Endocrinology Flashcards
what is the incidence of adrenocortical carcinoma
1-2 per million people per year
is adrenocortical carcinoma functional or nonfunctional
either!
functional - Cushing syndrome
The majority of adrenocortical carcinomas present with a clinical syndrome of
hormone excess or Cushing syndrome alone or are mixed with virilization syndrome
additional sx - weight gain, weakness, and insomnia that develop quickly over 3 to 6 months
common findings on CT for adrenocortical carcinoma
mass greater than 4 cm with higher attenuation
irregular borders
calcification
invasion to surrounding structures with lymph node enlargement
most common sites of mets for adrenocortical carcinoma
liver
lungs
lymph nodes
bone
due to mets, what other imaging do ppl w adrenocortical carcinoma need
CT scan of chest
CT scan of liver
Bone scan
can cytology of a fine-needle aspiration distinguish between a benign adrenal mass and an adrenocortical carcinoma
no - It can also lead to metastasis in the needle core site
what is the only potentially curative tx for adrenocortical carcinoma
surgical resection
when is adjuvant mitotane recommended for adrenocortical carcinoma
high-grade disease
intra-operative tumor spillage
large tumors with vascular or capsular invasion
how long would mitotane be continued in patients with adrenocortical carcinoma
5 years after surgical resection for high risk
3 years after surgical resection for low risk
symptoms of Cushing syndrome
due to cortisol excess
proximal muscle weakness
weight gain
headache
oligomenorrhea
erectile dysfunction
osteoporosis
central obesity
moon facies
buffalo hump
supraclavicular fat pads
thin extremities
HTN
acanthosis nigricans
hirsutism
Which of the following zones of the adrenal gland is responsible for the production of catecholamines
adrenal medulla
produces epinephrine, norepinephrine, and dopamine
what does the zona glomerulosa produce
the outermost layer
produces mineralocorticoids like aldosterone
what does the zona fasciculata produce
middle layer
produces glucocorticoids like cortisol
what does the zona reticula produce
innermost layer
produces androgens, such as dehydroepiandrosterone and androstenedione
Pheochromocytoma
a rare neuroendocrine tumor of the adrenal medulla which causes an excess production of catecholamines like epinephrine, norepinephrine, and dopamine
signs and symptoms of pheochromocytoma
paroxysmal or sustained hypertension
headache
palpitations
diaphoresis
may have cardiac manifestations which can be life-threatening
lab testing for pheochromocytoma
plasma fractionated free metanephrines
plasma fractionated catecholamines
serum CgA
clonidine suppression testing
what is the most sensitive lab test for pheochromocytoma
plasma fractionated free metanephrines
if there is high suspicion of pheochromocytoma and you find that they have elevated plasma fractionated free metanephrines, what tests should you do next to help confirm
24-hour urine for fractionated metanephrines and creatinine
imaging for pheochromocytoma
noncontrast CT of the abdomen followed by an immediate follow-up CT with nonionic contrast using a washout protocol
Pheochromocytomas typically retain > 40% of the contrast after 15 minutes
what must be treated prior to surgery for pheochromocytoma
hypertension and tachydysrhythmias
what can be used to treat hypertension and tachydysrhythmias in pheochromocytoma esp prior to surgery
Alpha-blockers, such as phenoxybenzamin
CCB
^these are given 10-14 days prior to surgery
can be used alone or in combo
Cardioselective beta-blockers, such as metoprolol XL, should be administered for control of tachydysrhythmias only after blood pressure has been controlled - given 2-3 days prior to surgery
what do pheochromocytomas consist of
chromaffin cells
treatment for pheochromocytomas
complete adrenalectomy - usually performed laparoscopically
what is the most common clinical (lab) presentation of hyperparathyroidism
hypercalcemia
Classical presentations of hyperparathyroidism
bone disease
nephrolithiasis
weakness
fatigue
neurobehavioral sx like depression or psychosis
how do you diagnose hyperparathyroidism
If an elevated serum calcium concentration is found on routine testing, confirmation by repeat lab draw is the first step
If an elevated level is found on repeat lab draw, the next step in evaluation is a serum parathyroid hormone
what is considered diagnostic for primary hyperparathyroidism
Elevated serum calcium and elevated serum parathyroid hormone
tx for sx hyperparathyroidism
parathyroidectomy
tx for asx hyperparathyroidism
surgery - if serum calcium concentration of 1.0 mg/dL or more above the upper limit of normal, bone density of hip, lumbar spine, or distal radius greater than 2.5 standard deviations below normal, previous asx vertebral fx, glomerular filtration rate (GFR) less than 60 mL/min, 24-hour urine calcium greater than 400 mg/day, nephrolithiasis on imaging, age < 50
what is the MC cause of primary hyperparathyroidism
parathyroid adenoma
what are the most common causes of hypoparathyroidism
post neck surgery (thyroidectomy, parathyroidectomy) or autoimmune destruction of the parathyroid gland
what other electrolyte abnormality can cause hypoparathyroidism
hypomagnesemia
signs and sx of hypoparathyroidism
tingling around the perioral area
paresthesias and muscle cramping of the hands and feet (carpopedal spasm)
tetany
laryngospasm
seizures
hyperactive DTR
Chvostek sign (facial twitching that is induced by tapping the facial nerve on the same side)
Trousseau sign (spasm in the hands after inflating a blood pressure cuff above the systolic pressure)
triad for diagnosis of hypoparathyroidism
hypocalcemia
low PTH
increased phosphate
what will EKG show for hypoparathyroidism
prolonged QT interval (increased risk of arrhythmia)
tx for hypoparathyroidism - acute vs non-acute
acute - IV calcium gluconate plus oral calcitriol (activated vitamin D)
non-acute - calcium (500 mg to 2,000 mg two to four times daily) and vitamin D
normal range for calcium
8.5-10 mg/dL
when is a thyroid nodule more likely to be benign
if the nodule is painful or tender to touch and if it is soft, smooth, and mobile upon palpation
how are thyroid nodules evaluated
thyroid scintigraphy (radionuclide scanning) - describes nodule as hot, warm, cold, depending on its uptake of the radioactive isotope
Hot thyroid nodules
Hot nodules take up more of the radioactive isotope than surrounding thyroid tissue and are indicative of autonomously functioning nodules, such as toxic adenomas or toxic multinodular goiters, and are rarely found to be malignant
Warm thyroid nodules
Warm nodules indicate normal thyroid function
Cold thyroid nodules
cold nodules indicate low functional or nonfunctional thyroid tissue. Cold nodules will have a decreased uptake of radioactive isotope compared to surrounding thyroid tissue on scintigraphy
what thyroid nodules carry the highest risk of malignancy
cold nodules
how to fully evaluate thyroid nodules
if there is a lower than normal TSH finding –> scintigraphy next
If the serum TSH is high or normal –> thyroid ultrasound
A fine-needle aspiration should be performed if there is any suspicion for malignancy on ultrasound
what do follicular cells secrete
thyroxine (or T4) and triiodothyronine (T3)
what do parafollicular cells secrete
thyrocalcitonin
Sonographic features of thyroid nodules suspicious for malignancy
microcalcifications
irregular borders
hyper echoic areas
increased vascularity
what are the 4 main types of thyroid carcinoma
anaplastic
follicular
medullary
papillary
what are thyroid hormone levels commonly like in thyroid carcinoma
normal TSH and T4 levels
The most common type of thyroid cancer
papillary thyroid cancer
what is the least aggressive thyroid cancer
papillary thyroid cancer
The greatest risk factor for papillary thyroid cancer is
head or neck radiation exposure as a child
what is a tumor marker for papillary thyroid cancer and follicular thyroid cancer
Thyroglobulin
second most common thyroid cancer
follicular thyroid cancer
what is follicular thyroid cancer associated with
iodine deficiency
what thyroid cancer is associated with MEN2
medullary thyroid cancer
what is used to monitor for residual disease after treatment or for recurrence of medullary thyroid cancer
calcitonin levels
what is the most aggressive type of thyroid cancer
anaplastic thyroid cancer
The most common cause of primary hypothyroidism in the United States
Hashimoto
what is the MC cause of primary hypothyroidism in the world
iodine deficiency
subclinical hypothyroidism
A normal T4 level and high TSH level
what antibody is positive in majority of people with Hashimoto
thyroid peroxidase antibody
how often should TSH be tested after starting levothyroxine
every 6 weeks
what can be used in addition to levothyroxine for hypothyroidism
Some patients may have impaired conversion of T4 to T3 and may benefit from liothyronine
The most common cause of hyperthyroidism
Grave’s disease - an autoimmune disease that affects TSH receptors by stimulating or blocking antibodies to the thyrotropin receptor
T3 toxicosis
T4 is normal and T3 is elevated –> more favorable prognosis
what antibodies may be present in grave’s disease
Thyroid-stimulating immunoglobulin antibodies - most sensitive
peroxidase antibodies
antithyroglobulin antibodies
what can be used to treat cardiac sx in hyperthyroidism
beta blockers
contraindication of Radioactive iodine ablation
pregnancy
Diabetes insipidus (DI) is characterized by
excretion of a large volume of dilute urine through the kidneys
Central DI
decreased secretion of antidiuretic hormone (ADH)
nephrogenic DI
decreased sensitivity to ADH in the kidneys, leading to decreased urine concentration
sx of DI
polyuria, polydipsia, and nocturia
Water deprivation followed by administration of vasopressin (ADH) to differentiate btwn nephrogenic and central DI
central DI: the ADH administered will act on the kidneys to concentrate the urine, leading to an increased urinary osmolality
nephrogenic DI: the urine osmolality will remain unchanged because the kidneys are already insensitive to ADH
drug of choice for central DI
desmopressin (ADH analog)
drugs of choice for nephrogenic DI
Nonsteroidal anti-inflammatory drugs, such as indomethacin, and thiazide diuretics
