Nephrology Flashcards
How does IV contrast cause renal failure?
vasospasm of afferent arteriole (decrease perfusion to glomeruli)
How long after an infection does post-Strep glomerulonephritis occur?
1-2 weeks after infection
Renal toxicity of a medication is due to the …. of the medication
trough (space interval of medications to decrease toxicity of medication)
What is the side effect of aminoglycosides (gentamicin)?
- renal toxic
2. ototoxicity
What is the difference between azotemia and uremia?
azotemia: renal insufficiency but no need for dialysis
uremia: renal insufficiency resulting in need for dialysis
What are complications of uremia? (9)
- need for dialysis
- anemia (decrease epo production)
- hyperkalemia
- pericarditis
- hypocalcemia (decrease active vitamin D)
- infections (wbc cant degranulate)
- metabolic acidosis & fluid overload (b/c cant get rid of organic acid)
- altered mental status
- bleeding (platelets cant degranulate)
What is the treatment for uremia induced bleeding?
DDAVP (desmospressin causes release of subendothelial stores of vWf and factor 8)
What are causes of pre-renal azotemia?
- dehydration/ shock/ blood loss
- renal artery stenosis
- hepatorenal syndrome
- ACE inhibitor effect on kidney
- low albumin states (nephrotic and liver disease)
What are causes of post-renal azotemia?
- bladder stone/clot
- bladder cancer
- prostate hypertrophy/ cancer
- bilateral ureteral disease
What is the driving force of GFR in kidney?
hydrostatic pressure in the glomeruli capillary
What is the initial clue to pre-renal azotemia?
BUN: creatinine ratio >20
b/c more time for urea to be reabsorbed b/c slow flow
What can falsely elevate BUN?
- increased protein in diet
2. GI bleeding (protein release)
What happens to urine sodium in pre-renal azotemia?
urine sodium < 10 (low b/c body reabsorbs sodium to increase intravascular volume)
What happens to the urine osmolality in pre-renal azotemia?
urine osmolality is high (>500); concentrated urine
high specific gravity >1.010
A pt presenting with hypertension with renal insufficiency most likely suffers from …
- primary hyperaldosteronism
- renal artery stenosis
(distinguish w/ aldosterone/renin ratio)
A pt with liver disease who develops renal insufficiency that does not respond to 1.5 liters of colloid (albumin) most likely suffers from …
hepatorenal syndrome
What dilates the afferent arteriole of the glomeruli?
Prostaglandins
How does NSAIDs result in pre-renal azotemia?
inhibit prostaglandins which prevent afferent arteriole dilation (results in constriction of arteriole)
What constricts the efferent arteriole of the glomeruli?
Angiotensin 2
How do ACE inhibitors result in pre-renal azotemia?
inhibit conversion of angiotensin 1 to angiotensin 2 preventing constriction of efferent arteriole (results in dilation of efferent arteriole)
Why is it that ACE inhibitors diminish the rate of progression to renal failure and uremia in pts with diabetes, HTN, multiple myeloma?
dilation of efferent –> decreased hydrostatic pressure in glomeruli –> decrease intraglomerular HTN
(never withhold ACE inhibitor)
What is the best blood pressure medication for pt with diabetes?
ACE inhibitors
What is orthodeoxia?
Change positions (sitting up) cause oxygen desaturation
What disease is associated with orthodeoxia?
hepatopulmonary syndrome