Renal Pathology (Warren) - W3 Flashcards
What are the three parts of the glomerular basement membrane?
What makes up the backbone of the GBM?
What gives the GBM its negative charge?
- 3 parts
- lamina rara interna
- lamina dense
- lamina rara externa - by podocytes
- Type IV collagen
- heparin sulfate gives negative charge
What proteins make up the slit diaphragm?
What do you see in the podocytes with nephrotic syndrome?
- nephrin and podocin
- podocyte fusion (flattened and merged) is characteristic of nephrotic syndrome
What part of the kidney tubule system is most sensitive to ischemia & toxins?
- Proximal tubules
How many people does chronic renal disease affect?
11% in US
What is the definition of azotemia?
- biochemical abnormality
- increased BUN and creatinine
- can be…
- pre-renal: hypoperfusion (hemorrhage, shock, dehydration, CHF)
- renal disease
- post-renal
What is the definition of uremia?
- azotemia and clinical symptoms
- gastroenteritis, anemia, peripheral neuropathy, pruritis (horrible itching), pericarditis
Symptoms of nephritic syndrome
- Hematuria - red cells in urine
- mild to moderate proteinuria
- hypertension
What are the clinical symptoms of nephrotic syndrome?
- >3.5gm/day proteinuria
- hypoalbuminemia
- edema
- hyperlipidemia
- lipiduria
What do you see with acute renal failure?
- rapid decline in GFR - rapid onset azotemia
- increased BUN/Cr
- oliguria or anuria
- caused by glomerular, tubulointerstitial or vascular disease
What do you see with chronic renal failure?
- GFR less than 60 ml/min for at least 3 months
- persistent albuminuria
- end result of all renal disease
What are the four stages of renal disease?
- Diminished renal reserve
- GFR 50% of normal
- see in elderly
- normal range BUN/Cr
- Renal insufficiency
- GFR = 20-50% of normal, azotemia, anemia, hypertension
- Renal failure
- GFR 20-25%, edema, metabolic acidosis, uremia
- End stage renal disease
- GFR <5% of normal
- need dialysis or transplant
What is clearance test and equation?
- clearance = approximation of glomerular filtration rate (GFR)
-
clearance = UV/P
- urine concentration x urine volume
What are the issues w/creatinine as measurement?
How does it compare to the true GFR?
- overestimation of true GFR
- secreted by proximal tubule
- related to muscle mass and meat in diet
- may have extrarenal elimation
What is the risk if a GFR is below 60?
When should you see a nephrologist?
- below 60 = high risk for CV disease
- below 30 = see nephrologist
In what situations do we use some clearance measures?
- Unusual body habitus
- severe muscle wasting
- Rapidly changing kidney function
- Patients with GFR of 60 or greater
- kidney donor eval
- research protocols
What is the BUN?
What is normal?
- major end product of protein nitrogen metabolism - liver will make urea from ammonia
- normal = 10-20 mg/dl
- can combine w/serum creatinine to determine cause of azotemia
What can cause a pre-renal increase in BUN?
- Catabolism (burns, fever, stress)
- high protein diet
- GI bleed
- Hemolysis
- Malignancy
-
decreased renal perfusion
- hypotension/shock
- CHF
- dehydration
- renal vein thrombosis
What is BUN sensitive to?
- decreased renal perfusion
- low flow activates renin-angiotensin system that increases water and Na reabsorption
- urea is passivley reabsorbed along with it
- serum BUN increases out of proportion to any change in the GFR
What are 3 diseases cause a renal increase in BUN?
- Glomerular disease
- ATN
- interstitial disease
What factors cause a post-renal increase in BUN?
-
Urinary Tract Obstruction
- benign prostatic hypertrophy
- prostatic carcinoma
- tumor of bladder or ureter
- retroperitoneal mass
- urinary calculi
- basically anything that affects OUTFLOW
What can cause a decrease in BUN?
- decreased synthesis - low protein intake, liver disease
- hemodilution - overhydration, psychogenic polydipsia, diabetes insipidus, pregnancy
- generally not diagnostically useful
How is creatinine formed and what is the normal excretion?
- waste product formed by the spontaneous dehydration of body creatinine
- Normal = 0.7-1.2mg/dL
- BETTER THAN BUN
What can cause a pre-renal increase in creatinine
-
Increased synthesis
- muscle hypertrophy
- muscle necrosis
- anabolic steroid use
- high meat diet
- intense exercise
-
Decreased reanl perfusion
- CHF, hypotension/shock
What can cause a post-renal increase in creatinine
- urinary tract obstruction






