Contrast Nephropathy

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• The peak rise in serum creatinine occurs within 2–5 days after the diagnostic procedure using IV contrast, and it returns to baseline in most cases

• Increase in serum creatinine of > 50% represents clinically important acute renal failure

GENERAL CONSIDERATIONS

• Most commonly seen after cardiac catheterization, especially if left ventricular angiography is carried out

• May be seen after CT scans or other diagnostic tests using contrast agents

• Hypoxic tubular injury due to vasoconstriction with release of free oxygen radicals is the likely mechanism

• Major risk factors:

  • – Prior renal insufficiency

  • – Diabetes mellitus

• Minor risk factors:

  • – Congestive heart failure

  • – Dehydration

  • – Hypotension

  • – Hypoxia

  • – Large amount of contrast

  • – Ionic and high osmolar contrast

  • – Repeated examinations at short intervals

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• No specific symptoms or signs

PHYSICAL EXAM FINDINGS

• No specific findings

DIFFERENTIAL DIAGNOSIS

• Atheroembolic renal failure

• Prerenal azotemia secondary to low cardiac output

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Increased serum creatinine over baseline before procedure using contrast

• Serum electrolytes: may be abnormal

ELECTROCARDIOGRAPHY

• Nonspecific ST-T–wave changes can occur

• Signs of hyperkalemia may occur

TREATMENT

HOSPITALIZATION CRITERIA

• Rising creatinine following procedure

MEDICATIONS

• When contrast nephropathy occurs, treatment is similar to that for any other cause of acute renal insufficiency

• Most patients improve spontaneously with conservative management

THERAPEUTIC PROCEDURES

• A few patients require temporary dialysis

• Need for long-term dialysis purely for contrast nephropathy is rare

SURGERY

• Shunt placement if long-term dialysis is needed

MONITORING

• ECG monitoring in hospital

DIET AND ACTIVITY

• As appropriate for renal and cardiac condition

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

• Falling serum creatinine

• Resolution of the problem

FOLLOW-UP

• Visit in 4–8 weeks to confirm stable renal function

COMPLICATIONS

• Persistent renal dysfunction

• Chronic dialysis

PROGNOSIS

• Good if renal function returns to normal

• Persistent renal dysfunction decreases survival

PREVENTION

• Adequate hydration (0.45% normal saline at 1 mL/kg/hour for 12 hours before and 12 hours after the procedure): the most important therapy for preventing contrast nephropathy in high-risk patients

• Statin drugs combined ...