TSH, the hormone released by the pituitary gland encourages the thyroid to release the hormones T3 and T4. A rise in the levels of TSH in the body indicates an underactive thyroid. Read on to know the effects of thyroid dysfunction and abnormally high TSH levels.
TSH or the thyroid stimulating hormone released by the pituitary gland plays a pivotal role in regulating the functions of the thyroid gland. TSH enables the thyroid to secrete the hormones thyroxine (T4) and triiodothyronine (T3). These hormones play an important role in generation of heat and energy. They help maintain normal body temperature and heart rate. They are essential for proper cell growth and metabolism of protein, fat, carbohydrate, and vitamins. If thyroid is not capable of producing sufficient T3 and T4, then pituitary gland releases more TSH to stimulate the thyroid. Therefore, high TSH levels in blood indicate an underactive thyroid.
Effects of Increased TSH Levels
on Thyroid
Normal TSH level ranges between 0.3 to 3.0 μIU/mL. When the levels of thyroid hormones drop, pituitary gland releases more TSH to stimulate the thyroid. Thus, high TSH levels are observed in individuals diagnosed with hypothyroidism. Although an increase in the level of TSH is necessary for proper functioning of the underactive thyroid, abnormally high TSH levels can induce hyperthyroidism. A TSH-producing pituitary adenoma (non-cancerous tumor) can lead to abnormally high TSH levels and hyperthyroidism.
on Bones
Abnormally high TSH levels can damage the bones. The levels of calcium in bones may decrease and the person may suffer from osteoporosis (low bone density resulting in brittle bones) and its consequences like frequent fractures.
on Heart
High blood TSH levels over an extended period can affect heart health adversely. The situation may lead to congestive heart failure. Correct diagnosis, prompt medication and proper treatment is essential to restore the balance of the hormones. A delay in treatment can prove to be fatal.
Underactive Thyroid and High TSH Levels
Symptoms of an underactive thyroid include
- Excessive tiredness, fatigue
- Memory problems, confusion
- Depression
- Excessive loss of hair
- Brittle nails
- Increased somnolence
- Constipation
- Cold intolerance
- Frequent attacks of cold
- Low sex drive
- Muscle pain, cramps
- Slurred speech
- Weight gain or difficulty losing weight
- Swollen hands, face and feet
- Dry skin
- Abnormal menstrual cycles
- Thickening of the skin
- Inability to recognize the taste of food
- Inability to recognize familiar smells
- Low metabolic rate
- Loss of appetite
- A severest form of hypothyroidism may lead to myxedema coma. The normal function of the brain is impaired and completely lost. Though rare in nature, myxedema coma can be life-threatening or even fatal.
Hyperactive Thyroid and Abnormally High TSH Levels
- Weight loss
- Fatigue
- Rapid heartbeat, palpitations
- Hot flashes
- Difficulty sleeping
- Nervousness
- Tremor of the hands
- Diarrhea
- Less menstrual flow or absence of menstrual periods
Symptoms of Pituitary Tumor
- Vision problems or sudden loss of vision
- Constant headache
- Lightheadedness
Other Causes of High TSH Levels
The presence of an autoimmune disease called Hashimoto’s disease is characterized by hypothyroidism and high TSH levels. Also referred to as autoimmune thyroiditis, this condition arises when the immune system itself attacks the thyroid gland, thinking of it as a foreign body. This can cause serious damage to the gland.
As the hypothalamus releases the hormone ‘thyrotropin’ and regulates the function of the pituitary gland, it also determines the production of TSH. Another hormone ‘somatostatin’, released by the hypothalamus, restricts the production of ‘thyrotropin’. So, dysfunction of the pituitary gland or imbalance of the hormones secreted by the pituitary gland can also affect blood TSH levels significantly. As an effect of radiation therapy, high TSH levels in spite of normal functioning of the thyroid are seen in some cancer patients.
The level of TSH in the body can be determined with the help of a simple blood test called TSH test. Hypothyroidism treatment involves daily use of the synthetic thyroid hormone levothyroxine (Levothroid, Synthroid, etc.). It is essential to consult a health care provider or an endocrinologist regarding the dosage and duration of the drug. The treatment may vary according to the underlying cause and nature of the effects of high TSH levels. The physician may prescribe drugs to alleviate the symptoms of pituitary tumor. Thyroidectomy (surgical removal of a part or the complete thyroid gland) is usually done as a last resort when the person does not find relief, despite prescription drugs and herbal remedies.
Disclaimer: This article is for informative purposes only, and should not be used as a replacement for expert medical advice.
