Comparison analysis of muscle enzymes in children with myocarditis and Duchene/Becker muscular dystrophy

Abstract

To compare the changes in muscle enzyme between children with myocarditis and Duchene/Becker muscular dystrophy (DMD/BMD), and to seek the explanations for variation. The retrospective analysis for 83 myocarditis children (myocarditis group) and 69 DMD/BMD children (DMD/BMD group), who were collected from Department of Pediatric of Shengjing Hospital affiliated to China Medical University since January 2008 to May 2015, was carried out. At the same time, 24 healthy children from the Department of Pediatric Development served as a control group. The examination indexes included creatine kinase (CK), creatine kinase-isoenzyme MB (CK-MB), creatine kinase isoenzyme MB mass (CK-MB mass), cardiac troponin I (cTnI) and high-sensitive-cTnT (hs-cTnT). 1) In the myocarditis group, the CK increased from 100 to 1 000 U/L, reached a peak after 5 days, which lasted for a week and then dropped to the normal; the CK-MB reached a peak after 5 to 7 days and dropped to the normal a month later; the CK-MB mass reached a peak on the first day and dropped to the normal after 3 weeks; the cTn reached to a peak after 5 days and dropped to the normal after about 17 days; hs-cTnT reached to a peak on the first day and dropped to the normal after about 19 days. 2) In the DMD/BMD group, the CK increased significantly and 27 cases had a CK value of more than 10 000 U/L. After the treatment for 1 to 2 weeks, their enzyme rose again after a slight drop. In terms of cTnI, 6 cases showed a moderate increase, 5 of them couldn't drop to the normal level until more than 3 weeks later; the hs-cTnT increased in the 45 cases, which lasted for more than 3 weeks in the 31 cases of them and showed a tendency of persisting increase. The cTnI and hs-cTnT rise significantly and possess wider observation window than CK and CK-MB mass in myocarditis children, with more sensitive and specific changes. The myocardial damage can occur before myasthenia and keep this trend for a long time in the DMD/BMD children. The trend of cTnI change in myocarditis children is similar to hs-cTnT, while hs-cTnT in DMD/BMD children is more sensitive than cTnI.