Flashcards in posterior pituitary disorders-Table 1 Deck (15):
What does the posterior pituitary secrete?
ADH and oxytocin
What causes DI?
What causes syndrome of inappropriate ADH?
too much ADH d/t head trauma, malignancy(SCLC, pancreatic cancer), drugs(vinca alkaloids, cyclophosphamide(akyle chemo), chlorpropamide, clofibrate)
What is the clinical presentation of SIADH?
decreased urine output, urine is concentrated, decreased serum osmolality, euvolemic hypotonic hyponatremia, HA, nausea, vomiting, seizures
How do you diagnose SIADH?
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….)
how do you treat SIADH?
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
What is the risk of correcting SIADH too quickly?
central ponteine demylination
What are the two types of DI?
Central DI and Nephrogenic DI
What are the causes for central DI?
trauma or tumor(50%), idiopathic(25%), other(25%) (think structural)
What are the causes for nephrogenic DI?
Lithium(bipolar), demeclocycline(used to treat SIADH), hypercalcemia, hpokalemia, infiltrative diseases(that effect kidney), Sjogren’s syndrome (think drugs)
What are some s/sx of DI?
Polyuria, polydipsia, low BP, loss of conciousness, and hypernatremia, nocturia
How do you tell central and nephrogenic DI appart?
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.
Tx for symptomatic DI pt?
start hypotonic fluids(D5W) for hypernatremia increase fluid intake, Central:DDAVP(desmopressin), Nephro: give HCTZ and or amiloride(K sparing diuretic)
How do you dx DI?
Clinically with CMP, UA, plasma ADH