Acute Renal Failure

Question 1

acute renal failure

Answer 1

• l/o renal fx -> decreased urine output -> azotemia and f/e imbalance (can impact other organs)
• abrupt decrease in GFR
• glomerular filtration (process) measured by GFR (rate at which process occurs)
• reversible but can lead to CRF

Question 2

expand more on GFR

Answer 2

• requires urine volume + creatinine in blood and urine
• need min. 400mL/day output to excrete wastes and prevent azotemia
• oliguria = 100-400mL/day
• anuria = <100 mL/day

Question 3

etiology

Answer 3

• 80-90% of ARF is pre/intrarenal and deals with hypoTN or hypovolemia
• 3 stages:

1. prerenal
   
   • ischemic/circulatory problem preventing proper perfusion to the kidney
2. intrarenal
   
   • eg) glomerulonephritis
3. postrenal
   
   • preventing obstr of urine flow out of the kidney (eg. BPH)

Question 4

patho of prerenal

Answer 4

eg) hemorrhage -> lose blood vol = hypoTN and hypovolemia, decreased perfusion to glomerulus -> ischemia and ischemic damage -> decreased filtration and oliguria

Question 5

patho of intrarenal

Answer 5

• acute tubular necrosis (ATN)
  eg) nephrotoxicity, tubular obstr
• 3 phases: initiating phase, maintenance phase, recovery phase

Question 6

initiating phase

Answer 6

• hrs to days
• from trauma to tubular injury
• precipitating event -> mnftns become apparent

Question 7

maintenance phase

Answer 7

• maintain problem NOT kidney fx
• decreased GFR
• oliguria, azotemia, edema

Question 8

recovery phase

Answer 8

• fixing problem

- gradual repair -> increase in GFR

Question 9

patho of postrenal

Answer 9

• ex) BPH -> hydronephrosis -> ARF

- obstr to urine flow

Question 10

manifestations

Answer 10

• oliguria, anuria
• f/e imbalance
• azotemia, proteinuria, hematuria
• complx: edema, HTN, pulm congestion

Question 11

diagnosis

Answer 11

• renal fx tests
• RIFLE
• early biomarkers (IL 18)

Question 12

RIFLE

Answer 12

• risk, injury, failure, loss, end stage renal disease

- use amount of creatinine in blood + urine, urine output and GFR

Question 13

IL 18

Answer 13

• interleukin 18
• mediator prod. together w/ inflmtn in proximal tubule when there’s ischemic damage b/c proximal tubule will be 1st area to be affected in kidney

Question 14

treatment

Answer 14

• reversible but not self-limiting
• early intervention -> use RIFLE, want to pick up disease in R or I stage
• cautious f/e replacement
• dietary modifications
• dialysis: intermittent dialysis (over a few hours)
• CRRT (chronic renal replacement therapy)

Question 15

what dietary modifications would you make?

Answer 15

• renal diet

- decrease protein intake -> proteins are broken down into ammonia -> decrease protein = avoid/decrease azotemia

Question 16

CRRT

Answer 16

• chronic renal replacement therapy
• slower than intermittent, advantage = continuous
• processes used: diffusion, convection, or both

Question 17

dialysis

Answer 17

hemodialysis: blood is filtered externally from body through a dialyser

peritoneal dialysis: dialysate introduced into the peritoneum, which acts a semi-permeable membrane that wastes are filtered through