Renal Approach to AKI and CKD

Question 1

What is AKI?

Answer 1

An abrupt decline in renal function

Question 2

What can AKI lead to?

Answer 2

Retention of urea and other waste products, dysregulation of extracellular volume, electrolyte problems

Question 3

How is kidney function measured?

Answer 3

Creatinine

Question 4

What is creatinine?

Answer 4

Metabolite of creatine phosphate from muscle; limited utility on its own in assessing kidney function (affected by factors like muscle mass); used in eGFR

Question 5

What is eGFR?

Answer 5

Multiple methods to estimate GFR (CKD-EPI, MDRD); use data such as age and gender combined with Cr to make an estimate of GFR

Question 6

eGFR is not very accurate in the setting of what?

Answer 6

fluctuating renal function (which is seen in AKI)

Question 7

What kind of relationship exists between Cr and eGFR?

Answer 7

Inverse relationship; as Cr increases eGFR decreases

Question 8

What is anuria?

Answer 8

Urine output <50-100mL/day

Question 9

What is oliguria?

Answer 9

Urine output <400-500mL/day (or <0.5mL/Kg/hour)

Question 10

What is azotemia?

Answer 10

Elevation in serum urea (BUN)

Question 11

What is pre-renal azotemia?

Answer 11

Elevation in BUN out of proportion to elevation in serum Cr, specifically due to poor renal perfusion

Question 12

What is uremia?

Answer 12

Elevated BUN with sx (N/V, confusion, metallic taste in mouth, fatigue, anorexia

Question 13

What is the urinary pattern for non-specific, pre-renal azotemia?

Answer 13

hyaline cast

Question 14

What is the urinary pattern for ATN?

Answer 14

Renal tubular epithelial cells, granular casts (muddy brown)

Question 15

What is the urinary pattern for AIN?

Answer 15

WBC, WBC cast, or urine eosinophils

Question 16

FENa is often used to differentiate between what?

Answer 16

Pre-renal AKI and ATN

Question 17

FENa <1% suggests what?

Answer 17

Pre-renal AKI

Question 18

FENa >2% suggests what?

Answer 18

ATN

Question 19

FENa is less accurate in patients taking what medication?

Answer 19

Diuretics (consider use of FEUrea instead)

Question 20

FEUrea <35% suggests what?

Answer 20

Pre-renal AKI

Question 21

FEUrea >50% suggests what?

Answer 21

ATN

Question 22

What are the basic treatment principles for AKI?

Answer 22

Tx depends on cause; all pts should avoid nephrotoxins, renally dose all meds, dialysis if needed

Question 23

What are the indications for dialysis?

Answer 23

A - acidosis (pH <7.1-7.2);
E - electrolytes (e.g. life threatening hyperkalemia);
I - intoxication (certain toxins such as methanol, ethylene glycol, lithium);
O - overload (severe volume overload);
U - uremia (if encephalopathy or pericarditis)

Question 24

Is there a specific GFR or Cr cutoff to initiate dialysis?

Answer 24

No

Question 25

What are the stages for CKD?

Answer 25

1, 2, 3a, 3b, 4 and 5

Question 26

What is stage 1 CKD?

Answer 26

> 90 GFR, normal or high

Question 27

What is stage 2 CKD?

Answer 27

GFR 60-89, mild decrease

Question 28

What is stage 3a CKD?

Answer 28

GFR 45-59, mild to moderate decrease

Question 29

What is stage 3b CKD?

Answer 29

GFR 30-44, moderate to severe decrease

Question 30

What is stage 4 CKD?

Answer 30

GFR 15-29, severe decrease

Question 31

What is stage 5 CKD?

Answer 31

GFR <15, kidney failure/ESRD

Question 32

In the absence of evidence of kidney damage, neither GFR category stage 1 or stage 2 fulfill the criteria for what?

Answer 32

CKD

Question 33

What has been added to CKD stages to better determine prognosis?

Answer 33

albuminuria

Question 34

What are the types of dialysis?

Answer 34

hemodialysis or peritoneal dialysis