Autoimmune thyroiditis; Hashimoto's thyroiditis
A variety of factors affect the decision of whether to treat a patient for hypothyroidism, which dosage to begin with, and how rapidly treatment should be started or increased:
Doctors should also consider:
Treating Overt Hypothyroidism. Patients with overt hypothyroidism, indicated by clear symptoms and blood tests that show high TSH (generally 10 mU/L and above) and low thyroxine (T4) levels, must have thyroid replacement therapy.
Treating Subclinical or Mild Hypothyroidism. Considerable debate exists about whether to treat patients with subclinical hypothyroidism (slightly higher than normal TSH levels, normal thyroxine levels, and no obvious symptoms). Some doctors opt for treatment and others opt for simply monitoring patients.
It is not clear if the benefits of treating subclinical hypothyroidism outweigh the risks and potential complications. Doctors who do not advocate treatment argue that thyroid levels can vary widely, and subclinical hypothyroidism may not persist. In such cases, overtreatment leading to hyperthyroidism is a real risk.
There is reasonable evidence and consensus to recommend treatment for subclinical hypothyroidism in the presence of other factors, including:
Treatment is optional in patients with subclinical hypothyroidism who have no obvious symptoms and normal cholesterol levels. Some doctors feel that treating this group of patients will prevent progression to overt hypothyroidism and future heart disease, as well as increase a patient's sense of well-being. However, the evidence to support treatment of this patient group is not nearly as strong. Many doctors recommend against treatment and suggest that these patients should simply have lab tests every 6 - 12 months.
Suppressive Thyroid Therapy. Suppressive thyroid therapy involves taking levothyroxine in doses that are high enough to block the production of natural TSH but too low to cause hyperthyroid symptoms. It may be used for patients with large goiters or thyroid cancer.
Suppressive thyroid therapy places patients, particularly postmenopausal women, at risk for accelerated osteoporosis, a disease that reduces bone mass and increases risk of fractures. Some researchers suggest, however, that such bone loss is too slight to pose any significant risk for fracture. Furthermore, the cholesterol-lowering benefits of suppressive therapy outweigh this small risk.
Bone density loss can be reduced or avoided by taking no higher a dose of thyroxine than necessary to restore normal thyroid function. In any case, doses of T4 must be continuously and carefully tailored in all patients to avoid adverse effects on the heart.
Treating the Elderly and Patients with Heart Disease. Thyroid dysfunction is common in elderly patients, with most having subclinical hypothyroidism. There is no evidence that this condition poses any great harm in this population, and most doctors recommend treating only high-risk patients. Elderly patients, particularly people with heart conditions, usually start with very low doses of thyroid replacement, since thyroid hormone may cause angina or even a heart attack. Patients who have heart disease must take lower-than-average maintenance doses. Doctors do not recommend treatment for subclinical hypothyroidism in most elderly patients with heart disease. Such patients should be closely monitored, however.
Treating Newborns and Infants with Hypothyroidism. Babies born with hypothyroidism (congenital hypothyroidism) should be treated with levothyroxine (T4) as soon as possible to prevent complications. Early treatment can help improve IQ and other developmental factors. However, even with early treatment, mild problems in mental functioning may last into adulthood. In general, children born with milder forms of hypothyroidism will fare better than those who have more severe forms.
Oral levothyroxine (T4) can usually restore normal thyroid hormone levels within 1 - 2 weeks. It is critical that normal levels are achieved within a 2-week period. If thyroid function is not normalized within 2 weeks, it can pose greater risks for developmental problems. Infants should continue to be monitored closely to be sure that thyroxine levels remain as consistently close to normal as possible. These children need to continue lifelong thyroid hormone treatments.
Treatment During Pregnancy and for Postpartum Thyroiditis. Women who have hypothyroidism before becoming pregnant may need to increase their dose of levothyroxine during pregnancy. Women who are first diagnosed with overt hypothyroidism during pregnancy should be treated immediately, with quick acceleration to therapeutic levels. Although not well proven, doctors often recommend treating patients diagnosed with subclinical hypothyroidism while pregnant. There are no risks to the developing baby when the pregnant woman takes appropriate doses of thyroid hormones. The pregnant woman with hypothyroidism should be monitored regularly and doses adjusted as necessary. If postpartum thyroiditis develops after delivery, any thyroid medication should be reduced or temporarily stopped during this period.
Treatment of Hypothyroidism and Iodide Deficiency. People who are iodide deficient may be able to be treated for hypothyroidism simply by using iodized salt. In addition to iodized salt, seafood is a good source. Except for plants grown in iodine-rich soil, most other foods do not contain iodine. The current RDA for iodide is 150 micrograms for both men and women, with an upper limit of 1,100 micrograms to avoid thyroid injury.
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