Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
main clinical / lab findings for ARF
(general) |
elevated BUN, Cr
oliguria < 400 ml day (sometimes) signs of dehydration |
|
|
% of patients with ARF that are nonoligiuric
|
20-30%
|
|
|
mcc of ARF inpatient
|
ATN 45%
prerenal obstruction |
|
|
mcc of ARF outpatient
|
prerenal 70%
obstruction |
|
|
clinical / lab signs of prerenal ARF
|
BUN/Cr ratio > 20
FeNa < 1% FEUrea (use for heavy diuretics) < 35% |
|
|
tx for prerenal ARF
|
fluid replacement
250-500 mL of NS or LR over 1-2 hours Continue infusion until BP normalizes, sodium reappears in urine. Usually fixes problem. |
|
|
clinical / lab signs of intrinsic ARF
|
BUN/Cr ratio <20
FeNa >2% urine sodium > 40 urine osmolality <400 casts in UA |
|
|
What is the role of diuretics for treating oliguric ARF?
|
Controversial whether this improves outcomes, but method is to use high dose loop diuretics (240-300 mg IV furosemide, 8-12 mg of IV bumetanide). Don't use higher doses b/c of ototoxicity.
|
|
|
How are fluids managed for oliguric ARF?
|
1. fluid restriction: no more than 1 L daily
2. sodium and potassium restriction: give 1 L of 0.5 N NaCl with no potassium supplement. |
|
|
What are the main electrolyte imbalances expected with ARF?
|
hyponatremia
hyperkalemia hypOcalcemia hypeRphosphatemia hypeRmagnesemia hypeRuricemia |
|
|
What is the formula for GFR?
|
Creatinine clearance:
CCr = (140-age) x kg / (72 x serum Cr) |
|
|
What is the normal anion gap?
What is it used for? |
variously defined
8-12 10-14 (12 +/- 2) mmol/L to help define cause of metabolic acidosis |
|
|
What is the formula for osmolar gap?
What is it used for? |
2Na + (glucose/18) + (BUN/2.8)
mainly used to dx ethylene glycol or methanol intoxication |
|
|
What is urine anion gap? How is it calculated?
What is it used for? |
UAG = (Na + K) -- Cl
used to distinguish between diarrhea and RTA as cause of nonanion gap metabolic acidosis. If UAG is negative (urine ammonia is high) , then diarrhea is likely cause If UAG is positive (urine ammonium is low), then renal problem like RTA is likely |
|
|
Does renal tubular acidosis cause an anion gap?
|
no, it causes normal anion gap acidosis.
|
|
|
A patient has anion gap acidosis; the MUDPILERS list of possible causes is reasonable. What tests should be done to narrow etiology?
|
1. serum glucose, to rule out DKA
2. serum ketone levels, also to rule out DKA 3. serum lactate, to check for lactic acidosis 4. serum salicylate to for toxicity 5. serum osmolality, to see if there is an osmolar gap (glycol poisoning) |
|
|
What is the osmolar gap good for?
|
In metabolic acidosis, it suggest glycol poisoning as cause.
|
|
|
How do you distinguish between ethylene and methanol poisoning?
|
Get blood levels of each. (So why not just do this from the beginning?)
Calcium oxalate crystals in urine suggest ethylene glycol poisoning. |
|
|
What is the danger of methanol poisoning?
|
blindness
|
|
|
What are the two main types of metabolic alkalosis?
|
NaCl responsive (volume depletion)
NaCl resistant (volume overload) |
|
|
Shortcut to distinguish RTA types
|
serum K and pH (5.3)
Only type 4 has elevated serum K+. So, if hyperkalemic, it's type 4. If not, look at urine pH. if pH is high (above 5.3), it's type 1. if pH is low (below 5.3), it's type 2. |
|
|
Which RTA types are in the distal tubule?
|
types 1 and 4
|
|
|
Which RTA types are in the proximal tubule?
|
type 2
|
|
|
What is the status of RTA wrt anion gap and urine anion gap?
|
normal anion gap acidosis
POSITIVE urine anion gap this is true for all types |
|
|
How do you treat RTA?
|
type 1: potassium and bicarb
type 2: potassium and bicarb (these are the hypokalemic types) type 4: mineralocorticoids, low K+ diet ( this is the hyperkalemic type) |
