Introduction

Hypothyroidism is a condition in which the thyroid gland fails to produce enough thyroid hormones. It is a common endocrine disorder that affects approximately 4.6% of the population and is more common in women than men (1). The thyroid hormones are important for the regulation of a variety of metabolic processes, including growth and development, energy metabolism, and the regulation of body weight (2). The pathophysiology of hypothyroidism is complex and not fully understood. This article will review the pathophysiology of hypothyroidism, its diagnosis, and its clinical manifestations.

Pathophysiology

Hypothyroidism is caused by a deficiency of thyroid hormones, either due to a lack of production or a lack of absorption. The most common cause of hypothyroidism is an autoimmune disorder known as Hashimoto's thyroiditis (3). In this condition, the body produces antibodies that attack the thyroid gland, causing the production of thyroid hormones to be reduced or stopped. Other causes of hypothyroidism include iodine deficiency, radiation therapy, and certain medications.

The thyroid hormones play an important role in the regulation of a variety of metabolic processes, including growth and development, energy metabolism, and the regulation of body weight. When the thyroid hormones are deficient, these processes are impaired, leading to a wide variety of symptoms.

The most common symptom of hypothyroidism is fatigue. Other symptoms include weight gain, dry skin, cold intolerance, constipation, depression, and muscle cramps. Other symptoms can include an enlarged thyroid gland (goiter), hair loss, and menstrual irregularities (4).

Diagnosis

The diagnosis of hypothyroidism is made based on clinical symptoms and laboratory tests. A blood test to measure the level of thyroid stimulating hormone (TSH) is the most commonly used test to diagnose hypothyroidism. An elevated TSH level is indicative of hypothyroidism (5). Other tests that may be used to diagnose hypothyroidism include a free thyroxine (FT4) test and a triiodothyronine (T3) test.

Clinical Manifestations

The clinical manifestations of hypothyroidism vary depending on the severity of the condition and the age of the patient. In adults, the most common symptoms are fatigue, weight gain, dry skin, cold intolerance, constipation, depression, and muscle cramps. In children, the most common symptoms are delayed growth and development, fatigue, and poor school performance.

Treatment

The treatment of hypothyroidism is aimed at restoring normal levels of thyroid hormone in the body. The most common treatment is the use of synthetic thyroid hormone, which is taken in the form of a pill. The dose of the medication is adjusted to maintain normal levels of thyroid hormone in the body. In some cases, surgery may be necessary to remove part or all of the thyroid gland.

Conclusion

Hypothyroidism is a common endocrine disorder that affects approximately 4.6% of the population. The pathophysiology of hypothyroidism is complex and not fully understood. The diagnosis of hypothyroidism is made based on clinical symptoms and laboratory tests. The clinical manifestations of hypothyroidism vary depending on the severity of the condition and the age of the patient. The treatment of hypothyroidism is aimed at restoring normal levels of thyroid hormone in the body.