People with thyroid disease have a variety of symptoms with a variety of causes. The unique butterfly-shaped gland, located in the mid-lower region of the neck, produces thyroid hormones responsible for regulating growth and metabolism. Too much or too little hormone causes dysregulation and worrisome symptoms. Although this gland is small and nearly nonexistent as one ages, it affects every cell in the body. The Cleveland Clinic reports 20 million persons have some form of thyroid disease.
Hyperthryoidism
Release of excess hormone from the thyroid causes disease. Thyroid hormone has an active form, triiodothyroxine (T3), and a non-active form, thyroxine (T4), that circulates through the bloodstream. If this balance is disturbed, patients can experience an extensive list of symptoms that range from early to late manifestations, as provided by UCLA Health:
Early symptoms include fatigue, frequent bowel movements, heat intolerance, palpitations and tachycardia. Late symptoms include goiter (visibly enlarged thyroid gland) or thyroid nodules, weight loss (rarely, weight gain), proptosis (eye protrusion) and coma. Additional symptoms are too numerous to list.
Grave's disease is the most common cause of hyperthyroidism. Overstimulation is caused by autodestruction of receptors located on the thyroid. In turn, this produces excess hormone, leading to hyperthyroid symptoms.
Nodular toxic goiter is another cause of hyperthyroidism. Hyperfunctioning mutated growths in the thyroid glands begin to release thyroid hormone autonomously on their own. This usually occurs as a response to a deficiency in iodine.
Thyroiditis is known by several names, including DeQuervain's and subacute thyroiditis. It is a painful inflammation of they thyroid gland that causes both hyperthyroid early on and hypothyroid symptoms late in the disease. Typically occurring after a viral illness, the cause is unknown and self-limiting, resolving in a few weeks.
Some other causes of hyperthyroidism include external administration of thyroid hormone, infections, trauma and destruction of the pituitary gland.
Hypothyroidism
Release of too little thyroid hormone is also a problem. Production of sufficient amounts of T3 and T4 is based on the availability of iodine. Without iodine, metabolism and growth are disturbed. UCLA Health says early symptoms include abnormal menstrual periods, cold intolerance and constipation. Late symptoms include heart failure; dry, flaky skin; hoarseness; myxedema (swelling of the lower shins); and goiter.
Hashimoto's thyroiditis is an autoimmune disorder that causes hypothyroidism. Antibodies targeted at the thyroid tissue destroy thyroid follicles, rendering the thyroid unable to manufacture thyroid hormones.
Iodine deficiency is the most common cause of hypothyroidism worldwide. In developing countries without access to iodine, the necessary chemical to make thyroid hormones, hormonal deficiencies often develop. Children with iodine deficiency experience dramatic growth and development retardation.
Thyroiditis, as described above, temporarily causes hypothyroidism late in the disease. After the disease runs its course and iodine is exhausted, patients return to normal thyroid levels and becomse euthyroid.
Other Causes
Some other causes of hypothyroidism include thyroid surgery, hyperthyroid treatment (ablation) and an abnormal pituitary gland. Symptoms of both hyperthyroidism and hypothyroidism can be disturbing and disruptive to a patient's quality of life. Most thyroid diseases are treatable with good outcomes.
