Question

A large bookcase falls upon an elderly man in his home. His left leg is pinned and he cannot move for 2 days until his neighbor finds him. He is hospitalized with massive trauma to his left leg, with resultant rhabdomyolysis (rhabdomyo means striated muscle tissue; lysis means "break down"). His pulses in that foot are unpalpable and the foot is pale and cool. Eventually his foot must be amputated.

Initial lab work is drawn that show a CK of 100,000 (normal serum CK is 0 to 200). Why is it so high?

a. As a compensatory response, the production of the enzyme creatine kinase (CK) is increased in the cells and then is excreted to "clean up" the cellular debris.
b. As a result of injury, the striated cell membranes lose integrity and there is leakage of intracellular substances such as CK into the surrounding tissue bed.
c. Creatine kinase (CK) is only found in striated muscle cells, so it makes sense that
rhabdomyolysis would result in greater release of CK.
d. Local tissue response to injury includes release of toxic, lytic substances such as CK.

Answer 1

The high CK levels in the elderly man's blood are a result of the injury causing the loss of integrity in the striated cell membranes and the leakage of intracellular substances like CK into the surrounding tissue.

Step-by-step explanation:

The correct answer is b. As a result of injury, the striated cell membranes lose integrity and there is leakage of intracellular substances such as CK into the surrounding tissue bed.

Rhabdomyolysis is the breakdown of muscle tissue, which leads to the release of intracellular substances, including creatine kinase (CK), into the surrounding tissue. In this case, the large bookcase falling on the elderly man caused massive trauma to his left leg, resulting in rhabdomyolysis and a significant increase in CK levels.

During rhabdomyolysis, the striated cell membranes of the muscle tissue are damaged, allowing CK to leak out. CK is present only in striated muscle cells, so it makes sense that rhabdomyolysis would result in a greater release of CK. The high CK levels indicate the severity of the muscle damage and the need for amputation of the foot.