Endocrine

Question 1

What labs are diagnostic of hypothyroidism

Answer 1

1. TSH elevated
2. Free T4 (thyroxine) next test
3. Thyroid peroxidase antibody to diagnose Hashimoto’s

Question 2

What lab test should be ordered to monitor the patient’s response to therapy in hypothyroidism?

How often?

Answer 2

TSH - make sure to titrate evo up till TSH is normal

Every 2mo (6weeks)

Question 3

Primary adrenal insufficiency labs?

Gold standard diagnosis

Answer 3

ACTH is normal, cortisol is low

GS: perform morning (8am) cortisol - <3mcg/dL of plasma cortisol + elevated ACTH >200
–> CONFIRM diagnosis with a COSYNTROPIN (synthetic cortisol injection) STIMULATION TEST**

45 minutes after cosyntropin IM = low cortisol <20

Question 4

Secondary adrenal insufficiency labs?

Answer 4

Low ACTH, cortisol is low or normal

Question 5

Most common cause of secondary adrenal insufficiency?

Answer 5

Long-term steroid cessation

Question 6

Aside from hormonal labs that labs are abnormal in adrenal insufficiency?

Answer 6

Hypoglycemia - due to low cortisol which makes glucose

Hypercalcemia - low calcium excretion by the kidneys

Hyponatremia and hyperkalemia, hypovolemia - due to low aldosterone which is supposed to perform Na retention/K excretion

Question 7

Tx of adrenal insufficiency?

Answer 7

Corticosteroids or mineralcorticosteroids
-hydrocort
-prednisone
-methylprednisone

*only give mineralcort (fludrocortisone) if hyponatremia also present

Question 8

What drugs inhibit steroid metabolism?

Answer 8

Azoles
Protease inhibitors (HIV - atazanavir, darunavir, etc)
Cobicistat (HIV - booster for protease inh)