by myxedematous infiltration (ie, accumulation of glucosaminoglycans in the tissues). The myxedematous changes in the heart result in decreased contractility, cardiac enlargement, pericardial effusion, decreased pulse, and decreased cardiac output. In the GI tract, achlorhydria and decreased intestinal transit with gastric stasis can occur. Delayed puberty, anovulation, menstrual irregularities, and infertility are common. 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 due to a change in metabolic clearance. In addition, hypothyroidism may result in an increase in insulin resistance. http://emedicine.medscape.com/article/12 2393-overview#a0104 Thyroid hormone replacement Levothyroxine is generally considered to be the treatment of choice for patients with hypothyroidism. Levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid) In active form, influences growth and maturation of tissues. Involved in normal growth, metabolism, and development. Produces stable levels of T3 and T4. Administered as a single dose in the morning on an empty stomach. May be administered PO/IV/IM Thyroiditis is an inflammation of the thyroid gland. It may be painful and tender when caused by an infection or trauma, or painless when caused by an autoimmune condition or medications. There are several types of thyroiditis. The most common

thyroiditis. Pregnant women who test positive for the thyroid antibody during their first trimester have a 30 - 50% chance of developing thyroiditis during the postpartum period. Excessive iodine intake may also contribute to thyroid disorders. In some cases or thyroiditis, there is no identifiable cause. Treatment Options: Thyroiditis generally involves three phases: overactive phase, underactive phase, and return to normal. Treatment is individualized to type and phase. Drug Therapies Depending on the particular type of thyroiditis, a physician may prescribe one or more of the following treatments:



Levothyroxine, if hypothyroidism or large goiter present



Aspirin, to relieve pain and inflammation



Corticosteroid medications (such as prednisone or dexamethasone), to reduce inflammation in severe cases



Propanolol, for hyperthyroidism



Thyroxine, to replace thyroid hormone (in cases of hypothyroidism)



Short term beta blockers, for hyperthyroid symptoms



disease and frequently obliterates much of the normal thyroid tissue. Follicular thyroid cells may be small or hyperplastic. The degree of fibrosis among patients also widely varies. Children usually have hyperplasia with minimal fibrosis. The blood contains autoantibodies to thyroid peroxidase and, frequently, autoantibodies to thyroglobulin. Autoimmune thyroiditis is also frequently part of the polyglandular autoimmune syndromes.

Antibiotics

Surgical and Other Procedures In rare cases, partial thyroid removal may relieve pressure. Complementary and Alternative Therapies Alternative therapies can help when used

http://emedicine.medscape.com/article/92 5249-overview#a0104

along with the medications your health care provider prescribes, but do not replace

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conventional medications. Make sure your doctor knows about any alternative therapies you are using or considering



using. Some supplements can interfere with conventional medications. http://www.umm.edu/altmed/articles/thyr

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oiditis-000164.htm Pathophysiology Acute suppurative thyroiditis is rare in childhood because the thyroid is remarkably resistant to hematogenously spread infection. Most cases of acute thyroiditis involve the left lobe of the thyroid and are associated with a developmental abnormality of thyroid migration and the persistence of a pyriform sinus from the pharynx to the thyroid capsule. The usual organisms responsible include Staphylococcus aureus, Streptococcus hemolyticus, and pneumococcus. Other aerobic or anaerobic bacteria may also be involved. Subacute thyroiditis is generally thought to be due to viral processes and usually follows a prodromal viral illness. Various viral illnesses may precede the disease, including mumps, measles, influenza, infect ious mononucleosis, adenoviral or Coxsackievirus infections, myocarditis, or the common cold. Other illnesses or situations associated with subacute thyroiditis includecatscratch fever, sarcoidosis, Q fever, malaria, emotional crisis, or dental work. The disease is more common in individuals with human leukocyte antigen (HLA)–Bw35. Because chronic thyroiditis in children is usually due to an autoimmune process, it is HLA-associated, similar to other autoimmune endocrine diseases. The specific alleles in the atrophic and goitrous forms of the disease vary. The histologic disease picture varies, but lymphocytic thyroid infiltration is the hallmark of the

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Acute thyroiditis A history of acute illness, including fever, chills, neck pain, sore throat, hoarseness, and dysphagia, is common. Neck pain is frequently unilateral and radiates to the mandible, ears, or occiput. Neck flexion reduces the severity of the pain. The pain worsens with neck hyperextension. Subacute thyroiditis Neck tenderness and swelling may occur. Occasionally, the initial symptoms are those of hyperthyroidism. Systemic symptoms such as weakness, fatigue, malaise, and fever are usually low grade. Chronic autoimmune thyroiditis is observed in the following 3 patterns: Goiter that is usually diffuse and nontender: Systemic illness is not evident. The thyroid gland is frequently 23 times its normal size and may be larger. The patient, parent, or physician may discover the goiter. Symptoms of hypothyroidism: In children, this frequently includes poor growth or short stature. Adolescent girls may have primary or secondary amenorrhea. Boys may have delayed puberty. Because the disease develops slowly, the patient or parent may not notice other signs of hypothyroidism, including constipation, lethargy, and cold intolerance. The child with diabetes may have decreasing insulin requirement. Symptoms of hyperthyroidism: These may include poor attention span, hyperactivity, restlessness, heat intolerance, or loose stools. Hyperthyroidism PathophysiologyThe hypermetabolic effect of thyrotoxicosis affects every organ system. The pituitary gland stimulates the thyroid to make thyroid hormone, which is released into the circulation to reach every cell in the body. Thyroid hormone is necessary for normal growth and development, and it regulates cellular metabolism. Excess

thyroid hormone causes an increase in the metabolic rate that is associated with increased total body heat production and cardiovascular activity (increased heart contractility, heart rate, vasodilation).

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