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
what types of thyroid cancer has a poor prognosis?
Anaplastic
how is thyroid cancer investigated?
Ix with fine needle aspiration cytology (FNAC)
where does thyroid cancer commonly spread to?
spreads to lymph nodes, bone and lungs
what does treatment of thyroid cancer include?
surgery, radio-iodine
describe the anatomy and embryology of parathyroid glands?
describe the physiology of parathyroid glands?
parathyroid hormone acts to control calcium level in the blood stream along with vitamin D
vitamin D is derived from sunlight we are deficient here especially during the winter months
it gets activated in the liver and kidney from hydroxycholwcalciferon to dihydroxycholecakciferon
if your calcium level in the blood stream was foul for any reason parathyroid glands would start to work harder to create PTH that acts on kidney and bone to increase calcium in the bloodstream and it acts on osteoclasts to increase calcium reabsorption from nephron
what does excess autonomous secretion of PTH lead to?
leads to excess calcium in blood stream = hypercalcemia
describe the different probabilities of primary disorders of parathyroid glands?
adenoma (80-90%), hyperplasia (10-20%), carcinoma (1%)
what are secondary causes of pathology of parathyroid glands?
renal failure, hypovitaminosis D
what are different types of parathyroid surgery?
Targeted Parathyroidectomy
Bilateral Neck Exploration
what does this image show?
ectopic parathyroid gland in the chest
what are the different parts of the adrenal gland?
adrenal Cortex & Medulla
describe the adrenal cortex?
Cortex synthesis and releases steroid hormones
Three Layers:
Zona Glomerulosa = Mineralocorticoids (=Aldosterone)
Zona Fasciculata = Glucocorticoids (=Cortisol)
Zona Reticularis = Androgens and Oestrogens
what does the adrenal medulla do?
Medulla secretes &
Adrenaline/Noradrenaline
what is the result of excess glucocorticoids?
cushings syndrome
what are symptoms of cushings syndrome?
Weight gain, central obesity, moon facies, buffalo hump fat pad, easy bruising, thin skin, poor wound healing, purple abdominal striae, hirsutism, infertility, depression, irritability, opportunistic infections.
what are signs of cushing syndrome?
Hypertension, diabetes, impaired glucose tolerance, osteoporosis, osteopenia, hypokalemia, leukocytosis with relative lymphopenia
what is the aetiology of cushings syndrome?
what is the result of excess mineralocorticoids?
Conn’s Syndrome
describe the features of conns syndrome?
Hyperalderonism
Primary / Secondary
Increased Na reabsorption by distal tubule and collecting duct of the nephron & Increased K/H excretion
Increased ECF volume
Hypertension +/- Hypokalemia
describe the synthesis and metabolism of catecholamines?
what is the result of excess catecholamines?
phaeochromocytoma
what is phaeochromocytoma?
Adrenal medulla secretes adrenaline + noradrenaline when stimulated by the sympathetic nervous system
Extra-adrenal chromaffin tissue – scattered throughout abdominal prevertebral sympathetic plexuses
10% Tumor
10% familial, malignant, multiple, extra-adrenal
what are symptoms of phaeochromocytoma?
(in paroxysms)
Tachycardia, palpitations, pallor, tremor, headache & sweating
what are signs of phaeochromocytoma?
Hypertensions, Orthostatic hypotension, Pallor, Retinopathy, Fever & Tremor
what investigations are done for phaeochromocytoma?
Urine / Plasma metanephrines MIBG Scans ->
what surgery can be done for cushings adenoma?
Right Transabdominal Laparoscopic Adrenalectomy
what are neuroendocrine tumours?
Tumors of gut endocrine cells
Carcinoid (=cancer-like)
Secrete serotonin, chromogranin
what are clinical features of neuroendocrine tumors?
Clinical features:
Asymptomatic
Intestinal obstruction / bleeding
what syndrome can be seen in advanced cases of neuroendocrine tumors?
Carcinoid syndrome in advanced disease
Flushing, diarrhea, bronchospasm
how are neuroendocrine tumors diagnosed?
Measure urinary 5-HIAA serum chromogranin
what are pancreatic neuroendocrine tumors?
Rare tumors
Pancreatic endocrine cells
Multiple endocrine neoplasia (MEN) Type 1
Insulinoma -> Hypoglycemia
Gastrinoma -> Peptic ulcers (Zollinger-Ellison syndrome)
Glucagonoma -> DM, Migratory skin erythema
what is Multiple Endocrine Neoplasia (MEN)?
Rare, autosomal dominant familial syndromes
Endocrine tumors in multiple organs
Germline Gene Mutations
MEN1
Tumor of the parathyroid glands often accompanied with tumors of the anterior pituitary + endocrine pancreas
Men2
Medullary thyroid cancer often accompanied with phaeochromocytoma and parathyroid tumors
