From the Guidelines
The evaluation and management of a 16-year-old with elevated creatine kinase (CK) levels should begin with a thorough history and physical examination to identify potential causes, and the most recent guidelines from 2021 1 recommend a step-wise approach based on the severity of symptoms and CK elevation. The history should include questions about muscle pain, weakness, dark urine, family history of muscle disorders, and medication use, as certain medications like statins can cause elevated CK levels 1. Physical examination should focus on muscle strength, tone, and reflexes, and laboratory testing should include comprehensive metabolic panel, thyroid function tests, inflammatory markers, and repeat CK measurement. If CK remains significantly elevated (>5 times upper limit of normal) without clear explanation, additional testing may include electromyography, muscle biopsy, and genetic testing for inherited myopathies such as muscular dystrophy or metabolic myopathies, as suggested by the 2013 study 1. Management depends on the underlying cause, and the 2021 guidelines 1 provide a grading system for myositis, with recommendations for treatment based on the severity of symptoms and CK elevation. For example, for mild weakness with or without pain (G1), the guidelines recommend continuing immune checkpoint inhibitor therapy and offering oral corticosteroids if CK is elevated, while for severe weakness with or without pain (G3-4), the guidelines recommend holding immune checkpoint inhibitor therapy and initiating high-dose corticosteroids. Consultation with neurology or rheumatology specialists is recommended for persistent unexplained elevations, and the approach is guided by the degree of elevation, associated symptoms, and suspected etiology, with the goal of identifying treatable causes and preventing complications. Some key points to consider in the management of elevated CK levels include:
- Discontinuation of offending medications, such as statins
- Hydration to prevent renal damage from myoglobinuria
- Specific treatments for identified disorders, such as muscular dystrophy or metabolic myopathies
- Monitoring for idiopathic CK elevation without symptoms
- Consultation with specialists for persistent unexplained elevations.
From the Research
Evaluation Approach
- The evaluation of a 16-year-old patient with elevated Creatine Kinase (CK) levels should start with a comprehensive history and physical examination to identify potential causes of hyperCKemia, such as muscle injury, infection, or medication side effects 2.
- Laboratory tests, including CK levels, should be obtained to confirm the diagnosis and assess the severity of the condition 3, 2.
- Electromyography (EMG) and muscle biopsy may be considered to further evaluate the patient and rule out underlying muscle disorders 4, 5.
Management Approach
- The management of hyperCKemia depends on the underlying cause and severity of the condition 2.
- In cases of rhabdomyolysis, aggressive fluid resuscitation and monitoring of renal function are crucial to prevent complications such as acute renal failure 6.
- Patients with asymptomatic hyperCKemia may require regular follow-up and monitoring to detect potential progression to muscle disease 4, 5.
- Education on the importance of CK monitoring and potential risks of rhabdomyolysis is essential for patients on medications such as isotretinoin 3.
Diagnostic Considerations
- A higher level of CK and younger age are predictors of a specific cause of hyperCKemia, and the presence of weakness increases the likelihood of a diagnosis other than idiopathic or familial hyperCKemia 2.
- Muscle biopsy is a valuable tool in the diagnosis of hyperCKemia, allowing for the detection of skeletal muscle abnormalities and the diagnosis of underlying muscle disorders 4, 5.
- The diagnosis of idiopathic hyperCKemia is made in cases where no underlying cause is found, and the patient has completely normal muscle findings 5.