Try searching for hypothyroidism. I've never heard it called hypothyroidy before....What it is though is a state in which the thyroid is underactive. Could be due to any number of things (like lack of iodine which is needed for thyroid hormone synthesis, Hx of Tx with antithyroid meds or radioactive iodine, if they've had a thyroidectomy, could also be autoimmune, congenital, or could be a problem with the pituitary gland which secretes thyroid stimulating hormone). If there's no pituitary problem, you usually see low levels of T3 and T4, and high levels of TSH. Signs and symptoms you may see are fatigue, lethargy, intolerance to cold, wt gain, no appetite, bradycardia, dry skin and hair, memory impairment, depression-like symptoms. Might also get a goiter (from the increase in TSH). Gets treated with synthroid. Hope that helped . . .