CONTRAST INDUCED NEPHROPATHY CIN

Question 1

What is Contrast-Induced Nephropathy (CIN)?

Answer 1

Reversible non-oliguric acute kidney injury occurring 24-48 hours after IV or intra-arterial contrast administration.

CIN does not occur with oral contrast.

Question 2

What are the mechanisms of CIN?

Answer 2

1. Renal vasoconstriction → ischemia.
2. Direct tubular epithelial toxicity → vacuolization, inflammation, necrosis.

Question 3

What is the clinical presentation timeline for CIN?

Answer 3

AKI within 24-48 hours, peak injury at 72-120 hours, serum creatinine returns to baseline in 7-10 days.

Question 4

What does urinalysis show in CIN?

Answer 4

Muddy brown casts, renal tubular epithelial cells, fractional excretion of sodium <1%.

Question 5

What is the main risk factor for CIN?

Answer 5

Preexisting CKD (serum creatinine ≥1.5 mg/dL or eGFR <60 mL/min/1.73 m²).

Question 6

List other risk factors for CIN.

Answer 6

• Diabetes (with CKD)
• High contrast volume
• Intra-arterial administration
• Advanced age
• Proteinuria
• Hypotension
• Volume depletion
• Congestive heart failure
• NSAID use
• RAAS blockade
• Cirrhosis

Question 7

How is CIN clinically defined?

Answer 7

As >0.5 mg/dL or >25% increase in serum creatinine within 48-72 hours.

Question 8

What are the long-term implications of CIN?

Answer 8

Associated with increased hospital and long-term morbidity/mortality.

Question 9

Does CIN often require dialysis?

Answer 9

Rarely requires dialysis (<2% of cases), but dialysis-dependent CIN has a 2-year survival rate <40%.

Question 10

What is the recommended volume expansion for outpatient prophylaxis against CIN?

Answer 10

3 mL/kg/hr for 1 hour pre-contrast, then 1-1.5 mL/kg/hr for 4-6 hours post-contrast.

Question 11

What is the preferred fluid for volume expansion in CIN prophylaxis?

Answer 11

Normal saline.

Question 12

What is the recommendation regarding N-acetylcysteine for CIN?

Answer 12

Not recommended due to no proven benefit.

Question 13

What should be done regarding statin therapy before contrast administration?

Answer 13

Continue if already on statins, but no need to start before contrast.

Question 14

What is remote ischemic preconditioning (RIPC) in relation to CIN?

Answer 14

Promising but not yet proven for CIN prevention.

Question 15

List historical prophylactic therapies for CIN that are not recommended.

Answer 15

• Theophylline
• Mannitol
• Furosemide
• Dopamine
• Atrial natriuretic peptide
• Fenoldopam
• Endothelin receptor antagonists

Question 16

Is hemodialysis recommended for CIN prevention?

Answer 16

Not recommended.

Question 17

What is the guideline for dialysis patients post-contrast?

Answer 17

Can delay post-contrast dialysis for 24-48 hours unless severe volume overload or reduced LV function.

Question 18

Should ACE-I/ARBs be discontinued before contrast exposure?

Answer 18

No clear evidence to discontinue.

Question 19

What are the types of iodinated contrast agents?

Answer 19

• High-osmolal (no longer used)
• Low-osmolal (600-700 mOsm/kg)
• Iso-osmolal (290 mOsm/kg)

Question 20

What is the risk associated with gadolinium contrast agents?

Answer 20

Risk of nephrogenic systemic fibrosis (NSF) in dialysis or severe CKD patients.

Question 21

What is recommended regarding gadolinium usage?

Answer 21

Use macrocyclic ionic chelate-based gadolinium, lowest dose possible, avoid repeated exposures.

Question 22

What are the key points regarding CIN?

Answer 22

1. CIN caused by renal vasoconstriction and direct tubular toxicity.
2. CIN typically non-oliguric, with creatinine returning to baseline in 7-10 days.
3. Main risk factor: Preexisting CKD.
4. Prophylaxis: Volume expansion with normal saline, minimal contrast volume, remove nephrotoxins.
5. No benefit from N-acetylcysteine, statins, or hemodialysis for prophylaxis.
6. RIPC is promising but not yet proven.