What Do Dangerously High TSH Levels Indicate?

Very high levels of Thyroid Stimulating Hormone indicate an underactive thyroid gland, or hypothyroidism, according to EndocrineWeb. High levels of TSH, which is diagnosed by blood tests, mean that the body is attempting to coax the thyroid gland into producing more of the thyroid hormone.

Older women are especially prone to hypothyroidism, which disturbs the normal balance of chemical reactions in the body, states Mayo Clinic. The most common causes of hypothyroidism and its associated slower metabolism are inflammation of the thyroid gland or surgical removal of part or all of the gland during treatment for other diseases such as cancer.

Symptoms of hypothyroidism include fatigue, weakness, weight gain or difficulty losing weight, dry hair, rough skin, hair loss, sensitivity to cold, muscle cramps, constipation, depression, irritability, memory loss, irregular menstrual periods and low libido, according to Mayo Clinic. Sustained high levels of TSH can result in the formation of a goiter, or enlarged thyroid gland. Untreated hypothyroidism can lead to obesity, joint pain, infertility and heart disease.

Hypothyroidism can be managed with a daily dose of thyroid pills, and the dosage must be tailored to the individual patient. If the dosage is too low, symptoms may continue while too much thyroid hormone can increase the risk of osteoporosis or heart attack, according to Mayo Clinic.