Acute Kidney Injury Flashcards Preview

Pathology > Acute Kidney Injury > Flashcards

Flashcards in Acute Kidney Injury Deck (39):
1

What is the definition of acute kidney injury?

An abrupt (within 48 hours) reduction in kidney function, defined as:
• Increase in serum creatinine of > 0.3mg/dL OR
• % increase in serum creatinine of 50% OR
• Oliguria of 6 hours

2

What is the relationship between acute kidney injury and critical illness?

AKI is often found in critically ill patients

3

What are the 3 groups of AKI causes?

- Prerenal Azotemia
- Intrinsic Renal Disease
- Postrenal Obstruction

4

What are the causes of prerenal azotemia?

i. True hypovolemia
ii. Decreased effective circulating volume
iii. Renal artery stenosis/occlusion
iv. NSAID/ACE-I/ARB mechanism

5

What are the causes of intrinsic renal disease?

i. Vascular causes
ii. Glomerular disease
iii. ATN
iv. AIN

6

What are the causes of postrenal obstruction?

i. Bladder outlet obstruction
ii. Bilateral ureteral obstruction
iii. Unilateral ureteral obstruction in a solitary kidney

7

What are the 2 most common causes of AKI?

- Prerenal Azotemia
- Ischemic ATN

8

What can prerenal azotemia progress to if it is not corrected?

Ischemic ATN

9

What is prerenal azotemia?

It is an appropriate response to renal hypo perfusion that leads to a build up of nitrogen compounds in the blood

10

What are some of the causes of prerenal azotemia?

- Decreased ECV
- Renal artery stenosis
- Drug-induced impaired renal autoregulation

11

What is the normal renal response to drop in BP?

- Afferent vasodilation
- Efferent vasoconstriction

12

What is the effect of NSAIDs on the GFR?

NSAIDs decrease the GFR by causing afferent arterial vasoconstriction

13

What is the effect of ACE-I/ARBs on the GFR?

They do not affect the GFR that much. They dilate the efferent arterioles which has a protective effect.

14

What are some of the risk factors for postern disease?

• Older men with prostate disease
• Solitary kidney
• Intra-abdominal (pelvic) cancer

15

What are the 4 categories of intrinsic renal disease?

- vascular causes
- glomerular diseases
- acute interstitial nephritis
- acute tubular necrosis

16

What are some of the causes of ATN?

• Sepsis
• Surgery
• Nephrotoxic exposures

17

What is the major cause of intrinsic renal disease?

ATN

18

What are the classical features of ATN?

- Muddy brown urine
- Oliguric Phase (HTN/Hyperkalemia/Volume Overload)
- Polyuric Phase

19

What are the two types of ATN?

- Ischemic
- Toxic

20

What are some of the vascular causes of intrinsic renal failure?

• Vasculitis
• Thromboembolic disease
• HUS/TTP
• Malignant HTN
• Scleroderma renal crisis

21

What is the main vascular cause of intrinsic renal failure?

Malignant HTN - which causes impending/progressive organ dysfunction

22

What are the two class of acute interstitial nephritis (AIN) that lead to intrinsic renal failure?

Drug Associated (NSAIDs and antibiotics)
Non-drug Associated (Infectious/Autoimmune)

23

What is the triad of signs in AIN?

Fever, peripheral eosinophilia, rash

24

Abdominojugular Reflex

Pushing on the umbilicus leads to jugular vein rising of more than 4 cm

25

What are signs that the body is too dry?

• Dry mucous membranes
• Skin tenting (only useful if positive in adults)
• Neck veins flat at 0 degrees

26

What are signs that the body is too wet?

• Abdominojugular reflux at 30-45 degrees
• S3 gallop
• Ascites

27

Prerenal Azotemia Urinanalysis

Hyaline Casts

28

Prerenal Azotemia Urine Specific Gravity

It will be high - 1.020

29

Prerenal Azotemia Osmolality

It will be high - greater than 500

30

Prerenal Azotemia FE of Na

It will be low - less than 1%

31

Prerenal Azotemia FE of Urea

Less than 35%

32

ATN Urinanalysis

Tubular Epithelial Casts

33

ATN Urine Specific Gravity

Low

34

ATN Osmolality

It will be low - less than 300

35

ATN FE of Na

Greater than 2%

36

ATN FE of Urea

Greater than 35%

37

What is the BUN:Cr ratio in prerenal azotemia?

Greater than 10:1

38

What is the BUN:Cr ratio in ATN?

10:1

39

What are the general indications for hemodialysis in acute kidney injury?

• Acidosis (severe and/or refractory)
• Electrolyte derangement (usually severe ↑K+)
• Intoxication syndrome (severe, dialyzable)
• Overload (significant pulmonary edema)
• Uremia (significantly symptomatic)

Decks in Pathology Class (203):