endocrine Flashcards
what is the embryological origin of the thyroid?
originates from the foramen cecum
when the descending tract doesnt close you can get thyroglossal duct cyst/mass
how can you assess the thyroid on physical exam
have them swallow (it should move) and stick out their tongue (it should also move)
how do you assess thyroid with imaging
U/S
if a person has a thyroid module and that is his only functioning thyroid tissue on U/S, do you still consider resection?
yes
what is the operation to remove the thyroid
sistrunk operation with removal of center of the hyoid
what % of the population has a palpable thyroid nodule
5-8% of women
1-2% men
increases with age
how do you assess thyroid nodule risk (for malignancy) via history
age (rates of cancer similar between ages but have better prognosis when younger)
sex
family history
growth symptoms of mass (rapidly growing masses are cancer until proven otherwise)
how do you assess thyroid nodule risk (for malignancy) via physical exam
- complete physical
- mass that grows fast is likely cancer but if it grows fast and is painful then resolves somewhat…unlikely to be cancer
- characterize the mass–> does it move when swallowing?
- lymphadenopathy
- voice
what is the best test for thyroid nodule risk assessment?
FNA
how do you assess thyroid nodule risk (for malignancy) via FNA
well differentiated thyroid cancer is based on age (staging differs on whether you are under or over 45)
dont investigate nodules that are less than 1 cm unless there is extension or associated LAD
atypia in a sample will likely be removed
what is the bethesda classification for thyroid cancer FNA?
- non diagnostic
- benign
- follicular lesion of unknown significance
- follicular neoplasm
- suspicious for malignancy
- malignant
what characteristics of a single thyroid nodule would suggest thyroid cancer
single nodule
calcifications
hypoechoic
taller than wide
heterogenous
hypervascular
take these ones out
indications for surgery for a multinodular goiter
- suspicion of malignancy/inability to rule out malignancy
- compressive symptoms (SOB, dysphagia, etc)
- hyperthyroidism
- cosmesis
- retrosternal goiters (hard to follow clinically and investigate, also hard to biopsy and it can only grow backwards into vital structures)
how does hyperthyroidism usually present
multinodular goiter, graves, solitary nodule
treatment for hyperthyroidism
anti thyroid medications
radioactive iodine
surgical management (not easy surgery)
what are the types of thyroid cancer
(most to least common)
- papillary
- follicular–> you need to see vascular or capsular invasion, which you can’t see on FNA, in order to determine if malignant or not–> usually do partial lobectomy to check
- medullary
- anaplastic (high mortality)
- lymphoma
- metastatic (often from breast)
risk factors for thyroid cancer
- previous radiotherapy/radiation exposure
2. family history
treatment of thyroid cancer
even for low risk thyroid malignancy you resect–> make sure to take out enough because there may be vascular and capsular invasion
(going back in a second time has high risk of hemorrhage)
lobectomy is thus primary treatment
what are the risks associated with thyroid surgery
-
damage to the recurrent laryngeal nerve
- -> also a non recurrent right laryngeal nerve goes straight across and can be easily injured - parathyroid risks–> hypercalcemia etc
- hemorrhage
what is the cause of primary hyperparathyroidism 85% of the time
adenoma of the parathyroid gland
what is the embryological origin of the 4 glands of the parathyroid
lower glands come from the branchial pouch and ascend from the thymus (can approach from the neck)
upper glands are posterior to the thyroid and come from the 4th pouch–> tend to be behind the place of the recurrent laryngeal nerve as opposed to the lower glands
how does a parathyroid nodule present
hypercalcemia
how do you assess the parathyroid gland
labs
imaging
physical exam
what are the characteristics of hypercalcemia you might expect to see in a patient with parathyroid nodule
moans bones psychic overtimes kidney stones fatigue
boney pain, abdo pain, depression, anxiety, anorexia, constipation, irritability, worsening or new depression, fractures, osteopenia or osteoporosis, polyuria, polydipsia, nocturia, pancreatitis
treatment for parathyroid disease
surgery (need experienced parathyroid surgeon)
ddx of hypercalcemia
- exogenous–> meds (i.e thiazide diuretics at initiation, lithium, tamoxifen, vitamin A and D)
- endogenous
- -cancer is most common cause in hospitals (direct invovement of bone from bony mets or multiple myeloma, or production of parathyroid like substance from a renal carcinoma etc… )
- -primary hyperparathyroidism
- -ganulomatous disease
- -paraneoplastic diseases
- -familial hypercalciuric hypercalcemia (inherited syndrome that mimics primary hyperparathyroidism)
what meds can be associated with hypercalcemia
thiazide diuretics at initiation, lithium, tamoxifen, vitamin A and D
how do you investigate parathyroid disease
PTH level (diagnosis primary hyperparathyroidism)
24 hour urine calcium
what are the two questions to ask yourself about adrenal masses
is it functioning?
is it malignant?
how do you investigate whether an adrenal mass is functioning?
hx and px aimed at signs of pheos, HTN, hypercortisolism
dexamethasone test for hypercortisolism
CONS syndrome–> investigate especially if hypertensive (renin-aldosterone ratios)
imaging
how do you investigate whether an adrenal mass is malignant?
2/3 adrenal masses are usually malignant
on imaging, a mass greater than 6cm has a 25% chance of being a primary adrenal
needle biopsy can be useful (mets disease to the adrenal is pretty poor prognosis but if theyre otherwise healthy you can try and take it out)–> most of the time youre gonna take it out anyway tho
HAVE TO MAKE SURE ISNT A PHEO FIRST
what cause of hypercalcemia is most common in the inpatient population? outpatient?
inpatient–> malignancy
outpatient–> primary hyperparathyroidism
what tests should you order when investigating primary hyperparathyroidism
serum calcium, ionized calcium, PTH
24 hour urine calcium, vitamin D
bone densitometry
CBC, lytes, BUN/Cr, alk phos
what is the etiology of primary hyperparathyroidism
- 85% single adenoma
- 8-10% 4 gland hyperplasia
- 3% double adenoma
- less than 1% carcinoma
indications for primary hyperparathyroidism surgery
either symptomatic or…
- calcium above 2.8
- bone density above -2.5 SD
- age less than 50
- renal dysfunction/urinary calcium levels/nephrocalcinosis
- functional symptoms
how do you image the parathyroid
U/S
sestamibi scan
define MEN I
primary hyperparathyroid
pituitary adenoma and neuroendocrine tumours of the pancreas and duodenum
define MEN IIa
pheochromocytoma
medullary thyroid cancer
primary hyperparathyroidism
define MEN IIb
pheochromocytoma
medullary thyroid cancer
marfanoid features
mucosal neuromas
how do you work up an adrenal incidentaloma
- aldosterone/renin ratio
- urine catecholamines and metanephrines
- urine free cortisol or low dose dexamethasone test
- dedicated adrenal imaging
