Hyperthyroidism, or overactive thyroidism, happens when there is too much thyroid hormone in the thyroid gland. That has an effect all over the body.
Within the neck is the thyroid gland. It has the appearance of a butterfly. The hormones which it produces and releases in the bloodstream regulate the growth and metabolism of the body. Too much hormone can affect many body functions.
There are many potential causes and a huge number of possible signs. It normally starts gradually but can start unexpectedly in younger people.
Hyperthyroidism is quite distinct from hypothyroidism. “Hyper” means so much thyroid hormone is present in the body. Very little, or an underactive thyroid, means “hypo.”
About 1.2 percent of people in the U.S. have an overactive thyroid.
This affects more women than men and will more likely occur over the age of 60.
Hyperthyroidism can severely impact different body functions including the heart without treatment. Medication, however, will usually regulate this by reducing the development of thyroid hormones.
Fast facts on hyperthyroidism
Here are some key points about hyperthyroidism. More detail is in the main article.
- Hyperthyroidism happens when the thyroid gland produces too much hormone.
- Graves’ disease is the most common cause.
- Medication can usually normalize hormone levels, but treatment may take 1 to 2 years.
- Untreated, hyperthyroidism can cause severe complications.
- With treatment, pregnancy should be able to progress normally.
Symptoms
Symptoms vary extensively, and differ between individuals. Patients with moderate hyperthyroidism are still unaware of getting it because the signs are not present.
Most of the symptoms contribute to the increase in metabolic rate.
They include:
- swelling in the neck caused by an enlarged thyroid gland, or goiter
- nervousness, irritability, mood swings, and decreased concentration
- diarrhea
- difficulty breathing
- fatigue, tiredness, and difficulty sleeping
- muscle weakness
- hyperactivity
- oversensitivity to heat, excessive sweating, and warm, damp skin
- increased appetite
- increased bowel movements and urination
- infertility and a loss of interest in sex
- itchy skin with raised itchy swellings (urticaria)
- nails become loose
- menstrual problems in women, especially lighter periods or absence of periods
- alopecia where hair is lost in patches
- accelerated heartbeat, sometimes with palpitations
- redness on the palms of hands
- sudden weight loss or gain
- trembling hands and shakiness
Signs vary from person to person, and both of these signs are uncommon in patients.
Diabetes patients may experience the symptoms of increased diabetes, such as fatigue and increased thirst.
Those with heart disease have an elevated risk of arrhythmia, heart failure and other cardiovascular hazards.
Treatment
Many drugs treat the symptoms of hyperthyroidism, such as issues with heart rhythm, while others regulate the development of thyroid hormones.
Beta-blockers will alleviate symptoms before more therapies begin to function. Most people should feel better in just a few hours, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Antithyroid drugs avoid too much thyroxine or triiodothyronine from producing the thyroid gland. Usage can be of methimazole or propylthiouracil (PTU).
This can take several weeks or months for the hormone levels to return to the normal range after beginning treatment. Total recovery time on average is between 1 and 2 years, but can take longer.
Adverse effects of medications include:
- allergic reactions
- reduction in white blood cells, increasing the chance of infections
- rarely, liver failure
Radioactive iodine is picked up by the active cells in the thyroid, and it destroys them. The destruction is local, and there are no widespread side effects. The dose of radioactivity contained in the radioiodine is very low and is not harmful.
Radioiodine treatment is not suitable for women who are pregnant or breastfeeding. Women should avoid getting pregnant for at least 6 months after treatment, and men should not father a child for at least 4 months.
Surgery can remove part of the thyroid gland if other treatments are not possible, for instance, during pregnancy, cannot tolerate other therapies, or has cancer.
Patients may find it useful to avoid food and other products that are high in iodine, such as seaweed and some cough medicines and multivitamins.
Causes
Several factors can cause hyperthyroidism.
Graves’ disease
It is the most popular cause, affecting more than 70 percent of cases. This is an autoimmune disorder.
Which causes the disease of Graves is unclear but it often runs in families, indicating a genetic basis.
Grave’s disease is most prevalent among women aged 20 to 40 and especially smokers.
This can cause confusion and double vision to the eyes. Patients usually have protruding pupils.
Nodular thyroid disease
Lumps form in the thyroid gland, known as nodules. Why they do develop is uncertain. They may contain irregular tissue from the thyroid, but they are normally benign or cancerous. They affect the normal thyroid activity, causing the thyroid to become overactive.
The thyroid can get swollen, but pain is not present. Someone with nodules could feel it with their fingertips.
Excessive iodine intake
Iodine is extracted from the blood by the thyroid gland. Iodine is extracted from foods like fish, bread, and salt. The iodine is used by the thyroid gland to produce thyroid hormones.
Thyroxine (T4), and triiodothyronine (T3) are the two most common thyroid hormones.
Taking additional iodine in supplements may produce too many of the hormones in the thyroid gland.
Thyroid hormone intake: People who receive thyroid hormones as a therapy need to follow up with their doctor periodically to ensure they are receiving the right dosage of thyroid medicine.
Medications
Many drugs used to treat heart attacks contain a large amount of iodine. They can cause changes in thyroid function. Amiodarone and lithium are options, used for treating bipolar disorder.
Thyroiditis
A thyroid inflammation which is often the result of a viral infection. Symptoms include fever, sore throat, painful coughing, severe nausea and neck pains.
Follicular thyroid cancer
In rare cases thyroid cancer may cause overactive thyroid. The malignant cells will begin producing either thyroxine or triiodothyronine.
Diet
No special diet will overcome a thyroid disorder.
Reducing excessive iodine intake in the diet, however, and avoiding iodine supplements can help to stop thyroid activity from becoming more imbalanced.
A balanced diet can help to maintain a healthy thyroid. If you want to take supplements, be sure to ask your doctor for advice about how many to take and what nutrients are best for you without impacting the development of thyroids.
Complications
The ophthalmopathy of Graves may cause eye pain or discomfort, light sensitivity and some problems with vision. The eyes might giggle.
It can help alleviate pain by using eye drops and wearing sunglasses.
Treatment with other medications, such as steroids or immunosuppressive medications, can decrease the swelling behind the eyes in extreme cases.
A thyroid storm is a unusual reaction that can be caused by an illness, accident, or trauma, like surgery, or childbirth; It may also occur in pregnant women with hyperthyroidism which is undiagnosed or poorly controlled.
The signs and symptoms include quick pulse, high fever, agitation, jaundice, vomiting, diarrhea, hallucinations, and dehydration.
The reaction is life-threatening. It needs medical emergency care.
The extent of hyperthyroidism and its effects depend on how well the body can respond to changes arising from excess thyroid hormones and how well patients are pursuing their treatment plan.
Diagnosis
The doctor will inquire about the symptoms, do a physical exam and probably order blood tests.
Advanced hyperthyroidism is generally easy to detect because the symptoms are apparent but in the early stages the diagnosis is not evident.
A blood test, called a thyroid function test, will indicate how well the thyroid gland functions. The test tests thyroid-stimulating hormone (TSH), thyroxin (T4), and triiodothyronine (T3) levels.
Using radioactive iodine to gage thyroid function, a special diagnostic examination of the thyroid gland is possible. It is known as the RAIU (Radioactive Uptake of Iodine).
Hyperthyroidism and pregnancy
A woman with hypothyroidism may find getting pregnant harder.
Thyroid hormone levels should go up slightly during pregnancy.
Women with an overactive thyroid can find their thyroid slightly enlarged during pregnancy. Many women who are sensitive but have not been diagnosed yet, during pregnancy, can have a slightly hyperactive thyroid.
During pregnancy extreme, untreated hyperthyroidism was associated with spontaneous abortion, low birth weight, high blood pressure from the mother and heart problems.
If the mother has a thyroid problem, thyroid function should be tested for the newborn, as this can have a profound impact on the brain growth.
Women who undergo care before pregnancy will continue to receive the same therapy but will need to change their dosage because thyroxine dose requirements typically increase. During pregnancy, levothyroxine is safe to take, because it has the same effects as the natural hormone.
It should however be taken 2 to 3 hours apart from any prenatal vitamins, as iron and calcium may interfere with thyroid hormone absorption.
Before becoming pregnant a woman will make sure her hyperthyroidism is under control.
Many pregnancies can be expected to proceed normally, with adequate care.
