Diagnosis and Management of Rhabdomyolysis in the Absence of Creatine Phosphokinase: A Medical Record Review. Issue 11 (15th May 2019)

• Record Type: Journal Article
• Authors: Chandel, Abhimanyu; Brusher, Kara; Hall, Victoria; Howard, Robin S; Clark, Paul A
• Is Part Of: Military medicine. Volume 184:Issue 11/12(2019)
• Page Start: 820
• Page End: 825
• Publication Date: 2019-05-15
• Subjects: Rhabdomyolysis -- creatine phosphokinase -- aspartate aminotransferase -- diagnosis; Surgery, Military -- Societies, etc; Medicine, Military -- Societies, etc; Medicine, Military -- Periodicals; Surgery, Military -- Periodicals; Medicine, Military; Surgery, Military; Military Medicine -- Periodicals; Periodicals; Electronic journals; 616.98023
• DOI: 10.1093/milmed/usz101
• Languages: English
• ISSNs: 0026-4075

Abstract

Abstract: Introduction: Rhabdomyolysis is often encountered in austere environments where the diagnosis can be challenging due to the expense or unavailability of creatine phosphokinase (CPK) testing. CPK concentration ≥5, 000 U/L has previously been found to be a sensitive marker for progression to renal failure. This study sought to propose a model utilizing an alternate biomarker to allow for the diagnosis and monitoring of clinically significant rhabdomyolysis in the absence of CPK. Materials and Methods: We performed a retrospective chart review of 77 patients admitted to a tertiary medical center with a primary diagnosis of rhabdomyolysis. A linear regression model with aspartate aminotransferase (AST) as the independent variable was developed and used to predict CPK ≥5, 000 U/L on admission and CPK values on subsequent hospital days. The study was approved and monitored by the Institutional Review Board at Walter Reed National Military Medical Center. Results: Ln(AST) explained over 80% of the variance in ln(CPK) (adjusted R 2 = 0.802). The diagnostic accuracy to predict CPK ≥5, 000 U/L was high (AUC 0.959; 95% CI: 0.921–0.997, P < 0.001). A cut point of AST ≥110 U/L in our study population had a 97.1% sensitivity and an 85.7% specificity for the detection of a CPK value ≥5, 000 U/L. The agreement between actual CPK and predicted CPK for subsequent days of hospitalization was fair with an intraclass correlation coefficient of 0.52 (95% CI: 0.38–0.63). The developed model based on day 1 data tended to overpredict CPK values on subsequent hospital days. Conclusions: We propose a threshold concentration of AST that has an excellent sensitivity for detecting CPK concentration ≥5, 000 U/L on day of admission in a patient population with a diagnosis of rhabdomyolysis. A formula with a fair ability to predict CPK levels based on AST concentrations on subsequent hospital days was also developed.