Physiology
What is TSH?
Hormone from pituitary gland that stimulates thyroid to produce T4 and T3
What is the most common form of hyperthyroidism in developed countries?
Graves' Disease
Most common cause of hypothyroidism in iodine-sufficient areas?
Hashimoto's Disease
What are measures are involved in Thyroid Function Tests
Free T3/T4, TSH
potentially TPO antibodies, TSI (autoimmune markers), total T4/T3
What is thyroid perioxidase?
Enzyme responsible for, in the presence of H2O2, oxidises iodine and aids formation of MIT/DIT
What is the name of the antibody that mimics TSH in Graves' Disease?
Thyroid Stimulating Immunoglobulin
TSH, elevated to due loss of negative feedback
Low TSH, low T3/T4
Primary or secondary hypothyroidism?
Secondary
Which of T3 or T4 is more active, and which is more prominent in blood?
T3 active form, T4 more abundant
T4 converted to T3 in peripheral tissues
What is the name of the condition that can cause a transient hyperthyroidism after a viral infection?
Subacute thyroiditis (De Quervain's thyroiditis)
Name of drug used for bipolar disorder that can cause hypothyroidism?
Lithium
- Inhibits thyroid hormone release
- Disrupts iodine uptake
- Toxic to follicular cells
What is T3 toxicosis?
Low TSH, High T3 and normal T4
Certain thyroid conditions cause the gland to preferentially produce more T3 than T4.
What is the role of the sodium-iodide symporter?
Moves iodide into follicular cells, stimulated by TSH
What is a thyroid storm?
A rare, life threatening exaggeration of hyperthyroidism symptoms.
What is thyroid dysgenesis?
Congenital cause of hypothyroidism that involves the thyroid being completely absent, or abnormally formed.
What is the name of the antibody causes disregulation of TPO, and can be measured in a TFT?