Renal Approach to AKI and CKD Flashcards
What is AKI?
An abrupt decline in renal function
What can AKI lead to?
Retention of urea and other waste products, dysregulation of extracellular volume, electrolyte problems
How is kidney function measured?
Creatinine
What is creatinine?
Metabolite of creatine phosphate from muscle; limited utility on its own in assessing kidney function (affected by factors like muscle mass); used in eGFR
What is eGFR?
Multiple methods to estimate GFR (CKD-EPI, MDRD); use data such as age and gender combined with Cr to make an estimate of GFR
eGFR is not very accurate in the setting of what?
fluctuating renal function (which is seen in AKI)
What kind of relationship exists between Cr and eGFR?
Inverse relationship; as Cr increases eGFR decreases
What is anuria?
Urine output <50-100mL/day
What is oliguria?
Urine output <400-500mL/day (or <0.5mL/Kg/hour)
What is azotemia?
Elevation in serum urea (BUN)
What is pre-renal azotemia?
Elevation in BUN out of proportion to elevation in serum Cr, specifically due to poor renal perfusion
What is uremia?
Elevated BUN with sx (N/V, confusion, metallic taste in mouth, fatigue, anorexia
What is the urinary pattern for non-specific, pre-renal azotemia?
hyaline cast
What is the urinary pattern for ATN?
Renal tubular epithelial cells, granular casts (muddy brown)
What is the urinary pattern for AIN?
WBC, WBC cast, or urine eosinophils
FENa is often used to differentiate between what?
Pre-renal AKI and ATN
FENa <1% suggests what?
Pre-renal AKI
FENa >2% suggests what?
ATN
FENa is less accurate in patients taking what medication?
Diuretics (consider use of FEUrea instead)
FEUrea <35% suggests what?
Pre-renal AKI
FEUrea >50% suggests what?
ATN
What are the basic treatment principles for AKI?
Tx depends on cause; all pts should avoid nephrotoxins, renally dose all meds, dialysis if needed
What are the indications for dialysis?
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)
Is there a specific GFR or Cr cutoff to initiate dialysis?
No
