Elevation of creatine kinase in acute severe asthma is not of cardiac origin

Objective: To study prospectively if, when plasma creatine kinase (CK) and plasma myoglobin are elevated, the origin of these abnormalities is cardiac or not, by measuring cardio-specific troponin T (cTT). Method: Fifteen patients with acute severe bronchial asthma (ASBA) were prospectively studied in the intensive care unit (ICU) with continuous electrocardiograph (ECG). Plasma CK, CK-MB, myoglobin and cTT were measured at 0, 4, 8, 12, 16 and 20 h in the ICU. Results: Five out of 15 ASBA patients had elevated CK, four of them presenting with an increase in CKMB. Plasma cTT was normal in every patient, including those with CK and/or myoglobin elevation. At admission to the ICU, myoglobin and CK were positively correlated (r = 0.760; p < 0.001). No patient was intubated. There was no difference in clinical signs or symptoms, medical history, laboratory values or ECC in patients with or without CK elevation. Conclusion: Patients admitted to an ICU for ASBA may present with an elevation of plasma CK, CK-MB and myoglobin not related to any heart injury. CK and CK-MB are not good markers of myocardial injury in ASBA patients due to the multitude of potential confounders. Therefore, troponin should be measured instead.