Creatinine phosphokinase elevation among exertional heat stroke patients

Background: Rhabdomyolysis, which can be defined as a CPK level greater than five times the upper limit of normal, is related to muscle breakdown and hypovolemia in heat stroke patients.1 CPK levels will likely be higher because of increased muscle breakdown in exertional heat stroke when compared with classic heat stroke. Methods: We reviewed 50 patients who came into the Emergency Department of Hamad General Hospital during the months of July to September 2015, and who were diagnosed with exertional heat stroke. Results: In 44 out of 50 heat stroke patients, the level of serum CPK was markedly elevated (mean 20,300 ± 25,500 U/l) compared with the elevated levels of other lab values (serum myoglobin 2500 ± 3000 ng/ml, creatinine 1.8 ± 2.4 mg/dL, BUN 90 ± 104 mg/dL, potassium 2.6 ± 3.6 mEq/L, sodium 135 ± 155 mEq/L) on admission. The repeated lab values after the 12th hour showed that the CPK rose further (28,500 ± 32,500 U/L) while the others (serum myoglobin 800 ± 1,200 ng/ml, creatinine 1.1 ± 1.4 mg/dl, BUN 35 ± 60 mg/dL, potassium 2.2 ± 3.4 mEq/L, sodium 110 ± 130 mEq/L) recorded a decrease. Conclusion: In our cohort of patients, CPK levels were significantly high in the setting of exertional heat stroke. A possible relation to renal failure need to be explored in a prospective research design. Keywords: exertional heat stroke, rhabdomyolysis, creatinine phosphokinase REFERENCE: [1] Santelli J, Sullivan J. An evidence based approach on emergency medicine. Emerg Med Prac. 2014;16:6–15.