Acute Renal Failure

Question 1

what are the 2 primary things kidney does?

Answer 1

-ultrafiltration & reabsorption

Question 2

what is Acute renal failure?

Answer 2

• loss of renal function:
  - fluid & electrolyte imbalance
  - azotemia (build up of nitrogenous wastes)
• glomerular filtration rate decreases (hrs to days)
• TYPICALLY REVERSIBLE

Question 3

what is the normal urine volume a day?

Answer 3

1,500ml

Question 4

the kidney has enormous________ reserve

Answer 4

functional

Question 5

what is the minimum volume of urine a day that has to be produced to prevent azotemia?

Answer 5

400ml/day

Question 6

what is oliguira

Answer 6

100-400ml/day

Question 7

anuria

Answer 7

less than 100ml day

Question 8

what is the etiology of acute renal failure?

Answer 8

3 groups:

     - prerenal (cardiac problem not enough blood going to kidneys) (primary reasons: hypotension & hypovolemia  
       - intrarenal 
       - postrenal

Question 9

Prerenal causes of acute renal failure

Answer 9

Hypovolemia: 
-hemmorhage 
-dehydration 
-excessive loss of gastrointestinal tract fluids 
-excessive l/o fluid d/t burn injury
Decreased Vascular Filling: 
-anaphylactic shock 
-septic shock 
Heart Failure Or Cardiogenic Shock 
Decreased Renal Perfusion: d/t sepsis, vasoactive mediators, drugs diagnostic agents

Question 10

Intranrenal causes of acute renal failure

Answer 10

Acute Tubular Necrosis:
-prolonged renal ischemia
Exposure Of Nephrotoxic Drugs, Heavy Metals & organic solevents
Intratubular Obstruction: resulting from hemoglobinuria, myoglobinuria, mycloma light chains or uric acid casts
Acute Renal Disease ex. (acute glomerulonephritis, pyelonephritis)

Question 11

_____ & _____ account for approx 80%-90% of acute renal failure

Answer 11

prerenal& intrarenal account for approx 80-90% if acute renal failure, primary reasons: hypotension & hypovolemia

Question 12

Patho of acute renal failure(3 phases of acute renal failure)

Answer 12

Initiating phase:
-precipitating event to tubular injury (means injurious event that leads to tubular injury)
Maintenance phase:
-Decrease in GFR, Oliguria
-azotemia
-Complications: Edema, pulmonary congestion, hypertension (from fluid retention)
Recovery phase:
-gradual tissue repair with increase in GFR (glomerular filtration rate)

Question 13

what are the 3 phases of acute renal failure

Answer 13

• initiating phase:
• maintenance phase
• recovery phase

Question 14

patho of acute renal failure caused by prerenal

Answer 14

inadequate renal perfusion (eg. hemorrhage) (-kidney receives blood for 2 reasons: function & own resources) causes oliguria & ischemia
THEN 3 PHASES

Question 15

patho of acute renal failure caused by intrarenal

Answer 15

acute tubular necrosis:
-nephrotoxic drugs, intratubular obstruction
THEN 3 PHASES

Question 16

patho of acute renal failure caused by postrenal

Answer 16

eg. BPH
obstruction to urine flow
THEN 3 PHASES

Question 17

manifestations of acute renal failure

Answer 17

-oliguria or anuria
-can encounter non-oliguric acute renal failure (clinically may encounter, particularly in elderly pateints), volume of urine normal but has acute renal failure (unclear answer why- suggestion-now earlier detection of cardiac problems then cardiac problems dealt with.
-fluid electrolyte imbalance
-azotemia
-proteinuria, hematuria
Complications: -edema & hypertension

Question 18

what are the complications of acute renal failure?

Answer 18

-edema & hypertension

Question 19

diagnosing acute renal failure

Answer 19

• GFR
• BUN (blood, urea, nitrogen), creatinine
• urine volume
• RIFLE (risk, injury, failure, loss, endstage renal disease)
  
  • rifle uses creatinine, GFR & urine output
• new: early biomarkers (eg. IL18 -interleukin 18, inflammatory mediator, interleukin produced in proximal tubule physiologically)

Question 20

what is an assessment used to diagnosis acute renal failure and what does it involve?

Answer 20

• RIFLE (risk, injury, failure, loss, endstage renal disease)
  
  • rifle uses creatinine, GFR & urine output

Question 21

what is a biomarker that indicates acute renal failure?

Answer 21

IL18 -interleukin 18, is an inflammatory mediator, interleukin produced in proximal tubule physiologically, damaged and then is released

Question 22

Treatment of acute renal failure

Answer 22

ACUTE RENAL FAILURE IS REVERSIBLE

• stat intervention (the sooner you intervene the better the outcome)
• cautious fluid & electrolyte replacement(because pt in renal failure)
• Diet modification(adequate calories though): low sodium(salt in blood) & low protein (protein breakdown release nitrogenous wastes, pt already has azotemia, adding to nitrogenous waste build up)
• Intermittent dialysis: hemodialysis(filtrating blood through artificial kidney) peritoneal dialysis(can also be used)
• CRRT-continuous renal replacement therapy(continuous 24hrs, ICU setting, diffusion or convection & combined)

Question 23

what is chronic renal failure

Answer 23

-progressive permanent renal damage

Question 24

what are the progressive states of chronic renal failure?

Answer 24

Diminished renal reserve(referring to functional reserve fx of kidney dropped):

• GFR less than 50% of normal (normal=120-130ml)
• because of large functional reserve asymptomatic (no signs of decreased renal function)

Renal insufficiency:
-GFR 20-50% of normal

Renal failure:

• GFR less than 20%
• End stage -GFR less than 5%

Question 25

Diminished renal reserve stage of chronic renal failure

Answer 25

• GFR less than 50% of normal (N=120-130ml/min)

- because of large functional reserve asymptomatic (no signs of decreased renal function)

Question 26

Renal insufficiency stage of chronic renal failure

Answer 26

-GFR 20-50% of normal

Question 27

renal failure stage of chronic renal failure

Answer 27

• GFR less than 20%

- end stage- GFR less than 5%