Can COVID-19 (Coronavirus Disease 2019) infection increase creatine kinase (CK) levels?

COVID-19 Infection Can Increase Creatine Kinase Levels

Yes, COVID-19 infection can significantly increase creatine kinase (CK) levels, with elevated CK being associated with worse outcomes including increased mortality and disease severity. 1, 2

Mechanism and Prevalence of CK Elevation in COVID-19

• SARS-CoV-2 infection can cause direct damage to muscles, leading to elevated CK levels 3
• The incidence of elevated CK in COVID-19 patients is approximately 17% according to pooled analysis 2
• COVID-19 may cause muscle injury through several mechanisms:
  • Direct viral infiltration via ACE-2 receptors on muscle cells
  • Systemic inflammatory response (cytokine storm)
  • Hypoxemia from respiratory failure
  • Rhabdomyolysis in severe cases 4

Clinical Significance of Elevated CK in COVID-19

Prognostic Value

• Elevated CK at admission is associated with a 3-fold higher risk of poor outcomes (OR 3.01) 2
• CK levels are typically higher in patients who experience more severe disease outcomes (median 126 U/L vs. 82 U/L in milder cases) 1
• CK levels >200 U/L are particularly associated with worse prognosis 1

Pattern of CK Elevation

• HyperCKemia in COVID-19 is generally transient, returning to normal during hospitalization in most patients 1
• CK levels strongly correlate with markers of inflammation and disease severity 5
• In severe cases, CK can reach extremely high levels, with reports of values exceeding 15,000 U/L in rhabdomyolysis cases 6

Comparison with Other Viral Infections

• The frequency of CK elevation in COVID-19 (27%) is similar to that seen in influenza infection (28%) 5
• However, baseline CK levels tend to be higher in influenza patients compared to COVID-19 patients 5
• Among ICU-admitted patients, 35.7% of influenza patients had CK levels >1,000 U/L compared to only 4.7% of COVID-19 patients 5

Clinical Implications

• Monitor CK levels in hospitalized COVID-19 patients, particularly those with:

  • Myalgia or muscle weakness
  • Elevated liver enzymes (which often accompany CK elevation)
  • Severe disease requiring ICU admission 4, 1

• Be vigilant for rhabdomyolysis in COVID-19 patients with significantly elevated CK (>5 times upper limit of normal), as this can lead to acute kidney injury 4

• Consider that CK elevation may occur not only during acute infection but also as a post-COVID complication, as demonstrated in case reports of rhabdomyolysis following recovery from COVID-19 6

Pitfalls to Avoid

• Don't assume mild CK elevation is always clinically significant - interpretation should consider the patient's overall clinical status
• Don't overlook other causes of CK elevation in COVID-19 patients (medications like statins, prolonged immobilization, critical illness myopathy)
• Don't miss the opportunity to monitor kidney function when CK is elevated, as rhabdomyolysis can lead to acute kidney injury 4

COVID-19 infection clearly affects muscle tissue, as evidenced by frequent CK elevation, but the exact mechanism remains under investigation. Whether this represents direct viral invasion of muscle or is secondary to the systemic inflammatory response is still being determined 5.