The highest CK elevation is observed in which condition?

• A. Duchenne muscular dystrophy
• B. Myocardial infarction
• C. Liver failure
• D. Osteoarthritis

Answer: (A)

Creatine kinase (CK) rises in the blood when muscle cells are damaged. The skeletal muscle damage seen in Duchenne muscular dystrophy is massive and ongoing, releasing large amounts of CK (especially the CK-MM isoenzyme) into the circulation. This results in markedly elevated CK levels, typically far higher than in other conditions listed. In myocardial infarction, CK does rise due to cardiac muscle injury, but the overall increase is usually smaller because it reflects primarily heart muscle damage and the peak is more transient. Liver failure does not cause a pronounced rise in CK from skeletal muscle, and osteoarthritis involves little to no muscle breakdown, so CK stays relatively normal. Therefore, the highest CK elevation is seen with Duchenne muscular dystrophy.