In medical terms, “hypo-“means too little and “hyper-“ means too much of something. Hypothyroidism is the condition caused by abnormally low output of thyroid hormones. Most patients will have loss of energy, tiredness, cold intolerance, dry skin and hair, slow heart rates, constipation, thinning hair, and menstrual irregularities. Modest weight gains occurs at times but not heavy weight gains. Most often hypothyroidism is the end result of a self-reactive immunological (autoimmune) disease whereby white blood cells invade the gland and destroy it (chronic lymphocytic thyroiditis or Hashimoto’s disease). Hypothyroidism from Hashimoto’s disease is frequent within 1-4 months after the birth of a child, since pregnancy is immuno-suppressive and the immune sytem rebounds after birth. The disease has antibody markers that the Clinic will screen you for. If present, then other autoantibody markers as present in APS-2 (see Addison’s disease) will be screened for. Often, other members of the family are affected by components of APS-2 and advice is provided by the Clinic how to identify them. Hashimoto’s disease is common in patients with type-1 diabetes. Lithium treatments regularly cause hypothyroidism by interfering with the thyroid’s ability to make normal hormones.
Newborn babies are screened for hypothyroidism by the State and are treated as soon as possible after detection by replacement thyroid hormones to avoid brain damage. Sometimes there is sufficient doubt about the diagnosis that infants are treated to avoid the risk of hypothyroidism to the developing brain. When brain development is nearly complete at 3 years of age, a trial off such hormones may be safely undertaken. Those who fail to secret enough thyroid hormone after 4-6 weeks are given thyroid hormone for life. Less commonly, hypothyroidism results from surgical removal or irradiation of the thyroid gland, biochemical lesions and deficiency of thyroid stimulating hormone (TSH) from the pituitary.
Thyroid replacement is by L-thyroxine (T4) in a dose sufficient to normalize blood thyroid hormone levels and reduce TSH levels (usually TSH is elevated found when there is a disease of the thyroid). The addition of T3 hormone (the active form) is almost never required.
This condition is caused by secretion of excessive thyroid hormones for the body’s needs. The two most common causes are a self reactive immunological (autoimmune disease) involving thyroid stimulating antibodies against the thyroid’s TSH receptors called Graves’ disease, and “toxic” thyroid nodule(s) or benign tumor(s) (adenoma(s)). Excessive secretion of thyroid hormones leads to emotional instability, inappropriate sweating or heat intolerance, rapid heart beating (palpitations), loose bowel motions, thinning or the hair, menstrual irregularity, weight loss, fatigue, and darkening of the skin if present for a long time. Some patients become aware of an enlargement of the thyroid (goiter) while those with Graves disease can develop protrusion of the eyes (proptosis) with inflammation (exopthalmos), and a partial paralysis of the eye lids resulting in a stare.
Patients are treated with beta blockers initially if needed to control symptoms. They are also treated with medications that block thyroid hormone synthesis, and usually become under control after 3-6 weeks. Some patients with nodular thyroids will require surgery or thyroid ablation with radio-iodine taken by mouth.
For patients with Graves’ disease, the options at this point are to continue medications with or without thyroid hormones to suppress the thyroid gland for two years. After this time, the medication is stopped to see whether Graves’ disease recurs. If hyperthyroidism does recur (about a 50% chance), then another course of these drugs can be initiated for another two years, with a further 50% chance of remission. The medications concerned do have some side effects which are clearly presented to patients at the time of their clinic visits. The Clinic will monitor you for these problems.
The alternative treatment is to give a dose of radio-iodine by mouth. However this therapy is usually associated with continued damage to the thyroid gland leading to need for thyroid replacement hormones (l-thyroxine) for life. Many patients especially if young, may have a combination autoimmune thyroid disease comprised of both Hashimoto’s and Graves’ diseases (Hashitoxicosis). Such patient often become hypothyroid with time even thought they were at first hyperthyroid. Management of Graves’ patients through pregnancy needs care since the antibody reactive against the TSH receptor can cross the placenta to the baby and if in high enough amounts, can induce transient Graves’ disease in the baby. Similarly, medication can cross the placenta too.
Nodules or “lumps’ in the thyroid gland are routinely sought in all Clinic patients. Studies by other indicate 1% of men and 5% of women have them. They are rare before adolescence. However thyroid ultrasound studies indicate that the real frequency of nodules in adults is much higher than suggested by clinical examination. Whereas most thyroid nodules are benign (adenomas or retention (colloid) cysts, a relatively small number are cancers, with papillary types most frequent followed by follicular types. Others are Hurtle cell tumors or medullary cancers which secrete a hormone named thyrocalcitonin. The latter tumors are often malignant and associated with multiple endocrine adenomas or MENs. These two types comprise 90% of thyroid cancers. Persons exposed to prior irradiation of the head and neck, a positive family history, single large nodules, those with enlarging solid nodules and nodules that fail to take up radio-iodine are those causing the greatest concerns. In such cases, a needle biopsy (fine needle aspiration or fna) under local anesthesia will be undertaken by the Clinic for pathological diagnosis. Thyroids affected by autoimmune thyroid disease may harbor a coincidental cancer too. As mentioned under hyperthyroidism, toxic nodules may secrete excessive amounts of thyroid hormones, but these types do not often degener