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Hashimoto's Hypothyroidism Technical Information

CAUSES OF HYPOTHYROIDISM Hashimoto's Thyroiditis Short explaination of what happens with Hashimoto's thyroiditis. The thyroid becomes infiltrated with white blood cells (lymphocytes) which are involved with immune reactions. The lymphocytes will gradually replace the normal thyroid tissue which causes enlargement of the thyroid. This cause a slow development of symptoms and signs of hypothyroidism. Eventually scar tissue will replace the lymphocytes over a period of time. Antibodies circulate in the blood serum appear with the thyroid inflammation. The antibodies are directed against two thyroid proteins, thyroglobulin and thyroid peroxidase(TPO). These thyroid proteins are critically important for normal thyroid function.

Thyroid Drug Information Center Site contains specific information on thyroid meds including research, types of meds as well as links to drug manufacturers sites. "There are a variety of different thyroid hormone replacement drugs.

Levothyroxine
Levothyroxine (or l-thyroxine) is the most commonly prescribed thyroid hormone replacement drug. It is a synthetic (man-made) form of the natural thyroid hormone thyroxine (also known as T4). Levothyroxine came into use for thyroid treatment in the 1950s, and was largely adopted as the primary thyroid hormone replacement drug, replacing the natural desiccated thyroid that had been used during the previous 50 year period.

...key controversy surrounding levothyroxine (T4) drugs is that they provide only one hormone. The human thyroid produces a variety of hormones, among them the two most important ones, T4 and T3. The T4 is converted by the thyroid and other peripheral organs into T3, and T3 is the active hormone that is actually used by the body at the cellular level. The assumption has been that in hypothyroidism, only T4 is needed, and that the body will convert T4 to T3 as needed. However, research from the New England Journal of Medicine has shown that the absence of T3 in thyroid hormone replacement treatments results in less satisfactory treatment, poorer quality of life, and worsened symptoms for the majority of patients. This has led to an increased use of natural desiccated thyroid products, additional synthetic T3, and synthetic producst that combine T4 and T3.

Liothyronine / Cytomel / T3 Drugs
Liothyronine (pronounced lye-oh-THYE-roe-neen) is a synthetic form of the T3 thyroid hormone. It is being more commonly added to levothyroxine treatment, to provide both T4 and T3 as part of the thyroid hormone replacement treatment.
In the U.S., the only brand of T3 available is Cytomel, manufactured by King Pharmaceuticals. Some compounding pharmacies can produce time-released capsules of liothyronine -- known as "Time-released T3" -- as a special order from your physician.

Liotrix / Thyrolar
Liotrix (pronounced LYE-oh-trix) is a synthetic drug that combines both levothyroxine and liothyronine (T4 and T3). The only brand of liotrix available in the U.S. is Thyrolar, manufactured by Forest Labs.

Natural Thyroid Drugs
Natural thyroid drugs are prescription thyroid hormone replacement drugs that are made from the desiccated thyroid glands of pigs. (They are not, as some rumors claim, made from the thyroid gland of cows, and because they are made from U.S. grain-fed pigs, present a almost non-existent risk of "mad cow" disease. Read Is There A Real Risk of Mad Cow Disease from Armour Thyroid). Natural dessicated thyroid drugs have been available since the late 1800s, but went out of favor in the 1950s, with the introduction of the heavily marketed synthetic levothyroxine. More recently, however, these drugs have become increasingly popular with patients and practitioners, in part because some patients feel better on these drugs. The primary brands are Armour Thyroid, made by Forest Labors, Western Pharmaceuticals' products Naturethroid and Westhroid, and Bio-tech's Bio-throid."

About.com Thyroid Disease Names & definitions to common lab tests used in diagnosing thyroid diseases.

Tests for Thyroid Disease Information about tests to diagnose thyroid disease, including the TSH, T4, T3, TRH and thyroid uptake tests.

Common Tests to Examine Thyroid Gland Function This site lists more tests used to diagnose thyroid disease.

Thyroid Function Diagnostic Tests Diagnostic Product Corporation site explains many common thyroid tests as well as providing information on thyroid disease.

Antithyroid Peroxidase Antibody (Anti-TPO) "Anti-TPO Abs mediate antibody-dependent thyroid cell destruction; levels correlate with the active phase of the disease. Measurement of this autoantibody is useful for resolving the diagnostic dilemma presented by the apparent inconsistency between elevated TSH and normal free T4 results. Given abnormally elevated TSH and euthyroid T4 results, a positive anti-TPO Ab test provides strong evidence for early, subclinical autoimmune disease. This assay is also used to monitor response to immunotherapy, to identify at-risk individuals (with family history of thyroid disease), and as a predictor of postpartum thyroiditis. Approximately 10 percent of asymptomatic individuals have elevated levels of Anti-TPO Ab, which may suggest a predisposition to thyroid autoimmune disease. Elevated levels are found in virtually all cases of Hashimoto's thyroiditis and in approximately 85 percent of Graves' disease cases."

immunofluorescence test positive for anti-microsomal antibody Picture of test slide with explaination. Anti-microsomal antibody is one of the autoantibodies that can be seen with autoimmune diseases of the thyroid. A major component of the antimicrosomal antigen is thyroid peroxidase (TPO)

Antithyroglobulin Antibodies (Anti-TG Ab) "The prevalence of Anti-TG Abs in thyroid autoimmune disease is significant (85 percent and 30 percent in Hashimito's thyroiditis and Graves' disease, respectively) but it is much lower than the prevalence of the Anti-TPO Abs. The diagnostic information provided by Anti-TPO assays is rarely improved upon by the addition of an Anti-TG determination. The growing trend is to adopt the anti-TPO Ab test as the front-line test for autoimmune disease and no longer to routinely use the anti-TG assay routinely for this purpose."

Thyroid Stimulating Hormone (TSH) "TSH has been recognized as an exquisitely sensitive indicator of thyroid status. TSH assays have therefore been widely adopted as the front-line thyroid function test. In ambulatory patients with intact hypothalamic and pituitary function, a normal TSH result excludes hypo- or hyperthyroidism; whereas elevated and suppressed TSH results are diagnostic of hypo- and hyperthroidism, respectively. Abnormal TSH results are generally confirmed with a complementary determination of thyroid hormone levels."

Total and Free Thyroxine (T4) "T4 assays complement TSH assays, and are used to confirm a thyroid disorder when this is suggested by an abnormal TSH result... In developing hypothyroidism, T4 (free T4) is the more sensitive indicator of developing disease than is T3 (Free T3), and is therefore preferred for confirming hypothyroidism that has already been suggested by an elevated TSH result."

Total and Free Triiodothyronine (T3) "In developing hyperthyroidism, T3 (free T3) is the more sensitive indicator of developing disease than is T4 (free T4), and the former is therefore preferred for confirming hyperthyroidism that has already been suggested by a suppressed TSH result.
T3 assays are also useful for the differential diagnosis of T3 thyrotoxicosis. This is a variant of hyperthyroidism that manifests itself with abnormally elevated T3 and suppressed TSH levels, whereas T4 levels remain within euthyroid (normal) limits."

Key Thyroid Function Tests Laboratory Values and Interpretation Test values for TSH, T3 & T4.

Thyroid Function Tests Normal Laboratory Values Site lists lab values for more thyroid tests including Serum thyroxine, Free thyroxine fraction, Free Thyroxine, Thyroid hormone binding ratio, Free Thyroxine index, Serum Triiodothyronine, Free Triiodothyronine, Free T3 Index, Radioactive iodine uptake, Serum thyrotropin (TSH), Thyroxine-binding globulin, TRH stimulation test Peak TSH, & Serum thyroglobulin. Thyroid microsomal antibody titer & Thyroglobulin antibody titer values are not listed because it varies with the method the lab uses.

American Thyroid Association Guidelines for Use of Laboratory Tests in Thyroid Disorders Guidelines for using diagnostic tests for hypothyroidism & hyperthyroidism.

The Manual Tender Point Survey "The American College of Rheumatology (ACR) conducted a multicenter study published in 1990 that specified two primary criteria that characterized FM: (1) three or more months of widespread pain defined as pain present above and below the waist on the right and left side of the body and along the midline and (2) report of pain at a minimum of 11/18 specified locations (tender points - TPs) throughout the body when palpated with 4 kilograms of digital pressure. The Manual Tender Point Survey (MTPS) outlined in this document describes a technique requiring approximately 5-10 minutes to perform. It is based on the 1990 American College of Rheumatology tender point protocol for FM. This guide will (1) describe the pressure application technique, (2) discuss the precise identification of survey sites, and (3) review the complete Manual Tender Point Survey examination including the standardized examination procedure and patient instructions."

The Doctor's Doctor "The laboratory, surgical pathology, and cytology reports are your property, but most patients do not ask for copies. This web site is dedicated to keeping patients informed and in control. We have created several web pages that can help you in your quest for knowlege."
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Thyroid Diseases Includes technical but easy to understand information on these thyroid diseases:Goiter, Hypothyroidism (Myxedema), Hyperthyroidism, Postpartum Thyroiditis, Thyroid Cancer. If you have any "why" questions, check this site out.

"Primary Hypothyroidism
In primary hypothyroidism, the disorder is at the site of the thyroid gland itself. Primary hypothyroidism may be acquired or congenital.
The most common cause of acquired hypothyroidism is Hashimoto's thyroiditis. Named after the Japanese physician who characterized and reported this thyroid disorder in 1912, Hashimoto's thyroiditis is an autoimmune disease that causes the gradual destruction of the thyroid gland. In the US, signs of a failing thyroid are apparent in approximately 10 percent of women by age 50, and 17 percent of women and 8 percent of men by age 60."

Anion gap "The normal level of anion gap is generally considered to be between 8 and 16 mEq (milliequivalents) per liter of blood.
It is generally accepted that if the anion gap level is 20 or above, this signals a problem. Too high of an anion gap level can mean that there is acidosis (too much acid in the blood) due to diabetes mellitus. The high anion gap level can also be due to lactic acidosis, in which the high level of acid is due a buildup of a substance called lactic acid. Lactic acid buildup is what causes the burning feeling in your muscles when lifting weights for many repetitions. A high anion gap can also be due to drug poisoning or kidney failure. The kidneys are two organs located on each side of the spine, behind the stomach. The kidneys filter (remove) wastes from the blood. When the anion gap is high, further tests are usually needed to diagnose the cause of the problem.
If the anion gap level is too low, this can mean that the person has hyponatremia (a decreased level of sodium in the blood). It can also mean that the person has multiple myeloma, which is cancer of the bone marrow. Bone marrow is a tissue that fills the center of long bones. Additional testing needs to be done to find out the reason for the anion gap level being too low."