Hypothyroidism Flashcards
What predisposes to hypothyroidism?
areas of increased iodine intake
white populations
What is the most common form of hypothyroidism?
Hashimotos thyroiditis
What genes is Hashimotos thyroiditis associated with?
HLA-DR3 and DR5
What is the pathophysiology behind Hashimotos thyroiditis?
CD8 autoimmune destruction of the thyroid gland leading to decreased thyroid hormone production
What age and gender commonly present with Hashimotos thyroiditis?
females>males
40-60yrs
What are the histological signs of Hashimotos thyroiditis?
T cell infiltration and inflammation
What is Hashimotos thyroiditis associated with?
MALT lymphomas
What are the symptoms of hypothyroidism?
puffy face and hands weight gain sluggish lid lag cold intolerance slow pulse pitting oedema hypercarotenemia - yellowing of skin
What are the biological investigations done for hypothyroidism?
increased TSH decreased free T3 and T4 increased creatine kinase increased LDL cholesterol increased MCV - macrocytosis decreased renal tubular water loss hyperprolactinaemia
What is the treatment for hypothyroidism in younger patients?
50-100ug levothyroxine - T4 - taken before breakfast
What is the treatment for hypothyroidism in older patients with a history of IHD?
25-50ug Levothyroxine - adjust based on response
Why is T4 used to treat hypothyroidism not T3?
T4 has a longer half life so it is easier to manage the levels and plasma concentrations
What biological antibody sign is present in hashimotos thyroiditis?
anti TPO (thyroid peroxidase)
