Endocrine Board Review 2014 Flashcards
What lipid disorder classically presents with feeding difficulty beginning in childhood?
Lipoprotein lipase deficiency
What is the signature physical exam finding in familial genetic hypercholestrolemia?
Tendon xanthomas
What is the signature physical exam finding in dysbetalipoproteinemia (type 3 hyperlipoproteinemia)?
Palmar xanthomas
Eliminating what from diet can dramatically reduce high triglycerides?
Alcohol
What two disorders cause both elevated cholesterol and triglycerides?
- Dysbetalipoproteinemia
- Familial combined hyperlipidemia
How do you diagnose dysbetalipoproteinemia?
Applipoprotein E genotyping
APOEE2/APOEE2
APOEE2/APOEE2
Disease?
Dysbetalipoproteinemia
APOEE4/APOEE4
Disease?
Alzheimer’s disease
What do patients with dysbetalipoproteinemia respond well to?
Fibric acids
What affect to fibric acid drugs have on the complications of diabetes?
Decreased retinopathy
Which drug class used to treat hyperlipidemia has been shown to improve diabetes control?
Bile acid-binding resin
e.g. Colesevelam
Does hypothyroidism raise cholesterol or triglycerides?
Raises cholesterol
If patients are experiencing muscle cramps and pain with statins then what approach can you use?
Can give every other day statin or weekly statin
Which lipid drug that is a peroxisome proliferator-activated receptor (PPAR) alpha agonist can cause lowering of HDL?
Fenofibrate
Is ABCA1 inhibited by metformin?
No
What lipid finding is found in Tangier disease?
Low HDL
What gene defect causes Tangier disease?
ABCA1 defects
What does insulin do to HDL levels?
Increase them
What is a common complication of hypobetalipoproteinemia?
Nonalcoholic fatty liver disease
Beta blockers can raise triglyceride levels in collagen-vascular diseases.
True or false?
True
What’s the test with the best predictive value for cardiovascular disease events in middle-aged men (other than a lipid panel)?
Coronary calcium score
What does cholesterol ester transfer protein (CETP) deficiency due to HDL cholesterol levels?
Increases HDL levels
What does hepatic lipase deficiency due to HDL cholesterol levels?
Increases HDL levels
Does interaction with protease inhibitors increase or decrease the risk of myositis with statins?
Increases risk of myositis
How do you differentiate between primary hyperparathyroidism and familial hypocalciuric hypercalcemia (FHH) if the calcium clearance to creatinine clearance is 0.01?
Genetic testing for a calcium-sensing receptor (CASR) mutation
What is the next step after diagnosing normocalcemic primary hyperparathyroidism in a patient with no symptoms?
Repeat calcium and albumin measurements in 6 - 12 months (these people may eventually develop hypercalcemia).
What does teriparatide do to serum calcium levels?
Slightly and transiently elevates calcium levels.
Patients who take teriparatide should have their bloodwork drawn how long after their dose for their serum calcium to return to normal?
16 hours
Can you see hypercalcemia in secondary hyperparathyroidism (e.g. because of vitamin D deficiency)?
No
What test can tell how old a vertebral fracture is?
Nuclear medicine bone scan.
Uptake for 1 to 2 years after a fracture
Is history of cigarette smoking included in the FRAX score calculation?
No (only current smoking)
What is the natural history of Paget’s disease near a weight-bearing joint?
Progressive joint destruction
Are the PTH levels of patients with adynamic bone disease low or high?
Low
What kind of bone disease do patients with chronic kidney disease get?
Adynamic bone disease (renal osteodytrophy)
Is a wrist fracture an indication for treatment for osteoporosis according to the National Osteoporosis Foundation guidelines?
No
What is a contra-indication of using teriparatide owing to the theoretical increased risk of developing osteosarcoma with it?
Patients with history of bone/skeletal irradiation/radiation treatment.
What is the first step in determining the cause of hypophosphatemia?
Distinguishing between gastrointestinal malabsorption/depletion from renal phosphate wasting by measuring tubular reabsorption of phosphate (serum/urine phosphorus levels) while the phosphate level is low.
What disease causes hypophosphatemia along with decreased 1,25 vitamin D levels?
Tumor-induced osteomalacia
What are the indications for treatment of Paget’s disease?
4 indications
- Involvement of a weight-bearing bone (e.g. spine or leg)
- Involvement near a joint
- Involvement of the skull
- Serum alkaline phosphatase level greater than 3 times the upper normal limit
What study should be done in patients suspected of having atypical bone fractures secondary to bisphosphonates?
Nuclear medicine bone scan (fractures are usually bilateral so you can see if a similar process is happening on both sides)
What is a ‘looser zone’ on a radiograph characteristic of?
Osteomalacia
____ international units of vitamin D daily increases the serum concentration of 25-OH vitamin D by ____ ng/mL
100 IU
1 ng/mL
How long does it take for 25-OH vitamin D levels to reach steady state with daily dosing of supplements?
2 - 3 months
What is the dosage for a calcium drip when treating hypocalcemia?
IV bolus of 150 mg calcium followed by continuous calcium infusion of 1 mg/kg/hr
How much elemental calcium does 1 ampule of calcium gluconate contain?
93 mg
How much volume does 1 ampule of calcium gluconate contain?
10 mL
How much elemental calcium does 1 ampule of 10% calcium chloride contain?
272 mg
How much volume does 1 ampule of 10% calcium chloride contain?
10 mL
Is an MRI or a CT safer during pregnancy?
MRI
Is an MRI with and without contrast safe during pregnancy?
Yes
What should you do during treatment if there is a discrepancy in prolactin level and adenoma size?
Monitor tumor size by MRI (as well as prolactin levels)
What proportion of patients with acromegaly respond to cabergoline?
One third.
What should you do if an acromegaly patient does not respond to cabergoline?
Start somatostatin analog.
Which drug used to treat acromegaly significantly worsens diabetes?
Pasireotide
Which drug used to treat acromegaly significantly improves diabetes?
Pegvisomant
What medications can be used to control hyperthyroidism secondary to a TSH-secreting tumor?
Somatostatin analogs
E.g. Lanreotide depot
Is cabergoline effective for TSH-secreting tumors?
No
What is the objective of treating hyperprolactinemia (secondary to microadenoma) causing amenorrhea in pre-menopausal women?
Treating the hypoestrogenism (indicated by restoring the menstrual cycle) so that her bone health is not affected.
What percentage of patients with Cushing’s disease and a post-operative morning cortisol level of greater than 10 microgram/dL have been cured?
Less than 10%
What should the morning cortisol level be after surgery for Cushing’s disease to indicate a cure?
Less than 5 microgram/dL
Do patients typically need hydrocortisone supplementation after successful transsphenoidal resection for Cushing’s disease, and for how long?
Hydrocortisone generally needed for several months initially for both maintenance and stress and later for just stress.
Should you do a cosyntropin stimulation test to check for adrenal insufficiency after transsphenoidal surgery for Cushing’s disease?
No.
It is not useful immediately after surgery because the adrenal glands themselves are not suppressed and will respond to exogenous ACTH resulting in a falsely reassuring result.
Why is acromegaly difficult to diagnose in pregnancy?
The placenta produces a biologically active variant of GH that stimulates IGF-1 production.
Is performing a glucose tolerance test and measuring GH response for diagnosing acromegaly useful in pregnancy?
No, because GH variant produced by the placenta does not suppress with hyperglycaemia.
What should you do if you suspect acromegaly in pregnancy?
Defer work-up until after delivery.
What medication can be tried for very aggressive macroprolactinomas that have been unresponsive to cabergoline, surgeries and gamma-knife radiotherapy?
Temozolomide
What should you do in patients with acromegaly that is only partially controlled by the highest dosage of lanreotide (or other somatostatin analogues)?
Add cabergoline.
Can reduce GH and IGF-1 levels by more than 50% in 50% of patients regardless of whether they have hyperprolactinemia
Does Pegvisomant control tumor growth in acromegaly?
No
Germline inactivating mutations in ____ predispose individuals to pituitary tumors, especially somatotropinomas.
AIP (aryl hydrocarbon receptor interacting protein)
What are mutations in AIP (aryl hydrocarbon receptor interacting protein) associated with?
Isolated familial pituitary adenomas
What are mutations in PRKAR1A associated with?
Carney complex
What does Mifepristone do to the potassium levels?
Decreases them (hypokalemia)
What does Mifepristone do to the cortisol levels?
Increases them
What does Mifepristone do to the ACTH levels?
Increases them
When should visual field testing be performed in a patient with an incidental non-secretory pituitary macroadenoma?
When the MRI shows significant supra-sellar extension with abutment of the optic chiasm.
Is there any data to show adverse effects of performing MRI scans or giving gadolinium during pregnancy?
No
What happens to the cortisol levels during pregnancy and why?
They increase for two reasons:
- Cortisol increases up to three times during pregnancy.
- Cortisol-binding globulin levels increase.
What is the likely diagnosis in a previously well female who presents with a pituitary mass near term of her pregnancy?
Lymphocytic hypophysitis
If a patient with panhypopituitarism is on oral estrogen - does stopping it increase or decrease the dose of hydrocortisone needed?
It has no effect.
If a patient with panhypopituitarism is on oral estrogen - does stopping it increase or decrease the dose of growth hormone needed?
It decreases the growth hormone needed.
If a patient with panhypopituitarism is on oral estrogen - does stopping it increase or decrease the dose of levothyroxine needed?
It increases the levothyroxine needed.
How do oral estrogens affect IGF-1 levels?
They act on the liver to decrease the responsiveness of the liver to growth hormone with respect to IGF-1 production.
Do estrogens stimulate or inhibit hepatic thyrotoxine-binding globulin?
Stimulate it.
How do you determine if a child on growth hormone therapy for growth hormone deficiency should be continued on growth hormone supplementation as an adult?
Re-test with a growth hormone stimulation test.
For how long does growth hormone need to be stopped before doing a growth hormone stimulation test?
1 month
What is the first step in determining whether a man is infertile?
Semen analysis
What medications can be used to treat modest hyponatremia in the setting of congestive heart failure?
Vasopressin receptor antagonists such as conivaptan and tolvaptan.
Is Demeclocyline used for acute or chronic hyponatremia?
Chronic, symptomatic hyponatremia
Mutations in which two genes cause combined pituitary hormone deficiencies?
- PROP1
- POU1F1 (PIT1)
Is diabetes insipidus more common in patients with pituitary adenomas or those with craniopharyngiomas?
Craniopharyngiomas
What is the typical MRI finding seen with Langerhans cell histiocytosis?
Stalk thickening on MRI
What is the gene most commonly associated with typical human obesity?
FTO gene
Does obesity related to MC4R, LEP and LEPR mutations develop in childhood or adulthood?
Childhood
What happens to resting energy expenditure when you successfully lose weight?
Energy expenditure decreases (body adapts to try to re-gain the lost weight)
For weight-stable, non-growing adults, energy expenditure in linearly related to lean body mass.
True or false?
True
What happens to energy expenditure during physical activity when you successfully lose weight?
Energy expenditure decreases
For a person who has successfully lost weight, the resting energy expenditure and the energy expended in physical activity both decline more than would be expected by the decline in lean body mass.
True or false?
True
Which parts of the hypothalamus regulate hunger and satiety?
Ventral tegmentum and nucleus accumbens.
Which part of the hypothalamus regulates physical activity and relays information about food intake to other parts of the brain?
Lateral hypothalamic area
Which part of the hypothalamus relays information from the gastrointestinal tract to the brain and organizes some of the mechanics of food intake and digestion?
Nucleus of the solitary tract and the dorsal vagal nucleus
What is the weight loss (percentage of baseline weight) provided by laparoscopic banding?
18 - 22%
What is the weight loss (percentage of baseline weight) provided by sleeve gastrectomy?
22 - 25%
What is the weight loss (percentage of baseline weight) provided by Roux-en-Y gastric bypass?
25 - 28%