Nephro - Acute Kidney Injury - Online MedED Flashcards Preview

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Flashcards in Nephro - Acute Kidney Injury - Online MedED Deck (18):
1

AKI divided into 3:

Prerenal
Intra-renal
Postrenal

2

Prerenal is due to:

Loss
Third space
Clogged vessels

3

Postrenal is:

Obstruction - hydroureter, hydronephrosis

4

Intrarenal is:

Look at nephron: glomerulus, tubules, interstitium (space in between)

5

Prerenal differential

Problems with pump: MI, CHF
Leaky: nephrosis, nephrotic syndrome, gastritis, cirrhosis, nutrition go down (less albumin)
Hole: diarrhea, dehydration, diaphoresis, hemorrhage
Clog: fibromuscular dysplasia (young female), renal artery stenosis (old male)

6

Postrenal differential

Ureters: cancer, stones
Bladder: cancer, stones, neurogenic bladder/spinal cord injury
Urethra: cancer, stones, BPH, tight foley, etc.

7

Intrarenal differential

Glomerulonephritis

8

Glomerulonephritis - urine

RBC casts - rule out nephrotic syndrome (>3/5 g protein/day, increased cholesterol, edema)

9

Acute interstitial nephritis - urine

Look for WBC casts (-itis is inflammation), eosinophils
-Look for reaction to antibiotics (TMP-SMX, penicillins, cephalosporins)

10

Acute tubular nephrosis - urine

Things in tubule that come into contact
Muddy brown casts (not sensitive or specific)
Ischemia
Exposure to toxins (IV contrast, myoglobin from rhabdo)
- Treatment is vigorous IVF

11

What are the 3 phases of acute tubular nephrosis?

1) Prodrome of Cr rise
2) Oliguric phase (urine output tanks)
3) Polyuric phase (urine output excessive)

12

What is nephrotic syndrome

>3.5 g protein/day
Cholesterol
Edema

13

Elevated Cr - what is the diagnostic approach

1) Start with rule out pre-renal - BUN/Cr ratio, Urine Na, Fractional excretion of Na, if on diuretic cannot use FeNa, use fractional excretion of urea instead
-If it is pre-renal:
BUN/Cr ratio > 20
Una < 10
FeNa < 1%
FeUrea < 35%

14

So what do you do if you determine patient is pre-renal

Volume down - give IVF
Volume up - give diuresis

15

So first step in elevated Cr is to rule out pre-renal... what to do next?

Rule out post-renal/obstruction
Use US/CT scan - hydroureter/hydronephrosis

16

What happens if determine post-renal

Put in Foley, nephrostomy (at level of ureter), surgery

17

After rule out pre renal and post renal... need to go to intrarenal (this is diagnosis of exclusion)

Use Hx and Px exam
Look at urinalysis
Get diagnosis
i.e. diabetic patient with glucose and protein - diabetic nephrophaty
i.e. HTN with elevated Cr - due to HTN
Might need to get Bx to prove dx

18

What are the acute indications for hemodialysis?

Acidosis
Electrolysis - K and Ca
Intoxication
Overload
Uremia