Hyperthyroidism: What It Is, Symptoms, Causes, and How to Treat It

Hyperthyroidism is a condition in which the thyroid gland produces too much thyroid hormone. As a result, your body's metabolism may speed up, leading to unintentional weight loss and rapid or irregular heartbeats, among other symptoms. There are various treatments available for hyperthyroidism. Anti-thyroid medications that slow down the production of thyroid hormones and radioactive iodine may be used. Sometimes, as part of the treatment, the entire thyroid gland or a portion of it may be surgically removed.

What is Hyperthyroidism?

The thyroid is a small, butterfly-shaped gland located at the front of your neck. This gland is responsible for producing two main hormones, thyroxine (T4) and triiodothyronine (T3), which control the energy use of cells. The release of T4 and T3 hormones helps regulate your metabolism.

Hyperthyroidism occurs when the thyroid gland produces too much T4, T3, or both. With proper diagnosis and treatment of this overactive thyroid condition, symptoms can be alleviated, and complications can be prevented.

What Are the Symptoms of Hyperthyroidism?

When there is an excess of T4, T3, or both in the blood, the metabolic rate increases. This condition is referred to as a hypermetabolic state. During a hypermetabolic state, it is likely that you will experience a high heart rate, high blood pressure, and hand tremors. You may also sweat excessively and have a low tolerance to heat. Hyperthyroidism can lead to more frequent bowel movements, weight loss, and irregular periods in women.

Additionally, the thyroid gland can enlarge into a goiter, which may be symmetrical or unilateral. Your eyes may bulge outward, giving a noticeable appearance. Other symptoms of hyperthyroidism include:

• Increased appetite
• Irritability, restlessness, and difficulty concentrating
• Weakness
• Palpitations, feeling of heartbeats (palpitations)
• Difficulty falling asleep
• Thinning and brittle hair, hair loss
• Itching
• Nausea and vomiting
• Breast development in men

If you experience the following symptoms, you should immediately see a doctor and seek emergency treatment:

• Dizziness
• Shortness of breath
• Loss of consciousness
• Rapid and irregular heartbeat

What Causes Hyperthyroidism?

Certain conditions lay the groundwork for the development of hyperthyroidism. For example, Graves' disease, an autoimmune disorder, is one of the most common causes of hyperthyroidism. In this disease, antibodies stimulate the thyroid to produce excessive amounts of hormones. Graves' disease is more common in women than in men, and there is evidence suggesting it may be a genetic condition. If there are individuals with Graves' disease in your family, it is important to inform your doctor.

Other causes of hyperthyroidism include:

• Excessive iodine intake
• Thyroiditis or thyroid inflammation causing leakage of T4 and T3 hormones from the gland
• Tumors in the ovaries or testes
• Benign tumors in the thyroid or pituitary gland
• Large amounts of tetraiodothyronine from diet or medications

What Symptoms Appear Alongside Hyperthyroidism?

• Heart problems: One of the most serious complications of hyperthyroidism is heart-related issues. Rapid heart rate, atrial fibrillation (an irregular heart rhythm that increases the risk of stroke), and congestive heart failure (where the heart cannot circulate enough blood to meet the body’s needs) are common issues associated with hyperthyroidism.
• Fragile bones: Untreated hyperthyroidism can lead to weak and brittle bones, a condition known as osteoporosis. Bone strength is related to the amount of calcium and other minerals in the bones. Excess thyroid hormone interferes with the incorporation of calcium into bones.
• Eye problems: People with Graves' disease may experience red or swollen eyes, light sensitivity, and blurred or double vision. If untreated, serious eye problems may lead to vision loss.
• Skin problems: In rare cases, people with Graves' disease develop Graves' dermopathy. This condition affects the skin, causing redness and swelling, particularly on the shins and feet.
• Thyrotoxic crisis: Hyperthyroidism carries a risk of thyrotoxic crisis. Symptoms can suddenly intensify, with fever and rapid pulse. Immediate medical help is necessary in this condition.

How is Hyperthyroidism Diagnosed?

When diagnosing hyperthyroidism, medical history and physical examination are evaluated first. During the examination, signs such as tremors, overly active reflexes, changes in the eyes, and hot, moist skin are closely analyzed. The thyroid gland is also assessed for enlargement, irregular movements, or tenderness when swallowing. Pulse rate and regularity are also important factors in diagnosing hyperthyroidism.

Blood tests are then used to confirm the diagnosis. Blood tests measuring thyroxine and thyroid-stimulating hormone (TSH) levels help verify the condition. High thyroxine and low TSH levels indicate overactive thyroid. The level of TSH is crucial because it is the hormone that signals the thyroid gland to produce more thyroxine.

If you are taking a biotin supplement, commonly found in multivitamins, thyroid tests may show inaccurate results. It is recommended to inform your doctor if you are using biotin or a biotin-containing multivitamin.

If blood tests indicate hyperthyroidism, your doctor may request further tests to understand why the thyroid is overactive. These tests include:

• Radioiodine uptake test: A small amount of radioactive iodine is taken orally to see how much accumulates in the thyroid. The iodine absorption is checked 4, 6, or 24 hours later. High radioactive iodine uptake suggests the thyroid is producing too much thyroxine, often due to Graves' disease or hyperfunctioning thyroid nodules.
• Thyroid scintigraphy: In this test, a radioactive isotope is injected into a vein, often in the elbow or hand. The thyroid gland’s image is then captured using a special camera system and displayed on a computer screen. This test helps determine how iodine is concentrated in the thyroid gland.
• Thyroid ultrasound: High-frequency sound waves are used to create images of the thyroid. Ultrasound is more successful than other tests in detecting thyroid nodules and carries no risks like radiation exposure.

How to Treat Hyperthyroidism?

If you have hyperthyroidism, your doctor will develop the most suitable treatment plan based on your age, physical condition, any underlying medical causes, personal preferences, and the severity of the disease.

Possible treatments include:

• Radioactive iodine: Radioactive iodine is taken orally, where it is absorbed by the thyroid gland, shrinking it and reducing its function. This treatment often resolves symptoms within a few months.
• Anti-thyroid medications: These medications work by preventing the thyroid from producing excess hormones. Symptoms usually improve within a few weeks or months, but treatment with anti-thyroid drugs often continues for at least a year and sometimes longer. However, in some cases, the disease may relapse. In rare cases, the medications can lead to severe liver damage. Allergic reactions to these drugs are rare, but they can cause rashes, hives, fever, or joint pain. These medications should be used with caution as they can make the body more susceptible to infections.
• Beta blockers: These medications are often prescribed to address symptoms like trembling and rapid heart rate, which are common in hyperthyroidism. Doctors may prescribe these medications to help patients feel better until thyroid levels return to normal. They are generally not recommended for asthma patients, and side effects may include fatigue and sexual dysfunction.
• Surgical method: If anti-thyroid drugs are not well tolerated or the disease recurs frequently, thyroid surgery may be used in cases of hyperthyroidism caused by nodules or when recommended by the doctor. The surgeon removes most of the thyroid gland during this procedure. Risks during the surgery include potential damage to the vocal cords and parathyroid glands that control calcium levels in the blood. Additionally, lifelong treatment with levothyroxine (L-thyroxine) may be required to maintain normal thyroid hormone levels.

After treatment, hyperthyroidism symptoms generally decrease, and you will begin to feel much better. However, your doctor will likely recommend monitoring your iodine intake through your diet, as excessive iodine can trigger or worsen hyperthyroidism. If you show signs of hyperthyroidism, don’t hesitate to consult your doctor.