Kidney-ADH dx and electrolytes Flashcards Preview

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Flashcards in Kidney-ADH dx and electrolytes Deck (21):
1

What type of urine and blood osmolality do you see with SIADH?

urine osmolality>blood osmolality
crazy conc'n urine, dilute blood.

2

What is SIADH a common cause of?

hyponatremia
b/c body compensates by decreasing aldosterone secretion

3

What can be the result of the hyponatremia seen in SIADH? How should this be corrected?

cerebral edema and seizures
correct slowly b/c low-->high the pons will die.
Central pontine myelinolysis (demyelination syndrome)-->locked in syndrome.

4

What are some common causes of SIADH?

LUNG AND BRAIN
Ectopic ADH via small cell lung cancer
pulmonary dx
CNS disorders/head trauma
DRugs--cyclophosphamide

5

What is the treatment for SIADH?

fluid restriction
IV hypertonic saline
conivaptan
tovaptan
demeclocycline (ADH antagonist)

6

What are some causes of central diabetes insipidus?

lack of ADH release from hypothalamus
pituitary tumor
autoimmune
trauma
surgery
ischemic encephalopathy
idiopathic

7

What are some causes of nephrogenic diabetes insipidus?

kidney resistant to ADH
hereditary or secondary to hypercalcemia
lithium use
demeclocycline use (ADH antagonist)

8

How do you diagnose central DI v. nephrogenic DI?

see dilute urine and conc'n blood.
do water deprivation test. and still see dilute urine (2-3 hrs)
give vasopressin analog. Works-central. Doesn't work-nephrogenic

9

What is the treatment for central DI?

desmopressin

10

What is the treatment for nephrogenic DI?

HCTZ (thiazide diuretics cause dehydration and prompt PCT to absorb more water)
Indomethacin (decreases GFR via afferent arteriole constriction)
Amiloride (inhibits the CT sodium channels that take up Lithium and allow it to inhibit ADH receptors).

11

Causes of hyperkalemia?

DO LABS
Digoxin
hyperosmolarity
lysis of cells
acidosis
beta blocker
high blood Sugar (insulin insensitivity)

**also ACE inhibitors, potassium sparing diuretics

12

What can cause hypokalemia?

Insulin (when correcting hyperkalemia give w/ IV dextrose)
beta agonist (albuterol)
alkalosis (bicarb)
cell creation

thiazide and loop diuretics

13

What happens when sodium gets too low or too high?

CNS effects stupor, coma. Seizures w/ hyponatremia.

14

What are 6 causes of hypernatremia?

6Ds
diuretics
dehydration
Diabetes Insipidus
docs (iatrogenic)
diarrhea
dx of kidney

15

What do you see with hypokalemia?

flattened t waves
u waves
muscle spasm
arrhythmias: increased QT interval, torsades de point

16

What do you see with hyperkalemia?

tented (peaked) t waves. Arrhythmias, Wide QRS like vtach.
muscle weakness

17

When potassium is low, what might else be low?

magnesium!

18

Symptoms of low Ca++?

tetany: check Trosseau and Chvostek
seizures
QT prolongation

19

Symptoms of high Ca++?

Stones (renal)
Bones (pain)
Groans (abdominal pain)
Thrones (increase in urinary frequency)
psychiatric overtones (delirium, altered mental status)

20

Low Magnesium causes what?

tetany
torsades de point
hypokalemia

21

High magnesium causes what? When might you see this ?

decreased deep tendon reflexes
lethargy
bradycardia
hypotension
cardiac arrest
hypocalcemia
**Mg given to moms in premature labor to stop contractions. Go too high see diminished reflexes.