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It is not clear if the benefits of treating subclinical hypothyroidism outweigh the risks and potential complications. Doctors who recommend against 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:
- High total or LDL cholesterol levels
- Blood tests that show autoantibodies indicating a future risk for Hashimoto's thyroiditis or other forms of other autoimmune hypothyroidism
- Blood tests that show TSH levels greater than 10 mU/L
- Goiter
- Pregnancy
- Female infertility associated with subclinical hypothyroidism
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. However, the cholesterol-lowering benefits of suppressive therapy may outweigh this 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.
Treatment of Special Cases
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Review Date: 05/03/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School; Physician, Massachusetts General Hospital.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
