L53 Flashcards
Creatinine is a metabolic product from (what) and (what)? Why do you care?
From arginine & creatine
Formed at constant rate
Plasma Cr used to monitor GFR (P Cr = 1/GFR)
- Everything that is filtered gets excreted in urine
Formation = filtration = elimination rate
Describe the 4 stages of change to Cr in the unsteady state of AKI
P Cr does NOT reflect GFR
- Generation = excretion (can’t see damage effects yet)
- G > E
- G = E as damage plateaus
- G
What is the cause of AKI if there are WBC casts + eosinophils in the urine?
Acute intersitital nephritis
What is the cause of AKI if there is protein, RBC casts and WBCs in the urine?
Acute glomerulonephritis
What is the cause of AKI if there are granular casts in the urine?
Acute tubular necrosis
Causes of pre-renalAKI
Volume loss: hemm, diarrhea/vomiting, diuretics Look intravasc depleted: - CHF - Nephrotic syndrome - Cirrhosis
Describe changes with pre-renal cause of AKI
- GFR
- BUN/Cr
- FE Na
↓RBF -> ↓GFR -> ↑Cr
↑BUN + ↓FE Na as trying to ↑ECF
4 big causes of intra-renal AKI
ATN
Acute interstitial nephritis
Acute glomerulonephritis
TTP, HUS
Give some examples of things that would cause ischemia leading to ATN
Hypotension
Cardiac bypass
Aortic crossclamp during aneurysm repair
Histo for ATN
Flattened epithelia
Debris in tubular lumen
+/- mitotic figures (if recovering)
Treat ATN
Supportive
Most common drugs that cause acute interstitial nephritis
Antibiotics
NSAIDs
What is the classic triad of acute interstitial nephritis (that may not be seen together)
**Fever + CVA tenderness
Rash
Eosinophilia
Urinalysis of acute interstitial nephritis
WBCs +/- casts
Eosinophils
Treat acute interstitial nephritis
Supportive
Remove the insult (but might not need to do this since presentation is delayed, drug may have already stopped)
5 big causes of rapidly progressive glomerulonephritis
- Goodpastures
- Granulomatous polyangitis
- Mircoscopic polyarteritis
- SLE
- Post-infectious (strep)
What is rapidly progressive GN?
Renal fxn deteriorates fast (days/wks), poor prognosis
Nephritic syndrome = inflam process = glomerular basement membrane disrupted
- ↑BUN
- HTN
- ↓Urine output
Urinalysis for RPGN
RBC casts indicates effects glomerulus
What is granulmoatosis polyangitis? What is the key histo finding
= Wegner's syndrome AI inflam of BVs **+ c ANCA** Symptoms: - Nephritis - Pulm infiltrates // hemoptysis
What is ANCA?
Anti-neutrophil cytoplasmic Abs
c = cytoplasmic
p = perinuclear
Treat Wegner’s
Steroids
Cyclophosphamide - immune suppression, cross links DNA
What do you see on renal biopsy for Wegner’s
Crescents
Segmental necrotizing lesions
Pauci-immune
What is Goodpasture’s disease?
Abs vs glomerular & alveolar basement membrane (T2 HST)
Pulm hemm + RPGN
Renal biopsy of Goodpasture’s
Crescent
LINEAR IgG deposits
Treat Goodpasture’s
Plasma exchange
Steroids (methylpredniolone)
Cyclophosphomide
What is the immuno-fluorescence + electron microscopy for RPGN after strep?
Lumpy bumpy on IF
Subepithelial humps on EM (immune deposits)
Treat TTP/HUS as cause of RPGN
Plasma exchange ASAP
What are causes of post-renal AKI
BLOCKAGE
@ ureter
@ bladder outlet obstruction
Dx post-renal cause of AKI
Palpable bladder
Large prostate
Hydronephrosis on imaging (enlarged renal pelvis)
