13 - AKI Flashcards
azotemia
accumulation of nitrogenous waste
polyuria amt
> 3 L/d
oliguria and anuria amt
oliguria <50 ml/d
2 most likely causes of anuria
urinary tract obstruction
vascular disaster causing no RBF
prerenal state definition
homeostasis maintained, but dec GFR
fall in capillary pressure, dec glomerular surface area
inc reabs by tubules
RAS, aldo, ADH, SNS activated
prerenal failure
prerenal state except now homeostasis is lost
still no permanent damage
prerenal etiologies
dec vascular volume: bleeding, GI loss, diarrhea, diuresis
ineffective circulating volume: sepsis, heart failure, shock, liver failure, pre-eclampsia
how do you distinguish prerenal state vs intrinsic kidney damage
prerenal will: have higher BUN:creatinine ratio (~20:1) nl urinalysis (instead of cellular material, RBCs or WBCs) very low urine Na low FeNa high urine osmolarity
diseases that cause prerenal failure
hepatorenal failure
RAS
NSAIDs (need PGs for renal regulation when volume depleted)
CHF
acute tubular necrosis pathophys
caused by multiple renal insults (preexisting damage, prerenal state, nephrotoxin or ischemia)
cells in tubules die, sloughed off in urine as casts
inflammatory mediates extend damage
recovery in 1-3 wks
nephrotoxins that cause ATN
iv contrast heme pigments (myoglobin, hemoglobin) certain abx (aminoglycosides) heavy metals (like cisplatin) carbon tetrachloride and solvents
cortical necrosis
causes patchy damage, some renal fn may remain
due to obstetrical disasters, DIC, HUS
anuria or oliguria common
papillary necrosis
long loops of henle, vasa recta, collecting ducts affected
flank pain w/ tissue in urine
often due to sickle cell, analgesic abuse, pyelonephritis
not usually oliguric or anuric
impairs ability to concentrate urine
uremia
sx associated w/ high amts of nitrogenous waste in blood
lethargy, nausea, sour taste, altered mental status, seizures
complications of AKI
uremia loss of volume/BP regulation > overload > cardio/pulm failure electrolyte abnormalities acidemia bleeding
