Hypothyroidism

Hypothyroidism is a medical condition characterized by the inability of the thyroid gland to produce an adequate amount of hormones for the body's needs.

The Thyroid Gland

The thyroid gland, located at the base of the throat, plays a significant role in the body's metabolism. It regulates several physiological processes, including body temperature, protein synthesis, skeletal and brain development, and the heartbeat. It accomplishes these tasks by producing and releasing three hormones into the bloodstream: triiodothyronine (T3), thyroxine (T4), and calcitonin.

What Is Hypothyroidism?

Hypothyroidism occurs when the thyroid gland cannot produce an adequate quantity of T3 and T4 hormones for the body's needs. This can be due to a poorly productive thyroid or tissues that are resistant to the action of thyroid hormones. It is classified as a thyroid disease, which also includes hyperthyroidism, goiter, thyroid nodules, thyroid cancer, and thyroiditis. These conditions are common, affecting a significant portion of the population, particularly women and elderly people.

Causes of Hypothyroidism

The causes of hypothyroidism are diverse, leading to the classification of the condition into four categories: primary, secondary, tertiary, and iatrogenic hypothyroidism.

1. Primary Hypothyroidism
   This results from a specific dysfunction of the thyroid gland itself, often due to autoimmune thyroid diseases, iodine deficiency, or partial or total removal of the thyroid gland.
2. Secondary Hypothyroidism
   This is caused by a malfunction of the pituitary gland, which regulates the activity of the thyroid. The malfunction may be due to pituitary tumors or lesions affecting the pituitary structure.
3. Tertiary Hypothyroidism
   This type of hypothyroidism is due to a malfunctioning of the hypothalamus, another gland that regulates the activity of the thyroid. Hypothalamic tumors or lesions can cause poor functioning of the hypothalamus.
4. Iatrogenic Hypothyroidism
   This type of hypothyroidism is caused by incorrect medical treatment, typically due to excessive doses of antithyroid drugs used to treat hyperthyroidism.

Symptoms of Hypothyroidism

The symptoms and signs of hypothyroidism can vary based on the severity of the condition and the age at which it appears. In fetuses and young individuals, it primarily affects intellectual and somatic development. In adults, symptoms can include dry skin, sparse hair, fatigue, cold skin, bradycardia, drowsiness, constipation, asthenia, and intolerance to low temperatures.

Diagnosis

The diagnosis of hypothyroidism relies on a physical examination and blood tests that measure the levels of TSH (pituitary hormone) and, in some cases, T3 and T4 (thyroid hormones). High levels of TSH and low levels of T3 and T4 indicate hypothyroidism.

Treatment

The treatment of hypothyroidism involves the daily intake of synthetic thyroxine (or synthetic T4) to restore the functional activity of the thyroid. The dosage must be tailored to the patient's needs, as excessive intake can lead to hyperthyroidism, while an insufficient dose may be ineffective. Regular monitoring of TSH levels helps determine the correct dosage.

Dietary Adjustments

Diet plays a crucial role in the management of hypothyroidism. Consuming a balanced diet rich in iodine can help prevent iodine deficiency, one of the main causes of primary hypothyroidism.

Prognosis

With early diagnosis and appropriate treatment, hypothyroidism can be effectively managed, leading to a favorable prognosis. However, failure to treat hypothyroidism can have serious health repercussions, including goiter, cardiac problems, peripheral neuropathy, myxedema, decreased fertility, and congenital defects in children born to affected women.