35: AKI, CKD Flashcards
creatinine
metabolite of creatine phosphate from muscle
what is creatinine used or?
estimating GFR
two main methods/calculators for estimated GFR (eGFR)
- CKD-EPI
2. MDRD
relationship between GFR and serum creatinine
higher GFR = exponentially less serum creatinine
anuria
urine <100 mL/day
oliguria
urine <500 mL/day
azotemia vs pre-renal azotemia vs uremia
- azotemia: elevated BUN
- pre-renal azotemia: elevated BUN out of proportion to serum Cr due to poor renal perfusion
- uremia: elevated BUN WITH symptoms
symptoms of uremia
N/V, confusion, fatigue, metallic taste in mouth, anorexia
four toxins that can cause acute tubular necrosis
- myoglobin (rhabdomyolysis)
- uric acid
- myeloma light chains
- IV contrast
two groups of drugs that can cause decreased renal blood flow -> pre-renal AKI
NSAIDs, ACEIs/ARBs
if pre-renal AKI is present long enough, what will develop (not CKD lol)
ATN (acute tubular necrosis)
two types of obstruction that will cause post-renal AKI
- bladder obstruction
2. bilateral ureteral obstruction
what do renal tubular epithelial cells and granular casts suggest?
ATN
what do WBC casts or urine eosinophils suggest?
AIN: acute interstitial nephritis
what does proteinuria, hematuria, and dysmorphic RBC casts suggest?
nephritic syndrome
what does heavy proteinuria, fatty casts, oval fat bodies, and minimal hematuria suggest?
nephrotic syndrome
FENA (fractional excretion of Na) formula**
Na excreted / Na filtered
FENa < 1% vs FENa > 2% suggests what?**
<1% -> pre-renal AKI
>2% -> ATN
in which pts is FENa less accurate, and FEUrea should be used?
pts on diuretics
what does FEUrea <35% vs >50% suggest?
<35% -> pre-renal AKI
>50% -> ATN
what happens if after 3 months of AKI, pts kidney function is not back to baseline?
Dxed with CKD
specific GFR and Cr cutoff to intiate dialysis
there is none
indications for dialysis
A: acidosis E: electrolyte imbalance I: intoxication with toxins O: overload (volume overload) U: Uremia (if encephalopathy or pericarditis)
six signs of kidney damage that can qualify as CKD criteria
- albuminuria
- urine sediment abnormalities
- electrolyte abnormalities
- histologic abnormalities
- structural abnormalities on imaging
- Hx kidney transplant
what does the amount of albuminuria signify in CKD?
prognosis
what causes anemia in CKD?
when kidneys produce less EPO
what causes bone pain and fragility in CKD?
kidneys not regulating Ca and Phosphorus -> secondary hyperparathyroidism
two ways CKD can lead to iron deficiency
- chronic blood loss from dialysis
2. decrease in GI Fe absorbtion
pathology of osteitis fibrosis cystica
CKD -> excess PTH -> osteoclast activation -> bone breakdown
findings of osteitis fibrosis cystica
subperiosteal bony reabsorption, bone cysts, “brown tumors” from microhemorrhages in bone
