Acute Renal Failure

Question 1

What is acute renal failure?

Answer 1

• abrupt (w/in 48 hr) reduction in kidney function
• absolute increase in SCr
• reduction in urine output

Question 2

Mortality of Pts Requiring Dialysis

Answer 2

40-90%

Question 3

Oliguric Renal Failure

Answer 3

• urine output < 400 mL/24 hours
• so urine output is less than that required to maintain solute balance
• higher mortality

Question 4

Anuric Renal Failure

Answer 4

• urine output < 100 mL/24 hours

- suggest complete obstruction, severe ATN, major vascular catastrophy

Question 5

Sxs of Acute Renal Failure

Answer 5

• fever, rash, joint pains, myalgias
• dyspnea, HF
• hemopytsis
• preceding bloody diarrhea
• preceding pharyngitis

Question 6

When can renal biopsy be done?

Answer 6

• exclude pre and post renal failure
• extra-renal manifestations that suggest a systemic disorder
• heavy proteinuria, RBC casts

Question 7

Rhabdomyolysis

Answer 7

• often develops in setting of crush injury
• CK > 10,000, + dipstick for blood but no RBCs
• patient usually has pink urine

Question 8

Tx of Rhabdomyolysis

Answer 8

• volume expansion
• fasciotomy when indicated for compartment syndrome
• avoid Ca2+ repletion unless neuromuscular manifestations present

Question 9

What are the mechanisms by which acute renal failure can occur?

Answer 9

• pre-renal: usually decreased renal blood flow
• intrarenal:
• post-renal: usually obstruction (eg enlarged prostate)

Question 10

What are the most common imaging modalities used for kidneys?

Answer 10

• US
• MRI
• CT
• radionuclide scan