Where does the thyroid diverticulum arise from and where does it go?
Floor of primitive pharynx and descneds into the neck
How is the thyroid connected to the tongue?
Thyroglossal duct
What happens when the thyroglossal duct persists?
Becomes the pyramidal lobe of thyroid
What is th normal remnant of the thyroglossal duct?
Foramen cecum
Where is the most common site of ectopic thyroid tissue?
Tongue
Presentation of thyroglossal duct cyst?
Anterior midline neck mass that MOVES with swallowing.
How is thyroid hormone formed?
- Iodine is transported into cuboidal cells of the thyroid follicle. 2. Iodine combines with thyroglobulin via peroxidase forming MIT and DIT. 3. MIT and DIT form T4 and T3. 4. T4 is sent out and converted to more active T3 in the peripheral tissue via 5’deiodinase.
Symptoms of Hyperthyroidism?
Heat intolerance, weight loss, inc appetitie, hyperactivity, diarrhea, inc reflexes, warm moist skin, fine hair, chest pain, palpitations, arrythmias, inc B-adrenergic receptors
Lab findings in hyperthyroidism?
Dec TSH, Inc free or total T4, Inc Free or total T3
Causes of Hyperthyroidism (Thyrotoxicosis)
- Toxic multinodular goiter. 2. Graves’ disease. 3. Thyroid storm. 4. Struma ovarii teratoma. 5. Subacute thyroiditis (de Quervarian’s)
Jod-Basedow phenomenon
When a pt with iodine deficient goiter gets thyrotoxicosis after iodine repletion (ex. recent study using IV iodine contrast)
Toxic Multinodular Goiter
Focal patches of hyperfunctoining follicular cells working independently of TSH due to mutaiton in TSH receptor. Inc rel of T3 and T4. Multiple hot nodules.
Are hot nodules malig?
No
Cause of Graves’ Disease
Autoimmune hyperthyroidism w/ thyroid-stimulating IgG.
Presentation of Graves’ Disease
Proptosis (exophthalmos), EOM swelling; pretibial myxedema; inc CT deposition; diffuse goiter
Special lab findings in Graves’
Inc resin radioactive T3 uptake and inc radioactive iodine scan
HLA assoc w/ Graves’?
HLADR3 and HLAB8
Definitive rx for Graves’?
Thyroidectomy
Pharmaceutical rx for hyperthyrodism?
- Propylthiouracil. 2. Methimazol. 3. B-blockers. 4. Radioactive Iodine
What is a thyroid storm?
Stress-induced catecholamine surge-> death (by arrythmia) and and coma.
What is subacute thyroiditis (de Quervian)
Self-limited hypothyroidism following a flu-like illness (usually viral infexn). Begins w transient hyperthyroidism and becomes hyper. Histo: granulomatous inflammation. TENDER thyroid. Assoc w/ HLAB35
Approach to Thyrotoxicosis
See SU 217
What happens to thyroid hormone levels during preg?
Increase in thyroid binding globulin; inc free T4 and T4; normal free T4 and T3
Single thyroid nodule and hyperthyroidism?
Toxic thyroid adenoma
