Endocrine Surgery Flashcards
What is a thyroglossal duct cyst?
Remnant of thyroglossal duct as a mobile midline neck mass
dx at 1-2 yo due to neck fat
tx Sistrunk operation (take out cyst, trunk, and medial portion of hyoid bone)
What is the embyrology of the thyroid?
Derivative of foramen cecum from the base of the tongue
How do you manage a thyroid nodule?
First get TSH levels
If euthyroid, get FNA for cancer Dx
Otherwise, work up for hypo or hyperthyroidism
What is a risk for malignancy for thyroid nodules?
Solid nodules, cold nodules (lack of radioiodine uptake), size >1.5 cm
What are the main causes of hyperthyroidism?
1) Graves’ disease
2) toxic adenoma
3) toxic multinodular goiter
What is Graves’ disease?
Autoimmune disease due to IgG against TSH-R causing exophtalmos, pretibial myxedema, and hyperthyroidism
How do you treat a thyroid storm?
Beta blockers and antithyroid drugs (PTU and methimazole block peroxidase)
What is a toxic adenoma?
Dx hot nodule on scan with peripheral suppression
tx is lobectomy if >2 cm, radio-iodine if <2 cm
What are the main causes of hypothyroidism?
Hashimoto thyroiditis
Subacute/De Quervain thyroiditis
acute bacterial thyroiditis
What is Hashimoto thyroiditis?
Autoimmune disease with lymphocytic infiltration, tx with Synthroid
anti-TSH, anti-microsomal, anti-thyrogolbulin, anti-peroxidase antibodies
What is De Quervain thyroiditis?
Subacute, painful granulomatous inflammation following viral URI
Tx with observation (self-resolving)
What are the types of thyroid cancers?
Papillary (80%) Follicular (10%) Medullary (4%) Anaplastic (1%) FNA can be used to dx papillary and medullary but not follicular (must see capsular invasion to DDx adenoma vs. carcinoma)
How is papillary cancer treated?
Associated with radiation, lymphatic spread, best px overall, bx shows “Orphan Annie nuclei” with psamomma bodies
Tx with total thyroidectomy with central LN excision–> modified radical neck dissection if LN are positive for cancer
How is follicular cancer treated?
Endemic to iodine-deficient regions, hematogenous spread, 2nd best px
Tx with hemilobectomy with biopsy because 80% are benign adenomas, total thyroidectomy if bx reveals malignant carcinoma
How is medullary cancer treated?
Medullary cancer AD inheritance with MEN 2A/2B syndromes, delta ret proto-oncogene, both lymphatic and hematogenous spread
bx amyloid deposits, third best prognosis
tx with total thyroidectomy for both cancer and ret + prophylaxis with central LN excision –> modified radical neck dissection if LN are positive for cancer
How do you treat anaplastic cancer?
Rare, worst px
tx is palliative only
What is post-thyroidectomy follow up?
Take patient off T4 for six weeks (T3 instead), increase TSH level, and make sure total thyroidectomy was performed; give radioactive iodine exam after six weeks to check if any metastases will light up
Continue to follow thyroglobulin levels
For medullary cancer, 24 hour urine for VMA or metanephrines (MEN syndrome can present with pheochromocytoma), follow calcitonin levels
What is a modified radical neck dissection?
Like radical neck dissection, but spares sternocleidomastoid muscle, CN XI, and internal jugular vein
What are the risk factors for thyroid cancer?
Superior laryngeal nerve (soft/deep voice)
Recurrent laryngeal nerve (hoarseness if unilateral, dyspnea if bilateral)
Parathyroid glands (hypoparathyroidism)
What is the embryology of the parathyroid gland?
Third branchial pouch becomes inferior glands and thymus, 4th becomes superior glands
What is DiGeorge syndrome?
Congenital absence of both 3rd and 4th branchial pouches, leading to hypocalcemia and thymic aplasia
What is PTH?
Secreted from chief cells; three functions: increases renal calcium and decreases phosphorous
increases bone calcium and phosphorous
stimulates 1-alphahydroxylase to activate vitamin D for indirect GI resorption of calcium
What is osteitis fibrosa cystica?
Rapid, painful loss of bone due to HPTH; “moth eaten skull”