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27 Cards in this Set
- Front
- Back
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What is pathway of blood (ie what vessels) in kidney?
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Interlobar artery
arcuate artery interlobular artery afferent arteriole glomerular capillary efferent arteriole |
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what does EFFERENT arteriole contraction due to filtration?
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Decrease RPF (renal plasma flow)
Increase GFR Increase filtration fraction (GFR/RPF) |
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What does afferent arteriole contraction due to GFR?
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Decrease GFR ( and RPF)
Filtration Fraction remains stable |
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What happens to BUN & Cr when GFR decreases?
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Both go up (i.e. renal failure)
If pre-renal (hypovolume), BUN increases more dramatically than Cr |
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What is impact of ACE-I on kidney?
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Cases afferent and efferent arteriole dilation
Eff > Aff, causing decrease GFR |
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Does 24 hour urine over or under estimate GFR?
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over estimates GFR by 10-20%
Cr secreted by tubules |
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What is role of angiotensin II?
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(Cleaved to active form by ACE in lung)
-Inc intravascular volume + BP -Efferent constriction -Release aldosterone -Release ADH from posterior pituitary -Increase thirst |
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where in kidney does aldosterone act?
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In collecting duct.
Na+ absorption and K secretion |
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How does ADH work?
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Collecting Duct
Inserts aquaporins into basolateral membrane of principle cells |
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where is action of thiazide diuretics? (HCTZ, chlorthalidone, metolazone)
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Distal convoluted tubule
(Blocks Na+ and Cl reabsorption) Also decreased calcium excretion (by augmenting Na/Ca2+ reabs. in prox tubule) |
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What is mechanism of loop diuretics?
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Blocks Na/K/Cl cotransporter in thick ascending loop
(I.e. lasix, bumetanide) (Thick ascending is most water permeable which typically follows active transport of solutes). overtime, tonicity of medulla is reduced with lasix |
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What is typical osmolality of plasma?
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290 mOsm/kg
Kidney regulates: mostly in loop of henle and collecting duct (ADH) |
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What are common (GU-related) causes of hypokalemia?
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Increased GI/urine losses
Diuretics laxatives amphotericin Postobstructive diuresis Cushing syndrome/hyperaldo states (Look for ST depression; also replete Magnesium) |
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EKG changes with hypokalemia
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U waves
ST depression T wave flattening QTc prolongation Ventricular dysrhthmias |
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EKG changes with HYPERkalemia
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peak T waves
shortened QT interval ST depressions Widening QRS |
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What are affects of parathyroid hormone (PTH)?
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-Increase urinary phosphate excretion
-inc renal Ca reabs -bone breakdown -vitD production->inc. intestinal calcium + phosphorus abs. |
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Which RTA has hyperkalemia as manifestation?
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Type IV - distal
Reduce H+/K+ excretion Treatment: regulate potassium |
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What is RTA Type 2?
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proximal tube failure to reabsorb bicarbonate
-nl citrate. no stones -give NaBiCarb |
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Which RTA has high urinary pH?
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RTA Type I
-You can't excrete acid (Type II + IV, acidic urine) |
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Does changing permeability of glomerular basement layer change GFR?
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No. GFR is already maximized for water and solutes.
Change in permeability merely allows things like albumin to pass. |
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In a patient with ischemic nephropathy, renal bx shows glomerulosclerosis and atheroembolism. Is this pt likedly to be salvaged with revasularization?
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No.
50% 5-year mortality with these findings due to death from CV/CVA related events |
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In which type of RVH do ACE-I NOT work for BP control?
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Bilateral RVD or solitary kidney RVD
aka one-kidney, one-clip model HTN due to volume expansion and since plaque prevents increase renal perfusion, ACE won't help |
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which fibromusclar dz:
-Children -progresses -may dissect |
Intimal
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Which fibromuscular dz:
"string on beads" |
Medial fibroplasia
-women, 25-50 -bilateral -rare to progress -assoc with Erlers Danlos IV |
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Will a pt with a high RI benefit from revascularization?
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Unlikely. High RI signifies small vessel and parenchymal damage.
RI>0.80 = bad |
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What is the biggest medical benefit of performing angioplasty/stenting for RVD?
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Lowers BP by 25/10
-No real change in GFR 10% risk of restenosis, 5% dissection |
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When would you perform surgical revascularization over stenting?
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Concomitant aortic repair
renal artery aneurysm Multiple failed endovascular attempts |
