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Hypothyroidism (Underactive Thyroid)
Hypothyroidism is a very common disorder, especially in women. The two most common symptoms of hypothyroidism:
The other common symptoms of hypothyroidism:
Hypothyroidism can also cause a high cholesterol level, high blood pressure and slowing of heart rate. It is quite common to mistakenly attribute these symptoms to "just getting old." Hypothyroidism can be easily diagnosed with a blood test.
Hashimoto's thyroiditis
Hashimoto's thyroiditis is an autoimmune disease of the thyroid gland and is the most common cause of hypothyroidism (underactive thyroid). It affects women much more frequently than men. A family history of thyroid disorder is usually present. An enlarged thyroid gland, known as a goiter, is also usually present. Sometimes, thyroid nodules are present. Diagnosis of Hashimoto's thyroiditis can be easily made by a blood test.
Treatment of Hypothyroidism
Hypothyroid patients are treated by replacing thyroid hormone. Most of these patients are hypothyroid due to Hashimoto's thyroiditis. Some are hypothyroid as result of radioactive iodine treatment for Graves disease. Others become hypothyroid as a result of thyroid surgery, usually done for the treatment of thyroid cancer. Some rare cases of hypothyroidism include congenital hypothyroidism, juvenile hypothyroidism and thyroiditis, as a result of post-delivery. The dose of thyroid hormone must be individualized and is adjusted according to the thyroid function test results. Requirement of thyroid hormone generally increases during pregnancy. A normal thyroid gland produces two types of thyroid hormones, Levothyroxine (or T4) and triiodothyronine (or T3). For replacement purposes, traditionally only T4 ( Synthroid, Levoxyl or Levothroid) was used because some of this T4 gets converted into T3 inside the body. However, a number of patients continue to have symptoms of hypothyroidism despite having a normal thyroid function test. These patients benefit from the addition of T3 ( Cytomel ) In the past, only a handful of endocrinologists were adding T3 (Cytomel) to T4 (Levoxyl, Synthroid or Levothroid) to replace thyroid hormone, but recently more and more endocrinologists are using combination therapy in many hypothyroid patients. An article published in the February 11, 1999 issue of the New England Journal of Medicine clearly indicated that combination therapy with T4 and T3 was superior to T4 therapy alone in controlling the patient's symptoms of hypothyroidism. In the past, I used to treat my hypothyroid patients with T4 (Levoxyl, Synthroid or Levothroid) alone. However, since the publication of the New England Journal of Medicine article, I have been combining Cytomel to Levoxyl or Synthroid in treating most of my hypothyroid patients. I am finding the combination of Cytomel and Levoxyl or Synthroid to be more effective in controlling the patient's symptoms than Levoxyl or Synthroid used alone.
Drugs to treat Hypothyroidism (Under-active thyroid gland)
Absorption of T4 (Levoxyl, Synthroid or Levothroid) is decreased if it is taken at the same time as iron (contained in most multivitamins) or certain antacids or sucralfate. You can take T4 about 2 hours apart from these drugs. For other drug interactions check with your pharmacist. Generally, it is a good idea to take T4 (Levoxyl, Synthroid or Levothroid) by itself, such as at bedtime, and other drugs at other times of the day.
Hyperthyroidism (Overactive Thyroid) Hyperthyroidism is a common endocrine disorder. Women are affected much more commonly than men. Hyperthyroidism can be easily diagnosed with a blood test.
Symptoms of hyperthyroidism:
Causes of Hyperthyroidism The common causes of hyperthyroidism are:
Graves disease Graves disease is an autoimmune disease of the thyroid gland. For some obscure reasons, the body starts producing antibodies which are directed at the thyroid gland. These antibodies are stimulatory in nature and thus force the thyroid gland to produce more and more thyroid hormone. Large quantities of thyroid hormone produce symptoms of hyperthyroidism (overactive thyroid) Sometimes, eye symptoms may be pronounced. These include bulging of the eyes, feeling of a foreign body in the eyes, excessive dryness of the eyes, blurry vision and double vision. Sometimes, eyesight may be in danger and requires immediate medical attention. Rarely it can affect skin as well.
Treatment options for Graves' disease include:
Antithyroid Drugs Tapazole (methimazole ) and PTU (propylthiouracil) are the two anti-thyroid drugs available in the US. These drugs are used to control the symptoms of hyperthyroidism (overactive thyroid). These anti-thyroid drugs are generally well tolerated, but occasionally side-effects may develop which include skin rash, liver toxicity and suppression of bone marrow resulting in a decrease in the number of white blood cells, predisposing the patient to serious life-threatening infections. Therefore, these drugs should be prescribed only by endocrinologists, who are experienced in using these drugs. Treatment of Graves disease patients with an anti-thyroid drug for a period of 18 - 24 months can result in about a 50% cure rate once the drug is stopped. In others, hyperthyroidism recurs upon discontinuation of the drug.
Radioactive Iodine Radioactive iodine is used in the treatment of Graves disease, thyroid cancer and occasionally, a multinodular goiter. Radioactive iodine is used in very small amounts (usually about 9 - 12 mCi) in the treatment of Graves disease and as such, it appears quite safe. Radioactive iodine must be used cautiously in patients who also have Graves eye disease, as there is a potential to aggravate the eye condition. In the treatment of recurrent thyroid cancer, large doses of radioactive iodine are used (which appear to be safe) until a cumulative dose of about 700 mCi is exceeded. Each case must be assessed on an an individual basis. Radioactive iodine must not be used in pregnant patients.
Goiter
A Goiter simply means an enlarged thyroid gland. The most common cause of a goiter in the US is Hashimoto's thyroiditis. Other common causes of a goiter in the US include multinodular goiter and Graves disease. In other parts of the world, iodine deficiency is a major cause for the development of a goiter. Rarely, a goiter may be harboring thyroid cancer.
Thyroid Nodule
A thyroid nodule is usually discovered by a physician during a routine physical examination of the patient. Sometimes a nodule is discovered by the patient. At times, a thyroid nodule is discovered incidentally on an ultrasound or CT scan of the neck or chest done for some other reason. Most thyroid nodules are not cancerous; However, a thyroid cancer may rarely be present in a thyroid nodule. Factors that increase the likelihood of thyroid cancer are: older age, large size of the nodule, family history of thyroid cancer, history of exposure to radiation to the head and neck area, history of exposure to a nuclear reactor disaster, atomic bomb survivors. A blood test for thyroid function should be carried out first. This test is normal in most cases and further testing will be necessary. Occasionally, the thyroid function test may indicate that a person is hyperthyroid (overactive thyroid). In these cases, chances of thyroid cancer are extremely low. An ultrasound guided Fine Needle Aspiration Biopsy (FNA) is the most practical way to evaluate a thyroid nodule.
Thyroid Cancer
Most thyroid cancers are slow growing tumors and generally carry a favorable prognosis. However, some thyroid cancers are quite aggressive and carry a poor prognosis. One dangerously aggressive form of thyroid cancer is called medullary thyroid cancer which is usually familial. Gene testing (a blood test) is now available to family members of a patient with medullary thyroid cancer who are also at risk for the development of this cancer.
A thyroid cancer is usually discovered as a result of a fine needle aspiration biopsy or the surgical biopsy of a thyroid nodule. Once thyroid cancer has been diagnosed, thyroid surgery is performed to remove all the thyroid tissue, followed in many cases by a dose of radioactive iodine which serves two purposes: A. It destroys any remaining thyroid cells, cancerous as well as non-cancerous. B. Once all the thyroid cells are destroyed, the body can no longer produce a substance called thyroglobulin (which is normally produced only by the thyroid tissue). Thus, measuring serum thyroglobulin becomes an excellent tool to detect the recurrence of thyroid cancer, indicated by an increase in thyroglobulin level.
Follow-up of most thyroid cancer patients include: Large doses of thyroid hormone to suppress serum TSH (thyroid stimulating hormone ) to prevent recurrence of the cancer. Measuring serum thyroglobulin on a yearly basis to detect any recurrence of the thyroid cancer. Total body scan on a yearly basis to detect any recurrence of the thyroid cancer. |
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