Renal Failure Flashcards
What conditions are at a higher risk for developing AKI?
- Hypertension
- Congestive cardiac failure
- Diabetes
- Multiple myeloma
- Chronic infection
- Myeloproliferative disorder
What are some examples of causes of Prerenal acute kidney dysfunction?
- Once MAP <80mmhg steep decline in GFR
- Hypovolemia
- Decreased cardiac output
- Decreased effective circulating volume
- Impaired renal autoregulation
What is Pre-renal Injury?
-Most common cause of renal failure (50-80%)
-Results from poor renal perfusion
-Reversed with restoration of renal perfusion/glomerular pressure
-BUN/Creatinine ratio > 20:1
-Calculate fractional excretion of
sodium (FeNa)
-Urinalysis often reveals hyaline
casts
What is is FeNa?
- FeNa = (UNa x PCr/PNa x UCr) X 100
- FeNa < 1% is suggestive of pre-renal azotemia
- FeNa >1% intrinsic renal failure
- FeNa >4% post-renal failure
What is Prerenal Treatment?
Volume expanding fluid (IVNS, LR, Packed RBCs if bleeding)
What is Intrinsic Renal Diseases?
-Acute Interstitial Nephritis (AIN)
-Acute Tubular Necrosis (ATN) 90% most
common*
-Glomerular Diseases
-Pyelonephritis
-Malignancy (MM)
-Renal artery embolism/thrombus (renal infarction)
-Vasculitis
What is Acute Interstitial Nephritis (AIN)?
-Typically allergic reaction to medication
-Post-infectious
-Autoimmune
What is the “classic presentation” of Acute Interstitial Nephritis?
- After recent new drug exposure
- Fever
- Skin rash
- Peripheral eosinophilia
- Oliguria
What is Medications associated with acute interstitial nephritis (AIN)?
-Antibiotics (B-lactams, sulfonamides, vancomycin,
erythromycin, rifampin)
-Acyclovir
-NSAIDS (can cause either direct toxicity or
allergy)
-Anticonvulsants (Phenytoin, valproate, carbamazepine)
What is Treatment of AIN?
- Discontinuation of offending agent often leads to reversal of renal injury
- Glucocorticoid therapy may accelerate renal recovery (6 week taper prednisone or IV methylprednisolone pulse 3 days)
- Damage may be permanent if long duration of exposure and high degree of tubular atrophy and interstitial fibrosis
What are Potential Nephrotoxins that cause ATN?
-NSAIDs -Chemotherapeutic agents -Aminoglycosides -Amphotericin -Vancomycin -Radiocontrast dye -Poison (ethylene glycol, heavy metals)
What is Acute Tubular Necrosis (ATN)?
acute tubular cell injury, usually reversible unless severe, prolonged
- Ischemia
- Sepsis
- Toxins
Laboratory Data for Acute Tubular Necrosis (ATN)?
- Pigmented granular casts (muddy-brown casts) on urinalysis
- Cr/BUN elevation
- FeNa >2%
What is Treatment for ATN?
-Aggressive volume replacement– hydrate (If nephrotoxic agent, volume depletion)
-If Oliguria present and extracellular-volume normalized consider loop-diuretic high dose (100-200mg Lasix) to improve urine output
-Protein restriction
-If it’s due to nephrotoxic agent, remove
offending agent
-Dialysis
What is Glomerular diseases?
- Infectious Disease associated Syndromes Post-streptococcal glomerulonephritis
- Nephrotic syndrome (Minimal change disease)
- Diabetic nephropathy
- Hypertensive nephropathy