Salt, sugar, sex, water

Question 1

DI -> desmopressin after water deprivation

What to expect for central vs nephrogenic DI?

Answer 1

Central: urine Osm should increase by >50% (thus, can treat with desmopressin)

Nephrogenic: no change (tx: drink water and give thiazides, which eliminates more Na than water)

Question 2

How to distinguish DI from primary polydipsia?

Answer 2

Water deprivation test
Primary polydipsia: urine gets concentrated (Osm>600mOsm/kg)
DI: urine stays dilute

Question 3

Glucose >600
Normal pH, bicarb, anion gap
No ketones
Serum Osm >320 (really high)
Altered sensorium

How to treat?

Answer 3

Hyperosmolar hyperglycemic state (HHS)
Caused by T2DMs who don’t take their meds (relative deficiency of insulin) -> high glucose but not DKA -> osmotic diuresis

Tx: NORMAL SALINE TO REPLACE FLUIDS!!!!!

Question 4

Virilization, salt wasting

What is high?

Answer 4

21-hydroxylase deficiency

-> high 17-hydroxyprogesterone

Question 5

Virilization, salt overload

What is high?

Answer 5

11B-hydroxylase deficiency

Lots of 11-deoxycorticosterone (has weak mineralocorticoid -> salt RETENTION) and 11-deoxycortisol

Question 6

What kind of CAH?

Phenotypically female
Fluid and salt retention, HTN

Answer 6

17a-hydroxylase deficiency

Increased corticosterone (weak glucocorticoid)

Question 7

partial 21-hydroxylase deficiency? (nonclassic CAH)

Answer 7

presents in adolescence
hyperandrogenism (hirsutism, acne) and elevated 17-hydroxyprogesterone

note that this kinda looks like PCOS but PCOS should NOT have elevated 17hydroxP!!

Question 8

Medications that trigger pheo attack (high BP, HR)

Answer 8

Anesthetics or Nonselective beta blockers (-> unopposed alpha adrenergic stimulation -> vasoconstriction, paradoxical HTN)

Therefore, alpha adrenergic blockers (phenoxybenzamine) should be administered prior to beta blocker

Question 9

Metformin

Answer 9

Inhibits hepatic gluconeogenesis
Increases peripheral sensitivity to insulin

Side effects: weight loss, GI upset, lactic acidosis
Contraindicated in >80yo, renal insufficiency, hepatic failure, or heart failure

Question 10

Glipizide, glyburide, glimepiride

Answer 10

Sulfonylureas

Increases endogenous insulin secretion
-> Hypoglycemia and weight GAIN

Question 11

Rosiglitazone, pioglitazone

Answer 11

Thiazolidinediones

Increased insulin sensitivity.
Weight GAIN, edema, hepatotoxicity, bone loss
Contraindicated in HEART FAILURE

Question 12

Sitagliptin, linagliptin, and other gliptins

Answer 12

DPP-4 inhibitors (inhibits degradation of GLP1)

WEIGHT NEUTRAL
My lips are silent because I am neutral

Question 13

Exenatide, liraglutide, and other -tides

Answer 13

Incretins
GLP-1 agonists. Delays absorption of food. Increases insulin secretion and decreases glucagon secretion.

Nausea, pancreatitis. WEIGHT LOSS

Question 14

Dapagliflozin and other flozins

Answer 14

Inhibit SGLT2 in proximal tubule to decrease glucose reabsorption

UTIs, vulvovaginal candidiasis
WEIGHT LOSS, decreased BP

Question 15

Dexamethasone suppression test

Answer 15

Low dose ->
If cortisol low (suppressed) = normal
If cortisol high (not suppressed) = Cushing’s syndrome = too much cortisol for ANY reason
Note: this is easier than just measuring the 24-hr urine cortisol, which would tell you the same thing.

High lose ->
If cortisol is low = a pituitary adenoma producing ACTH, which is suppressible by high cortisol. (Kinda weird)
If cortisol is STILL high -> measure ACTH
If ACTH is high = ectopic ACTH-producing tumors (eg small cell lung)
If ACTH is low = adrenal thing making cortisol

Question 16

Frontal bossing, wide-spread teeth
Enlarged hands, feet
Coarsening of facial features
Large tongue
Skin tags

Answer 16

Acromegaly (increased GH)
Can have bitemporal hemianopsia from pituitary mass
Increased risk of carpal tunnel, OSA, T2DM, HEART DISEASE (leading cause of death!)
Measure IGF-1 (GH is not reliable because it’s pulsatile)

Question 17

Effect of prolactin on GnRH, LH, and FSH

Answer 17

Prolactin inhibits GnRH secretion -> lowers LH, FSH

-> infertility, galactorrhea, amenorrhea

Question 18

How high is prolactin in prolactinoma?

Answer 18

> 200

Question 19

Treatment of prolactinoma?

Answer 19

Dopamine agonists (cabergoline, bromocriptine)

If refractory to medical management or with compressive effects (eg visual), do surgery

Question 20

How to diagnose DI? (Two tests)

Answer 20

Water deprivation test: water restriction

• > urine concentrated (psychogenic polydipsia)
• > urine still dilute (DI)

DDAVP/desmopressin replacement test (a synthetic analogue of ADH)

• > if urine concentrated -> central
• > if urine still dilute -> nephrogenic (ADH resistance = kidneys fail to respond to circulating ADH)

Question 21

Causes of nephrogenic DI

Answer 21

Lithium

Demeclocycline (ADH receptor antagonist used for treating SIADH)

Question 22

In SIADH, what is urine sodium level?

Answer 22

> 40 mEq/L

Question 23

Treatment for SIADH?

Answer 23

Fluid restriction!!
If Na<110 or patient comatose/seizing, give hypertonic saline SLOWLY
(If too fast -> central pontine myelinolysis)

Question 24

Stuff in serum and urine for pheochromocytoma

Answer 24

Elevated plasma-free metanephrines (metanephrine and normetanephrine)

Or 24-hr urine metanephrines and catecholamines

Question 25

What meds to give pre-op for resection of pheochromocytoma?

Answer 25

Alpha-adrenergic blockade first (phenoxybenzamine) to control hypertension, THEN beta blockade to control tachycardia.

Do NOT give beta blockade first, since unopposed alpha stimulation -> severe hypertension

Question 26

Resection of medullary carcinoma… what is the most important screening test prior to surgery?

Answer 26

Urine metanephrines

To look for occult pheo to prevent hypertensive crisis during surgery

Question 27

Hypertension, headache, polyuria, muscle weakness

Hypokalemia, met alkalosis, hypoMg

Answer 27

Hyperaldosterone

Aldo-to-renin ratio is increased >30

Question 28

How to treat hyperaldosteronism from bilateral adrenal hyperplasia?

Answer 28

Aldo receptor antagonist (eplerenone preferred over spironolactone due to fewer side effects)