What are the common causes of thyroid hormone imbalance?
Physicians classify thyroid hormone imbalance into two main thyroid disorders even though there are multiple causes to both of these disorders. The two main disorders that we will focus on are hypothyroidism and hyperthyroidism. Hypothyroidism is an underproduction of thyroid hormones while hyperthyroidism is an overproduction of thyroid hormones produced by the thyroid gland. Hypothyroidism is more common than hyperthyroidism and unfortunately there is no cure, but there is treatment available. The most common cause of hypothyroidism is Hashimoto's thyroiditis, which is an autoimmune disease, where the body attacks its own thyroid gland. The exact cause of this disease is unclear but it is found to be passed down from one generation to another. A person will have an increased risk of inheriting Hashimoto's if they have either another autoimmune disease such as T1DM (Type 1 Diabetes Mellitus), Lupus, RA (Rheumatoid Arthritis) or if they have a family member that develops Hashimoto's.
Iodine deficiency may cause hypothyroidism as well because iodine is an essential element used to synthesize thyroid hormones. The body does not produce iodine naturally therefore, we need to obtain iodine from dietary sources such as dairy products, shellfish, iodized salt, soy milk and seaweed. Overall when there is a iodine deficiency in the body then thyroid hormones such as T3 (triiodothyronine) and T4 (thyroxine) cannot be produced and a goiter, which is an enlarged thyroid gland, may develop instead. Pituitary gland damage may also contribute to hypothyroidism. The signal to produce thyroid hormones comes from the hypothalamus in the brain and travels to the pituitary gland, another gland found in the brain. If the pituitary gland is damaged, then the signal from the pituitary gland to the thyroid gland is blocked, and the thyroid gland may not receive the signal to produce or slow production of thyroid hormones. Other causes of hypothyroidism are being born with a damaged or even missing a thyroid gland. This includes having a part or even the whole thyroid gland surgically removed. Thyroid hormones cannot be produced if there is a dysfunctional thyroid gland and this dysfunctional thyroid may interfere with the body's daily functions.
The most common cause of hyperthyroidism is Grave's Disease, which is an autoimmune disease that causes an overproduction of thyroid hormones from the whole thyroid gland. In grave's disease the immune system produces antibodies that signal to the thyroid gland to grow and produce more thyroid hormones than the body requires. Another cause of hyperthyroidism is multi nodular goiter, which results in additional thyroid hormone-producing nodules to develop in the thyroid gland. These nodules release excess thyroid hormones causing an overproduction of thyroid hormones. It is unclear why these nodules form but if a physician suspects you have developed a nodule then he or she may recommend a biopsy to check it for cancer. The physician may also recommend to have it removed via either surgery or radioactive iodine. Radioactive iodine tablets are given to the patient for treatment of multi nodular goiter, where the iodine is absorbed by the thyroid cells, which destroys the cells and stops the production of thyroid hormone. Now because there are no longer thyroid hormones being produced this may lead the patient to develop hypothyroidism, where the patient will need to be treated with thyroid hormone replacement therapy indefinitely. Another cause of hyperthyroidism is iodine excess. High sources of iodine are found in iodine-rich medications such as amiodarone. For example, one 200 mg tablet of amiodarone contains 75 mg of iodine. This is much higher than the 150 micrograms daily intake of iodine recommended in adults.Therefore, patients taking amiodarone to treat an irregular heart beat are at high risk for iodine excess induced hyperthyroidism.
Why is maintaining your hormone balance important?
Many hormones circulate throughout the body, but it is the thyroid hormones produced from the thyroid gland that have the greatest impact. It is estimated that 13 million people in the United States have an undiagnosed thyroid condition that may or may not impact their daily activities. This is why it is important to diagnosis people with thyroid conditions s First, the thyroid gland takes in iodine found in our diet and combines it with tyrosine, which is an amino acid. Next, it is converted to T3 (Triiodothyronine) and T4 (Thyroxine). T3 contains 3 iodine atoms and is considered the active thyroid hormone and T4, which contains 4 iodine atoms is the inactive thyroid hormone. T3 is mainly produced from the conversion of T4 to T3 in a process called deiodination (removal of one iodine atom) and this process occurs primarily in the liver and kidneys. Many factors and drugs may block this conversion such as stress, starvation, beta-blockers, amiodarone, corticosteroids, iodinated contrast media and PTU (propylthiouracil). There are also environmental factors that may increase the conversion such as cold temperatures. Thyroid hormones are essential for our body because they play a major role in regulating the body's everyday functions. For example, they help regulate the body's metabolism, body temperature, women's menstrual cycles and help with brain development and even help maintain bone density.
How does the body regulate thyroid hormone balance?
There are two glands found in the brain, the hypothalamus and pituitary, which help the body maintain the proper balance between T4 and T3 thyroid hormone levels. First, the hypothalamus releases TRH (thyroid releasing hormone), which signals to the pituitary who increases or decreases its levels of TSH (thyroid stimulating hormone). The pituitary then communicates with the thyroid gland to produce more or less T4 or T3 thyroid hormones. This type of regulation is known as a negative feedback loop. Therefore, when T3 or T4 levels are low in the blood, the pituitary releases more TSH, which tells the thyroid to produce more thyroid hormones. Similarily, if T3 or T4 levels are too high in the blood then the pituitary will slow its release of TSH, which tells the thyroid gland to slow production of thyroid hormones. It is important to maintain the proper balance of T3 and T4 thyroid hormones in order for the body to perform everyday functions.
How do I know if I have thyroid hormone imbalance?
Thyroid hormone deficiencies are more prevalent among women than men. It is also more common for women to develop hypothyroidism slowly over time without displaying any obvious signs or symptoms. Even the most obvious symptoms of thyroid imbalance may present as a different condition. Therefore, it can be hard to differentiate the signs and symptoms between different conditions. For example, abnormalities with a woman's menstrual cycle may be seen as a sign of excess thyroid production, but it may also be a sign of thyroid hormone deficiency as well. Other signs to be aware of could be a sudden increase in sensitivity to the heat or cold, feeling tired more easily, and even developing muscle weakness. If you suspect any of the below warning signs or symptoms then you should contact your physician to be screened for a thyroid condition.
Warning signs & symptoms:
- Changes in weight
- Extreme fatigue
- Irregular menstrual cycle
- Memory decline
- Muscle weakness
- Changes in appetite
- Visual Disturbances
What happens after I am screened for a thyroid condition?
If your physician uses a thyroid function test (TFT) to observe your thyroid activity then he or she may suspect that you have a thyroid condition. These tests are used to help diagnose many diseases such as hypothyroidism, Hashimoto's disease, hyperthyroidism, Grave's disease, thyroid nodules, thyroid cancer and may even be used to monitor the effectiveness of hyperthyroidism treatment. Screening all patients using TFTs presenting with abnormal TSH and free T4 levels may be expensive therefore, physicians utilize different strategies to limit any unnecessary laboratory testing. If a patient's TSH levels are normal then no testing is required. If a patient's TSH levels are normal but presents with symptoms of thyroid dysfunction then the FT4 levels will be checked. If the TSH levels are high then FT4 levels will need to be checked to determine or rule out hypothyroidism. Likewise if TSH levels are too low then the physician will likely check FT4 and T3 levels to determine or rule out hyperthyroidism. The last strategy is utilized if pituitary or hypothalamic disease is suspected then the physician will likely check both TSH levels and FT4.
Can I diagnosis my own thyroid condition?
No, the only way to be properly diagnosed with a thyroid condition is through a blood test given by a physician. The physician may also give a physical exam or use an imaging scan to assist with diagnosing the thyroid condition. The blood test will measure TSH, total T4 (unbound T4 plus bound), FT4 (free, unbound T4), total T3 (unbound T3 plus bound), and FT3 (free, unbound T3). The total T3 test is usually ordered if there are abnormal TSH levels presented in the labs and if the FT4 test is not elevated. High TSH levels typically indicates hypothyroidism indicating poor thyroid gland function. Similarily low TSH levels may indicate an overproduction of thyroid hormone, or hyperthyroidism. A normal range of TSH levels would be 0.4-5.0mlU/L. High serum levels of total T4 may also indicate hyperthyroidism, while low serum levels of total T4 may indicate hypothyroidism. The normal range of serum total T4 is 4.6-11.2 mcg/dL. However, if a patient is pregnant or taking oral contraceptives then the levels of total T4 may appear to be higher which may not indicate a thyroid condition. Similarily, if a patient is taking corticosteroids, using medicines to treat asthma, arthritis or is considered critically ill then these factors may lower total T4 levels.
Free or total T3 may also be ordered along with thyroid antibodies to help confirm the diagnosis of Grave's disease. The physician may also order FT3 values in intervals to monitor a thyroid condition and assess the effectiveness of a thyroid treatment. Generally, high levels of total or free T3 lab values may help confirm a diagnosis of hyperthyroidism and low total or free T3 lab values may help confirm a diagnosis of hypothyroidism. A typical normal range of total T3 is 75-195 ng/dL. Physician's may also use the lab values to assess for the effectiveness of a thyroid disorder treatment as well. For example, patients with hyperthyroidism will have their FT4, FT3 and TSH levels checked regularly especially if they are on any anti-thyroid drugs that may decrease the efficacy of their treatment. On the other hand, patients with hypothyroidism will have their TSH and FT4 levels checked regularly to ensure the right dose of thyroid treatment is given and to help the patient return to euthyroid (normal functioning thyroid).
What is Hypothyroidism?
Hypothyroidism is a treatable condition where there is an underproduction of thyroid hormones T3 and T4 produced from the thyroid gland. The most common cause of hypothyroidism is Hashimoto's thyroiditis, which is an autoimmune disease. In a normal thyroid gland production of these two hormones help regulate the body's metabolism, body temperature, and are essential in helping the brain, liver and other vital organs function properly. However, if there is little to no hormone being produced then these hormone imbalances can lead to serious conditions such as myxedema coma (extremely low thyroid levels). Therefore, it is necessary that we replenish these levels with synthetic, natural, or combined T3/T4 combinations in order to correct these hormone imbalances and prevent other serious health conditions.
Signs and Symptoms of Thyroid Deficiency:
- Fatigue/exercise intolerance
- Sensitivity to Cold
- Dry Skin
- Aching Muscles
- Irregular Menstrual Cycles
- Decreased Libido
- Slow Metabolism
- Weight Gain with Decreased Appetite
- Fluid Retention
- Swollen Neck
- Slowed Speech
- Hoarse Voice
- Thinning Hair
- High Cholesterol and Triglyceride levels
- Low Blood Sugar
- Memory impairment
What is Hyperthyroidism?
Hyperthyroidism occurs when the thyroid gland is producing too much thyroid hormones T3 and T4. If left untreated an overproduction of thyroid hormones can lead to thyrotoxicosis and even life-threatening conditions such as thyroid storm (excessive thyroid hormone concentration). Signs and symptoms of thryotoxicosis may include anxiety, fatigue, excessive sweating, heat intolerance, tremors, palpitations, increased heart rate, weight loss, warm and moist skin. The most common cause of hyperthyroidism is Grave's disease, which is an autoimmune disease where your thyroid produces more thyroid hormones than your body requires.
Signs and Symptoms of Excess Thyroid Hormone:
- Weight loss with Increased Appetite
- Increased bowel movements
- Heat Intolerance
- Hair Loss
- Missed or Light Menstrual Cycles
- Swollen Neck
- Heart Palpitations
Thyroid Replacement Hormone Treatment:
There are a variety of commercially available thyroid replacement hormones used in the treatment of hypothyroidism. Commercially available thyroid medications include both synthetic and natural thyroid replacement hormones. Synthetic T4 is Levothyroxine (Synthroid, Levoxyl) while natural thyroid includes desiccated thyroid or thyroid extract (Armour thyroid, Nature-Throid), which is derived from pork. Synthetic T3 Liothyronine (Cytomel) may also be used in the treatment of hypothyroidism, but the mainstay treatment in hypothyroidism is synthetic T4 Levothyroxine. Treating patients with hypothyroidism using commercially available thyroid medications may not correct some patient's hormone imbalances. Some patients may require a specific strength that is commercially unavailable, or they may require a specific T4:T3 ratio in their compounded thyroid medication.
Possible side effects:
- Weight gain or loss
- Vomiting and/or diarrhea
- Appetite changes
- Menstrual cycle changes
- Sensitivity to heat
- Hair loss
- Leg cramps
- Joint and/or muscle pain
Folsom Medical Pharmacy can create different strengths of human identical thyroid compounded hormone T4, T3 and combined T4:T3 that is specialized to fit the individual needs of every patient.
Advantages of Compounded Thyroid Medications:
- Specific strengths that may not be commercially available
- Eliminate inactive ingredients that may cause adverse reactions
- Compounded thyroid medications with specific amounts of T4 and T3
- Pure human identical T4 or T3
Abdalla, S, Bianco, A. Defending Plasma T3 is a Biological Priority. Clinical Endocrinology. 2014;81(5): 633-641.
Graves Disease. NIH U.S. National Library of Medicine. https://www.ghr.nlm.nih.gov/condition/graves-disease#genes. Published April 28, 2020. Accessed May 12th, 2020.
Hashimoto Thyroiditis. NIH U.S. National Library of Medicine. http://www.ghr.nlm.nih.gov/condition/hashimoto-thyroiditis#inheritance. Published April 28th, 2020. Accessed May 12th, 2020.
Leung A, Braverman L. Consequences of Excess Iodine. Nature Reviews Endocrinology. 2013;10(3):136-142.
Leung, A.Thyroid Emergencies. Journal of Infusion Nursing. 2016;39(5):281-286.
Nature-Throid (thyroid)- Full Prescribing Information. Prescriber's Digital Reference. http://www.pdr.net/full-prescribing-information/Nature-Throid-thyroid-496. Published 2020. Accessed May 8th, 2020.
NIH U.S. National Library of Medicine. Levothyroxine. MedlinePlus. http://www.medlineplus.gov/druginfo/meds/a682461.html. Published 2019. Accessed May 7th, 2020.
T3 (Free and Total). AACC Lab Tests Online. http://www.labtestsonline.org/tests/T3-free-and-total. Published 2001. Accessed May 8th, 2020.