What could cause electrical shock and paresthesia below the hip when moving the neck?

Lhermitte's Sign: Cervical Spinal Cord Pathology

The electrical shock sensation and paresthesia below the hip triggered by neck movement is most likely Lhermitte's sign, indicating cervical spinal cord pathology that requires urgent neurological evaluation and cervical spine MRI.

What This Symptom Represents

• Lhermitte's sign is a classic neurological finding characterized by an electric shock-like sensation radiating down the spine and into the extremities when the neck is flexed or moved 1
• This phenomenon occurs when there is irritation or compression of the cervical spinal cord, causing abnormal transmission of signals along the posterior columns 1
• The sensation traveling below the hip indicates involvement of the lower spinal cord segments, suggesting pathology at the cervical or upper thoracic level 2

Most Common Underlying Causes

Cervical Spinal Cord Compression

• Cervical stenosis with cord compression is a leading cause, particularly in patients with developmental narrowing of the spinal canal 2
• Disc herniation at cervical levels can compress the spinal cord and produce these symptoms 3, 2
• Cervical spondylosis with osteophyte formation may narrow the canal and irritate the cord 3

Cervical Instability and Ligamentous Injury

• Capsular ligament laxity can cause excessive vertebral movement, leading to intermittent cord compression with neck motion 3
• Whiplash-associated disorders may result in cervical instability that produces neurological symptoms including paresthesias 4
• Cervical instability from ligamentous injury can cause nerve irritation and vertebrobasilar insufficiency 3

Demyelinating Disease

• Multiple sclerosis commonly presents with Lhermitte's sign due to demyelination of the cervical spinal cord 1
• This should be considered especially in younger patients without trauma history

Critical Red Flags Requiring Immediate Evaluation

The American Heart Association identifies these concerning features that mandate urgent assessment 1:

• Tingling in the extremities (present in this case)
• Pain or tenderness in the neck or back
• Sensory deficit or muscle weakness involving the torso or upper extremities
• Age ≥65 years
• History of trauma, fall from height, or motor vehicle accident

Diagnostic Approach

Immediate Imaging

• MRI of the cervical spine without contrast is the reference standard for diagnosing spinal cord pathology and soft tissue injuries 1
• MRI can identify cord compression, disc herniation, ligamentous injury, and demyelinating lesions 1
• CT cervical spine is appropriate if MRI is contraindicated, though it has limited sensitivity for cord and soft tissue pathology 1

Clinical Examination Priorities

• Assess for cervical spine tenderness, particularly midline and paraspinal palpation 1
• Test upper extremity strength in all myotomes to detect radicular involvement 1, 5
• Evaluate for signs of myelopathy including hyperreflexia, clonus, and Babinski sign 2
• Document any limitation of cervical range of motion 1

Management Considerations

Immediate Precautions

• Minimize neck movement until spinal cord pathology is excluded, as manipulation could worsen cord injury 1
• Manual stabilization of the head and neck is reasonable if there is concern for instability 1
• Avoid immobilization devices unless trained in their use, as they may cause harm 1

Specialist Referral

• Urgent neurosurgical or spine surgery consultation is warranted for any patient with signs of cord compression 1, 2
• Neurological evaluation is essential to assess for progressive myelopathy 2, 5

Common Pitfalls to Avoid

• Do not dismiss these symptoms as musculoskeletal neck pain – the presence of electric shock sensations with neck movement indicates cord involvement and requires neurological workup 1
• Do not delay imaging in patients with neurological symptoms, as progressive cord compression can lead to permanent deficits 2, 5
• Recognize that cervical stenosis may be developmental and asymptomatic until a minor injury precipitates symptoms 2
• Be aware that neurological symptoms may be transient initially but can progress to permanent dysfunction if the underlying pathology is not addressed 2, 5