Related Experiment Videos
Clinical significance of low creatine phosphokinase values in patients with connective tissue diseases
Insights
Serum creatine phosphokinase (CPK) levels are often low in patients with connective tissue diseases. A normal CPK value does not rule out myositis in these conditions.
Area of Science:
- Rheumatology
- Clinical Biochemistry
Background:
- Connective tissue diseases (CTDs) encompass a range of autoimmune disorders.
- Serum creatine phosphokinase (CPK) is an enzyme primarily found in muscle tissue.
Observation:
- A frequent observation of low serum CPK values in patients diagnosed with CTDs.
- Established reference ranges for serum CPK in healthy males and females.
Findings:
- Significantly lower geometric mean CPK values were observed in patients with systemic lupus erythematosus, rheumatoid arthritis, and Sjögren's syndrome compared to healthy controls.
- Low serum CPK levels can be present even in the absence of steroid treatment.
- Normal serum CPK values were noted in some patients with active myositis.
Implications:
- Low serum CPK may serve as a potential biomarker for CTDs.
- A normal CPK level should not preclude the diagnosis of myositis in patients with suspected CTDs.
- Further research into the utility of CPK levels in diagnosing and monitoring CTDs is warranted.
Abstract:
We have noted that values for serum creatine phosphokinase (CPK) are frequently low in patients with connective tissue diseases. Geometric mean values were 96.0 units/L among 121 disease-free males and 50.2 units/L among 63 disease-free females. The geometric mean values were 31.7 units/L in 11 males and 35.2 units/L in 49 females with systemic lupus erythematosus; 15.1 units/L in three males and 13.0 units/L in ten females with rheumatoid arthritis; and 41.6 units/L in 19 females with Sjögren's syndrome. Values within the normal range may occur in the face of active myositis in these illnesses. Findings of a low serum CPK values may occur in the absence of steroid treatment. Thus, a low serum CPK value is frequently found in patients with connective tissue diseases and a normal value should not dissuade one from the diagnosis of myositis.