Endocrine surgery Flashcards
Endorcrine glands role?
Endocrine glands secrete molecules (called hormones) into the bloodstream which act on target cells in distant sites usually to maintain metabolic equilibrium (homeostasis).
The often exhibit feedback inhibition – IE activity of target tissues down – regulates activity of the original gland.
what are examples of endocrine glands?
Pituitary
Parathyroid
Thyroid
Pancreas
Adrenal
describe the physiology of the thyroid?
thyroid gland is composed of flakes of colloid surrounded by epithelial cells
thyroid hormones get synthesised under the action of TSH
thyroid hormone synthesised from iodine coupled to tyrosine to produce T3 and T4
these get stored in the colloid
when they are secreted under the action of TSH get thrown out into the bloodstream
The negative feedback loop thyroid gland is under pituitary control and TSH checks on the thyroid its causing to secrete thyroxin and thyroxin feeds back onto the pituitaryto reduce the secretion of TSH
what are effects of the thyroid hormone?
Increase in Carbohydrate/Lipid catabolism
Increase protein synthesis
Increase in basal metabolic rate
Growth and Maturation
describe the embryology of the thyroid gland?
thyroid gland starts at base of tongue in foramen caecum
and descends during embryological development
to lie in anterior triangle of neck and often leaves some remnants in the tract called the thyroglossal tract - they can later go onto produce thyroglossal cysts
describe anatomy of the neck breifly?
describe anatomy of the thyroid gland?
what is thyrotoxicosis?
Thyrotoxicosis = Clinical syndrome of excess circulating thyroid hormones, commonly due to over-secretion of thyroid hormones by the thyroid gland (=Hyperthyroidism)
what are primary causes of hyperthyroidism?
Graves’ Disease, toxic MNG, solitary toxic nodule
what are secondary causes of hyperthyroidism?
TSHoma, excess exogenous T3/4, thyroiditis
what are primary causes of hypothyroidism?
autoimmune thyroiditis, dietary insufficiency, surgery, radioiodine
what are secondary causes of hypothyroidism?
Pituitary failure
what is goitre?
enlargement of the thyroid gland
what are three different types of goitres?
Endemic
Sporadic
Multi-nodular
what types of neoplasms can affect the thyroid gland?
Adenoma
Carcinoma
Papillary
Follicular
Medullary
Anaplastic
what are causes of goitre?
Genetics
MNG
AITD
Iodine deficiency
Infiltrative disease – malignancy
TSHoma
how are goitres classified according to WHO classification?
0 impalpable – Invisible
1a palpable – Invisible on extension
1b palpable – Visible on extension
2 Visible
3 Visible at a distance
what might be implications of goitre?
SVC syndrome (5-9%)
Pemberton’s, Venous collaterals
Stridor
what are complications of a thyroidectomy?
Bleeding
Voice change – damage to recurrent laryngeal nerve
Hypocalcemia – Temporary & Permanent (=Hypoparathyroidism)
Long-term thyroid supplements
Wound problems
Vocal cord function
Medico-legal issue
Redo surgery
Voice change / Aspiration / Dyspnea
Hypoparathyroidism
Chvosteck / Trousseau’s sign
Paresthesia, numbness, tetany
Rx calcium and Vitamin D supplements
what are four types of thyroid cancer?
Papillary, follicular, medullary and anaplastic
what does medullary thyroid cancer arise from?
arises from calcitonin secreting C-Cells
what types of thyroid cancer has a good prognosis?
papillary and follicular types