The thyroid gland is a butterfly-shaped endocrine gland located in the neck, in front of the trachea.
It produces hormones that regulate metabolism, energy generation, and overall growth and development.
Thyroid diseases are common and can affect the structure or function of the thyroid gland.
They are broadly classified into hypothyroidism, hyperthyroidism, thyroid nodules, and thyroid cancer.
Hypothyroidism
Introduction
Hypothyroidism, or underactive thyroid, occurs when the thyroid gland does not produce enough thyroid hormones (thyroxine T4 and triiodothyronine T3).
This results in a slowing down of the body's metabolic processes.
Causes
Autoimmune Disease: Hashimoto's thyroiditis is the most common cause, where the immune system attacks the thyroid gland.
Iodine Deficiency: Insufficient iodine intake can impair thyroid hormone production.
Thyroid Surgery: Removal of the thyroid gland can lead to hypothyroidism.
Radiation Therapy: Radiation treatment for head and neck cancers can damage the thyroid gland.
Medications: Some drugs can interfere with thyroid hormone production.
Congenital Hypothyroidism: A condition present at birth due to a defective thyroid gland.
Symptoms
Fatigue
Weight gain
Cold intolerance
Dry skin and hair
Constipation
Muscle weakness and cramps
Depression
Bradycardia (slow heart rate)
Menstrual irregularities
Diagnosis
1. Blood Tests:
Measurement of thyroid-stimulating hormone (TSH) and free thyroxine (T4) levels.
High TSH and low T4 indicate hypothyroidism.
2. Thyroid Antibody Tests:
To diagnose autoimmune thyroiditis (Hashimoto's thyroiditis).
Pathophysiology of Hypothyroidism:
Hashimoto's Thyroiditis: Autoimmune destruction of the thyroid gland leading to reduced thyroid hormone production.
Iodine Deficiency: Inadequate iodine intake results in insufficient thyroid hormone synthesis.
nodules can produce excess thyroid hormones independently.
Treatment
Thyroid Hormone Replacement: Levothyroxine, a synthetic form of T4, is the standard treatment to normalize hormone levels.