Introduction and Aims Acute severe asthma is a life threatening condition. Mechanical ventilation may be indicated in about third of asthmatics admitted to the intensive care unit and has a mortality rate of 8%.1 Several reports have identified elevated CK levels during an episode of acute severe asthma. Intense muscular workload during an acute episode and drugs such as steroids, anaesthetic induction agents, aminophylline and salbutamol are all implicated in raising plasma CK levels. Our aim was to retrospectively evaluate the CK levels and clinical implications in patients with acute severe asthma, who were admitted to our intensive care unit.
Methods This was a retrospective survey of all asthmatics admitted to intensive care unit between October 2009 and July 2011. Patient’s case notes were screened to identify demographics and clinical details.
Results Thirty asthmatics with 37 admissions were identified. Three patients had multiple admissions. Mean age was 37 and two third were female. Twelve patients had CK levels performed as part of clinical management. Seven patients (58%) had CK levels ≤320 IU/ml and 5 patients (42%) had CK levels ≥320 IU/ml. Patients with raised CK levels had more intubations, ICU days and hospital days. IV aminophyline and IV salbutamol infusions were more frequent in patients with raised CK levels. The elevated CK was noted on average 1.8 days after the admission (Table 1). Three patients with raised CK levels had severe renal failure with evidence of myoglobinuria. Statistical analysis is not performed due to small number of patients.
Discussions Acute severe asthmatics may develop raised CK levels with evidence of myoglobinuria and subsequent renal failure. The exact mechanisms are not fully explored. Intravenous beta2-agonists with combination of IV aminophylline may be a contributory factor. Prospective studies are needed to evaluate the path ophysiological mechanisms and clinical implications.
McFadden ER Am J Respir Crit Care Med 2003.
Pathologyharmony.co.uk (for reference range).