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

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).

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.

Five out of 15 ASBA patients had elevated CK, four of them presenting with an increase in CK-MB. 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 ECG in patients with or without CK elevation.

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.