Endocrine Surgery review Flashcards
What structure does the left recurrent laryngeal nerve pass under?
- ligamentum arteriosus (ductus arteriosus in fetal development)
What nerve innervates the cricothyroid muscle?
- external branch of superior laryngeal nerve
What does the cricothyroid muscle do?
- controls pitch of voice
Patient reports low pitch after thyroidectomy…what happened?
- you injured the external branch of the superior laryngeal nerve
Describe primary hyperparathyroidism
- unregulated overproduction of PTH resulting in elevated calcium levels
Describe secondary hyperparathyroidism
- up regulation of PTH in the setting of low calcium
- seen frequently in patients with ESRD
Describe tertiary hyperparathyroidism
- up regulation of PTH as a result of chronic secondary hyperparathyroidism
- patient has developed thyroid hyperplasia
how do you treat tertiary hyperparathyroidism
- resection of 3.5 parathyroid glands
what is the first thing you check when working up a patient’s thyroid function?
- get a thyroid stimulating hormone level (TSH)
- in clinical practice you will usually pair this with a T3/T4 level on the off chance the TSH is abnormal…easier for patient to get both test simultaneously
what germinal area are the inferior parathyroid glands derived from?
3rd pharyngeal pouch
where are ectopic inferior parathyroid glands typically located?
within the thyrothymic ligament
- remember that inferior parathyroid glands descend with the thymus from the 3rd pharyngeal pouch
what size of thyroid nodule gets FNA no matter what else is seen on Ultrasound
1.5 cm or larger get an FNA no matter what
what are the suspicious features of a thyroid nodule that would prompt FNA
- solid vs cystic
- irregular borders
- hypoechogenicity
- microcalcifications
- more tall than wide
- increased intranodular vascularity
most common cause of hyperaldosteronism
bilateral adrenal hyperplasia
what is Conn Syndrome
primary aldosteronism
Hypertension refractory to medication
hypokalemia
what does this person have
Conn Syndrome
- AKA: primary aldosteronism
is radiation uptake increased or decreased in acute thyroiditis?
decreased
how does PTH cause release of calcium from bones?
- activate Osteoblasts which intern activate the osteoclasts that cause calcium to be released from bones
- Osteoclasts do not have PTH receptors
how does PTH work to increase calcium absorption in the gut?
- indirectly increase absorption via vitamin D increase
- does this by increasing activity of enzyme 1-alpha-hydroxylase found on renal tubes (activate precursor to Vitamin D)
You encounter Hurthle cells on FNA from a thyroid nodule, next step?
- diagnostic thyroid lobectomy
hurthle cells can be seen in hashimotos, colloid nodules, and Hurthle cell carcinoma
Confirmed Hurthle cell carcinoma in thyroid nodule, next step?
Total thyroidectomy with central lymph node dissection +/- modified radical neck dissection if + LNs found
severely elevated calcitonin levels, what should you think about?
medullary thyroid carcinoma
you suspect medullary thyroid carcinoma, what should you check for
pheochromocytoma, 25% of MTCs are caused by RET proto-oncogene mutation
most common cause of congenital adrenal hyperplasia
deficiency of 21-hydroxylase
results in deficiency of glucocorticoids and mineralocorticoids, which causes negative feedback on pituitary -> increase in ACTH production
most common lab abnormality in congenital adrenal hyperplasia, which will diagnose the issue
elevated 17-hyrdoxyprogesterone
because there is a deficiency in 21-hydroxylase
what should your AM cortisol and ACTH be in primary adrenal insufficiency?
low cortisol
high ACTH
you suspect adrenal insufficiency, you do an AM cortisol and ACTH. They come back low for both…next step?
- so this may be secondary or tertiary adrenal insufficiency
- CRH stimulation test
what is a normal response to a 250 mcg ACTH test?
a cortisol level greater than 18 mcg/dL
what kind of islet cells make insulin?
beta islet cells
what kind of islet cells make glucagon?
alpha islet cells
what kind of islet cells make somatostatin?
delta islet cells
What causes the hyperpigmentation in adrenal insufficiency?
lack of negative feedback on pituitary causes unregulated increase in ACTH, which stimulates melanocytes
how do you treat a thyroid storm
- treat precipitating event
- methimazole or propylthiouracil (PTU if after thyroidectomy)
- dexamethasone can be useful
if you have a non-recurrent RLN on the left, what other anomaly does the patient have?
- a right sided aortic arch
if you have a non-recurrent RLN on the right what other anomaly does the patient have?
- an aberrant subclavian that runs behind the esophagus (arteria lusoria)
indication for resection in an adrenal mass < 4cm, based on imaging
- heterogenous
- hyper vascular
- > 10 hounds field units
orientation of RLN and inferior thyroid artery
- on right the RLN runs anterior to ITA
- on left the RLN runs posterior to ITA
During pregnancy which anti-thyroid Drug can you use?
- PTU is preferred during 1st trimester
- can be changed to methimazole afterwards
how do you track recurrence of well differentiated thyroid cancer
thyroglobulin
common metabolic derangement of primary hyperaldoteronism
- hypernatremia
- hypokalemia
