From the Guidelines
Asymptomatic elevation in serum Creatine Kinase (CK) levels should be approached with caution, and the decision to investigate or intervene should be based on the degree of elevation and the clinical context.
Key Considerations
- Degree of Elevation: The degree of CK elevation is crucial in determining the next steps. Elevations of more than 10 times the upper limit of normal (ULN) are considered significant and may warrant discontinuation of potentially offending agents, such as statins, and close monitoring 1.
- Clinical Context: The clinical context, including the presence of symptoms, underlying conditions, and medications, is essential in interpreting CK elevations. For example, in athletes, CK elevations are common after intense exercise and may not necessarily indicate muscle damage 1.
- Monitoring and Intervention: For asymptomatic patients with moderate CK elevations (between 3 and 10 times the ULN), careful monitoring of symptoms and more frequent CK measurements are recommended. In cases where CK levels are significantly elevated or symptoms develop, intervention may be necessary, including discontinuation of offending agents or initiation of corticosteroids 1.
Management
- Mild Elevations: For mild elevations, continuation of current therapy with monitoring may be appropriate.
- Moderate to Severe Elevations: For moderate to severe elevations, especially in the context of symptoms or significant elevation (more than 10 times the ULN), discontinuation of potentially offending medications and consideration of corticosteroids may be necessary 1.
- Special Considerations: In specific contexts, such as immune-related adverse events in patients treated with immune checkpoint inhibitors, the management of myositis (including CK elevation) involves a graded approach based on the severity of symptoms and CK levels, with options ranging from continuation of therapy with monitoring to permanent discontinuation of the offending agent and initiation of immunosuppressive therapy 1.
From the Research
Workup for Asymptomatic Elevation in Serum Creatine Kinase (CK) Levels
The workup for asymptomatic elevation in serum CK levels involves a series of diagnostic tests to identify the underlying cause of the elevation. The following steps are recommended:
- Repeated CK determination to confirm the persistence or recurrence of hyperCKemia 2
- Electromyography (EMG) to assess muscle function and identify any abnormalities 2, 3
- Muscle biopsy to examine the muscle tissue for any signs of disease or damage 2, 3
- Genetic work-up by a panel or whole exome sequencing if EMG and muscle biopsy are noninformative 2
- Physical and laboratory examinations to rule out other potential causes of hyperCKemia, such as cardiac, metabolic, or endocrine disorders 4
- Counseling on the risk of malignant hyperthermia and the importance of informing anesthesiologists and surgeons about the condition before elective surgery 2
Potential Causes of Asymptomatic HyperCKemia
Asymptomatic hyperCKemia can be caused by a variety of factors, including:
- Primary (hereditary) myopathies, such as dystrophinopathies, myotilinopathies, and calpainopathy 2
- Acquired myopathies, such as polymyositis and mitochondrial myopathy 3
- Macroenzymes, such as macroCKemia, which can cause decreased clearance of CK 5
- Other conditions, such as sarcoid myopathy, central core disease, and McArdle's disease 3
Importance of Workup
A thorough workup is essential to identify the underlying cause of asymptomatic hyperCKemia, as some conditions may require specific treatment or management. For example, patients with asymptomatic hyperCKemia should avoid excessive exercise and require sufficient hydration to prevent renal failure 2, 5. Additionally, patients with a history of asymptomatic hyperCKemia should inform their healthcare providers about their condition before undergoing elective surgery to minimize the risk of malignant hyperthermia 2.