Acute Kidney Injury

Question 1

Prerenal descriptio

Answer 1

factors that decrease circulation in renal blood flow

Question 2

Prerenal causes

Answer 2

obstruction, low blood pressure, low cardiac output

Question 3

Prerenal can be reversed by

Answer 3

treating cause and increasing renal perfusion

Question 4

Intrarenal causes

Answer 4

CT contrast, nephrotoxic drugs, sepsis

Question 5

Intrarenal results from

Answer 5

ischemia and nephrotoxins

Question 6

most common cause of intrarenal AKI

Answer 6

Acute tubular necrosis

Question 7

Acute tubular necrosis

Answer 7

(1) Glomerular filtration rate decreased
(2) Potentially reversible if identified early and treated
Appropriately
(3) Other ways of developing ATN is major surgery, shock, blood transfusion reaction, muscle injury from trauma, and prolonged hypotension.

Question 8

Post renal description

Answer 8

mechanical obstruction of outflow which results reflux into renal pelvis, impairing kidney function

Question 9

Post renal causes

Answer 9

kidney stones, tumor, BPH, prostate cancer, trauma

Question 10

Risk

Answer 10

a) increase serum creatinine x1.5, or decrease GFR >25%
b) UOP <0.5 mL/kg/hr x 6hrs

Question 11

Injury

Answer 11

a) Increase serum creatinine x2 or GFR decrease > 50%
b) UOP <0.5 mL/kg/hr x 12 hours

Question 12

Failure

Answer 12

a) Increase serum creatinine x3 or GFR decrease >75%
b) UOP <0.3 mL/kg/hr x 24 hours or anuria x 12 hours

Question 13

Loss

Answer 13

Persistent acute kidney failure; complete loss kidney
function > 4 week

Question 14

End stage kidney disease

Answer 14

Complete loss of function > 3 months

Question 15

Oliguric phase

Answer 15

production of abnormally small amounts of urine (usually prerenal)

Question 16

Oliguric phase urinary changes

Answer 16

a) Oliguria (reduction in UOP to less than 400 mL/day
1) usually occurs within 1-7 days
2) usually lasts 10-14 days
3) seen with prerenal causes
4) nonoliguric AKI – UOP> 400mL/day (50% pts)
5) If the cause if from ischemia, oliguria occurs within 24 hours.
b) Anuria (most often seen with obstruction; and seen with
interstitial nephritis and ATN
c) Urinalysis findings – casts, RBCs, WBCs, protein;
specific gravity may be fixed at 1.010, urine osmolality 300mOsm/kg

Question 17

Oliguric fluid volume

Answer 17

-Hypovolemia can exacerbate aki
- fluid retention: JVD, bounding pulses, edema, hypertension
- Complications: HF, pulmonary edema, pericardial and pleural effusions

Question 18

Oliguric phase metabolic acidosis

Answer 18

Decreased bicarbonate
Severe acidosis – Kussmaul respirations

Question 19

Oliguric phase sodium balance

Answer 19

• Increased urinary sodium excretion
• Serum sodium normal or decreased

Question 20

Oliguric phase potassium excess

Answer 20

hyperkalemia (ECG changes)

Question 21

Oliguric phase hematologic disorders

Answer 21

• Leukocytosis
• Infections

Question 22

Oliguric phase waste product accumulation

Answer 22

• Increased serum BUN, creatinine

Question 23

Oliguric phase neurologic disorders

Answer 23

• Fatigue, difficulty concentrating
• Seizures, stupor, coma

Question 24

Diuretic phase

Answer 24

a) May last 1 to 3 weeks
(1) UOP 1-3 L up to 5L per day
b) Hypovolemia
c) Hypotension
d) Hyponatremia
e) Hypokalemia
f) Dehydration
g) At end of phase, acid base, electrolyte and BUN/creatinine values stabilize
h) If the patient receives dialysis during the oliguric phase, diuretic phase may be decreased or absent

Question 25

Recovery phase

Answer 25

a) Lasts 3- 12 months, may not have full recovery
b) Increased GFR
c) Decreased BUN, creatinine

Complications
(1) Renal insufficiency
(2) Chronic Renal Failure

Question 26

Serum creatinine

Answer 26

may not be evident until there is a 50% loss of kidney function and more specific to kidney injury than BUN

Question 27

Urinalysis

Answer 27

(a) Urine sediment (cells, casts, protein, hematuria, pyuria, crystals)
(b) Urine osmolality
(c) Urine sodium
(d) Urine specific gravity

Question 28

Diagnostic studies

Answer 28

(1) Renal ultrasound – first test done
(2) Renal scan- access abnormalities in kidney blood flow, tubular function, and collecting system
(3) CT scan – can identify lessions, masses, obstructions, and vascular abnomalies
(4) Renal biopsy -best method for confirming intrarenal causes of AKI

Question 29

Contraindications for contrast medium

Answer 29

(a) Magnetic resonance imaging (MRI) or Magnetic resonance angiography (MRA)
(b) Contrast-induced nephropathy (CIN)

Question 30

Diabetic taking metformin contraindications for contrast medium

Answer 30

hold 48 hours before and after use of contract medium to decrease the risk of lactic acidosis.

Question 31

If contrast is needed for high-risk patients

Answer 31

use Low dose and optimal hydration

Question 32

Ensure adequate intravascular volume and cardiac output

Answer 32

Loop diuretics [Lasix], osmotic diuretics [mannitol]

Question 33

Oliguric phase management

Answer 33

fluid restriction; may have to limit fluids to 1000 mL/day

Question 34

Diuretic phase Management

Answer 34

may require 1 to 4 L of fluid per day

Question 35

Prerenal disease Management

Answer 35

match fluid replacement to fluid losses

Question 36

Prevent and correct Hyperkalemia

Answer 36

Diet restrictions, hemodialysis, patiromer, (bind with K+ in GI tract), regular insulin IV, sodium bicarbonate, kayexalate, calcium gluconate)

Question 37

Prevent and correct Metabolic acidosis

Answer 37

(i) Metabolic acidosis with mild respiratory alkalosis compensation
(ii) Administer sodium bicarbonate if serum
bicarbonate <15 mEq/L
(iii) If pt. dialyzed, use dialysate with
bicarbonate to help buffer

Question 38

Indications for RRT

Answer 38

volume overload, elevated K+, metabolic acidosis [HCO3 < 15], BUN > 120 mg/dL, significant change in mental status, pericarditis, pericardial effusion or cardiac tamponade

Question 39

Renal replacement therapy (RRT) types

Answer 39

Peritoneal dialysis
Intermittent hemodialysis
Continuous renal replacement therapy

Question 40

Continuous renal replacement therapy

Answer 40

(i) slower blood flow than hemodialysis
(ii) needs anticoagulation
(iii) Ultrafiltrate – water and non-protein solutes removed by the procedure
(iiii) Contradicted with hyperkalemia, pericarditis

Question 41

(Promote improved nutritional status by

Answer 41

• Provide adequate caloric intake with increased carbohydrates and dietary fat
• Restrict K+, Na+, phosphates
• Calcium supplements or phosphate-binding agents
• If unable to take oral intake, enteral feedings
• Administer vitamin supplements (folic acid,
  pyridoxine and water-soluble vitamins frequently necessary)

Question 42

Prevent Contrast-induced nephropathy (CIN)

Answer 42

-Extensive hydration before and after any procedure using
contrast media
-Patients at high risk may receive oral acetylcysteine with oral hydration
-Avoid diuretics during this time
-Stop nephrotoxic drugs (aminoglycoside antibiotics,
NSAIDs, chemotherapeutic agents) prior to procedure

Question 43

1. What are intrarenal causes of acute kidney injury (AKI) (select all that apply)?
   a. Anaphylaxis
   b. Renal stones
   c. Bladder cancer
   d. Nephrotoxic drugs
   e. Acute glomerulonephritis
   f. Tubular obstruction by myoglobin

Answer 43

c. Bladder cancer
f. Tubular obstruction by myoglobin

Question 44

An 83-year-old female patient was found lying on the bathroom floor. She said she fell 2 days ago and has not been able to take her heart medicine or eat or drink anything since then. What conditions could contribute to prerenal AKI in this patient (select all that apply)?
a. Anaphylaxis
b. Renal stones
c. Hypovolemia
d. Nephrotoxic drugs
e. Decreased cardiac output

Answer 44

c. Hypovolemia
e. Decreased cardiac output

Question 45

Acute tubular necrosis (ATN) is the most common cause of intrarenal AKI. Which patient is most likely to develop ATN?
a. Patient with diabetes
b. Patient with hypertensive crisis
c. Patient who tried to overdose on acetaminophen
d. Patient with major surgery who required a blood transfusion

Answer 45

b. Patient with hypertensive crisis