posterior pituitary disorders-Table 1

Question 1

What does the posterior pituitary secrete?

Answer 1

ADH and oxytocin

Question 2

What causes DI?

Answer 2

insufficient ADH

Question 3

What causes syndrome of inappropriate ADH?

Answer 3

too much ADH d/t head trauma, malignancy(SCLC, pancreatic cancer), drugs(vinca alkaloids, cyclophosphamide(akyle chemo), chlorpropamide, clofibrate)

Question 4

What is the clinical presentation of SIADH?

Answer 4

decreased urine output, urine is concentrated, decreased serum osmolality, euvolemic hypotonic hyponatremia, HA, nausea, vomiting, seizures

Question 5

How do you diagnose SIADH?

Answer 5

clinical CMP, UA(NA, Uosm)= kidneys should be trying to absorb sodium d/t serum hyponatremia, but here the urine sodium will be inappropriately high (basically high water reabsorption….)

Question 6

how do you treat SIADH?

Answer 6

asymptomatic: restrict fluids and/or demeclocycline symptomatic: 3%NaCl and serial sodium levels, don’t exceed sodium level more than .5-1mEq/L/H—once corrected r/o drugs/trauma/malignancies(Lung/pancreatic)-do CT and CXR

Question 7

What is the risk of correcting SIADH too quickly?

Answer 7

central ponteine demylination

Question 8

What are the two types of DI?

Answer 8

Central DI and Nephrogenic DI

Question 9

What are the causes for central DI?

Answer 9

trauma or tumor(50%), idiopathic(25%), other(25%) (think structural)

Question 10

What are the causes for nephrogenic DI?

Answer 10

Lithium(bipolar), demeclocycline(used to treat SIADH), hypercalcemia, hpokalemia, infiltrative diseases(that effect kidney), Sjogren’s syndrome (think drugs)

Question 11

What are some s/sx of DI?

Answer 11

Polyuria, polydipsia, low BP, loss of conciousness, and hypernatremia, nocturia

Question 12

How do you tell central and nephrogenic DI appart?

Answer 12

CMP, UA, plasma ADH(central=low/nephrogenic=normal or elevated), Water deprivation test: compare P(osmo) and U(osmo) serially measured while pt does not drink water(done under supervision)= Positive result= continue to urinate dilute urine, while plasma osmo goes up, if you give ADH during this test, nephro will not change curve, if central then will have normal curve.

Question 13

Tx for symptomatic DI pt?

Answer 13

start hypotonic fluids(D5W) for hypernatremia increase fluid intake, Central:DDAVP(desmopressin), Nephro: give HCTZ and or amiloride(K sparing diuretic)

Question 14

How do you dx DI?

Answer 14

Clinically with CMP, UA, plasma ADH

Question 15

What is the difference between DI and DM?

Answer 15

DI should have normal glucose level, DM should have elevated glucose levels