High TSH levels can be caused by thyroid problems, such as hypothyroidism or Hashimoto’s thyroiditis, or may be a sign of a pituitary gland tumor in the brain.
In most cases, high TSH can lead to symptoms like tiredness, weight gain, constipation, feeling cold, hair loss, dry skin, and brittle hair and nails.
TSH (thyroid-stimulating hormone) is produced by the pituitary gland in the brain and stimulates the thyroid to release the hormones T3 and T4. High TSH levels should always be evaluated by an endocrinologist along with T3, T4, and other thyroid function tests.
Main symptoms
The most common symptoms of high TSH include:
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Fatigue or tiredness;
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Unexplained weight gain;
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Constipation;
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Dry skin;
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Hair loss;
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Weak or brittle nails;
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Numbness or tingling in the hands;
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Irregular or heavy menstrual periods.
Some people may also experience depression, low libido, a slower heart rate, or difficulty tolerating cold temperatures.
These symptoms are usually linked to hypothyroidism. However, when high TSH is caused by a pituitary tumor, it can sometimes lead to symptoms of hyperthyroidism instead.
What does high TSH mean
Having a high TSH level, or elevated ultrasensitive TSH, means the pituitary gland is producing more thyroid-stimulating hormone than normal.
This typically happens when thyroid hormone levels (T3 and T4) are low, causing the pituitary gland to increase TSH production in an attempt to stimulate the thyroid. It can also occur due to problems with the pituitary gland itself.
TSH blood test results should always be interpreted by a primary care provider or an endocrinologist along with other thyroid tests to identify the underlying cause and determine the best treatment.
Also recommended: Thyroid Tests: 9 Tests That Assess Thyroid Functioning tuasaude.com/en/thyroid-testsPossible causes
1. Hypothyroidism
Hypothyroidism is characterized by high TSH and low T3 and T4 levels, leading to symptoms such as tiredness, weakness, dry or rough skin, and weight gain.
In this case, high TSH occurs because the pituitary gland is trying to stimulate a thyroid that is underactive.
What to do: Treatment should be guided by a primary care provider or an endocrinologist and usually involves thyroid hormone replacement with levothyroxine, a medication that restores thyroid hormone levels.
2. Congenital hypothyroidism
Congenital hypothyroidism is a condition present at birth in which the thyroid gland cannot produce enough hormones, which can affect a baby’s growth and development.
It is typically diagnosed through newborn screening (heel prick test) that shows high TSH and low T3 and T4 levels.
What to do: Treatment involves the use of levothyroxine, prescribed by a pediatrician or pediatric endocrinologist to replace missing thyroid hormones and help normalize TSH levels.
3. Subclinical hypothyroidism
Subclinical hypothyroidism is defined by elevated TSH and normal T4 levels. People with this condition often have few or no symptoms.
What to do: An endocrinologist may recommend levothyroxine therapy, even if no symptoms are present, to help reduce the risk of cardiovascular problems and prevent progression to overt hypothyroidism.
4. Hashimoto’s thyroiditis
Hashimoto’s thyroiditis is a chronic autoimmune inflammation of the thyroid gland, marked by high ultrasensitive TSH and low T3 and T4 levels.
It occurs when the immune system produces antibodies that attack thyroid cells, damaging the gland and reducing hormone production.
What to do: Treatment is generally managed with levothyroxine to replace thyroid hormones. In severe cases, surgery may be needed to remove the thyroid gland.
5. Pituitary adenoma (TSH-secreting tumor)
A TSH-secreting pituitary adenoma, also known as a TSHoma, is a benign tumor of the pituitary gland that produces excess TSH.
This causes high TSH along with high T3 and T4 levels, leading to symptoms of hyperthyroidism such as heart palpitations, arrhythmias, or weight loss.
What to do: Treatment usually involves surgery to remove the tumor after controlling hyperthyroidism with medications such as methimazole. In some cases, radiation therapy may also be recommended.