Hypothyroidism
Hypothyroidism is a pathologic state caused by insufficient
secretion of thyroid hormones by the thyroid gland. There are several
distinct causes for chronic hypothyroidism, most common being Hashimoto's
thyroiditis and postoperative or hypothyroidism following radioiodine therapy for hyperthyroidism.
Severity of hypothyroidism is variable. Some patients are classified as
subclinical hypothyroid when only diagnostic findings show thyroid
hormone abnormality. Others have moderate symptoms that can be mistaken
for other diseases and states. Advanced hypothyroidism is easily recognized
even for non-specialist.
Hypothyroidism signs and symptoms are :
In the elderly, hypothyroidism is relatively common and can be easily missed. It is an important but treatable cause of depression in this age group.
Neonatal period
Thyroid hormone is very important to neural development in the neonatal
period. A deficiency of thyroid hormones can lead to cretinism. For this
reason it is important to detect and treat thyroid deficiency early. In
Australia and many other countries this is done by testing for TSH on the routine neonatal heel pricks performed by law on all new born babies.
Hashimoto's Thyroiditis
This is part of the spectrum of auto-immune diseases and is related to Graves' disease, lymphocytic thyroiditis as well as other organ related auto-immune conditions such as Addison's disease, diabetes, premature menopause and vitiligo. Hashimoto's is a lymphocytic and plasmacytic thyroid inflammation that eventually destroys the thyroid. Patients require permanent thyroid replacement.
Pituitary failure
Reduction or loss of TSH secretion by the pituitary is a very rare cause of hypothyroidism.
Iatrogenic
(or Doctor induced).
Treatment
Substitution of thyroid hormones by taking thyroxine (T4) tablets. Doses are
started with smaller amounts of thyroxine and then slowly titrated
under control of TSH levels. Usually the maintenance dose is about
1-2 mcg per kilogram of body weight.
Controversy exists about the usefulness of administrating triiodothyronine (T3) as well as T4.
Some thyroid deficiency is a side effect of treatment for thyroid cancer, and Graves' disease.
See also :
DMOZ, hyperthyroidism
Referenced By
Dementia | Guthrie test | List of rare diseases/H | List of rare diseases starting with H | Senile | Senility | Thyroid | Thyroid gland
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