Hyperthyroidism
What is Hyperthyroidism?
Hyperthyroidism is a condition that occurs when the thyroid gland becomes overactive and releases too much thyroid hormone into the bloodstream. It can affect anyone but is about 10 times more common in women than men and typically begins between the ages of 20 and 40. In blood tests, T3 and T4 levels are high, while TSH levels are low.
The thyroid glands, located at the back of the neck, secrete hormones that regulate metabolism and organ functions. Therefore, they play a vital role in the body. When these glands enlarge or fail to function properly, they can produce too little or too much hormone, leading to disruptions in the body's overall functioning.
In hyperthyroidism, the excessive secretion of thyroid hormones speeds up the body's metabolism, causing it to become overactive. This leads to symptoms such as rapid weight loss, excessive sweating, and heart palpitations.
When a person with these symptoms visits a doctor, blood tests showing low TSH and high T3 and T4 levels confirm a diagnosis of hyperthyroidism.
Treatment options include medications that suppress excess hormone production, radioactive iodine therapy (also known as radioiodine therapy), or, if necessary, surgery to remove the thyroid gland.
Causes
Graves’ Disease
One in four cases of hyperthyroidism is caused by Graves' disease, an autoimmune disorder. In Graves' disease, the body reacts against itself, causing the thyroid to become overactive and secrete excessive hormones. This accelerates metabolism, increases heart rate, and prevents weight gain, eventually leading to a potentially life-threatening condition.
Symptoms include irritability, heart palpitations, weight loss, high blood pressure, enlarged thyroid gland, bulging eyes, light sensitivity, double vision, red eyes, and swollen eyelids. The exact cause of Graves’ disease is unknown, but it is most common in young or middle-aged women and tends to run in families. Smoking also increases the risk.
Toxic Nodular Goiter (Multinodular Goiter)
Hyperthyroidism caused by toxic nodular goiter occurs when one or more thyroid nodules become overactive. Unlike Graves' disease, this condition does not typically cause eye symptoms or skin issues. The cause is unknown.
Certain Medications
Medications such as interferons (used in cancer treatment), amiodarone (used for heart rhythm disorders), and lithium (used in bipolar disorder) can alter thyroid hormone levels. Symptoms may be temporary and resolve after stopping the medication, but you should never discontinue medications without consulting your doctor. These types of thyroiditis can also cause pain, sometimes requiring pain relief.
Thyroiditis (Thyroid Inflammation)
Thyroiditis can cause temporary hyperthyroidism, which may be followed by hypothyroidism as seen in Hashimoto’s thyroiditis. Hyperthyroidism may also result from excessive intake of thyroid hormone tablets. Rarely, a benign pituitary tumor may cause excess TSH, leading to hyperthyroidism.
Other Causes Include:
- High levels of hCG (human chorionic gonadotropin), a hormone that may increase thyroid hormone production. This can occur during early pregnancy, multiple pregnancies, or molar pregnancy (abnormal tissue in the uterus).
- Pituitary adenoma (a noncancerous tumor in the pituitary gland)
- Thyroid cancer (rarely, a cancerous thyroid tumor can affect hormone production)
Symptoms
Common symptoms of hyperthyroidism include:
- Heart palpitations
- High blood pressure
- Excessive sweating
- Irritability
- Restlessness
- Warm, moist skin
- Heat intolerance
- Weight loss (despite good appetite)
- Hand tremors
- Thinning, brittle hair and hair loss
- Thin skin
- Persistent diarrhea
- Eye symptoms (bulging eyes)
- Sensitivity to bright light
- Insomnia
- Irregular or missed periods
- Goiter (enlarged thyroid gland)
Diagnosis Methods
Diagnosis is based on measuring hormone levels in the blood and may be supported with imaging tests.
- Thyroid Function Test (Blood Test): Measures hormone levels. Low TSH and high T3/T4 indicate hyperthyroidism.
- Thyroid Ultrasound: Provides detailed images of the size, structure, and changes in the thyroid.
- Thyroid Scintigraphy: Used to detect nodules. A small amount of radioactive material is swallowed, which is absorbed by the thyroid. The patient lies under an imaging device to obtain a detailed image of the gland.
Treatment Methods
The goal of hyperthyroidism treatment is to return thyroid hormone levels to normal. Treatment varies from person to person and is tailored by your doctor based on factors such as:
- Your age, overall health, and medical history
- Type of hyperthyroidism
- Severity of the disease
- Tolerance to specific medications or procedures
- Disease progression expectations
- Your preferences