Original Contribution Clinical factors in predicting acute renal failure caused by rhabdomyolysis in the ED Chun-Yu Chen MD a, b, c , Yan-Ren Lin MD, PhD d , Lu-Lu Zhao MD e , Wen-Chieh Yang MD a , Yu-Jun Chang MS f , Han-Ping Wu MD, PhD g, h, ⁎ a Department of Pediatrics, Division of Emergency Medicine, Changhua Christian Hospital, Changhua, Taiwan, ROC b School of medicine, Chung Shan Medical University, Taichung, Taiwan, ROC c Chienkuo Technology University, Changhua, Taiwan, ROC d Department of Emergency Medicine, Changhua Christian Hospital, Changhua, Taiwan, ROC e Department of Pediatrics, Buddhist Tzu-Chi General Hospital, Taipei Branch, Taipei, Taiwan, ROC f Laboratory of Epidemiology and Biostatistics, Changhua Christian Hospital, Changhua, Taiwan, ROC g Department of Pediatrics, Buddhist Tzu-Chi General Hospital, Taichung Branch, Taichung, Taiwan, ROC h Department of Medicine, School of Medicine, Tzu-Chi University, Hualien, Taiwan, ROC abstract article info Article history: Received 7 January 2013 Received in revised form 26 March 2013 Accepted 27 March 2013 Purpose: This study aimed to determine the clinical factors in predicting acute renal failure (ARF) in rhabdomyolysis and investigate the potential risk of renal replacement therapy (RRT). Basic Procedures: From 2006 to 2011, we retrospectively analyzed 202 patients 65 years or younger with a definite diagnosis of rhabdomyolysis and serum creatinine phosphokinase levels greater than 1000 IU/L. The related clinical factors were analyzed in the patients with ARF caused by rhabdomyolysis. In addition, receiver operating characteristic curves were used to establish the appropriate cutoff values of serum biomarkers in predicting ARF. Main Findings: The most common causes of rhabdomyolysis were trauma (n = 54; 26.7%) and infections (n = 37; 18.3%). Of the 202 patients, 29 (14.4%) developed ARF, and RRT was indicated for 5 of these 29 patients. Predictive factors for ARF were dark urine, initial and peak serum myoglobin level, rhabdomyolysis caused by body temperature change, and an elevated serum potassium level. Receiver operating characteristic analysis showed that the best cutoff value of initial serum myoglobin level for predicting ARF was 597.5 ng/mL. Risk factors for RRT in patients with ARF were etiologies of rhabdomyolysis, peak blood urea nitrogen and creatinine levels, and the creatinine phosphokinase level on the third day as rhabdomyolysis developed. Principal Conclusions: Age, dark urine, etiologies, serum levels of blood urea nitrogen, creatinine and potassium, and initial and peak serum myoglobin levels may serve as important factors in predicting ARF in patients with rhabdomyolysis. We suggest that the appropriate cutoff value of initial serum myoglobin for predicting ARF is 600 ng/mL. © 2013 Elsevier Inc. All rights reserved. 1. Introduction Rhabdomyolysis is characterized by skeletal muscle breakdown with leakage of muscle contents, including electrolytes, myoglobin, and other sarcoplasmic proteins (eg, creatine kinase, lactate dehy- drogenase, alanine aminotransferase, and aspartate aminotransfer- ase) into the circulation [1,2]. The major causes include trauma, ischemia, exertion, drugs, toxins, metabolic disorders, electrolyte disorders, and infections [2-5]. Typically, patients with rhabdomyol- ysis present with muscle pain, weakness, and reddish-brown urine caused by myoglobinuria. Nevertheless, the severity of rhabdomyol- ysis varies from an asymptomatic increase in creatine phosphokinase (CK) to serious complications such as acute renal failure (ARF), cardiac arrhythmias, compartmental syndrome, hypovolemic shock, and disseminated intravascular coagulopathy [4-10]. Acute renal failure is the most important and serious complication of rhabdomyolysis. It has been reported that 10% to 40% of patients with rhabdomyolysis develop ARF and that 5% to 15% of cases of ARF are attributable to rhabdomyolysis [6]. However, in a larger study of 191 children with a CK level greater than 1000 U/mL who were sent to the emergency department (ED), the prevalence of ARF was 5%, with a requirement for renal replacement therapy (RRT) in 3 of the 9 patients with renal failure [11]. Preventing the progression to ARF and early detection of ARF appear to be important issues in rhabdomy- olysis. However, it is still unclear which factors are highly correlated with ARF and how they can be used to predict ARF in patients with rhabdomyolysis. In this study, we analyzed the clinical spectrum of American Journal of Emergency Medicine 31 (2013) 1062–1066 ⁎ Corresponding author. Department of Pediatrics, Buddhist Tzu-Chi General Hospital, Taichung Branch, Taichung 42743, Taiwan, ROC. Tel.: +886 4 36060666x3117; fax: +886 4 36021123. E-mail address: arthur1226@gmail.com (H.-P. Wu). 0735-6757/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajem.2013.03.047 Contents lists available at SciVerse ScienceDirect American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem