Wednesday, February 3, 2010

Renal II

Challenge: For each of the following, would you expect these findings in prerenal acute kidney injury or acute tubular necrosis (ATN)?

1. Mannitol administration.
2. ACE-inhibitors.
3. Severe burns.
4. A history of vomiting and diarrhea.
5. Muddy brown casts.
6. Bland urinalysis with rare hyaline casts.
7. Improvement of creatinine within 48 hours after IV fluid administration.
8. FENa < 1%
9. BUN/Cr = 12:1.
10. Urine Na+ = 50meq/L.


Suheil said...

1. You mean history of mannitol administration? Pre-Renal Failure- (cause excessive mannitol can cause dehydration which can lead to pre-renal failure)
2. Pre-Renal Failure
3. Pre-Renal Failure
4. Pre-Renal Failure
5. ATN
6. Pre-Renal Failure
7. Pre-Renal Failure
8. Pre-Renal Failure
9. Pre-Renal Failure
10. ATN

i really hope i'm right.. most of them are just guesses :(

Craig Chen said...

Renal II

Causes of prerenal disease include volume depletion (GI , renal, respiratory, or skin loss including burns, third spacing), hypotension, low effective circulating volume states (cirrhosis, heart failure, nephrotic syndrome), renal ischemia (bilateral stenosis, hepatorenal syndrome), and impairment of autoregulation (NSAIDs, ACEi). The U/A is normal or near normal (hyaline or fine granular casts are okay). FENa is <1%. BUN/Cr > 20:1. Urine sodium is <20meq/L, urine osm >500mOsm, and oliguria.
Causes of ATN include ischemia, nephrotoxins (aminoglycosides, amphotericin, cisplatin, contrast, mannitol). U/A shows muddy brown granular and epithelial casts and free renal tubular epithelial cells. FENa is >2%. BUN/Cr = 10-15:1. Plasma Cr rise is progressive at a rate >0.3mg/dL/day. Urine sodium is >40meq/L, urine osm <450 mOsm.
Thus, 1 is both prerenal and ATN. Prerenal is 2, 3, 4, 6, 7, 8. ATN is 5, 9, 10.

Source: UpToDate.