Hashimoto's Thyroiditis (Hashi's)
It's the most common of the thyroid disorders, with a genetic link, the tendency toward developing this autoimmune disorder has a tendency to run in families.
It's still not known exactly what triggers the disorder, but there is very strong evidence that excess iodine intake is definately one of them.
With Hashi's the body cycles between hyPERthyroid and hyPOthyroid as the gland struggles to maintain fucntion as it is being destroyed by the Hashi's antibodies.
With each cycle the gland reovers less and less until the body eventually stays hypo.. Until the gland is ulitimately destroyed.
Hormone replacement is the best treatment, so far. Sufficient levels of replacement must be give to totally suppress TSH levels. That is to say that TSH levels need to be as close to zero as possible, without causing thyroid hormone levels (Free T4 and Free T3) to go over range and cause the body to become 'hyper' in response to an excess of thyroid hormone.
It is UNTRUE that a low TSH is an absolute indicator of a hyPERthyroid state.
TSH is the Thyroid Stimulating Hormone. It is released by the Pituitary Gland as an instruction to the Thyroid Gland as to how much hormone it is supposed to release. Once the thyroid gland is missing, or destroyed, it no longer gives it's feedback as to what is going on in the body.
The Hypothalamus, Pituitary and Thyroid Glands make up the 'feedback' loop involved in maintaining proper levels of hormone. Once that loop is disrupted, either from loss of proper function of one of the glands, or the introduction of replacement hormone, TSH becomes a useless indicator of body response to the replacement hormone.
Always monitor Free T4 and Free T3 levels, once you are on replacement hormone, as well as symptoms and body response... it's the best way to determine proper dosing of replacement hormone.