Renal exam-structure and fxn of kidney

25%-filtrate in glomerulus goes to urine, rest to efferent arterioles, forced in due to pressure difference, forced out of capillaries and into bowman's capsule

PGs, overrides effect of AT II normally, causes vasodilation, more blood flow, more filtrate produced, increases GFR, ATII vasoconstriction decreases amt of blood entering and decreases GFR

NSAIDs-inhibit PG synthesis, increase arterial tone, vasoconstriction due to increased activity of AT II, decrease in GFR

ATII is primary, constriction, increase pressure and increase GFR

ACE inh and ARBs, vasodilation, decrease GFR

reabsorption, major site of ammonia production, 75%

reabsoption-additional 25%, concentration/diluting urine

final concentration of urine, 5-10% reabsorbed

reasorb NaCl and secrete K in response to aldo, reabsorb water due to ADH

erythropoietin, prod and secretion of renin by juxtaglomerular apparatus in response to decrease afferent arteriole pressure, decrease renal flow or increase in renal sympathetic activity

activation of Vit D3, gluconeogenesis, metabolism of endogenous compounds and drugs (e.g. steroilds, insulin) P450 enzymes

filtration + secretion-reabsoprtion

H20, electrolytes, glu, small aa, creatinine

less than 50 angstroms, alb 35

less than 20,000 daltons, alb 65,000

only +, alb is -

only unbound, bound are secreted renally, abx, pcn, ceph

maintain acid base and potassium balance, H, K, NH4, organic acids and bases, creatinine, protein-bound drugs

reabsorb important compounds from filtrate back into blood

500-1600 ml/day

4-8

1.003-1.030, <1.010 relatively hydrated, >1.010 dehydrated

50-1200mOsm/kg, assesses ability of tubules to concentrate urine (fxn of ADH)

glucose, protein, ketones, nitrites, lukocyte esterase, RBC, WBC and casts

<10mg/dl, alb <30mg/gm Cr

0-1 RBC, <5 WBC and occassional cast

aging, muscle mass, diseases, diet, drugs (trim, cimet, fenof increase SCr by competing with tubular secretion, chronic steroid use decreases SCr due to decrease muscle mass), tubular secreation

CrCl=Ucr X V/Pcr, needs to be refrig, large possibility of error, Ucr (conc of creatinine in urine at end of collection(mg/dl), Vm urine flow rate(ml/min), Pcr concentration of creatinine in plasma at midpoint of collection

rises by 0.5 mg/dl or more when baseline <3 mg/dl, or creatinine rises by 1 mg/dl or more when baseline creatinine is 3 mg/dl or more

more accurate than cockcroft-gault in pts with chronic kidney disease, diabetes, or transplanted kidneys

under 18 or over 70, pregnant, racial groups other than caucasians and african-americans

older pts, better to round to 0.8 instead of 1

prego, extreme ages and weights, pts with malnutrition, pts with skeletal muscle diseases, pts with para or quad, vegetarians and rapidly changing kidney fxn,

calc LBW using ht prior to amp, calc effect of limb as a % of LBW, subtract % from LBW

6%

9%

15%

12

18%

30%