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The thyroid is a small butterfly-shaped gland that lies at the bottom of your neck, normally just below Adam’s apple.
It makes a hormone that your whole body uses, and this hormone is particularly important in the regulation of the body’s energy and metabolism.
Goiter is an enlarged thyroid gland. Having goiter can mean a number of things.
In goiter, the gland can be functioning normally, underactive (a condition known as hypothyroidism), or overactive (a condition known as hyperthyroidism).
The gland can be generally enlarged throughout, as depicted in the image below, or it can enlarge due to one or more nodules within the gland.
The elevated levels of thyroid hormones can affect the entire body and can result in dizziness, fluctuations in weight, feeling hot, increased blood pressure, increased heart rate, and fatigue.
The thyroid uses the iodine in our body to make two main hormones, T3 and T4. It primarily makes T4 and our body converts T4 to T3.
This process is controlled by another hormone called thyroid-stimulating hormone (TSH), which is made by the pituitary gland in the brain.
Timely diagnosis of an overactive thyroid is imperative to stabilize the condition and prevent future complications.
What Is Hyperthyroidism?
Hyperthyroidism occurs whenever there is an excessive amount of thyroid hormone in the bloodstream.
There are various causes of hyperthyroidism. Because the whole body uses the thyroid hormone, a broad variety of signs and symptoms appear in the body.
Hyperthyroidism occurs in about 1.3% of the US population and is more likely to occur in women, especially those over 60 years old.
Other risk factors for hyperthyroidism include a family medical history of thyroid disease, a personal or family medical history of any autoimmune disease, smoking, and increased iodine exposure.
Causes of Hyperthyroidism
Common causes of hyperthyroidism include:
- Graves’ disease: Graves’ disease is the most common cause of hyperthyroidism.
It is an autoimmune disease where the immune system sees part of the thyroid as a foreign body, like a bacteria or virus, and makes an antibody to combat it.
In Graves’ disease, the antibody is made against the TSH receptor. These antibodies drive the thyroid gland to overproduce thyroid hormone, and the brain has no control.
Grave’s disease normally affects women between the ages of 20 and 40 years.
- A toxic nodule or toxic multinodular goiter is another cause of hyperthyroidism due to inappropriate thyroid hormone secretion.
In this case, one or more thyroid nodules start to produce the thyroid hormone autonomously, while the remainder of the thyroid gland appropriately stops making the thyroid hormone in response.
As women age, they are more likely to suffer from a toxic nodule or toxic multinodular goiter.
- Often, hyperthyroidism occurs when the thyroid gland becomes inflamed and the stored thyroid hormone is released all at once.
This condition is called thyroiditis. Thyroiditis is a transient condition that resolves on its own or can lead to hypothyroidism.
- Other causes of hyperthyroidism include excessive intake of thyroid hormone, excessive intake/exposure to iodine, abnormal secretion of TSH, or rarely tumors in the testes or ovaries.
Signs and Symptoms of Hyperthyroidism
Because thyroid hormone is used by the entire body, there are potentially a broad variety of symptoms and signs that may occur.
It is also important to remember that in the very early stages of hyperthyroidism, often called subclinical hyperthyroidism, a person may not have any noticeable symptoms at all or they may be very subtle and nonspecific.
Younger people tend to ignore the early symptoms, such as nervousness, shaking, rapid heartbeats and heat intolerance, often attributing them to stress.
Older people tend to have different symptoms like problems sleeping, unintentional weight loss, and/or with a rapid, irregular heart rhythm called atrial fibrillation.
Hyperthyroidism can be indicated by various signs such as:
- Fatigue or muscle weakness
- Sleep troubles
- Irregular heartbeat (arrhythmia)
- Rapid heartbeat (palpitations)
- Unintentional weight loss
- Nervousness or irritability
- Diarrhea or more frequent loose stools
- Increased sensitivity to heat
- Mood swings
- Hand tremors
- Profuse sweating
- Experiencing a twitch in the face and limbs
- Fragile nails that may get loosened
- Red palms
- Protruding eyes in some cases
- Changes in the menstrual cycle or irregular menstruation
- Fine, brittle hair and hair loss
- Skin thinning
- Goiter, which involves an enlarged thyroid gland that gives a swollen appearance to the neck
How Is Hyperthyroidism Diagnosed?
If there is any suspicion of a potential thyroid problem, it is important to see your doctor or healthcare professional as soon as possible.
After a thorough history and physical exam, blood tests will be done to check your TSH, T3, and T4 levels.
Hyperthyroidism is indicated by:
- Higher than normal levels of T3 and T4
- Lower than normal level of TSH
Sometimes, depending on the clinician’s level of suspicion, a thyroid antibody test is also done with the initial screening tests.
A low or suppressed TSH with upper-normal to elevated T3 and T4 hormone levels is indicative of a hyperthyroid state.
At times, the thyroid laboratory results are abnormal but do not follow this typical pattern. At this point, further testing or referral to a thyroid specialist (endocrinologist) may be ordered.
Occasionally, other laboratory tests are needed, especially if thyroiditis or one of the rarer causes of hyperthyroidism is suspected.
- A thyroid ultrasound is a noninvasive test that uses sound waves to tell the doctor what the thyroid gland looks like and what size it is.
- A thyroid scan and uptake is a type of nuclear test that utilizes radioactive iodine. This test will tell the doctor what part of the thyroid gland is making the thyroid hormone and how hard it is functioning.
It is up to the doctor or specialist to put all of the pieces of the puzzle together to figure out the correct diagnosis.
How Is Hyperthyroidism Treated?
The best treatment option for hyperthyroidism will depend on the cause and severity of the hyperthyroid state.
Consideration must also be given to the patients’ age and the other health conditions present.
The three main treatments are radioactive iodine, antithyroid medications, and surgery.
The standard treatment methods are as follows.
a. Radioactive Iodine
Radioactive iodine is actually the most commonly used hyperthyroid treatment in the United States.
Radioactive iodine is used to curb the excessive production of hormones through the destruction of the thyroid gland.
Because the thyroid gland is the only organ in the body to use iodine to make a hormone, iodine is used as a vehicle to deliver a special form of radiation exclusively to the overactive portion of the thyroid gland.
This treatment does not require hospitalization and it is normally given in pill form. It will only destroy what holds onto it. Therefore, the adjacent healthy tissues are not affected.
It may take up to 6 months to see the full effect of the treatment. This will result in hypothyroidism in most cases, requiring thyroid hormone supplementation. Rarely, a second treatment dose may be needed.
Besides hypothyroidism, other side effects of radioactive iodine treatment include nausea, a metal taste in the mouth, and swollen salivary glands.
Precautions can be taken to help prevent some of these, and other precautions need to be followed for the first week after treatment.
Radioactive iodine treatment is not recommended if you are pregnant or breastfeeding. It is also advised not to become pregnant for at least 6 months after treatment.
One reason not to have radioactive iodine therapy is when you have Graves’ disease as it may worsen the bulging of the eyes (orbitopathy).
Two oral medications for hyperthyroidism are available, namely, methimazole and propylthiouracil (PTU). These medications interfere with how the thyroid makes the thyroid hormone.
Oral medications can be used to treat hyperthyroidism but do not normally offer a permanent cure.
Some patients with Graves’ disease will go into remission after taking the medications for up to 18 months. However, there is no certainty on how long the remission will last.
The most common side effects of antithyroid medications are hives, itching, and rashes.
Rarely, these medications can affect your bone marrow and its ability to produce white blood cells, rendering you prone to infections.
Liver function also needs to be monitored through tests when using these medications.
Methimazole is generally used more often than PTU because it is thought to have less side effects. However, it cannot be used during pregnancy.
If antithyroid medications are needed in the first trimester of pregnancy, PTU is recommended. (1)
Sometimes, your doctor will give a beta-blocker to help treat the symptoms of hyperthyroidism. This is not an antithyroid medication but is frequently given with methimazole and PTU.
Beta-blockers slow down the heart rate, lower the blood pressure, and reduce the shaking of the hands (tremors) that are so common with hyperthyroidism.
Surgical removal of the thyroid gland (thyroidectomy) is sometimes recommended.
Occasionally, just the overactive/hyperfunctioning nodule or one lobe of the thyroid is removed. In other cases, a subtotal or total thyroidectomy is performed.
Depending on the extent of the surgery, permanent hypothyroidism may result, requiring lifelong thyroid hormone supplementation.
Other potential side effects include damage to the nerves that go to the voice box leading to hoarseness or loss of voice, surgical scarring on the outside of the neck, and damage to the parathyroid glands which can result in problems with low calcium levels.
If you undergo surgery and radioactive iodine treatment, you will have to rely on medications for the rest of your life to maintain the levels of the thyroid hormones.
Lifestyle Changes That May Help
Introducing changes in your diet may help enhance the efficacy of your medications and support the health of your thyroid.
a. Keep a Check on Your Iodine Intake
The primary step is to become aware of the iodine content of your diet or supplements.
Excessive intake of iodine is often associated with an increased risk of thyroid problems, but this does not mean you need to give up iodine completely as iodine serves an important purpose in the overall functioning of your body.
If you have already been diagnosed with hyperthyroidism, it is recommended that you keep a close tab on the amount of iodine you consume on a daily basis and do not add iodine to your diet or take it in supplement form.
You should neither over-indulge nor starve yourself of iodine-rich foods but adjust your intake to meet the daily requirement without surpassing the upper limit of the stipulated dietary allowance. (2)(4)
For severe, life-threatening hyperthyroidism, your doctor may prescribe high doses of iodine that will therapeutically slow your thyroid down and will prepare you for surgery.
There is never an instance when you should take iodine on your own if you have hyperthyroidism as it will make you sicker.
b. Dietary Changes
Patients with hyperthyroidism have been shown to have increased markers of oxidative stress, and many have lost significant weight.
There are no studies to suggest that any specific type of diet is best for people with hyperthyroidism. However, it is a good time to become aware of how you can support your body with a diet high in antioxidants.
It is important to balance your macronutrients and pay attention to what you are eating in general as weight fluctuations are common during the diagnosis and treatment of an overactive thyroid.
In particular, more protein may be necessary if there has been a lot of weight loss and muscle wasting, an unfortunate consequences of hyperthyroidism. Consultation with a registered dietician may be beneficial.
To that end, you must consult your health care provider and nutritionist to discuss a suitable diet plan.
Inform them about any extra-dietary sources of iodine such as iodine supplements, cough medicines, or multivitamins that you may be taking.
Taking all the relevant factors into account, these experts will determine which foods need to be limited or avoided completely.
c. Consider Nutritional Supplements
As stated earlier, it is important to balance your iodine intake. Too little or too much iodine intake can affect your thyroid function. Iodine is not the only thing that will affect your thyroid, though.
Address your nutritional deficiencies by taking doctor-approved supplements. These include:
- Selenium may help balance thyroid function. A study showed that taking a selenium supplement along with medical therapy for Graves’ disease for 6 months had a positive effect on response to the medication. (7)(8)
- Calcium and vitamin D levels need to be optimized due to the detrimental effects of hyperthyroidism on the bones. Optimal replacement is necessary if deficiency is found. (3)
Ask your doctor if you should take a multivitamin/mineral supplement and additional B vitamins.
- Soy can interfere with the absorption of thyroid hormone. Inconsistencies in absorption can lead to confusion in the interpretation of lab results and inappropriate adjustment of medications.
It is important to keep soy-containing foods and supplements a few hours away from thyroid hormone supplementation.
The likelihood of developing hyperthyroidism is more in women than in men. Women are eight times more susceptible to developing hyperthyroidism than men.
While the problem may develop in women in their early 30s, it is more likely to affect women over 60.
According to the American Thyroid Association, adults, particularly women, starting from the age of 35, should get a blood test every 5 years to review any occurrence of thyroid problems.
The factors that can make you more prone to developing an overactive thyroid are:
Other factors that can make you prone to developing an overactive thyroid include a personal or family medical history of a thyroid disorder or goiter and any autoimmune disease such as pernicious anemia, type 1 diabetes mellitus, rheumatoid arthritis, lupus, and primary adrenal insufficiency.
Some women develop thyroid disease during or after pregnancy.
Taking certain heart medications that contain iodine also increases your risk of developing a thyroid illness.
What Are the Complications of Untreated Hyperthyroidism?
Unaddressed hyperthyroidism can have severe complications that can have severe consequences on your overall health:
- Despite having high levels of hormones in your bloodstream when you are hyperthyroid, taking medications for your hyperthyroidism can lower your thyroid hormone levels, and if not monitored, these levels can become too low.
Irregularly monitored hormone levels can reflect symptoms of an underactive thyroid such as fatigue, increased cholesterol levels, mild weight gain, depression, and slowing of mental and physical activities.
- In some cases of Graves’ disease, a simultaneous condition in the eye called Graves’ ophthalmopathy can develop.
This is marked by bulging of the eyes, pain in the eye, sensitivity to light, and vision problems such as double vision.
Although very rare, Graves’ ophthalmopathy may also lead to loss of eyesight.
- Uncontrolled hyperthyroidism in a pregnant woman can affect the health of both the mother and the baby.
Hence, it is advised to keep track of your thyroid hormone levels before you intend to get pregnant.
- It will affect the heart, leading to a rapid irregular heart rhythm called atrial fibrillation, which can lead to stroke. It can also cause hypertension and congestive heart failure.
- It will affect the bones and cause osteoporosis, increasing the risk of fracture.
- It will cause muscle wasting and can lead to difficulty walking.
- When untreated and then faced with another stress or injury, thyroid storm may develop. This is an extremely rare but potentially fatal condition.
Does Hyperthyroidism Necessarily Lead to Weight Loss?
Individuals with hyperthyroidism tend to have a higher basal metabolic rate, which may lead to increased burning of calories.
A rapid calorie loss may promote unintentional weight loss, a typical symptom of hyperthyroidism.
Contrary to this, some patients with hyperthyroidism may gain weight rather than lose it.
This may happen by the interplay of several other factors such as fitness, eating habits, insulin sensitivity, and genetics.
A proper medical review is necessary to help ascertain the primary reason behind the associated weight gain.
When to See a Doctor
Because the symptoms of hyperthyroidism are nonspecific, diagnosing it can be a daunting task.
Make a note of your symptoms and consult your primary care physician or endocrinologist if you experience dizziness, rapid irregular heartbeat, and elevated systolic blood pressure.
An undiagnosed case of hyperthyroidism can result in fatal and life-threatening consequences.
Here are some questions your doctor may ask you.
- What medications, including supplements, are you taking?
- What are your symptoms?
- Does the problem run in your family?
- Tell me about your daily schedule?
- Have you experienced a sudden weight gain?
Here are some things you may want to ask your doctor?
- What treatment option do you feel is best for me & why?
- Will my condition improve with medication?
- Do I need a surgery?
- Are these medications safe to take with my ongoing medications?
- What lifestyle changes do you suggest?
- Are there any possible side effects that I will experience during the treatment?
- Will it create a complication in my pregnancy?
Follow-Up Post Diagnosis
Once you have been diagnosed with hyperthyroidism, your doctor is likely to recommend a treatment method suitable for your condition.
To help you keep track of your health, doctors recommend that you must:
- Follow up with your doctor as recommended to assure you are responding to therapy; you may require dosage adjustment, alternative therapies, or evaluations.
- Monitor your thyroid hormone levels by getting a blood test done every 2-6 months after you start taking the prescribed medications or undergoing therapies.
- If the treatment adopted was radioactive surgery, make sure to get a blood test more frequently or as recommended by your doctor.
- A hyperactive thyroid makes sure you do not gain weight despite increased food intake. However, once you have started taking medications and your thyroid function is restored to normal, keep a close watch on your weight.
The Bottom Line
Hyperthyroidism can adversely affect your entire body.
If you have any symptoms to suggest an overactive thyroid, make an appointment with your doctor or healthcare professional. Be sure to take all of your supplements with you to your visit.
Write out any questions you have ahead of time so you are sure they will be addressed.
The decision making involved in hyperthyroidism is complicated, and the individual with hyperthyroidism is emotionally labile due to the elevated hormones.
Hence, it is a good idea to bring a trusted family member or friend along to help make sure you have gathered all the information correctly.
Remember that more than one treatment can be used to manage the condition and often antithyroid medications are required when someone is extremely hyperthyroid to start.
Complementary therapies such as meditation and yoga may also be beneficial.
Aside from the standard medications used to treat an overactive thyroid, introduce dietary changes and yoga in your routine to help your body stabilize the levels of thyroid hormones.
Expert Answers (Q&A)
Answered by Dr. Tharsan Sivakumar, MD (Endocrinology)
Hyperthyroidism is a treatable condition. Common symptoms of hyperthyroidism include:
• Weight loss
• Irritability and/or anxiety
• Diarrhea or frequent bowel movements
• Heat intolerance (feeling hot all the time)
• Heart palpitations
• Eye irritation or eye bulging
If you are experiencing these symptoms, it is important to see your healthcare provider. Blood tests may be conducted to evaluate for thyroid dysfunction. It is important to note, however, that these are nonspecific symptoms.
Thus, having one or more of these symptoms does not necessarily mean you have hyperthyroidism. A blood test and sometimes a thyroid uptake and scan can help confirm if you indeed have hyperthyroidism.
Hyperthyroidism is a disorder that can be treated. However, left untreated, it can lead to a number of long-term consequences, including osteoporosis (weak/brittle bones), heart arrhythmias (irregular heart rhythms), weight loss, and eye problems (bulging or irritated eyes). It can also lead to a thyroid storm, which can be fatal.
Thyroid cancer has been linked to hyperthyroidism in a few cases. (9) The good news is that most people who have hyperthyroidism do not have thyroid cancer.
Most people with thyroid cancer do not have any symptoms. For this reason, it is important to check with your healthcare providers to determine if screening is warranted depending on your risk factors, such as a family history of thyroid cancer or neck radiation exposure during your childhood.
The various causes of hyperthyroidism have not been fully decoded as of yet. It is well understood that genetic factors can predispose an individual to develop hyperthyroidism, but the exact triggers are yet unknown.
Extreme amounts of stress can precipitate thyroid dysfunction, but stress is not believed to be a common cause of hyperthyroidism.
Women are more predisposed to hyperthyroidism than men. Specifically, women are more likely to develop Graves’ disease, which is the most common type of hyperthyroidism.
Hyperthyroidism typically causes weight loss. Hypothyroidism typically causes weight gain.
In women, hyperthyroidism can cause lighter periods and/or menstrual irregularity, which can reduce fertility.
In men, hyperthyroidism can reduce sperm count, which can reduce fertility. Thus, if an individual has hyperthyroidism, it is important to treat the condition and normalize the thyroid hormone levels before trying to conceive.
No specific dietary changes will help in the management and prevention of hyperthyroidism, except a general recommendation to avoid food that has a very high content of iodine such as kelp (seaweed).
Some healthcare providers believe that reducing or eliminating foods that are immunogenic (allergenic), such as gluten-containing or lactose-containing products, may help. However, there is not enough scientific evidence at this point to make such a general recommendation.
About Dr. Tharsan Sivakumar, MD, FRCPC: Dr. Sivakumar is the Director of the Institute of Diabetes & Endocrinology and the President-Elect of the American Association of Clinical Endocrinologists (AACE), Canadian Chapter.
He is board certified by the American Board of Internal Medicine in Endocrinology, Diabetes, & Metabolism, as well as Internal Medicine. He is also a diplomate of the American Board of Clinical Lipidology.
In addition, he is certified by the Royal College of Physicians and Surgeons of Canada in Internal Medicine as well as Endocrinology and Metabolism.
His areas of clinical and research interest include diabetes, lipidology, and general endocrinology. He has a number of publications in prominent peer-reviewed medical journals.