L53

Question 1

Creatinine is a metabolic product from (what) and (what)? Why do you care?

Answer 1

From arginine & creatine
Formed at constant rate
Plasma Cr used to monitor GFR (P Cr = 1/GFR)
- Everything that is filtered gets excreted in urine
Formation = filtration = elimination rate

Question 2

Describe the 4 stages of change to Cr in the unsteady state of AKI

Answer 2

P Cr does NOT reflect GFR

1. Generation = excretion (can’t see damage effects yet)
2. G > E
3. G = E as damage plateaus
4. G

Question 3

What is the cause of AKI if there are WBC casts + eosinophils in the urine?

Answer 3

Acute intersitital nephritis

Question 4

What is the cause of AKI if there is protein, RBC casts and WBCs in the urine?

Answer 4

Acute glomerulonephritis

Question 5

What is the cause of AKI if there are granular casts in the urine?

Answer 5

Acute tubular necrosis

Question 6

Causes of pre-renalAKI

Answer 6

Volume loss: hemm, diarrhea/vomiting, diuretics
Look intravasc depleted:
- CHF
- Nephrotic syndrome
- Cirrhosis

Question 7

Describe changes with pre-renal cause of AKI

• GFR
• BUN/Cr
• FE Na

Answer 7

↓RBF -> ↓GFR -> ↑Cr

↑BUN + ↓FE Na as trying to ↑ECF

Question 8

4 big causes of intra-renal AKI

Answer 8

ATN
Acute interstitial nephritis
Acute glomerulonephritis
TTP, HUS

Question 9

Give some examples of things that would cause ischemia leading to ATN

Answer 9

Hypotension
Cardiac bypass
Aortic crossclamp during aneurysm repair

Question 10

Histo for ATN

Answer 10

Flattened epithelia
Debris in tubular lumen
+/- mitotic figures (if recovering)

Question 11

Treat ATN

Answer 11

Supportive

Question 12

Most common drugs that cause acute interstitial nephritis

Answer 12

Antibiotics

NSAIDs

Question 13

What is the classic triad of acute interstitial nephritis (that may not be seen together)

Answer 13

**Fever + CVA tenderness
Rash
Eosinophilia

Question 14

Urinalysis of acute interstitial nephritis

Answer 14

WBCs +/- casts

Eosinophils

Question 15

Treat acute interstitial nephritis

Answer 15

Supportive

Remove the insult (but might not need to do this since presentation is delayed, drug may have already stopped)

Question 16

5 big causes of rapidly progressive glomerulonephritis

Answer 16

1. Goodpastures
2. Granulomatous polyangitis
3. Mircoscopic polyarteritis
4. SLE
5. Post-infectious (strep)

Question 17

What is rapidly progressive GN?

Answer 17

Renal fxn deteriorates fast (days/wks), poor prognosis
Nephritic syndrome = inflam process = glomerular basement membrane disrupted
- ↑BUN
- HTN
- ↓Urine output

Question 18

Urinalysis for RPGN

Answer 18

RBC casts indicates effects glomerulus

Question 19

What is granulmoatosis polyangitis? What is the key histo finding

Answer 19

= Wegner's syndrome
AI inflam of BVs
**+ c ANCA**
Symptoms:
- Nephritis
- Pulm infiltrates // hemoptysis

Question 20

What is ANCA?

Answer 20

Anti-neutrophil cytoplasmic Abs
c = cytoplasmic
p = perinuclear

Question 21

Treat Wegner’s

Answer 21

Steroids

Cyclophosphamide - immune suppression, cross links DNA

Question 22

What do you see on renal biopsy for Wegner’s

Answer 22

Crescents
Segmental necrotizing lesions
Pauci-immune

Question 23

What is Goodpasture’s disease?

Answer 23

Abs vs glomerular & alveolar basement membrane (T2 HST)

Pulm hemm + RPGN

Question 24

Renal biopsy of Goodpasture’s

Answer 24

Crescent

LINEAR IgG deposits

Question 25

Treat Goodpasture’s

Answer 25

Plasma exchange
Steroids (methylpredniolone)
Cyclophosphomide

Question 26

What is the immuno-fluorescence + electron microscopy for RPGN after strep?

Answer 26

Lumpy bumpy on IF

Subepithelial humps on EM (immune deposits)

Question 27

Treat TTP/HUS as cause of RPGN

Answer 27

Plasma exchange ASAP

Question 28

What are causes of post-renal AKI

Answer 28

BLOCKAGE
@ ureter
@ bladder outlet obstruction

Question 29

Dx post-renal cause of AKI

Answer 29

Palpable bladder
Large prostate
Hydronephrosis on imaging (enlarged renal pelvis)