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 nonsteroidal antiinflammatory drugs (NSAIDs). 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.

Past medical history (PMH)

Obesity, obstructive sleep apnea (OSA), hypertension (HTN), osteoarthritis (OA).

Medications

Motrin (ibuprofen), Percocet (oxycodone with acetaminophen), oxycodone, lisinopril.

Physical examination

VSS.
HEENT: Dry mucosal membranes (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 (click to enlarge the image).

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 (click to enlarge the image).


BUN and Cr improvement with IV hydration in prerenal ARF (click to enlarge the images).


Renal ultrasound in prerenal ARF (click to enlarge the image).

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: 04/20/2010

14 comments:

  1. This is a good practical case and very useful for new clinicians.

    For any clinician:
    No foley catheter unless oliguric, anuric, obstructed since any catheter is a foreign body and increases infection risk.

    Rehydrate if U/A has high spec gavity, mucous membranes dry, or if BUN is >30 times the creatinine as in this case. Even CHF pts get dry if not in heart failure. If in doubt, do CXR, BNPT, listen for crackles.

    Start with 250cc IVF if BNPT not less than 150 or give carefully while checking lung bases posteriorly after each bolus along with pulse ox, etc as above.

    Half of pts in acute renal failure are septic. Look for and eliminate source such as pneumonia, foreign body, pyelonephritis, joint infections. May be afebrile/ low temp or low WBCs with sepsis.

    Do cultures, check lactate ASAP to detect sepsis BEFORE the BP drops. Lactic acid "the troponin of sepsis." If septic, give a lot of fluids (up to 10 liters often) since capillary leak syndrome will lead to severe hypotension. If septic expect edema to develop with IV boluses yet be aware pt is intravascularly depleted. No pressors without fluids "pressors are not your friend" as per lecturers on Surviving Sepsis campaign.

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  2. Be careful about using the term "dehydration" when you mean volume depletion. Dehydration refers to water loss alone. Volume depletion more accurately describes that there are electrolyte losses as well, as is always the case. You certainly can have situations where there is more free water loss as compared to isotonic losses (this causes hypernatremia), but it's still called "volume depletion".

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  3. Agree. Volume depletion is the correct term for most such cases.

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  4. dr.Ahmed
    why pre renal ARF? what is the cause in this case why ARF not from intersticial nephritis from NSAIDS (Acute intersticial niphritis)it is logic.ther is no bleeding or starvation??so what is the cause??

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  5. "why pre renal ARF?" - because of history, FeNA, clinical response to fluid replacement, etc.

    "what is the cause in this case why ARF not from intersticial nephritis from NSAIDS (Acute intersticial niphritis)it is logic."

    UA did not show evidence of nephritis. Also, if would have different clinical response.

    "ther is no bleeding or starvation??so what is the cause??" - Cause of pre-renal ARF in this case is most likely poor PO intake in hot climate.

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  6. hi.how i download these cases?thanks

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  7. There is no way to download the cases short of using the "Save As" in the browser and save pages one by one. I think they may be working on a downloadable PDF book but this is not yet available.

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  8. Another interesting discussion that can be had about this case is with regard to the disproportionately high potassium seen at presentation.

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  9. RE: "disproportionately high potassium seen at presentation"

    Lisinopril (ACE inhibitor) is the likely contributing factor.

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  10. Good Case, indeed

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  11. Great case!! I just wish there were many more.

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  12. Hey there.

    Great to find these cases. :-)
    Just have one complaint..
    We are students from Denmark, and some of your "codes" are pretty deficult to understand when English are not your main language. Especially under the psysical examination we got kinda lost. Could you post a "translation", not as much an explation, but maybe just in full words?

    Thx alot for this bookmark though.

    ReplyDelete
  13. All medical abbreviations are available here:

    http://en.wikipedia.org/wiki/List_of_medical_abbreviations

    Try searching by first letter (at the top), or just use the search box of Wikipedia.

    ReplyDelete
  14. is the NSAID affect the renal performance ?

    if it yes why u didnt change the drug ?

    (:

    ReplyDelete