Pathological changes in the structure and function of the thyroid gland represent

Pathological changes in the structure and function of the thyroid gland represent one of the most common groups of diseases. Thyroid pathologies can alter its structure and function simultaneously or independently of each other. The primary function of the thyroid gland is the synthesis of thyroid hormones (FT4, FT3), which play a crucial role in body growth and development, metabolic regulation, and reproduction. The production of thyroid hormones is controlled by TSH (Thyroid-Stimulating Hormone), a hormone secreted by the pituitary gland in the brain, which serves as the primary screening test for thyroid function.

Underproduction of thyroid hormones relative to the body's needs is called hypothyroidism, which is characterized by the following symptoms:

• Fatigue, lack of energy, lethargy

• Difficulty losing weight

• Edema (swelling)

• Cold intolerance

• Dry skin

• Hair loss

• Somnolence (excessive sleepiness)

• Muscle and joint pain, limb weakness

• Tendency toward depression

• Emotional lability

• Memory impairment, difficulty concentrating

• Constipation

• Menstrual irregularities, decreased fertility

• Reduced sweating

• Blurred vision

• Hearing impairment

• Voice changes

In iodine-sufficient countries, the leading cause of hypothyroidism is chronic autoimmune thyroiditis (Hashimoto's thyroiditis). To diagnose this condition, additional laboratory tests are required: ANTI-TPO (antibodies against thyroid peroxidase) and ANTI-TG (antibodies against thyroglobulin).

Overproduction of thyroid hormones relative to the body's needs is called hyperthyroidism (thyrotoxicosis), which is characterized by the following symptoms:

• Increased nervousness

• Anxiety

• Rapid heart rate (tachycardia)

• Increased sweating

• Heat intolerance

• Hyperactivity

• Tremor (shaking)

• Increased frequency of bowel movements

The most common cause of thyrotoxicosis is Graves' disease, an autoimmune disorder that requires the laboratory determination of the following antibodies for diagnosis: anti-TSH R (antibodies against thyroid-stimulating hormone receptors).

The manifestations of thyroid functional disorders are diverse and associated with various diseases. The patient's comorbidities, age, and reproductive status determine the interpretation of thyroid function tests.

In addition to function, it is essential to evaluate the structure of the thyroid gland. Structural abnormalities may accompany or cause functional disorders, although they can also exist in the presence of normal thyroid function (euthyroidism). The primary instrumental study used to evaluate thyroid structure is a thyroid ultrasound, which allows us to assess the gland's size, volume, shape, parenchymal echostructure and echogenicity, the presence of focal lesions (e.g., nodules, cysts), as well as inflammatory and diffuse changes.

Consequently, to evaluate the functional and structural status of the thyroid gland at the initial stage, the following studies are required:

• TSH

• FT4

• Thyroid ultrasound

The need for additional investigations is determined after these initial tests are interpreted by an endocrinologist.