hyperthyroidism or Thyrotoxicosis
Hyperthyroidism, also called overactive thyroid, is when the thyroid gland makes more thyroid hormones than your body needs. The thyroid is a small, butterfly-shaped gland in the front of your neck. Thyroid hormones control the way the body uses energy, so they affect nearly every organ in your body, even the way your heart beats. Thyrotoxicosis is the name given to the clinical effects experienced due to an excess of thyroid hormones in the bloodstream. Hormones produced by the thyroid gland control how fast or slow the body works (metabolic rate). Too much thyroid hormone (thyroxine and triiodothyronine) speeds up the metabolism and results in the signs and symptoms of thyrotoxicosis.
Causes of hyperthyroidism or thyrotoxicosis
Hyperthyroidism has several causes.
Graves’ disease: Graves’ disease is the most common cause of hyperthyroidism. Graves’ disease is an autoimmune disorder. With this disease, your immune system attacks the thyroid and causes it to make too much thyroid hormone.
Overactive thyroid nodules: Thyroid nodules are lumps in your thyroid. Thyroid nodules are common and usually benign, meaning they are not cancerous. However, one or more nodules may become overactive and produce too much thyroid hormone. The presence of many overactive nodules occurs most often in older adults.
Thyroiditis: Thyroiditis is inflammation of your thyroid that causes stored thyroid hormone to leak out of your thyroid gland. The hyperthyroidism may last for up to 3 months, after which your thyroid may become underactive, a condition called hypothyroidism. The hypothyroidism usually lasts 12 to 18 months, but sometimes is permanent. Several types of thyroiditis can cause hyperthyroidism and then cause hypothyroidism:
- Subacute thyroiditis
- Postpartum thyroiditis
- Silent thyroiditis
Too much iodine: Your thyroid uses iodine to make thyroid hormone. The amount of iodine you consume affects the amount of thyroid hormone your thyroid makes. In some people, consuming large amounts of iodine may cause the thyroid to make too much thyroid hormone.
Some medicines and cough syrups may contain a lot of iodine. One example is the heart medicine amiodarone. Seaweed and seaweed-based supplements also contain a lot of iodine.
Too much thyroid hormone medicine: Some people who take thyroid hormone medicine for hypothyroidism may take too much. If you take thyroid hormone medicine, you should see your doctor at least once a year to have your thyroid hormone levels checked. You may need to adjust your dose if your thyroid hormone level is too high. Some other medicines may also interact with thyroid hormone medicine to raise hormone levels. If you take thyroid hormone medicine, ask your doctor about interactions when starting new medicines.
Symptoms
Hyperthyroidism can mimic other health problems, which can make it difficult for your doctor to diagnose. It can also cause a wide variety of signs and symptoms, including:
- Unintentional weight loss, even when your appetite and food intake stay the same or increase
- Rapid heartbeat (tachycardia) — commonly more than 100 beats a minute
- Irregular heartbeat (arrhythmia)
- Pounding of your heart (palpitations)
- Increased appetite
- Nervousness, anxiety and irritability
- Tremor — usually a fine trembling in your hands and fingers
- Sweating
- Changes in menstrual patterns
- Increased sensitivity to heat
- Changes in bowel patterns, especially more frequent bowel movements
- An enlarged thyroid gland (goiter), which may appear as a swelling at the base of your neck
- Fatigue, muscle weakness
- Difficulty sleeping
- Skin thinning
- Fine, brittle hair
Younger patients tend to exhibit symptoms of sympathetic activation (eg, anxiety, hyperactivity, tremor) .Older patients have more cardiovascular symptoms (eg, dyspnea, atrial fibrillation).
Complications
- Heart problems
- Brittle bones
- Eye problems
- dermopathy
- Thyrotoxic crisis
References
https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659#:~:text=Hyperthyroidism%20(overactive%20thyroid)%20occurs%20when,treatments%20are
https://www.virginiamason.org/thyrotoxicosis
https://emedicine.medscape.com/article/121865-overview
https://www.yourhormones.info/endocrine-conditions/thyrotoxicosis/
https://www.niddk.nih.gov/health-information/endocrine-diseases/hyperthyroidism
