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68 Cards in this Set
- Front
- Back
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What are the 3 main things you should evaluate when looking at an H/E stained renal biopsy section on Light microscopy?
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-Overall glomerular cellularity
-Symmetry of the glomerulus -Thickness of capillary walls |
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What is normal glomerular cellularity?
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Cell nuclei should not be clustered or overlapping
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What is increased cellularity within capillary lumena indicative of?
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Leukocyte infiltration
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Where in the kidney should tubules be almost back to back?
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In the cortex (not the medulla)
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Why should the tubules be almost back-to-back in the renal cortex?
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Bc there is almost no interstitium there
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What is space btwn tubules in the cortex a sign of?
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Something wrong in the interstitial compartment (edema or fibrosis)
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What is the thickness of intrarenal arteries normally? Why?
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Thin - they have very little intima or space btwn endothelium and muscularis
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What are 2 pathologic processes that can expand the arterial intima in renal arteries and with what condition is each associated?
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-Collagen in arteriosclerosis
-Proteinaceous insudate in acute thrombotic microangiopathy |
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What contributes more to ESRD, glomerular or tubular/interstitial diseases?
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Glomerular by far
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What is an acronym for the 10 variants of tubular and interstitial renal diseases?
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APPACUNSAV
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What is APPA?
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Acute tubular necrosis
Polycystic kidney disease Pyelonephritis Acute interstitial nephritis |
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What is CUN?
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-Crystal nephropathy
-Uric acid nephropathy -Nephrolithiasis |
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What is SAV?
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-Sarcoidosis
-Acute transplant rejection -Viral infections |
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What viral infection is associated with tubular/interstitial diseases?
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BK virus
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What is the main way to differentiate between Nephrotic and Nephritic syndromes?
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Nephrotic = bland sediment - just protein
Nephritic = exotic sediment with dysmorphic RBCs, RBC casts, and activity |
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How much protein will be seen in a 24 hr urine specimen in
-Nephrotic syndrome -Nephritic syndrome |
Nephrotic = >3.5g/day
Nephritic = <3 g/day |
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What is a quicker way to look for nephrotic range proteinuria?
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Spot urine protein:creatinine ratio
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So if you measure 100 mg of protein and 100 mg of creatinine in a patient's spot urine, what is their protein/day excretion roughly?
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100/100 = 1 g/day
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What is the usual cause of nephrotic range proteinuria?
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Glomular diseases
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What should you not forget to evaluate for in nephrotic range proteinuria though?
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Other secondary causes like tumors, drugs, systemic conditions, and infections.
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What amount of proteinuria do tubular or interstitial diseases tend to cause?
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Non-nephrotic range
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What causes dysmorphic RBCs?
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Damage to the GBM - glomerular disease
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What do muddy brown casts point to?
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Acute tubular necrosis
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Why does a drop in blood pressure cause acute tubular necrosis?
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Because when oxygen supply to the tubules is lost, their normally HIGH metabolic activity drops and they die.
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What is the blood pressure range in which the kidney has good autoregulation of GFR?
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70-175 mm Hg
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What happens to the kidney's autoregulation of GFR when BP drops very low below 70-80 mm Hg?
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GFR then drops very low as well
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What can be a cause of acute tubular necrosis?
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Surgery
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Do cases of acute tubular necrosis normally get biopsied?
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no
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If you did do a biopsy for ATN, what might you see?
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-Regenerating flattened tubular epithelium
-Frank necrosis |
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What does frank necrosis look like?
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No normal epithelial cells at the lumen periphery; they all died and fell into the middle of the tubule lumen.
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What is the usual outcome of acute tubular necrosis? Why?
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Completely recovery - tubule epithelial cells have high regenerative capacity.
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What can cause Acute interstitial nephritis?
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Drug-induced hypersensitivity - cephalosporins
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What will microscopy show in acute interstitial nephritis?
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-Edema increases the space between tubules
-Lymphoplasmocytic infiltrate in the interstitium |
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What cells are often prominent in cases of Acute interstitial nephritis caused by drug-induced hsn?
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Eosinophils
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What is the usual timeframe required for acute interstitial nephritis to develop due to drug hypersensitivity?
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1-2 weeks
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In cases where there is bilateral CVA tenderness and fever/chills/dysuria, low bp, high creatinine and WBC count, think:
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Pyelonephritis
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Do we normally biopsy for pyelonephritis?
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No
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If we did do a biopsy in pyelonephritis, what findings would be seen?
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Intratubular aggregations of pmns - inflammation WITHIN the tubules
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What is the usual outcome of pyelonephritis when treated?
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Complete recovery of normal kidney function
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What is Indinavir?
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An HIV antiviral med
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What type of renal damage can Indinavir cause?
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Nephropathy due to indinavir crystal precipitation within tubules
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What does the precipitation of intratubular indinavir crystals lead to?
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Histiocytic reactions and sloughing of degenerated tubular epithelial cells
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What is the morphologic appearance of indinavir crystals?
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Spindle shaped
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What is the mechanism by which Chemotherapy for NHLymphoma can lead to renal disease?
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-Chemo melts the tumor
-Lots of waste goes to the kidney -Lots of Uric acid causes gout -Hyperuricemia damages kidney |
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What are 2 characteristic findings in urate nephropathy?
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-Urate crystals
-Tophaceous inflammation |
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How do Tophi develop in hyperuricemia?
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By precipitation of urate crystals that gets surrounded by inflammation and giant cells.
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What is the shape of uric acid crystals that precipitate in Gout?
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Needle-shaped
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What do physicians often prescribe now before chemo begins to prevent the precipitation of urate crystals?
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Allopurinol
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What is an iatrogenic cause of calcium-phosphorus precipitation leading to intratubular deposits of calcium oxalate?
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Fleets enema bowel prep for colonoscopy
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What is increased excretion of calcium oxalate called?
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Hyperoxaluria
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What type of kidney damage does hyperoxaluria cause?
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Diffuse degeneration of proximal tubules
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If a 50-something male presents with 10-year history of increasing abdominal girth and high BP, and his dad died young of a CVA, what do you suspect?
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PCKD, autosomal dominant
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What is his mom's brother had the cerebral bleed?
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X-linked recessive
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Why is there increased freq of intracranial bleeds in patients with PCKD?
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Bc the collagen defect is all over and they often get berry aneurysms in the brain too.
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Where do the cysts in ADPKD develop within the kidney?
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In the tubules - that's why it's discussed here in this lecture. OHHHHhhhh
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Where do the cysts in ARPKD tend to develop?
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In the medulla, and the kidneys don't get as enlarged as in ADPKD either.
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A 40 yr old Afr Am woman presents with chronic cough and DOE, vague fatigue and 20lb weightloss over last 6 months; mild hypercalcemia and creatinine is elevated to 2:
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Sarcoidosis
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What histologic finding is pathognomonic for sarcoidosis?
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Non-necrotizing (noncaseating) granulomatous inflammation
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What are 3 other common histologic findings in renal sarcoidosis?
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-Lymphoplasmacytic infiltrate in interstitium
-Interstitial fibrosis -Epithelioid-like multinucleate giant cells |
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Why do patients with sarcoidosis get hypercalcemia?
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Because the sarcoid tissue has enzyme that activates Vit D to its active form and that stimulates increased GI uptake
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If a 25 yr old comes in for f/u post kidney transplant and has an elevated creatinine that is 2x higher than baseline, think:
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rejection due to failure to comply with anti-rejection meds regimen!!
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What is the classic histologic finding in acute kidney rejection?
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Tubulitis
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What is Tubulitis?
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Infiltration of the tubular epithelium by lymphocytes
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What does all the inflammation within and around the tubules in tubulitis lead to?
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Edema and increased space between tubules
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If a 65 yr old comes in for f/u post kidney transplant and has an elevated creatinine that is 2x higher than baseline, think:
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Taking too much anti-rejection meds so now a virus has caused inflammation
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What is the classic virus to cause interstitial inflammation in the kidney?
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Polyoma BK virus
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What will histologic exam of a biopsy show in polyoma BK virus infection?
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Huge nuclei of tubular epithelial cells due to viral inclusions
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What is polyoma virus BK infection caused by?
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OVER immunosuppression
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