Causes of an overactive thyroid gland

An overactive thyroid gland is a condition that causes levels of thyroid hormones to rise and speed up vital body functions.

• Graves' disease is the most common cause of an overactive thyroid gland.

• Heart rate may increase, blood pressure rise, heart rate may be disturbed, patients may sweat excessively, feel nervous and anxious, have difficulty sleeping, and lose weight without intentionally doing so.

• Blood tests can confirm the diagnosis.

• Medicines such as methimazole or propylthiouracil can help control an overactive thyroid gland.

Hyperthyroidism affects 1% of the population in the United States of America. Hyperthyroidism can occur at any age, but it is most common in menopausal and postpartum women.

the reasons

The most common causes include the following:

• Graves' disease

• Inflammation of the thyroid gland

• Poisonous multinodular goitre

Graves disease is the most common cause of hyperthyroidism, an autoimmune disorder. In autoimmune disorders, a person's immune system produces antibodies that attack the body's own tissues. The antibodies damage the cells of the body and impair their ability to function. However, in Graves' disease, antibodies stimulate the thyroid gland to produce and release more thyroid hormones into the blood. This cause of an overactive thyroid gland is often hereditary and in most cases leads to an enlarged thyroid gland.

The thyroid gland can become inflamed, and this is called thyroiditis. Inflammation may be caused by a viral infection (subacute thyroiditis), by autoimmune inflammation of the thyroid gland that occurs after birth (silent lymphocytic thyroiditis), or in rare cases by chronic autoimmune inflammation (thyroiditis). Hashimoto). Initially, inflammation causes an overactive thyroid gland, as the hormones stored in the inflamed gland are released. Later, this is followed by hypothyroidism due to the depletion of stored hormones. Ultimately, the gland returns to its normal function.

A toxic multinodular goiter (Plummer's disease), in which many nodules form within the thyroid gland, and it increases with age, but it is not common in teens and young adults.

Other causes of an overactive thyroid gland include the following:

• Growths within the thyroid gland that cause too much thyroid hormone production (toxic thyroid nodules)

• some medicine

• Overstimulation of the thyroid gland due to an overactive pituitary gland

A toxic thyroid nodule (an adenoma) is an area of ​​abnormal tissue within the thyroid gland. This abnormal tissue produces thyroid hormones even without stimulation from thyroid stimulating hormone (TSH, a hormone produced by the pituitary gland to stimulate the thyroid gland to produce thyroid hormones). Thus, the nodules escape from the mechanisms that control the functioning of the thyroid gland and the production of thyroid hormones in large quantities.

Medicines and iodine can cause an overactive thyroid gland. Medicines include amiodarone, interferon-alpha, and, in rare cases, lithium. Excessive iodine levels (which may occur in people who take certain types of expectorants, or contrast agents containing iodine for x-ray imaging) can cause an overactive thyroid gland.

An overactive pituitary gland can lead to too much production of TSH, which in turn leads to overproduction of thyroid hormones. However, this is an extremely rare cause of an overactive thyroid gland.

Symptoms

The thyroid gland becomes enlarged in most people who are hyperactive. The gland may be enlarged as a whole, or a nodule may develop only in a specific area. If the patient has subacute thyroiditis, the gland may become painful spontaneously or with palpation.

The symptoms of an overactive thyroid gland (regardless of its cause) reflect the acceleration of the body's functions:

• Increased heart rate and blood pressure

• Arrhythmia

• Excessive sweating and feeling of extra warmth

• Shaking hands

• Nervousness and anxiety

• Difficulty sleeping (insomnia)

• Weight loss despite increased appetite

• Increased activity level despite fatigue and weakness

• Frequent defecation, often diarrhea

These symptoms may not occur in older adults with hyperthyroidism, but they sometimes have what is called apathetic hyperthyroidism, manifesting weakness, confusion, avoidance of meeting people, and depression. An overactive thyroid gland may cause changes in the eyes. A person with an overactive thyroid gland may appear to be staring around.

Graves' disease

If the cause of an overactive thyroid gland is Graves' disease, ophthalmic symptoms include puffiness around the eyes, increased tear production, irritability and unusual sensitivity to light. Two distinct additional symptoms may occur:

• Exophthalmos eyes

• Double vision diplopia

The eyes protrude towards the outside due to the inflammation of the orbit behind them. The muscles that move the eyes also become inflamed and unable to function properly, making it difficult or impossible to move the eyes or coordinate their movements, resulting in poor vision. The eyelids may not close completely, exposing the eyes to foreign body damage and dryness. These eye changes may begin before any other symptoms of an overactive thyroid gland, which gives an early indication of Graves' disease, but they often appear when other symptoms of an overactive thyroid gland are noticed. Ocular symptoms may appear or worsen after excessive thyroid hormone secretion and have been managed and controlled.

When Graves' disease affects the eyes, the skin, especially over the fronts of the legs, may become thickened and have orange peel-like texture. The thickened area may become itchy and red, and look hard when pressed with a finger. As with deposits behind the eyes, this problem may begin before or after other symptoms of an overactive thyroid gland appear.