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Excessive plasma K + increase after ischemic exercise in myotonic muscular dystrophy
Author(s) -
Wevers Ron A.,
Joosten Ed M. G.,
van de Biezenbos J. B. Margot,
Theewes Ad G. M.,
Veerkamp Jacques H.
Publication year - 1990
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880130107
Subject(s) - myotonic dystrophy , creatine , muscular dystrophy , creatine kinase , medicine , myotonia , endocrinology , phosphate , physical exercise , chemistry , inorganic phosphate , biochemistry
Changes in plasma electrolyte levels upon ischemic forearm exercise were studied in myotonic muscular dystrophy (MyD) patients, disease control groups, and healthy volunteers. Significant differences were observed in the pH and the concentrations of creatine kinase and Na+ before exercise between healthy volunteers and MyD patients. In comparison with healthy volunteers a lower pH and higher concentrations of both CK and Na+ were found in MyD patients. The concentrations of K+, inorganic phosphate, lactate, and ammonia increase upon exercise in all groups. The mean increase in plasma K+ for healthy volunteers amounted to 0.8 m M (=23%). In MyD patients a significantly higher increase in plasma K+ was found [mean 2.2 m M (= 65%)]. No abnormal release of K+ from muscular tissue was found in the disease control groups. Data on the postexercise increase in the concentration of other muscular constituents such as creatine kinase, inorganic phosphate, or creatine exclude the possibility of a generally increased membrane permeability in MyD. The abnormally high increase of plasma K+ upon muscular exercise seems to be specific for MyD and may be related to the biochemical defect in this disease.