Does Guillain-Barré syndrome (GBS) have elevated Creatine Kinase (CK) levels?

Creatine Kinase Elevation in Guillain-Barré Syndrome

Guillain-Barré syndrome (GBS) can be associated with elevated creatine kinase (CK) levels in approximately 16-27% of patients, particularly in those with the acute motor axonal neuropathy (AMAN) subtype rather than the demyelinating form.

Clinical Significance of CK Elevation in GBS

Prevalence and Patient Characteristics

• Elevated CK occurs in approximately 16-27% of GBS patients 1, 2
• Patients with elevated CK are more likely to:
  • Be male 1, 2
  • Have preceding infections 1
  • Test positive for anti-GM1 antibodies 1
  • Have the acute motor axonal neuropathy (AMAN) subtype rather than acute inflammatory demyelinating polyneuropathy (AIDP) 1, 2

Clinical Presentation Differences

Patients with elevated CK levels in GBS tend to have:

• Less sensory involvement (hypoesthesia) 1
• Less cranial nerve involvement 1
• Less urinary retention 1
• More prominent motor symptoms 1
• Potentially more severe limb weakness and respiratory muscle paralysis 3

Mechanism of CK Elevation in GBS

The elevation of CK in GBS is believed to result from:

• Rapid extensive denervation due to severe axonal degeneration of motor nerve terminals 4
• Hyperexcitability in regional muscles leading to recurrent muscle cramps 4
• Persistent release of muscular CK into circulation 4

Timing and Duration of CK Elevation

• CK elevation may not be present at initial presentation
• It can become evident approximately three weeks after the onset of GBS 4
• Elevated levels may persist for longer than one month 4

Clinical Implications

Diagnostic Considerations

• CK elevation is not part of the standard diagnostic criteria for GBS 5, 6
• Normal CK levels do not rule out GBS
• Marked CK elevation should prompt consideration of complications such as rhabdomyolysis 7, 3

Monitoring and Management

• Monitor CK levels in GBS patients, especially those with severe motor involvement
• Watch for potential complications of significant CK elevation:
  • Electrolyte disorders (particularly hyperkalemia) 7
  • Acute kidney injury 3
  • Multisystem complications 3

Prognostic Value

• There is no significant difference in disability at peak between GBS patients with normal versus elevated CK levels 1
• However, patients with GBS complicated by rhabdomyolysis may require more intensive monitoring and supportive care 7, 3

Differential Diagnosis When CK is Elevated

When elevated CK is found in a patient with suspected GBS, consider:

• GBS with secondary muscle involvement
• GBS complicated by rhabdomyolysis 7, 3
• Other conditions that can cause both weakness and CK elevation:
  • Glycogen storage diseases (types IIIa, IV, V, VII) 5
  • Mitochondrial myopathies 5
  • Inflammatory myopathies 5

Key Takeaways

1. CK elevation is not uncommon in GBS, occurring in approximately 16-27% of patients
2. Elevated CK is more common in the axonal subtype (AMAN) than the demyelinating form (AIDP)
3. CK elevation may not be present initially but can develop weeks after symptom onset
4. Significant CK elevation warrants monitoring for complications like rhabdomyolysis and kidney injury
5. The presence of elevated CK does not significantly alter the standard treatment approach for GBS, which includes intravenous immunoglobulin or plasma exchange

Remember that while CK elevation can occur in GBS, the core diagnostic features remain progressive bilateral weakness and areflexia, with supportive evidence from CSF examination and electrodiagnostic studies.