Acute Kidney Injury

Question 1

Criteria of AKI

Answer 1

Serum Creatinine Rises by 26umol/L within 48 hours
or
Serum Creatinine Rises 1.5 fold from reference value within 7 days
or
Urine Output is less than 0.5ml/kg/hr for 6 consecutive hours

Question 2

Calculating Urine Output

Answer 2

Take total urine volume divide by hours then divide by weight

mL/kg/hours

Question 3

AKI
- Risk Factors

Answer 3

CKD

Volume Depletion

Nephrotoxic Drugs

Obstruction of Urinary Tract

Question 4

Renal Disease-Related Chronic Conditions

Answer 4

Hypertension and Diabetes

Question 5

AKI
- Signs

Answer 5

• Edema
• Foamy or Coloured Urine
• Orthostatic Hypotension (Dizziness when standing)
• Hypertension

Question 6

AKI
- Assessment

Answer 6

Serum Creatinine and BUN/Urea
- Both are elevated in acute changes to kidney function

Question 7

What are the different types of AKI

Answer 7

Prerenal
Intrarenal (Intrinsic)
Postrenal

Question 8

What is the most common kind of AKI

Answer 8

Prerenal (60%)
Intrarenal (35%)
Postrenal (5%)

Question 9

Prerenal AKI
- What is it?

Answer 9

Renal Hypoperfusion
- Reduction in blood flow reaching the renal arterioles

Question 10

Prerenal AKI
- Causes (Volemia)

Answer 10

Hypovolemia from:
- Hemorrhage
- Gastrointestinal Fluid Loss
- Renal Fluid Loss
- Extravascular (Blood moves into the tissues, less blood sent into kidneys)

Question 11

Prerenal Causes
- Causes (Hemodynamics)

Answer 11

Altered Renal Hemodynamics:
- Low cardiac output state
- Systemic Vasodilation (Sepsis AKA Distributive Shock)
–> Blood moves from the plasma to tissues
- Renal Vasoconstriction
- Impaired Renal Autoregulatory Response
- Hepatorenal Syndrome

Question 12

Prerenal AKI
- Symptoms

Answer 12

Orthostatic Hypotension
Dehydration
- Tachycardia
- Reduced Jugular Venous Pressure
- Decreased Skin Turgor
- Dry Mucous Membranes

Question 13

Prerenal AKI
- Lab Values

Answer 13

Made up of High Urea, High Creatinine (Sodium and Water have all been absorbed)
- Concentrated Urine

Water and Sodium is reabsorbed
- Low Sodium and Water in Urine

Question 14

Postrenal AKI
- What is it

Answer 14

Obstruction at any level of the urinary tract that prevents urine flow
- Has to occur in both kidneys at the same time

Question 15

Postrenal AKI
- Causes

Answer 15

Physical Barrier
- Kidney Stones
- Prostate Hypertrophy
- Cancer

Drugs that Crystallize
- Sulfonamide
- Methotrexate
- Acyclovir

Question 16

Postrenal AKI
- Symptoms

Answer 16

Pain
Anuria (Lack of pee)
Pyuria

Question 17

Postrenal AKI
- Lab Values

Answer 17

Urinalysis
- Cellular Debris
- Hematuria (Variable)
- Some WBC in urine

• High Sodium (Sodium is not reabsorbed)
• Either increase or no change in Urea
• Less Concentrated (Water is not reabsorbed)

Question 18

Intrarenal AKI
- What is it

Answer 18

Acute injury to the kidney itself
- Either acute or chronic cases

2nd most common kind of AKI

Question 19

Intrarenal AKI
- Causes

Answer 19

• Drugs
• Toxins
• Ischemia
• Infection
• Autoimmune Disease

Question 20

Intrarenal AKI
- Damaged Sites

Answer 20

Glomerulus
Vascular/Microvascular (Renal Arterioles/Blood Capillaries)
Tubular (ATN = Acute Tubular Necrosis)
Interstitium (AIN = Acute Interstitium Necrosis)

Question 21

Intrarenal AKI
- Glomerular

Answer 21

• Acute Glomerulonephritis
• Vasculitis
• Thrombotic Microangiopathy (Hemolytic Uremic Syndrome) = Damage to small blood vessels

Question 22

Intrarenal AKI
- Vascular/Microvascular

Answer 22

• Renal Infarction
• Renal Artery Stenosis
• Renal Vein Thrombosis
• Malignant Hypertension
• Scleroderma
• Atheroembolic

Question 23

Intrarenal AKI
- Tubular Causes

Answer 23

Ischemic
- Prolonged Prerenal State
- Sepsis
- Systemic Hypotension

Nephrotoxic
- Aminoglycosides
- Methotrexate
- Cisplatin
- Myoglobin
- Hemoglobin

Question 24

Intrarenal AKI
- Interstitium

Answer 24

Medications:
- Penicillins
- Cephalosporins
- Ciprofloxacin
- NSAIDS
- Phenytoin
- Tumour Infiltration (Lymphoma, Leukemia)

Question 25

Intrarenal AKI
- Lab Values

Answer 25

Urine Sediment: Casts, Cellular Debris, Protein

RBC + WBC in Urine

High Sodium
Fe(Na) is greater than 2%

Either increase or neutral change in urea

Question 26

Prerenal vs Intrarenal vs Postrenal

Answer 26

Prerenal
- Very concentrated urine
= Low blood flow to kidneys, water and sodium are still being reabsorbed

Intrarenal
- Presence of RBC, WBC, Cast, Cellular Debris in urine
- High Sodium
= Sign of damage and cell death

Postrenal
- Presence of Cellular Debris in urine
- High sodium

Question 27

Treatment of AKI

Answer 27

• Hydrate (IV fluids like 0.9% NaCl)
• Diuretics (Furosemide)
  –> Only if volume over loaded
• Dialysis
• Stop nephrotoxic agent
• Treat underlying disease
• Adjust dosage of medications

Question 28

AKI and Diuretics

Answer 28

Only to be used in patient that have some urine output
- Meant to reduce pulmonary edema and heart failure

Furosemide and Metolazone

Question 29

AKI and Dialysis

Answer 29

0.9% NaCl (Normal Saline)

Advantage
- Can correct electrolytes
- Remove uremic toxins
- Treats fluid overloaded patients

Disadvantages
- Causes hypotension which can exacerbate AKI
- Poor venous access makes dialysis difficult
- Infection at site of IV
- Kidneys may not recover

Question 30

When do we Dialyze

Answer 30

When one of the following occurs

A: Acid- base abnormalities
E: Electrolyte Imbalance
I: Intoxications
O: Fluid Overload
U: Uremia