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P&T Block 5 Renal > L52 > Flashcards

Flashcards in L52 Deck (28)
1

Define acute kidney injury

Rapid ↓fxn
↑Cr + BUN

2

What are the 3 categories of damage that can cause AKI?

Pre-renal
Intrinsic kidney injury
Post-renal

3

Describe why the ↓RBF cause pre-renal failure? Explain the change to BUN, Cr?

↓GFR
Kidney is being under profused:
1. Retain Na (H2O) = ↓FE Na
2. Reabsorb BUN, Cr is not: ↑ratio

4

What disease is the mot common cause of intrinsic kidney injury that leads to AKI? Name the 2 possible causes.

Acute tubular necrosis -> AKI
Due to ischemia or toxins

5

Ischemic cause of acute tubular necrosis:
- Biopsy?
- Reversible or not?

HYPOPROFUSION
No biopsy - very typical presentation (small/no urine)
Reversible if you remove the block in time
Results in death of tubular cells that may slough into tubular lumen

6

What are the changes to the kidney grossly with ischemic ATN?

Large, pale kidneys
- Cortex BVs constricted b/c ↓RBF
- Medulla becomes congested with blood

7

What is the microscopic histo changes with ischemic ATN? Explain prox vs distal tubule changes.

Ischemic -> reversible cell damage
Cells SWELL, interstitial edema
No inflammatory cells
Some cell death, scattered (not regular like toxic cause ATN)
1. Prox tubules lose specification from swelling, "distalization"
2. Distal tubules + hyaline casts

8

Does urine sediment change in ischemic ATN?

No

9

How does the urine profile change through the initial, maintenance, and recovery phases of ischemic ATN?

Initiating: ↑Uosm, very [ ] urine indicates injury, basically excreting what gets filtered to it
Recovery: ↓Uosm as urine becomes dilute again, ↓BUN/Cr

10

What histo changes indicate you're recovering from ATN?

Mitosis
Nuclear enlargement

11

What is the BUN:Cr ratio for intrinsic renal failure AKI?

↓BUN/Cr
BUN reabsorption is impaired b/c kidney damaged

12

What is diffuse cortical necrosis?

Widespread cortical infarct of BOTH kidneys
Likely due to combo do vasospasm + DIC
Think septic shock, big surg (GYN), hemorrhage: ↓renal profusion

13

What are exogenous toxins that can cause toxic ATN?

IV contrast scans
Aminoglycosides
MTX
Heavy metals
Cyclosporin/tacrolimus (transplant)

14

What are endogenous toxins that can cause toxic ATN?

Hgb (hemolytic anemia)
Myoglobin (rhabdo) - crush injury
Uric acid
HyperCa

15

Main differences in damage between ischemic v toxic ATN

Ischemic - patchy throughout the nephron w/ skip areas
Toxic: damage to all prox tubules

16

Key finding in urine for ATN

Muddy brown, granular casts

17

What is acute drug induced interstitial nephritis?

Pt has allergic rxn to a normal drug at kidney (vs drugs that would damage any kidney at high doses via toxic ATN)
*Latent period* 1-2 wks after you take drug
May be months after if took NSAIDs
Fever, rash, hematuria, CVA tenderness

18

What are the histo findings that indicated drug induced interstitial nephritis?

Eosinophils in the urine + ↑IgE serum
Inflam cells (nephritis)
Maybe granulomas
↑BUN (azotemia)

19

How does acute cell mediated allograft rejection look different on histo than drug-induced interstitial nephritis?

Allograft rejection - immune cells vs tubules
Nephritis - inflam cells in interstitium

20

What is acute pyelonephritis? Gross vs histo appearance

Acute infection of cortex
Gross - abscesses
PMNs in the tubules and interstitium
- WBCs in urine +/- WBC casts

21

2 causes pyelonephritis?

Ascending UTI (rose from bladder), GNs:
- E. Coli
- Proteus
- Kleb & Enterobacter (urine bag on pts bed)
Blood infection spread to kidneys

22

Clinical presentation acute pyelo

CVA tenderness
Fever

23

Clinical risk factors for acute pyelo

Indwelling catheter (nosocomial)
Urinary tract obstruction
Vesicourteteral reflex
Diabetes
Preggo

24

2 major complications of acute pyelo

Papilary necrosis - more likely if diabetic or cause was obstruction (gray/white tips of renal pyramids)
Perinephritic abscess b/c pus went through renal capsule

25

If a pt has vasculitis, how would it present in the kidney?

Vasculitis = fibrinoid necrosis = necrotic damage to BV wall
Proteins leak into the BV wall and stain bright pink

26

Do you need to get a biopsy to dx vascular processes in the kidneys for large, medium, or micro vasculature?

Microvasculature

27

Give examples of diseases that would cause thrombotic microangiopathy in the kidney

Vasc damage -> thrombosis -> vasc obstruction -> distal ischemia
2ary renal failure
TTP (ADAM TS 13 def - can't cleave VWF)
HUS (EColi O157H7)
Drugs
AI: SLE

28

What are the 2 types of glomerulonephritis that microvascular pathology can cause (via glomerular injury)

Necrotizing
Cresentic (RPGN) - see crescents of damaged Bowman's