Can rhabdomyolysis cause high-sensitivity cardiac troponin T (hs-cTnT) to be elevated?

Can Rhabdomyolysis Cause Elevated HS Troponin T at 70?

Yes, rhabdomyolysis can cause elevated high-sensitivity cardiac troponin T (hs-cTnT) levels, including values around 70 ng/L, due to skeletal muscle injury rather than true cardiac damage. This represents a false-positive elevation that requires careful clinical interpretation.

Mechanism and Evidence for Troponin Elevation in Rhabdomyolysis

Rhabdomyolysis can lead to elevated hs-cTnT through several mechanisms:

• Cross-reactivity with skeletal muscle proteins: While cardiac troponins are considered cardiac-specific, severe skeletal muscle damage in rhabdomyolysis can lead to false-positive elevations, particularly for troponin T 1

• Severity correlation: Higher degrees of muscle damage (indicated by very high CK levels) correlate with increased likelihood of troponin elevation 2

• Differential specificity: High-sensitivity troponin T (hs-cTnT) is more likely to be elevated in rhabdomyolysis than high-sensitivity troponin I (hs-cTnI), which maintains better cardiac specificity 3

Clinical Interpretation of Elevated hs-cTnT in Rhabdomyolysis

The 2021 ESC guidelines explicitly list rhabdomyolysis among conditions that can cause cardiac troponin elevation without acute coronary syndrome 4. When interpreting an elevated hs-cTnT of 70 ng/L in a patient with rhabdomyolysis:

Key Diagnostic Considerations:

1. Pattern of elevation: A single elevated value has limited diagnostic value

   • Look for characteristic rise and fall pattern of troponin to differentiate acute cardiac injury from non-cardiac causes 4
   • Stable or minimally changing troponin values suggest non-cardiac etiology

2. Magnitude of elevation:

   • Values up to 3x the upper reference limit (typically 30-60 ng/L) have limited (50-60%) positive predictive value for AMI 4
   • A value of 70 ng/L falls within this intermediate range where non-cardiac causes are common

3. Clinical context:

   • Absence of chest pain, ECG changes, or other cardiac symptoms suggests non-cardiac cause
   • Presence of clear alternative explanation (rhabdomyolysis) increases likelihood of false-positive

Differentiating True Cardiac Injury from False Positive

To determine if the elevated hs-cTnT of 70 ng/L represents true cardiac injury:

1. Serial measurements: Obtain serial troponin measurements to assess for dynamic changes

   • Significant rise/fall pattern (>20% change) suggests acute cardiac injury
   • Stable values suggest chronic elevation or false positive 4

2. ECG assessment: Look for ischemic changes

   • Studies show that patients with rhabdomyolysis and elevated troponin without ECG changes likely represent false positives 1

3. Echocardiography: Consider if diagnosis remains unclear

   • Absence of wall motion abnormalities in setting of elevated troponin and rhabdomyolysis suggests false positive 2

Clinical Implications and Management

When rhabdomyolysis is the suspected cause of hs-cTnT elevation:

• Don't dismiss elevated troponin: While likely a false positive, elevated troponin in rhabdomyolysis is associated with higher morbidity and longer hospital stays 2

• Consider underlying causes: Certain etiologies of rhabdomyolysis (sepsis, hypotension, substance use) are more likely to cause troponin elevation and may require specific management 2

• Monitor for complications: Patients with both rhabdomyolysis and elevated troponin often require more intensive care 2

• Consider troponin I: If cardiac injury must be definitively ruled out, hs-cTnI may be more specific than hs-cTnT in the setting of severe skeletal muscle damage 3

Common Pitfalls to Avoid

1. Assuming all troponin elevations indicate MI: The 2021 ESC guidelines explicitly list numerous non-coronary causes of troponin elevation, including rhabdomyolysis 4

2. Failing to obtain serial measurements: A single elevated value without clinical context is insufficient for diagnosis

3. Ignoring the clinical significance: Even if "false positive," elevated troponin in rhabdomyolysis may indicate higher disease severity and need for more intensive monitoring

4. Overlooking renal function: Impaired renal clearance in rhabdomyolysis patients can contribute to troponin elevation, though this is a minor factor compared to the muscle injury itself 2