What is Hyperthyroidism? Symptoms, Causes, treatment

What is Hyperthyroidism?

Hyperthyroidism occurs when the thyroid gland secretes high levels of thyroid hormones (T3 and T4), which can wreak havoc on the body. It is diagnosed through blood tests that check T3, T4, or thyroid stimulating hormone (TSH) levels, as these hormones play critical roles in metabolic processes and overall bodily function.

The Role of the Thyroid Gland and Its Hormones

The thyroid gland, which is butterfly-shaped and located below the larynx (voice box), is central to hormone production. Not only does it produce T3 and T4, but it also secretes calcitonin. However, when it comes to metabolic regulation, T3 and T4 are the stars of the show. These hormones help the body burn calories, determine how quickly cells regenerate, aid in food digestion, and stimulate the sympathetic nervous system—resulting in increased alertness, faster reflexes, and elevated heart rate and blood pressure.

An essential aspect of thyroid hormone production is the presence of iodine. The thyroid cannot synthesize T3 and T4 without it. Foods rich in iodine, such as seafood, seaweed, eggs, and dairy, are crucial for maintaining appropriate levels. Too much iodine can trigger hyperthyroidism, while too little may lead to hypothyroidism.

TSH, produced by the anterior pituitary gland, plays a pivotal role in regulating the thyroid. When the hypothalamus releases thyrotropin-releasing hormone (TRH), it prompts the anterior pituitary to secrete TSH, which in turn stimulates the thyroid to release T3 and T4. Disruptions in this negative feedback loop can lead to imbalances in thyroid hormone levels.

Signs and Symptoms

Because hyperthyroidism means “high thyroid,” the body’s functions accelerate. Key symptoms include:

• Weight Loss: Excessive burning of calories leads to noticeable weight loss.
• Heat Intolerance: Patients often feel excessively hot and sweaty.
• Increased Heart Rate and Blood Pressure: Overstimulation of the sympathetic nervous system can cause elevated heart rate and blood pressure.
• Diarrhea: Rapid movement of food through the intestines reduces nutrient absorption.
• Smooth Hair and Soft Skin: Increased blood flow often results in softer skin and smoother hair.
• Cardiac Dysrhythmias: Conditions like atrial fibrillation may occur.
• Personality Changes: Patients can become moody, restless, and irritable, often struggling with insomnia.

Causes of Hyperthyroidism

Several factors can lead to hyperthyroidism:

• Graves’ Disease: The most common cause, Graves disease is an autoimmune condition where the body produces thyroid-stimulating immunoglobulin (TSI). This antibody mimics TSH, causing the thyroid to release excessive T3 and T4. Unique symptoms include protruding eyeballs and a waxy, orange peel appearance on the skin (myxedema pretibial type).
• Toxic Nodular Goiter (TNG): Unlike Graves disease, TNG involves nodular growths on the thyroid that independently secrete thyroid hormones without autoimmune involvement.
• Thyroiditis: Inflammation of the thyroid gland can cause the release of stored thyroid hormones into the bloodstream.
• Excess Iodine Intake: Overconsumption of iodine-rich foods or supplements can lead to an overproduction of thyroid hormones.

Treatment Options

Medications and other treatments include:

Anti-Thyroid Medications:

• Methimazole (Tapas): Commonly used for Graves disease, it inhibits thyroid hormone synthesis but is not suitable for the first trimester of pregnancy.
• Propylthiouracil (PTU): Preferred during early pregnancy despite its increased risk of liver failure, which necessitates monitoring liver enzymes.
• Side Effects: These medications can cause granulocytopenia (a reduction in white blood cells) and aplastic anemia (a decrease in red blood cells), so vigilant monitoring is required.

Additional Treatment Options:

• Radioactive Iodine: Patients ingest a radioactive iodine capsule that is absorbed by the thyroid, gradually destroying the gland. This treatment is permanent but not recommended for pregnant or nursing women. Side effects can include a metallic taste, nausea, or swollen salivary glands.
• Thyroidectomy: Surgical removal of the thyroid gland may be necessary, especially if other treatments are ineffective. Postoperative care includes monitoring for thyroid storm, managing parathyroid function (as these glands regulate calcium), and preventing respiratory distress due to swelling or bleeding.

Supportive Medications:

• Beta Blockers: Often prescribed to lower heart rate and blood pressure, easing symptoms such as heat intolerance.
• Glucocorticoids: Used post-thyroidectomy to suppress the immune response.