Renal 2 Flashcards
normal serum creatinine
0.6-1.2 mg/dl
normal serum BUN
blood urea nitrogen
(remember 50% excreted)
*8-20 mg/dl
what is standard GFR
- *is age related
- ie/ 20-29 yrs if 116 mL/min
- nephrons die as you get older (have fewer the older you get)
how much nephron death if renal failure
> 80%
GFR tells you…
what rate blood should flow over glomerulus
what happens to kidney function as you get older
begins to function less effectively, urine output is less concentrated when older
what is the anion gap
more negative than positive anions (metabolic acidosis)
estimation for an individual’s GFR is based on what
Based on age, male/female, and African American or not
renal failure is…
-the loss of function r/t nephron damage
common causes of CRF
Diabetes (43%), HTN (25%), glomerulonephritis (8%)
describe acute renal failure
- only 50% decrease in nephrons can cause failure
- ARF is a sudden onset and may last < 3 mos
- good prognosis
describe chronic renal failure
-In CRF, 90-95% of the nephrons are lost before failure is obvious
what is acute kidney injury
is a sudden decrease in kidney function that causes disturbances in fluid, electrolyte and acid/base balance
what are the severity grades of AKI
- RIFLE
- Risk : Cr increased 1.5 times or GFR decreased >25%
- Injury: Cr increased 2 times or GFR decreased > 50%
- Failure: Cr increased 3 times or GFR decreased > 75%
- Loss: complete loss of renal function for >4 wks
- End-stage kidney disease: need for renal replacement therapy for > 3 months
treatment of chronic kidney injury
longterm dialysis
how do you determine the severity (generally speaking) of AKI
- look at the Cr and GFR
- no injury until Cr is 3x normal or GFR decreased >75% (about 30 or 40)
treatment of AKI
- *fluid, get fluid up (fix GFR), save nephrons, see if fluid challenge will help
- want fluid output to increase
- If does not help, short term dialysis is necessary
types of ARF
Prerenal azotemia and intrarenal
describe prerenal ARF
- lost blood flow to kidneys
- sudden and severe drop in blood pressure (SHOCK)
treatment of prerenal ARF
-correct by increasing BP, giving volume, improve C.O. -prolonged damage can lead to intrarenal failure
describe intrarenal ARF
- death to nephrons and direct damage to kidneys d/t infection, inflammation, toxins, drugs, and reduced blood flow
- *aka ATN (acute tubular necrosis)
onset of ARF
Hours to days, precipitating event until oliguria, BUN and Cr increase
onset of ARF only takes ____ if in shock
Onset only takes about 6 hrs to stop functioning if in shock
describe oliguric phase of ARF
- Urine output of 100-400ml/day
- does not respond to diuretics or fluid challenges
- BUN and CR increase, K, Magnesium and Phosphate increase, Na is retained, but masked with fluid, dilutional -lasts 8-15 days
what is the treatment if oliguric
fluid challenge
stages of ARF
onset, oliguric, diuretic, recovery
AKI has a high _____
- *mortality rate
- In critically ill patients, 50-80% mortality rate for those who develop ATN
describe the diuretic phase of ARF
- Urine output increases rapidly, can be 10L/day of dilute urine
- electrolyte losses occur, BUN decreases last 2-6 weeks, until BUN falls,
- renal tubular function return
describe the recovery phase of ARF
Functions at lower level, may take up to 12 months to return to normal
what is acute tubular necrosis
- results from prolonged hypoperfusion
- ischemic ATN comes from prerenal AKI
- *It is important to recognize this early
- Tubular epithelial cells become hypoxic and damaged so that it is difficult to repair
generally speaking what is ATN
- Hypoperfusion and death to nephrons
- causes Ischemia, swelling, problems in cell
