Acetylcysteine for radiocontrast nephropathy

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

Nephrotoxicity as a cause of acute kidney injury in children

Many different drugs and agents may cause nephrotoxic acute kidney injury (AKI) in children. Predisposing factors such as age, pharmacogenetics, underlying disease, the dosage of the toxin, and concomitant medication determine and influence the severity of nephrotoxic insult. In childhood AKI, incidence, prevalence, and etiology are not well defined. Pediatric retrospective studies have reported incidences of AKI in pediatric intensive care units (PICU) of between 8% and 30%. It is widely recognized that neonates have higher rates of AKI, especially following cardiac surgery, severe asphyxia, or premature birth. The only two prospective studies in children found incidence rates of 4.5% and 2.5% of AKI in children admitted to PICU, respectively. Nephrotoxic drugs account for about 16% of all AKIs most commonly associated with AKI in older children and adolescents. Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, amphotericin B, antiviral agents, angiotensin-converting enzyme (ACE) inhibitors, calcineurin inhibitors, radiocontrast media, and cytostatics are the most important drugs to indicate AKI as significant risk factor in children. Direct pathophysiological mechanisms of nephrotoxicity include constriction of intrarenal vessels, acute tubular necrosis, acute interstitial nephritis, and-more infrequently-tubular obstruction. Furthermore, AKI may also be caused indirectly by rhabdomyolysis. Frequent therapeutic measures consist of avoiding dehydration and concomitant nephrotoxic medication, especially in children with preexisting impaired renal function.

Evidence-based Practice for the Use of N-acetylcysteine

The use of N-acetylcysteine has increased in the prevention of radiographic contrast induced nephrotoxicity. Many nurses need to be aware of the proper administration and action of this prophylactic agent. This article discusses the research behind the use of N-acetylcysteine and the protocol for administration to prevent radiographic contrast-induced nephrotoxicity.

Prevention of radiocontrast nephropathy with N-acetylcysteine in patients with chronic kidney disease: a meta-analysis of randomized, controlled trials

BACKGROUND

Radiocontrast nephropathy (RCN) is a common cause of hospital-acquired acute renal failure. Results of several studies using N-acetylcysteine (NAC) for the prevention of RCN have yielded conflicting results. We performed a meta-analysis of group data extracted from previously published studies to assess the effect of NAC on the prevention of RCN in patients with pre-existing chronic kidney disease (CKD).

METHODS

Ovid's multidatabase search for MEDLINE, Cochrane Central Registry of Controlled Trials, Cochrane Database of Systematic Reviews, and HealthSTAR were used to identify candidate articles. Abstracts from proceedings of scientific meetings also were screened. We selected blinded and unblinded randomized controlled trials (RCTs) performed in humans 18 years and older with pre-existing CKD, defined by a mean baseline serum creatinine level of 1.2 mg/dL or greater (> or =106.1 micromol/L) or creatinine clearance less than 70 mL/min (<1.17 mL/s). The overall risk ratio (RR) for the development of RCN was computed using a random-effects model.

RESULTS

Eight RCTs (n = 885 patients) published in full-text articles were included in the primary analysis. In the control group, the overall rate of RCN was 18.5% (95% confidence interval [CI], 15 to 22). In the primary analysis, overall RR for RCN associated with the use of NAC was 0.41 (95% CI, 0.22 to 0.79; P = 0.007). In a sensitivity analysis that included 4 additional RCTs published in abstract form, RR remained significant at 0.55 (95% CI, 0.34 to 0.91; P = 0.020).

CONCLUSION

NAC reduces the risk for RCN in patients with CKD.

Contrast medium-induced acute renal failure and cholesterol embolism after radiological procedures: incidence, risk factors, and compliance with recommendations

BACKGROUND: After radiological procedures, the incidence of acute renal failure varies greatly, and cholesterol embolism may not always be recognized. Little, if anything, is known about whether recommendations for the prevention of either complication are correctly implemented. METHODS: We performed a prospective epidemiological study in a large population (n=809) of consecutive inpatients in a university hospital. The patients were monitored for risk factors, ongoing medications, and details of preventive measures and of radiological procedures. Contrast nephropathy was defined as a 25% rise in serum creatinine. Cholesterol embolism was defined by the presence of two typical signs. We analyzed the incidence, risk factors, and prevention of contrast nephropathy and cholesterol embolism. RESULTS: The most frequent procedure that our patients underwent was cardiac angiography (50%). The incidence of contrast nephropathy was 7%. We confirmed the classical risk factors (diabetes, dose of contrast medium, and renal insufficiency) and added potentially nephrotoxic medications as an independent risk factor. Fluid therapy, commonly proposed in high-risk patients, was adequately carried out in only 12% of patients. The incidence of cholesterol embolism was 4%, with 10% renal involvement. Arteriosclerosis and renal insufficiency were risk factors, but anticoagulation therapy was not. CONCLUSION: Adequate fluid therapy and discontinuation of nephrotoxic medications should be more systematically implemented in the prevention of contrast nephropathy. Recognition of cholesterol embolism is crucial.