OVERVIEW OF THE THYROID
The biggest endocrine gland in human
Function : synthesis thyroid hormone; triiodothyronine (T3) and thyroxine (T4)
Hormone synthesis and release is achieved by an intricate negative feedback mechanism involving gland an hypothalamic-pituitary axis
Autoregulation depend on iodine: Wolff-Chaikoff effect
Thyroid hormones are bounded to specific serum binding protein
In extrathyroidal tissue: T4 change to T3 by using 5-deiodinases in liver
80% of T4 and T3 is metabolized by non deiodination
THYROID EVALUATION
Symptoms of thyroid excess or deficiency
A history of familial thyroid abnormality
Examination of the thyroid for enlargement, consistency, nodularity
Medication history
Appropriate thyroid function test
THYROID FUNCTION TEST
Most common lab used: TSH, total T4, free T4, total T3, free T3
TSH : the most cost effective screening test however, not reliable in secondary hypothyroidism
FT4 : patients recently treated for thyroid disorder
A nonspecific indice : cholesterol and other lipid profile, SGOT, SGPT, CPK, Cr
HYPERTHYROIDISM
EPIDEMIOLOGY
Women > men (2% : 0.2%)
Peak incidence in children: 10-12 year old
Grave disease is the most common cause of hyperthyroidism: 20-50 year old
THE CAUSES OF HYPERTHYROIDISM
Toxic diffuse goiter (Graves’ disease): production of thyroid stimulating antibodies
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dr khaled
or
thyroid disorders
الإثنين نوفمبر 08, 2010 6:15 am