Prerenal Acute Renal Failure due to Volume Depletion

Author: V. Dimov, M.D.
Reviewer: S. Noor, M.D., Cleveland Clinic

A 67-year-old African American male is admitted to the hospital with chief complaint of generalized weakness and potassium level of 6.5 mEq/L. His laboratory results show acute renal failure (ARF). The patient has severe osteoarthritis and takes high-dose NSAID. In the recent heat wave, he noticed that he did not go to bathroom as often as he used to for the last 2-3 days.

PMH

Obesity, OSA, HTN, OA.

Medications

Motrin, Percocet, Oxycodone, Lisinopril.

Physical examination

VSS.
HEENT: Dry MM.
Chest: CTA (B).
CVS: Clear S1S2.
Abdomen: Soft, NT, ND, +BS.
Extremities: no c/c/e.

Laboratory results

BMP shows acute renal failure. BUN/Cr were normal several months ago.


BMP in prerenal ARF

What is the most likely diagnosis?

Prerenal ARF due to volume depletion.

How to confirm the diagnosis?

UA.
Urinary sodium and creatinine to calculate the fractional excretion of sodium (FENA).

What other tests would you order?

BMP in 6 and 24 hours.
Renal ultrasound to rule out urinary obstruction and nephrolithiasis.

What treatment would you start for this patient?

Insulin 10 units IV with D50, 1amp. IV x 1.
Kayexalate 45 gm po x 1.
Foley catheter.
Strict I/O.
NS at 150 cc/hr x 2 L, then 125 cc/hr, adjust the rate of IVF according to I/O, avoid fluid overload.
Hold ACEi and NSAIDs

What happened?

FENA of 0.77 % confirmed the diagnosis of prerenal failure.
Renal U/S ruled out urinary obstruction.
The patient had good urine output with IVF and was in a positive fluid balance.
Potassium normalized after treatment with Kayexalate, Insulin and D50.
There was a downward trend in BUN and creatinine.


BUN and Cr in prerenal ARF


BUN and Cr improvement with IV hydration in prerenal ARF


Renal ultrasound in prerenal ARF

Final diagnosis

Prerenal Acute Renal Failure due to Volume Depletion.

What did we learn from this case?

ARF is frequently defined as an acute increase of the serum creatinine level by 25 % from baseline.

The fractional excretion of sodium (FENa) is useful in diagnosing pre-renal ARF. FENa is less than 1 % in many patients with prerenal ARF. Intravenous hydration is the mainstay of treatment.

References

Acute Renal Failure. M. Agrawal, R. Swartz. American Family Physician, April 1, 2000.

Related reading

Hypovolemia versus Dehydration. Renal Fellow Network, 2009.

Published: 08/23/2006
Updated: 04/22/2009