Removal of all or part of the thyroid gland is called thyroidectomy. Thyroid cancer generally necessitates the removal of the entire thyroid gland. Getting enough calcium is of special concern for those who have had thyroid removal surgery. Anyone taking thyroid replacement hormone must follow specific instructions for calcium supplementation. In addition, the thyroid surgery itself may cause a temporary problem with calcium levels.
Calcium and Thyroid Medication
After your thyroid is removed, your body can no longer manufacture thyroid hormones, and you must take daily hormone replacement medication for the rest of your life. Levothyroxine, also called T4 or thyroid hormone and sold under brand names such as Synthroid, is commonly prescribed for patients with reduced or no natural thyroid function. Certain supplements, including calcium, may cause your body to absorb less of this medication. Patients should take calcium supplements either four hours before or four hours after taking levothyroxine.
Thyroid Medication and Calcium Depletion
A patient who has had her thyroid removed because of cancer is typically given thyroid hormone at a high enough level to suppress her TSH, or thyroid stimulating hormone, levels. Doctors do this to reduce the risk of growth or recurrence of thyroid cancer cells. Whether or not suppressive levels of thyroid hormone can contribute to calcium depletion and lead to osteoporosis remains controversial. A 1994 study reported in "Journal of Clinical Endocrinology and Metabolism" found that as long as patients are carefully monitored, their bone mass is not significantly affected by suppressive levels of thyroid medication. However, a study from May 2000 as reported in "European Journal of Endocrinology" found that long-term treatment with levothyroxine was associated with a slightly increased risk of osteoporosis-related bone fracture. If you must take suppressive doses of thyroid hormone as follow-up treatment for thyroid cancer, speak to your doctor about your calcium needs.
Hypocalcemia Symptoms
Following thyroid removal surgery, a small percentage of patients display signs of hypocalcemia, or an abnormally low blood calcium level, because the parathyroid glands are not functioning properly. This is usually temporary, and may occur around 24 to 48 hours after surgery. Symptoms include numbness or tingling in the hands and feet and around the lips. Patients may also complain of muscle cramps, headache or a crawling sensation in the skin.
Hypocalcemia Treatment
If you have hypocalcemia, your doctor will probably recommend that you take a calcium supplement whenever you have symptoms, which should go away within 20 to 30 minutes of taking calcium. Any problems with hypocalcemia should disappear within seven to 10 days after your thyroid removal surgery, according to the Columbia University Department of Surgery. If you continue to have problems, speak to your physician.
References
- Drugs.com: Synthroid
- Thyroid Cancer Survivors' Association: Thyroid Stimulating Hormone (TSH) Suppression
- "Journal of Clinical Endocrinology and Metabolism"; Carefully Monitored Levothyroxine Suppressive Therapy Is Not Associated with Bone Loss in Premenopausal Women; C. Marcocci et al.; April, 1994
- "European Journal of Endocrinology"; The Effect of Long-term, Non-suppressive Levothyroxine Treatment on Quantitative Ultrasonometry of Bone in Women; P. Hadji et. al., May, 2000
- Columbia University Department of Surgery: New York Thyroid Center - Hypocalcemia
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