Endocrine Disorders Flashcards
what are you concerned about in a patient with a past history of radiation to the neck?
low dose ionizing radiation exposure (< 2000rad) carries 40% risk of thyroid cancer (MC - papillary ca)
what do you do in a pt who presents with nodule on thyroid with previous history of neck radiation?
proceed straight to thyroidectomy
what is special about diagnosis of medullary thyroid cancer?
AD Inheritance via mutation in RET Oncogene
- measure calcitonin levels, if high screen for RET mutation
- if mutation found, evaluate for MEN prior to surgery
patient has no identifiable risk factors for thyroid cancer but has a solitary nodule that is not hard nor fixed - what do you do next?
FNAB
when should you remove a cyst from the thyroid gland?
if it is > 4 cm big OR if it recurs several times following aspiration
- determined by USG
standard of care for diagnosing thyroid nodules
FNAB
what do you do with a FNAB result of “colloid nodule”
benign result
- medical management with thyroid suppression and routine F/U
what do you do with a FNAB result of “papillary carcinoma” or “medullary carcinoma?”
thyroidectomy
psammoma bodies on FNAB of thyroid
marker of papillary carcinoma - do thyroidectomy
amyloid deposits on FNAB of thyroid
suggest medullary cancer - do thyroidectomy
undifferentiated cells on FNAB of thyroid
suggests anaplastic cancer
- do either chemotherapy or radiation OR salvage operative therapy
Hurthle cells on FNAB of thyroid
signifies either adenoma or low grade cancer
- do lobectomy; if turns out to be cancer, total thyroidectomy indicated
follicular cells on FNAB of thyroid
does not rule out cancer, therefore must do a lobectomy for diagnostic purposes
lymphocytic infiltrate on FNAB of thyroid
suggests either lymphoma or chronic lymphocytic thyroiditis
- can differentiate by flow cytometry
tx. of thyroid lymphoma
radiation
tx. of chronic lymphocytic thyroiditis
no surgical tx. necessary
- may require thyroid hormone replacement therapy
major serious complications following thyroid surgery
- recurrent laryngeal N. paralysis - hoarseness or cord palsy (bilateral)
- external branch of superior laryngeal N. paralysis - high pitched singing voice
- hypoparathyroidism
MC type of thyroid cancer
papillary cancer
- MC between age 30 and 40
tx. of pt with papillary cancer lesion < 1 cm and no history of previous radiation
thyroid lobectomy and isthmusectomy
- had the pt had a previous history of neck irradation, you would do a total thyroidectomy
tx. of pt with papillary cancer lesion > 1.5 cm
total thyroidectomy
which thyroid ca. is more prevalent in iodine-deficient regions?
follicular cancer
- MC between ages 40-50
Tx. of microinvasive follicular carcinoma
lobectomy and isthmusectomy
- unless it is > 4 cm, then do total thyroidectomy
Tx. of clear follicular cell ca.
total thyroidectomy for any lesion > 1 cm
tx of medullary carcinoma
total thyroidectomy with removal of central neck LNs - lateral neck dissection usually needed for palpable nodes or large primary lesions
post op management of papillary thyroid ca.
thyroid suppression with thyroid hormone
I-131 ablation
post op management of follicular thyroid ca.
I-131 ablation
- allows successful monitoring for recurrent thyroid ca.
post op management of medullary thyroid ca.
radioactive ablation is NOT useful bc tumors come from C-cells
- external irradiation may be beneficial
what can you use to monitor pts with medullary thyroid ca. post-op?
serum calcitonin and CEA levels
what additional tests should you order in symptomatic hypercalcemia?
PTH
serum ALP
phosphate levels
MC lesions causing primary hyperparathyroidism
parathyroid adenomas
how do you tx. a parathyroid adenoma?
exploratory surgery of neck
- surgeon examines the parathyroid and excises the adenoma with biopsy of one other gland to ensure normalcy
when would you do a radical resection of parathyroids?
carcinoma
how can you do minimally invasive parathyroid surgery?
do sestamibi scan first to determine site of adenoma, make small neck incision and remove only adenoma w/o exploration of remaining glands
what do you do if there is a “missing” parathyroid gland on surgery?
must find it
- MC locations are thymus (inferior glands), intrathyroidal, tracheoesophageal groove and in carotid sheath
what do you do if you find a persistent intrathymic parathyroid?
thymectomy through cervical incision or median sternotomy
at what calcium level is parathyroid exploration warranted?
> 11 mEq/L
initial management of acute hypercalcemia
rehydration with Normal Saline
- once rehydrated, give furosemide which leads to brisk diuresis high in Calcium
MC benign cause of hypercalcemia
parathyroid adenoma
tx. scheme of acute hypercalcemia with symptoms
- IVF - normal saline
- furosemide
- bisphosphonates
- tx. underlying cause
tx. of secondary hyperparathyroidism (for ex. due to renal failure)
surgical removal of all but 50g of parathyroid tissue (transplantation into forearm)
indications for surgical management of secondary hyperparathyroidism
bone pain
fractures
intractable pruritus
ectopic calcifications in soft tissues
you are undergoing neck exploration for a parthyroid adenoma in a patient with hypercalcemia- during operation he develops huge spike in BP - what should you do? what do you suspect?
terminate operation immediately, admit pt to ICU, give patient both alpha and beta blockers – evaluate for pheochromocytoma
what is important during resection of a pheochromocytoma?
- pt should be on alpha blockers for atleast 10 days prior to surgery
- must ligate venous drainage from tumor before manipulating tumor
- minimal manipulation of tumor
- to prevent surge of catecholamines during surgery
where do extra-adrenal pheochromocytomas usually occur?
along abdominal aorta in a distribution similar to symphathetic chain
if h.pylori test is negative with basal serum gastrin > 00 pg/mL - what do you suspect
gastrinoma (Zollinger-Ellison) syndrome
diagnostic tests for Zollinger-Ellison
- serum gastrin > 1000 pg/dL
- positive calcium or secretin stimulation test
- localize lesion with CT or MRI
Tx. of sporadic, solitary gastrinoma
surgical resection
Whipple triad
- fasting hypoglycemia (< 60)
- sympomatic hypoglycemia
- relief by administration of glucose
- seen in pts with insulinoma
if an insulinoma is non-resectable, what medical therapy can be used?
diazoxide - inhibitor of insulin release
MEN2a
medullary thyroid cancer
parathyroid hyperplasia
pheochromocytoma
management of incidentally discovered adrenal mass
lesions > 5 cm: surgery recommended
lesions < 5 cm: full biochemical workup; if nonfunctioning, can monitor with serial CT scans but if it changes in size, removal is necessary
worrisome features of a thyroid nodule
- young/male
- history of radiation to the neck
- solid mass on USG
- cold nodule on scan
diagnostic test of choice for thyroid nodule
FNA and cytology
next step if a FNAB of a thyroid nodule turns up indeterminate?
surgery
- usually lobectomy first
tx of follicular cancer of thyroid
total thyroidectomy
- mets tx. with radioactive iodine ablation
next step when lab results show you high Calcium and low phosphate levels
PTH determination
sestamibi scan to localize adenoma
first test in someone with Cushing features
overnight dexamethasone suppression test
diagnostic W/U for Cushing’s
- overnight dexamethasone suppression test
- no suppression at low dose –> 24 hr urinary cortisol level - high dose suppression test
- if suppresses: do MRI of head (pituitary)
- if she does not suppress: do MRI/CT of adrenals
pt comes in bc of virulent PUD; she has multiple duodenal ulcers in first and second portions of duodenum as well as watery diarrhea - dx?
Zollinger Ellison
dx. of Zollinger-Ellison
first: serum gastrin levels
- may add secretin stimulation test
second: CT scans with vascular and GI contrast of pancreas
baby with extremely low blood sugar is found to have high levels of insulin in the blood - dx and tx?
nesidioblastosis
- tx. pancreatectomy
tx of insulinoma if inoperable
diazoxide
- inhibits insulin release
48 yo woman with severe migratory, necrolytic dermatitis; she is thin, has mild stomatitis and mild DM - dx?
glucagonoma
- determine glucagon levels and CT scan
tx. of glucagonoma
surgery
- if inoperable, Somatostatin can help sx
- streptozocin: chemotherapy agent
CF of hyperaldosteronism
female with HTN
hypokalemia, hypernatremia
metabolic alkalosis
initial diagnostic tests for hyperaldosteronism
determine aldosterone and renin levels
- will show high aldosterone, low renin
how can you differentiate adrenal hyperplasia from an adenoma producing aldosterone?
adrenal hyperplasia shows postural changes (more aldsterone when upright than when lying down)
tx. of adrenal hyperplasia vs adenoma
hyperplasia - medically with spironolactone
adenoma - surgically
dx of pheochromocytoma
24 hr urinary metanephrine or VMA; if elevated, get a CT scan of adrenals
what test has high sensitivity and specificity for pheochromocytoma
MIBG scan
you find a young man to have elevated BP in both arms; in his legs, the BP is normal
dx. coarctation of aorta
first test to order in coarctation of aorta
CXR
- then CT-angio
first test for renal artery stenosis
Duplex scan of renal arteries
tx of renal artery stenosis due to fibromuscular dysplasia
angiographic balloon dilation with stenting
