The thyroid gland is a small, butterfly-shaped gland located at the base of the neck. It produces thyroid hormones that regulate metabolism, growth, development, and body temperature. When the thyroid gland does not function properly, it can cause several health problems. Here are some of the main diseases caused by thyroid dysfunction:
Hypothyroidism
Hypothyroidism, also called underactive thyroid, is a condition where the thyroid gland does not produce enough thyroid hormones. This can slow down metabolism and cause symptoms like fatigue, weight gain, hair loss, feeling cold, constipation, dry skin, depression, and impaired memory.
Common causes of hypothyroidism include:
- Hashimoto’s thyroiditis – an autoimmune disorder where the immune system attacks the thyroid
- Thyroid surgery
- Radiation treatment to the thyroid
- Congenital hypothyroidism – hypothyroidism present from birth
- Medications like lithium, amiodarone, interferon alpha
- Too little or no iodine in the diet
- Pituitary disorders
Hypothyroidism is usually treated with synthetic thyroid hormone medication like levothyroxine to restore normal thyroid hormone levels.
Hyperthyroidism
Hyperthyroidism is the opposite of hypothyroidism – it is a condition where the thyroid gland is overactive and produces too much thyroid hormone. This speeds up metabolism and can cause symptoms like weight loss, rapid heart rate, hand tremors, sweating, anxiety, and diarrhea.
Common causes of hyperthyroidism include:
- Graves’ disease – an autoimmune disorder where antibodies overstimulate the thyroid
- Toxic adenomas – benign tumors on the thyroid that overproduce hormones
- Inflammation of the thyroid – thyroiditis
- Excess iodine intake
- Taking too much synthetic thyroid hormone medication
Treatment for hyperthyroidism aims to slow down thyroid hormone production and commonly involves medications like methimazole, radioiodine therapy, or thyroid surgery.
Goiter
A goiter is an enlargement of the thyroid gland that forms a visible, painless swelling at the front of the neck. While goiters are often associated with hyperthyroidism and hypothyroidism, they can also occur due to iodine deficiency, thyroid inflammation, thyroid cysts, thyroid cancer, and other conditions.
Small goiters that are not causing symptoms usually do not require treatment beyond regular monitoring. However, large goiters that are problematic may be treated with radioiodine therapy or thyroid surgery.
Thyroid nodules
Thyroid nodules are lumps that form on the thyroid gland. Most are benign (non-cancerous), however a small percentage can be cancerous. Symptoms depend on the size – small nodules often cause no symptoms while larger nodules may cause swelling, pain, difficulty swallowing or breathing.
Thyroid nodules are usually detected during a routine physical exam. An ultrasound is done to characterize the nodules. Treatment depends on the type of nodules – most benign nodules just require monitoring while suspicious nodules may need a biopsy or to be surgically removed.
Thyroid cancer
There are several types of thyroid cancer, with the most common being:
- Papillary thyroid cancer – Usually grows slowly and has a good prognosis.
- Follicular thyroid cancer – More aggressive than papillary cancer.
- Medullary thyroid cancer – Can run in families and be associated with other endocrine tumors.
- Anaplastic thyroid cancer – A rare but very aggressive type.
Risk factors for thyroid cancer include radiation exposure, family history, and certain genetic syndromes. Symptoms can include a lump or nodule in the neck, hoarseness, difficulty swallowing, swollen lymph nodes, and pain.
Treatment typically involves surgery to remove part or all of the thyroid, followed by thyroid hormone therapy and radioactive iodine therapy. The prognosis is usually excellent, especially for slower growing types detected early.
Thyroiditis
Thyroiditis refers to inflammation of the thyroid gland, usually caused by an autoimmune attack or a viral infection. Symptoms can include pain, swelling, difficulty swallowing, and temporary hyperthyroidism or hypothyroidism.
Common types of thyroiditis include:
- Hashimoto’s thyroiditis – The most common cause of hypothyroidism in the US. Causes gradual destruction of the thyroid.
- Postpartum thyroiditis – Occurs after pregnancy. Usually starts as hyperthyroidism followed by hypothyroidism.
- Subacute thyroiditis – Caused by a virus, usually involves painful thyroid swelling and inflammation.
- Drug-induced thyroiditis – Caused by medications like amiodarone, interferon-alpha.
- Radiation thyroiditis – Occurs after radiation treatment to the thyroid.
- Acute thyroiditis – A rare bacterial infection of the thyroid gland.
Treatment focuses on managing symptoms and restoring normal thyroid function with thyroid hormone medications if needed.
Myxedema coma
Myxedema coma is an extremely rare but life-threatening state of extreme hypothyroidism. It may occur in people with undiagnosed or untreated hypothyroidism who are subjected to trauma, stress, surgery, or severe infection.
Symptoms include confusion, decreased consciousness, hypothermia, hypoventilation, hypotension, and hypoglycemia. It is considered a medical emergency requiring hospitalization and immediate treatment with thyroid hormone replacement.
Thyroid storm
Thyroid storm is a rare, life-threatening condition of extreme hyperthyroidism. It may be triggered by trauma, surgery, infection, or discontinuing anti-thyroid medications in someone with uncontrolled hyperthyroidism.
Symptoms include high fever, tachycardia, nausea, diarrhea, dehydration, delirium, seizures, shock, and coma. Hospital treatment with medications to lower thyroid hormone levels is urgently needed.
Conclusion
Thyroid disorders are common, affecting around 20 million Americans. The main diseases caused by thyroid problems include hypothyroidism, hyperthyroidism, goiters, thyroid nodules, thyroid cancer, and thyroiditis. Extreme thyroid dysfunction can also result in emergencies like myxedema coma and thyroid storm.
Fortunately, most thyroid conditions are very treatable, especially when detected early. Getting regular thyroid screening through annual checkups and knowing the signs and symptoms of thyroid disease allows for earlier diagnosis and treatment.