What is the management and treatment approach for a patient presenting with Lenoir's sign?

Management of Lenoir's Sign (Épine de Lenoir)

Lenoir's sign, a clinical indicator of cervical myelopathy, requires prompt neurological evaluation and appropriate imaging to determine the underlying cause and prevent progression of neurological damage.

Clinical Presentation and Significance

• Lenoir's sign (épine de Lenoir) is characterized by an electric shock-like sensation that travels down the spine, arms, and sometimes legs when the neck is flexed, similar to Lhermitte's sign 1, 2
• This sign is an important clinical indicator of cervical spinal cord pathology and should prompt immediate evaluation to prevent progression of neurological damage 3
• The sign is caused by stretching of demyelinated fibers in the posterior columns of the cervical spinal cord during neck movement 1

Diagnostic Approach

Initial Assessment

• Perform a thorough neurological examination focusing on upper motor neuron signs including hyperreflexia, Babinski sign, Tromner sign, and clonus, which are highly specific for cervical myelopathy 4
• Assess for other neurological symptoms including weakness, sensory changes, gait abnormalities, and bladder/bowel dysfunction 3
• Document any history of trauma, which may suggest post-traumatic spinal cord injury without radiographic abnormality (SCIWORA) 5

Imaging Studies

• MRI of the brain and cervical spine is the first-line imaging modality with highest diagnostic yield for identifying the underlying cause 6
• MRI should be performed within 24 hours if symptoms are severe or progressive 6
• If MRI is unavailable, urgent CT of the cervical spine should be performed, followed by MRI when available 6
• Look for key MRI findings including:
  • Spinal cord compression, edema, or signal changes 6
  • Disc herniations or degenerative changes 3
  • Evidence of demyelination suggestive of multiple sclerosis 2

Management Based on Etiology

Degenerative Cervical Myelopathy

• For mild symptoms without significant cord compression:

  • Cervical collar immobilization to limit movement and prevent further damage 3
  • Activity modification to avoid neck flexion and extension 3
  • Regular neurological monitoring for signs of progression 4

• For moderate to severe symptoms or evidence of significant cord compression:

  • Referral to neurosurgery or spine surgery for evaluation 3
  • Surgical decompression may be necessary if there is evidence of persistent spinal cord compression 5

Multiple Sclerosis or Other Demyelinating Conditions

• Refer to neurology for comprehensive evaluation 3
• High-dose corticosteroids may be indicated for acute demyelinating episodes 3
• Disease-modifying therapies should be initiated if multiple sclerosis is diagnosed 2

Vitamin B12 Deficiency (Subacute Combined Degeneration)

• Check serum vitamin B12 levels, methylmalonic acid, and homocysteine 1
• Initiate vitamin B12 supplementation (typically intramuscular injections initially) 1
• Symptoms typically improve with appropriate B12 replacement therapy 1

Post-Traumatic (SCIWORA)

• Immediate spinal immobilization with a rigid cervical collar 5
• Consider high-dose steroid therapy according to spinal cord injury protocols 5
• Avoid activities that could exacerbate injury 5
• Surgical intervention may be necessary if there is evidence of instability or persistent compression 5

Camptocormia (Bent Spine Syndrome)

• If Lenoir's sign is associated with abnormal trunk flexion, consider evaluation for camptocormia 7
• Determine if primary (axial myopathy) or secondary to neurological disorders like Parkinson's disease 7
• Management includes physical therapy, walking aids, and treatment of underlying cause 7

Follow-up and Monitoring

• Schedule follow-up within 2-4 weeks to assess response to treatment and symptom progression 3
• Repeat imaging may be necessary if symptoms worsen or fail to improve with conservative management 3
• Consider referral to specialized centers for complex cases or those requiring surgical intervention 3

Precautions and Patient Education

• Advise patients to avoid activities that trigger the symptom, particularly extreme neck flexion 2
• Educate patients about warning signs that should prompt immediate medical attention (progressive weakness, numbness, bowel/bladder dysfunction) 3
• Provide appropriate pain management while addressing the underlying cause 3

Special Considerations

• In elderly patients or those with vascular risk factors, consider vascular causes of myelopathy 3
• In patients with professional voice requirements, be aware that cervical pathology can sometimes affect laryngeal function 3
• For patients with concurrent visual symptoms, consider expanded neurological evaluation including ophthalmological assessment 3