Endocrine Flashcards
What is a significant difference in zoledronic acid and calcitonin in the emergency setting?
Zoledronic acid takes 48 hours to work, so if someone is having symptomatic hypercalcemia refractory to fluids then choose calcitonin
The initial step in evaluating hypercalcemia is what?
PTH
The big differentiation point in hypercalcemia is PTH dependent versus independent.
Dependent causes: hyperparathyroidism
Independent causes:
- Elevated PTHrp: hypercalcemia of malignancy
- Elevated vitamin D 1,25: granulomatous disease, lymphoma
- Elecated vitamin D 25: vitamin D intoxication
- Abnormal protein gap, SPEP: MM
The fasting glucose level that defines DM is _____.
126
Demand for insulin decreases or increases during illness?
Increases
This is why DKA often presents because of URIs or other illnesses.
What kind of insulin do patient’s implantable pumps give?
Implantable pumps give a slow drip of fast acting insulin, just like IV pumps but it’s in the subcutaneous tissue instead.
When insulin is labeled 100-U or 50-U, what does that mean?
It means the number of units per mL, so 100-U has 100 U/mL and 50-U has 50 U/mL.
Fast acting insulin delivered subcutaneously has a half-life of about ________________ hours.
3-4
If someone on an insulin pump is hypoglycemic, then one of two things likely happened: _______________________.
they weren’t eating enough or they overdosed themselves
The point is that pumps just give a basal rate and manual pushes, so hypoglycemia is not likely from pump malfunction. Pump malfunction – such as from infection, dislodgement, running out of insulin, or mechanical issue – will result in hyperglycemia.
What defines HHS?
Hyperglycemia and AMS (not of another etiology) without ketosis or acidosis
Review the ranges of potassium and what to do in DKA?
Less than 3.5: give IV potassium first before insulin (20-30 mEq/hr)
3.5 - 5.5: give IV fluids with potassium while giving insulin (20-30 mEq per liter)
Greater than 5.5: give IV fluids without potassium while giving insulin
In general you should not give bicarb to those with DKA. What are the exceptions?
Shock
Cardiac arrest
What blouses are recommended in DKA and HHS?
20 mL/kg
Why does pregnancy change levothyroxine dose needs?
Estrogen increases the amount of thyroxine-binding globulin (TBG) which decreases the amount of circulating T3 and T4.
Describe the pathophysiology of postpartum thyroiditis.
It is similar to Hashimoto’s thyroiditis. Postpartum thyroiditis presents with a brief hyperthyroid phase (due to the antibody attack and release of thyroxine) followed by a hypothyroid phase. It usually resolves and does not require treatment.
When a woman with hypothyroidism becomes pregnant, what is the management algorithm for her levothyroxine?
Increase her prepregnancy dose by 30% and recheck TSH in 4 weeks
Why is hyperthyroidism often missed in the elderly?
They are more likely to present with “apathetic hyperthyroidism” which presents with fatigue and weight loss. They are also more likely to be on beta blockers which will blunt the tachycardia that you’d normally see in someone with hyperthyroidism.
Keep hyperthyroidism in mind when an elderly patient has new-onset atrial fibrillation, new-onset worsening of heart failure, weight loss, or fatigue.
Under which circumstances should you treat subclinical hypothyroidism (elevated TSH with normal T4)?
- Convincing symptoms of hypothyroidism (unless the person is older than 70 and their TSH is less than 6.9)
- TSH 7 - 9.9: treat if younger than 70 regardless of symptoms
- TSH greater than 10
- Pregnant with history of spontaneous miscarriage
Note: obtain anti-thyroid peroxidase antibodies because if these are elevated it is an indicator that the person is going to progress to over hypothyroidism.
What is the one serious adverse effect of subclinical hypothyroidism?
Recurrent miscarriages
Steroid courses less than _____ weeks do not require tapering to prevent adrenal insufficiency.
3
A patient presents with new-onset hypothyroidism. What medications do you need to assess if they’re taking that could cause hypothyroidism?
Amiodarone
Lithium
What does vanillylmandelic acid test for?
Pheochromocytoma
Note: it is not the preferred screening test, though. The more sensitive test is urinary metanephrines and catecholamines.
What things can cause a falsely positive urinary metanephrines screen?
Things that alter the amount of catecholamines in the serum: TCAs, decongestants, cocaine, and methamphetamine
Review triggers of euglycemic DKA in those taking SGLT2 inhibitors.
- Major illness
- Fasting
- Alcohol abuse
- Discontinuation of insulin
- Intense exercise
Review the workup of galactorrhea.
First, women need to have a breast ultrasound and (if older than 30) a mammogram. If either of those is abnormal then you refer for biopsy.
Second, if the imaging is negative then do a serological workup including TSH and prolactin.
If the serological workup is negative, then you can provide reassurance and follow-up.
Note: also consider medicines and supplements as a cause of galactorrhea, such as antipsychotics.
What test helps differentiate constitutional pubertal delay from familial short stature?
Bone age
Pubertal delay presents with a chronological age greater than the bone age, whereas familial short stature presents with chronological age equal to bone age.
A normal growth velocity (on a chart or by report of maintaining percentile over years) is characteristic of which two causes of short stature?
Constitutional pubertal delay and familial short stature
Disorders of hormones that cause short stature such as hypothyroidism, Kallman syndrome, and CNS masses present with loss of growth velocity.
A patient with ESRD presents with labwork that seems to show primary hyperparathyroidism: elevated calcium, elevated vitamin D, and elevated parathyroid hormone. What is likely happening?
Tertiary hyperparathyroidism
ESRD causes secondary hyperparathyroidism by two ways: the kidneys fail to secrete phosphate and the kidneys fail to generate active vitamin D. Chronic secondary hyperparathyroidism can induce the parathyroid glands to become autonomous and fail to respond to hypercalcemia, called tertiary hyperparathyroidism.
The key to the labwork is that it looks like hyperparathyroidism (elevated PTH, elevated Ca, elevated vitamin D) but the phosphorous is also high!
Under which circumstances should you measure an ACTH level?
ACTH should be measured when you are concerned for Cushing’s syndrome (autonomous, inappropriate ACTH secretion) and there is a positive dexamethasone suppression test.
