Hypothyroidism is a medical condition characterized by an underactive thyroid gland, which results in insufficient production of thyroid hormones. These hormones play a crucial role in regulating various bodily functions, and a deficiency can lead to a range of symptoms and health issues. Understanding the symptoms, causes, and types of hypothyroidism is essential for accurate diagnosis and effective management.

Symptoms:

1. Fatigue: Persistent tiredness and low energy levels are common symptoms of hypothyroidism.
2. Weight Gain: Unexplained weight gain, often accompanied by difficulty losing weight despite efforts.
3. Cold Sensitivity: Feeling unusually sensitive to cold temperatures, with cold hands and feet.
4. Dry Skin and Hair: Dry skin, brittle nails, and hair loss are common manifestations of hypothyroidism.
5. Muscle and Joint Pain: Aches and stiffness in muscles and joints can be symptoms of an underactive thyroid.
6. Constipation: Slowed digestive processes may lead to constipation.
7. Depression: Hypothyroidism can contribute to mood changes, including feelings of depression.
8. Menstrual Irregularities: Irregular or heavy menstrual periods may occur in women with hypothyroidism.

Causes:

1. Autoimmune Thyroiditis (Hashimoto’s Disease): The most common cause of hypothyroidism is an autoimmune condition where the body’s immune system mistakenly attacks and damages the thyroid gland. This leads to a gradual decrease in thyroid hormone production.
2. Thyroidectomy or Radioactive Iodine Treatment: Surgical removal of the thyroid gland or treatment with radioactive iodine for hyperthyroidism can result in hypothyroidism.
3. Iodine Deficiency: Insufficient iodine in the diet can lead to hypothyroidism, as iodine is essential for the production of thyroid hormones.
4. Medications: Certain medications, such as lithium and amiodarone, can interfere with thyroid function and lead to hypothyroidism.
5. Congenital Hypothyroidism: Some individuals are born with an underactive thyroid gland, a condition known as congenital hypothyroidism. Early detection and treatment are crucial to prevent developmental issues.

Types:

1. Primary Hypothyroidism: This is the most common type and refers to a dysfunction of the thyroid gland itself. Hashimoto’s disease is the leading cause of primary hypothyroidism.
2. Secondary Hypothyroidism: This type results from a dysfunction of the pituitary gland or hypothalamus, which are responsible for regulating thyroid hormone production. Tumors, radiation therapy, or other conditions affecting these glands can lead to secondary hypothyroidism.
3. Subclinical Hypothyroidism: In this condition, blood tests reveal a slightly elevated thyroid-stimulating hormone (TSH) level, but the levels of the actual thyroid hormones (T3 and T4) are within the normal range. Subclinical hypothyroidism may progress to overt hypothyroidism over time.
4. Overt Hypothyroidism: This is the more advanced stage of hypothyroidism, where both TSH and thyroid hormone levels are outside the normal range. Symptoms are usually more pronounced in overt hypothyroidism.
5. Transient Hypothyroidism: Temporary hypothyroidism can occur after childbirth (postpartum thyroiditis) or during recovery from subacute thyroiditis. In these cases, thyroid function may return to normal over time.