Acute Kidney Injury/Acute Renal Failure - AO

Question 1

What does AKI lead to in the body?

Answer 1

Retention of substances in the blood that kidneys normally excrete

1) Fluid overload
2) Hyperkalemia
3) Hyperphosphatemia
4) Hypocalcemia
5) Metabolic Acidosis
6) Nitrogenous wastes (Urea & Creatinine)

Question 2

What does an acute rise in creatinine mean?

Answer 2

Deterioration of renal function (↓ GFR)

Question 3

What are the 3 criteria established by KDIGO to diagnose AKI?

Answer 3

1) ↑ Serum Cr > 0.3 mg/dL w/in 48 hours
2) ↑ Serum Cr > 1.5 x baseline w/in 7 days
3) ↓ Urine output < 0.5 mL/kg/hour for 6 hours

Question 4

What are the physiologic causes of Prerenal, Intrinsic, and Postrenal AKI?

Answer 4

1) Prerenal: ↓ renal perfusion
2) Intrinsic: injury to blood vessels, glomeruli, tubules, or interstitium
3) Obstruction in voiding or collecting parts of the kidney

Question 5

What are risk factors for prerenal AKI?

Answer 5

1) Hypovolemia
2) Cardiovascular Dz (i.e. ↓ CO)
3) Decompensated Liver Dz (i.e. cirrhosis)
4) Peripheral vasodilation (i.e. sepsis)
5) Medications causing intrarenal vasoconstriction (i.e. NSAIDS, ACE/ARB, amphotericin, IV contrast)

Question 6

What are risk factors for intrinsic AKI?

Answer 6

1) Glomerular Disorder (i.e. glomerulonephritis)
2) Tubular causes (i.e. ATN, nephrotoxic meds)
3) Interstitial causes (i.e. infection, AIN)
4) Renal Vascular Disorders (i.e. Renal artery thrombosis, embolism, RAS, HTN)

Question 7

What is Acute Interstitial Nephritis (AIN)?

Answer 7

Immune mediated tubulointerstitial injury caused by a drug hypersensitivity reaction inducing an allergic response to the interstitium.

Question 8

What is the clinical presentation of AKI?

Answer 8

• Weight Gain
• peripheral edema
• Hypovolemia
• Tachycardia
• orthostasis
• dry mucous membranes
• poor skin turgor
• Cramps
• extreme thirst
• anorexia
• weakness/lethargy

Question 9

What are the PE findings of AKI?

Answer 9

• Edema
• Confusion
• Asterixis
• Dyspnea & Crackles
• Cola-Colored urine
• Palpable bladder
• CVA tenderness
• Low urine output

Question 10

What labs would be helpful in determining the cause of AKI?

Answer 10

• Creatinine (to determine baseline)
• Microscopic U/A
• Pts with oliguria → FENa ( < 1% = prerenal cause; > 2% = Intrinsic renal cause)

Question 11

What is the management plan for a patient with AKI?

Answer 11

1) Address underlying cause
2) prevent further injury
3) maintain adequate volume status & hemodynamics

Question 12

How would you manage a patient with hyperkalemia?

Answer 12

1) IV calcium gluconate (normalize membrane excitability & stabilize myocardium)
2) Insulin w/ glucose IV (↑ cellular K+ uptake)
3) Beta-2 adrenergic agonist (albuterol → ↑ cellular K+ uptake)
4) Dialysis

Question 13

How would you manage a patient with metabolic acidosis as a result of AKI?

Answer 13

IV sodium bicarbonate

Question 14

What are indication for dialysis in patients with AKI?

Answer 14

1) Fluid overload refractory to diuretics
2) Hyperkalemia (K+ > 6.5)
3) Metabolic acidosis (pH < 7.1)
4) Signs of uremia (i.e. pericarditis, seizures, asterixis, vomiting secondary to uremia, ↓ in mental status)