Contrast-induced nephropathy

As contrast media -induced renal failure acute renal failure after the use of X-ray contrast agents is known in medicine. As a cause of the contrast agent -induced kidney failure, are a direct toxic damage of kidney tubule cells by the contrast agent, as well as a narrowing of the renal vessels ( vasoconstriction ), which leads to a reduction of oxygen supply in the renal medulla discussed.

Risk groups

A relevant renal damage in patients with normal renal function by the administration of contrast media is extremely rare or does not occur. However, the risk of contrast medium -induced renal failure in patients with pre-existing renal impairment increased ( the risk increases with increasing renal impairment ); the incidence in these groups depending on the study 1-45 %. The risk increases in combination with:

• Diabetic nephropathy,
• Reduced blood flow to the kidneys, for example as a result of volume depletion ( hypovolemia ) or heart failure (heart failure ),
• The application of large amounts of contrast medium.

Diagnosis

The decline in renal function usually manifests itself in an increase in serum creatinine 24 to 48 hours after administration of the contrast agent. A decrease in urine output ( oliguria ) is not observed in the control. Most of the decrease in renal function is temporary. Only in rare cases a dialysis treatment may be required, mostly when the time of the contrast medium is already a significant impairment of renal function.

The differential diagnosis of acute tubular necrosis or Einschwemmung a blood clot ( embolism ) must be taken in the renal vessels into consideration.

Treatment

Optimum treatment of the contrast agent- induced kidney failure is not known. There should be a volume depletion can be avoided at the time of the investigation.

In moderate or severe renal impairment (glomerular filtration rate <45 ml / 1.73 m² with intravenous administration of contrast medium or <60 ml / 1.73 m² at intra-arterial administration of contrast medium ) should be carried out preventive measures, particularly if additional diabetes mellitus is. It should be considered in studies without contrast medium, so an ultrasound (sonography), an MRI without gadolinium or a CT scan without contrast agent administration can be performed without restrictions. Can not be avoided, a contrast agent in patients with renal impairment, the risk of renal failure can be reduced by the following measures:

• The best evidence is the use of prophylactic intravenous hydration. Despite a number of studies so far could not be clarified whether isotonic bicarbonate is superior to a physiological saline solution. The originally used half electrolyte solution, however, is no longer in use. Common regimens include: The best validated: Physiological saline 1 ml / kg / hour, 6-12 hours before the test until 6-12 hours after the examination. A possible, but not formally evaluated in ambulatory patients alternative or emergency tests: 3 ml / kg / hour, an hour before the examination, and 1-1.5 ml / kg / hour for 4-6 hours after the examination.
• Isotonic bicarbonate solution (150 ml of sodium bicarbonate 1 meq / ml ad 850 ml Glucose 5%), 3 ml / kg one hour before the test and 1 ml / kg / hr over 6 hours after the procedure.

Forecast

In patients with renal failure kontrastmittelinduziertem after cardiac catheterizations in the further course of mortality (mortality) is increased. It is not clear whether the increased mortality is due to the contrast agent -induced kidney failure, or to the fact that in high-risk patients, the incidence of renal failure and mortality kontrastmittelinduziertem are simultaneously increased.