Acute kidney Flashcards
Stage 1 AKI
SrCr 26 increase or 1.5-1.9 fold
<0.5ml/kg/hr for 6-12hS
Stage 2 AKI
SrCr >2-2.9 fold increase
<0.5/ml/kg/hr for >12h
Stage 3 AKI
SrCr >3 fold or 354 mmol/L increase
<0.3/ml/kg/hr >24 or anuria for >12h
AKI risk factors
CKD (less renal buffer)
Volume depletion
Nephrotoxic agents
Obstruction of urinary tract (BPH)
AKI Sx
Urinary habit change, sudden weight gain, flack paint, foamy urine, orthostatic hypotension
- Check ACR, SrCr, BUN, Urine volume
Prerenal AKI causes
- Blood volume loss (hemorrhage, renal loss, GI loss, sepsis, hepatorenal syndrome)
- Low cardiac output
- severe burns
hepatorenal syndrome
Vasodilators made in liver cause systemic decrease in BP leading to hypo perfusion of kidney
Prerenal AKI Sx
Thirst
Orthostatic hypotension
Dehydration (tachycardia, decreased skin turgor, dry mucous membranes)
Lab picture of pre renal AKI
- Hyaline casts
- Fena <1%
- Una <20mmol/L
- SG >1.020
Post renal causes
Bilateral kidney stones, prostate hypertrophy
Crystallizable drugs (sulphonamide, methotrexate, acyclovir)
Post renal Sx
Pain
Anuria
Pyuria
Lab picture of post renal AKI
cellular debris
hematuria (variable)
Una >40mmol/L
Fena >2%
none to moderate urea increase
Lab picture of infrarenal AKI
Casts and cellular debris
hematuria (for sure)
pyuria
Una >40mmol/L
Fena >2%
None to moderate urea increase
AKI treatment
- Hydrate >200ml Normal saline/hr
- D/C drug
- Diuretics if volume overload
- Dialysis for serious electrolyte imbalance or volume overload
AEIOU
When to start dialysis
- Acid- base abnormalities
- electrolyte imbalance
- intoxications
- fluid overload
- uremia (declining mental status)
ACE or ARB
Cause Pre-renal by preventing efferent arteriole constriction
They are a sick day skip to help kidneys adapt to low fluids
NSAIDS
Cause pre-renal by preventing PG from dilating afferent arteriole
Intrarenal acute tubular necrosis
Cell death in two phases (Oliguric, within 24h lasting 1-3 weeks) (Diuretic phase, slow return). High chance on CKD with incomplete recovery
- Aminoglycosides
- Amphotericin B
Aminoglycosides
Gentamicin, tobramycin
Causes cation charge damage to proximal tubular cells blocking filtration causing Intrarenal acute tubular necrosis
- When giving AG make sure to hydrate like crazy
Intrarenal acute tubular necrosis lab picture
Epithelial cell casts and free cells
High urine sodium >40
FeNa >3%
Amphotericin B
Toxic build up in distal tubule causing infrarenal acute tubular necrosis, can be helped if given by liposomal formulations
Intrarenal acute interstitial nephritis
Delayed hypersensitivity that occurs ~14 days after exposure, causes lymphocytic infiltration of the intersitium and inflamm response causes damage
- Penicillins and lithium
- can be treated with prednisone for 4 weeks
Intrarenal acute interstitial nephritis Sx
Fever, rash, Blood and WBC in urine, metabolic acidosis, hyperkalemia, salt wasting
Intrarenal acute interstitial nephritis lab picture
WBC and WBC casts
hematuria
FeNa >1%
Urine sodium >40mmol/L
Obstructive nephropathy
post renal AKI
From crystallizable drugs or myoglobin from rhabdomyolysis
- Aggressive hydration and diuretics to blast through block
- Urine alkalization to reduce crystals
Extrarenal urinary tract obstruction
BPH and anticholinergic drug together