Hyperthyroidism

What is Hyperthyroidism?

Hyperthyroidism is a common condition that involves the overproduction of thyroid hormones. A lot of people mistakenly think it’s the same thing as thyrotoxicosis. While they’re related, they’re not exactly the same. Thyrotoxicosis is a state where there’s too much thyroid hormone getting into different parts of your body.

While hyperthyroidism can lead to thyrotoxicosis, they are technically different things. This article will provide simple explanations of both hyperthyroidism and thyrotoxicosis. Hyperthyroidism can be caused by different things, show different symptoms, and can be treated in various ways.

There are two types of hyperthyroidism: overt and subclinical. In overt hyperthyroidism, the thyroid stimulating hormone (TSH) levels are low or suppressed, and the triiodothyronine (T3) and/or thyroxine (T4) levels are high. TSH is the hormone that tells your thyroid to make and release other hormones. T3 and T4 are the hormones that are directly released by your thyroid. When T3 levels are high, TSH levels are low or suppressed, and T4 levels are normal, it’s called ‘T3 toxicosis.’

Subclinical hyperthyroidism is when TSH levels are low or suppressed but T3 and T4 levels are normal. Both overt and subclinical hyperthyroidism can lead to significant health problems in the long run.

What Causes Hyperthyroidism?

Hyperthyroidism is a condition where your thyroid gland produces too much thyroid hormone. There are several causes for this condition, with the three most common being:

Graves disease: an autoimmune disorder that happens when the body’s immune system mistakenly attacks the thyroid gland.
Toxic multinodular goiter: this happens when nodules, or small lumps, develop in the thyroid gland causing it to enlarge and produce extra thyroid hormone.
Toxic adenoma: this is a non-cancerous growth in the thyroid gland that causes it to produce too much thyroid hormone.

Other less common causes of hyperthyroidism can include:

Excessive consumption of iodine.
Pituitary adenomas, which are non-cancerous tumors in your pituitary gland that can overstimulate the thyroid.
Conditions that cause high levels of human chorionic gonadotrophin (a hormone), such as certain kinds of tumors in men and certain pregnancy complications in women.
Ectopic thyroid in struma ovarii: a rare condition where thyroid tissue is found in the ovaries causing the body to produce too much thyroid hormone.
Proliferation of thyroid tissue due to extensive spreading of thyroid cancer.

In some instances, drugs like amiodarone (a heart medication), lithium (used for mood disorders), and certain types of cancer medications can cause thyroid inflammation (thyroiditis), leading to hyperthyroidism. Other forms of thyroiditis, including Hashitoxicosis, painless thyroiditis, painful subacute thyroiditis, suppurative thyroiditis, and Riedel thyroiditis can also be a cause.

“Factitious thyroiditis” refers to a condition that occurs due to excessive or inappropriate use of thyroid hormone medication. Because these medications often cause weight loss, they can sometimes be misused.

In the US and most Western countries, Graves disease is the most common cause of hyperthyroidism. It commonly affects younger people because it’s connected to the immune system. However, in older people and in areas where there’s a shortage of dietary iodine, toxic multinodular goiter is the most common cause.

Risk Factors and Frequency for Hyperthyroidism

Hyperthyroidism, a condition where the thyroid gland is overactive, occurs differently around the world, based on dietary iodine. Women are more likely to have hyperthyroidism than men. Other factors that can lead to hyperthyroidism include smoking, having too little or too much iodine, not having enough selenium, certain genetic factors, and taking particular drugs. Graves’ disease, which affects mostly younger patients, is the top cause of hyperthyroidism for this age group. It usually occurs in people aged between 30 and 50. Toxic multifocal goiter, on the other hand, usually occurs in older individuals and is the most common cause of hyperthyroidism among them. Both conditions are generally found in women, particularly those with notable family and personal medical histories. Thyroid nodular disease is also more common in women, being 5 to 15 times more likely than in men. Autoimmune thyroid disorders like Graves’ disease are more widespread in areas with sufficient iodine intake, while nodular thyroid diseases are more common where there’s iodine deficiency.

A 1977 survey in northeastern England showed hyperthyroidism in women is approximately ten times more common than in men, with an incidence of 80 cases per 100,000 women after 20 years.
In the United States, about 1.3% of the population experiences hyperthyroidism, with 0.5% having severe hyperthyroidism and 0.7% having mild hyperthyroidism.
A study found that the prevalence of hyperthyroidism in Europe is 0.75%, quite similar to that in China at 0.78%.
About 6% of people taking Amiodarone in iodine-sufficient areas had Amiodarone-induced thyrotoxicosis (AIT), and the figure increased to 10% in iodine-deficient areas.

Signs and Symptoms of Hyperthyroidism

Hyperthyroidism, or an overactive thyroid, results in increased levels of thyroid hormones. These hormones affect various body systems, causing a variety of symptoms. People with this condition often experience unintentional weight loss, although some may actually gain weight due to increased appetite. Other symptoms commonly include palpitations or racing heart, shaking or tremors, intolerance to heat, difficulty breathing during physical activity, anxiety, irritability, fatigue, muscle weakness, frequent bowel movements or even severe diarrhea, hair loss, reduced sex drive, and irregular or absent menstrual periods in women.

Those diagnosed with a specific type of this condition, called subacute thyroiditis, may also experience significant pain in the front of the neck and fever. Upon physical examination, doctors might notice a fast heart rate, high blood pressure, tremors, skin that’s warm and moist, overly quick reflexes, and a generally anxious demeanor. In some cases, symptoms can be severe enough to resemble heart failure.

Eye symptoms are quite common in people with hyperthyroidism, and include lid lag (a delay in the movement of the eyelid) or retraction (a pulling back of the eyelid). However, certain symptoms related to the eyes, such as double vision, excessive tearing, redness, and pressure behind the eyes, only occur in a specific form of hyperthyroidism known as Graves’ disease. Other symptoms specific to Graves’ disease include thick, scaly skin and swelling on the front of the lower legs, and swelling of the soft tissue of the hands with finger clubbing.

Examination of the thyroid often reveals distinct changes depending on the type of hyperthyroidism. In Graves’ disease, the thyroid typically swells uniformly without nodules. A non-uniform, nodular enlargement is found with a toxic multinodular goiter, while a single large nodule is usually palpable in cases of a toxic adenoma. If the thyroid is extremely tender to touch, this could indicate the presence of subacute thyroiditis.

Testing for Hyperthyroidism

If you’re showing signs of hyperthyroidism like heightened metabolism, increased heart rate, weight loss etc., your doctor will likely perform certain tests to confirm the diagnosis. They will begin by ordering a blood test to check the levels of certain hormones like TSH (thyroid-stimulating hormone), free T4, and total T3. A decrease in TSH combined with an increase in free T4 and total T3 typically suggests overt hyperthyroidism. If your TSH is low but T4 and T3 are normal, this could suggest mild/subclinical hyperthyroidism. If only T3 is elevated while TSH is low and T4 is normal, this condition is referred to as ‘T3 toxicosis’.

Certain factors can potentially affect the TSH test results. Heterophile antibodies, which can occur due to infections or certain medicines, may cause a false increase in TSH levels. Consuming a high amount of biotin in dietary supplements can sometimes interfere with the test and give a false low TSH and false high free T4 levels.

Once a diagnosis of hyperthyroidism is confirmed, your doctor may measure the levels of the thyrotropin receptor antibody (TRAb) to help identify the cause behind your hyperthyroidism. If TRAb levels are elevated, this can confirm Graves’ disease as the cause. Various tests are used to measure TRAb levels, and some of these, like the Immulite method and TBII assays, are known for their high accuracy.

If your TRAb levels are normal, your doctor might order a radioiodine thyroid uptake and scan. However, pregnant and nursing women cannot undergo this test. This scan involves swallowing a capsule containing I-123 isotope which is taken up by the thyroid cells. The pattern of uptake seen on the scan can help identify the underlying condition. But this test doesn’t help distinguishing between type 1 and type 2 amiodarone-induced thyrotoxicosis (a side effect of a heart medication called amiodarone).

The result of the test is categorised as high/normal activity or low/absent activity. For example, in Graves’ disease, the radioiodine uptake is usually high or normal.

A Thyroid ultrasound using color Doppler is another test that can help identify the root of the problem. This test measures the blood flow through the thyroid gland. Increased or normal blood flow points to Graves’ disease, while low blood flow is seen in thyroiditis. This test can also differentiate between the two types of amiodarone-induced thyrotoxicosis.

Treatment Options for Hyperthyroidism

The treatment of hyperthyroidism varies based on the specific cause. People with hyperthyroidism often feel symptoms like a racing heart, anxiety, and shaking. Medications like beta-blockers (for example, atenolol) can help manage these symptoms. In cases where beta-blockers cannot be used, calcium channel blockers like verapamil might be an alternative.

This explanation focuses on hyperthyroidism treatment for the most common causes, which are Graves disease, toxic multinodular goiter, and toxic adenoma, in patients who are not pregnant.

The need for treatment is determined based on various factors. These can include very high thyroid-stimulating hormone (TSH) levels, age over 65, younger age with other health conditions (like heart disease or osteoporosis), or persistent high TSH levels after months.

There are three primary treatments for hyperthyroidism: radioactive iodine therapy, thionamide therapy, and less commonly thyroid surgery. Deciding between these depends on the specific cause, other health conditions the patient has, and their personal preference. In the United States, radioactive iodine has been the typical choice, but more recently, anti-thyroid drugs have become more common.

Anti-thyroid drugs (ATDs), specifically a group of drugs called thionamides, work by blocking thyroid hormone production. They also have some effect on the immune system. Though these drugs can help manage symptoms, they don’t permanently fix the underlying problem, and hyperthyroidism can return once the drug treatment is stopped.

It usually takes several months on thionamides to reach a healthy thyroid hormone level. There are different types of thionamides – methimazole is preferred for its convenience and safety, except for during pregnancy. In pregnancy, propylthiouracil (PTU) is used instead due to methimazole’s risk to the developing baby.

Radioactive iodine (RAI) therapy can be a good choice for many patients, particularly those at high risk of complications from surgery or from using thionamides. This treatment carries some risks and isn’t suitable for everyone, such as pregnant women or those with serious eye problems related to Graves disease. Radioactive iodine therapy uses radioactive iodine to destroy some of the cells in the thyroid, reducing its hormone production.

Finally, surgery to remove part or all of the thyroid is another possible treatment. This might be the best option for women planning to become pregnant within the next six months, patients with Graves disease related eye problems, those who can’t tolerate thionamides, or in case of a suspected thyroid cancer. The surgery option should be avoided for people with health conditions that make surgery too risky. As with drug treatments, the thyroid status should be checked frequently after surgery.

Hyperthyroidism, a condition where your thyroid is overactive, can be tricky to diagnose because it shares symptoms with other conditions – like palpitations, frequent bowel movements, and weight loss.

To pinpoint if it’s hyperthyroidism, doctors will usually examine your thyroid gland. Depending on what they find, they might suspect:

Graves’ disease, painless thyroiditis, or factitious hyperthyroidism if your thyroid feels normal but you’re showing hyperthyroid symptoms. An enlarged but not painful thyroid could also indicate Graves’ disease.
De Quervain thyroiditis, or subacute thyroiditis, if your thyroid is enlarged and tender to touch.
Thyroid adenoma if there’s a single nodule in the thyroid.
Toxic multinodular goiter if there are multiple nodules in the thyroid.

Other conditions that could bring about hyperthyroidism symptoms include euthyroid hyperthyroxinemia, where the levels of the hormones T4 and T3 are high but the TSH hormone falls within normal range, and struma ovarii.

What to expect with Hyperthyroidism

Hyperthyroidism, which can be as a result of Graves’ disease or toxic multinodular goiter (an enlarged thyroid gland with multiple nodules), typically has positive outcomes. This is due to the high success rates of definitive treatments and the effective management of symptoms. Nevertheless, like any disease, the future health state (prognosis) of a patient depends on several factors. These include how the disease is managed, how the patient responds to treatment, and whether they follow the recommended treatment plan.

Possible Complications When Diagnosed with Hyperthyroidism

If hyperthyroidism isn’t managed or treated, severe forms of the condition, known as a thyroid storm, can occur. People experiencing a thyroid storm might speed up body function resulting in symptoms such as rapid heartbeat, increased bowel movement, excessive sweating, anxiety, fever, and signs of multi-organ failure. This severe condition could be life-threatening and needs urgent care. Especially in individuals over 60 years, the risk of dying from it is approximately 16%.

If hyperthyroidism is left untreated or not adequately managed for a long period, it can increase the risk of sudden heart problems, irregular heartbeat rhythm (known as atrial fibrillation), stroke, brittle bones (osteoporosis), infertility, menstrual cycle abnormalities, and even death. Even a mild form of hyperthyroidism – known as subclinical hyperthyroidism – is associated with an increased risk for abnormal heart rhythms, brittle bones, hip fractures, and death.

Rapid heartbeat
Increased bowel movement
Excessive sweating
Anxiety
Fever
Signs of multi-organ failure
Sudden heart problems
Irregular heartbeat rhythm (Atrial fibrillation)
Stroke
Brittle bones (Osteoporosis)
Infertility
Menstrual cycle abnormalities
Death

Preventing Hyperthyroidism

Learning about hyperthyroidism is not very different from learning about other diseases. It’s important for patients to understand why they should stick to their treatment plan. They also need to be aware of the signs and symptoms of severe hyperthyroidism, also known as a thyroid storm.

Frequently asked questions

Hyperthyroidism is a common condition that involves the overproduction of thyroid hormones.

In the United States, about 1.3% of the population experiences hyperthyroidism, with 0.5% having severe hyperthyroidism and 0.7% having mild hyperthyroidism.

Signs and symptoms of hyperthyroidism include: - Unintentional weight loss, although some individuals may actually gain weight due to increased appetite. - Palpitations or racing heart. - Shaking or tremors. - Intolerance to heat. - Difficulty breathing during physical activity. - Anxiety and irritability. - Fatigue and muscle weakness. - Frequent bowel movements or severe diarrhea. - Hair loss. - Reduced sex drive. - Irregular or absent menstrual periods in women. In the case of subacute thyroiditis, individuals may also experience significant pain in the front of the neck and fever. Physical examination may reveal a fast heart rate, high blood pressure, tremors, warm and moist skin, quick reflexes, and an anxious demeanor. Severe cases of hyperthyroidism can resemble heart failure. Eye symptoms are common in hyperthyroidism, including lid lag or retraction. However, specific eye symptoms such as double vision, excessive tearing, redness, and pressure behind the eyes are only present in Graves' disease. Other symptoms unique to Graves' disease include thick, scaly skin and swelling on the front of the lower legs, as well as swelling of the soft tissue of the hands with finger clubbing. Examination of the thyroid can reveal distinct changes depending on the type of hyperthyroidism. In Graves' disease, the thyroid typically swells uniformly without nodules. A non-uniform, nodular enlargement is found in toxic multinodular goiter, while a single large nodule is usually palpable in cases of a toxic adenoma. Tender thyroid upon touch may indicate the presence of subacute thyroiditis.

There are several causes of hyperthyroidism, including autoimmune disorders like Graves disease, the development of nodules in the thyroid gland, non-cancerous growths in the thyroid gland, excessive consumption of iodine, pituitary adenomas, high levels of human chorionic gonadotrophin, ectopic thyroid in struma ovarii, proliferation of thyroid tissue due to thyroid cancer, drugs like amiodarone and lithium, certain types of thyroiditis, and factitious thyroiditis.

The doctor needs to rule out the following conditions when diagnosing Hyperthyroidism: - Graves' disease - Painless thyroiditis - Factitious hyperthyroidism - Enlarged but not painful thyroid (which could also indicate Graves' disease) - De Quervain thyroiditis or subacute thyroiditis - Thyroid adenoma - Toxic multinodular goiter - Euthyroid hyperthyroxinemia - Struma ovarii

The types of tests that are needed for hyperthyroidism include: 1. Blood tests: These tests measure the levels of certain hormones like TSH (thyroid-stimulating hormone), free T4, and total T3. Abnormal levels of these hormones can indicate hyperthyroidism. 2. Thyrotropin receptor antibody (TRAb) test: This test helps identify the cause of hyperthyroidism. Elevated TRAb levels can confirm Graves' disease as the cause. 3. Radioiodine thyroid uptake and scan: This test involves swallowing a capsule containing I-123 isotope, which is taken up by the thyroid cells. The pattern of uptake seen on the scan can help identify the underlying condition. 4. Thyroid ultrasound using color Doppler: This test measures the blood flow through the thyroid gland. Increased or normal blood flow can indicate Graves' disease, while low blood flow is seen in thyroiditis. These tests help diagnose hyperthyroidism and determine the specific cause, which then guides the appropriate treatment.

Hyperthyroidism can be treated through various methods depending on the specific cause and individual factors. The three primary treatments for hyperthyroidism are radioactive iodine therapy, thionamide therapy, and thyroid surgery. Radioactive iodine therapy uses radioactive iodine to reduce hormone production in the thyroid. Thionamide therapy involves the use of drugs called thionamides, such as methimazole or propylthiouracil, to block thyroid hormone production. Thyroid surgery, which involves removing part or all of the thyroid, may be necessary in certain cases. The choice of treatment depends on factors such as the cause of hyperthyroidism, the presence of other health conditions, and patient preference.

The side effects when treating Hyperthyroidism can include: - Rapid heartbeat - Increased bowel movement - Excessive sweating - Anxiety - Fever - Signs of multi-organ failure - Sudden heart problems - Irregular heartbeat rhythm (Atrial fibrillation) - Stroke - Brittle bones (Osteoporosis) - Infertility - Menstrual cycle abnormalities - Death

The prognosis for hyperthyroidism is generally positive due to the high success rates of definitive treatments and the effective management of symptoms. However, the future health state of a patient depends on several factors, including how the disease is managed, how the patient responds to treatment, and whether they follow the recommended treatment plan.

An endocrinologist.