Urology and Nephrology Intro Flashcards
What is Azotemia?
Abnormal increase in concentration of nitrogenous wastes in blood.
What are some pre-renal causes of azotemia?
perfusion
- dehydration
- hypoadrenocorticism
- cardiac disease
- shock
- hypovolemia
What are some renal causes of azotemia?
parenchymal disease
- infectious cysts
- Inflammation
- Neoplasia
- toxins
What are some post-renal causes of azotemia?
obstructive
- blockage - ureteral/bladder or urethral
What is renal failure?
clinical syndrome that occurs when kidneys are no longer able to maintain:
- regulatory function
- excretory function
- endocrine function
retention of nitrogenous solutes and derangements of fluid, electrolytes and acid-base balance
Renal failure occurs when how much of the nephron population is non-functional?
> 75%
What is renal disease?
presence of morphological or functional lesions in one or both kidneys, regardless of extent
What is uremia?
constellation of clinical signs and biochemical abnormalities associated with critical loss of functional nephrons.
Includes extra-renal manifestations of renal failure (eg: uremic gastropathy, hyperparathyroidism)
What are some techniques used to test glomerular function?
Accurate - clearance of radioisotopes with renal scintigraphy - Iohexal/inulin/creatinine clearance tests Indirect - serum urea levels - serum creatinine levels - cystatin C - SDMA - symmetrical dimethylarginine
What is the gold standard test for glomerular function?
clearance of radioisotopes with renal scintigraphy
What happens if concentration of urea in the renal medulla get too low?
doesn’t maintain solute gradient -> medullary washout
True or False? Urea Clearance is a reliable estimate of GFR.
False
What are the indirect methods for estimating glomerular function?
- serum urea levels
- serum creatinine levels
- cystatin C
- SDMA (symmetrical dimethylarginine)
True or False? The relationship between creatinine and GFR is linear.
False
What does GFR have to decrease to for azotemia to develop
GFR has to drop to 25%
True or False? Creatinine level cannot prognosticate on the magnitude of azotemia.
True
What is cystatin C produced by?
all cells with a nucleus.
True or False? Cystatin C is not reabsorbed by the proximal tubular cells.
False. it is almost completely reabsorbed by the proximal tubular cells and catabolized to it’s constituent amino acids.
What is SDMA (Symmetric Dimethylarginine)?
a methylated form of the amino acid arginine, which is produced in every cell and relayed around the bodies circulation during protein synthesis.
