Lhermitte’s sign is an electric shock-like sensation that travels down the spine. This article explores its characteristics and implications, clarifying any perceived danger.
Understanding Lhermitte’s Sign
Lhermitte’s sign, sometimes called Lhermitte’s phenomenon or the “barber chair phenomenon,” is a transient sensation. It typically feels like an electric shock, buzzing, or tingling that originates in the neck and radiates down the spine, often extending into the arms, legs, and occasionally the trunk. This sensation is usually brief, lasting only a few seconds. The primary trigger is neck flexion, such as bending the head forward. Other actions like coughing, sneezing, or yawning can also elicit this sensation. Lhermitte’s sign is a symptom, not a disease, resulting from the stimulation of irritated or damaged nerves in the spinal cord.
Underlying Causes and Significance
Lhermitte’s sign is not inherently dangerous or life-threatening. However, its appearance indicates an underlying condition affecting the spinal cord, specifically nerves in the cervical (neck) region. The sensation arises from damage to the myelin sheath, the protective covering around nerve fibers, which disrupts normal electrical signal transmission. When this myelin is compromised, neck movements can cause affected nerves to overreact, sending a shock-like signal.
The conditions causing Lhermitte’s sign vary in significance. Less serious causes include neck injury, cervical spondylosis (arthritis in the neck), or vitamin B12 deficiency. Radiation therapy to the cervical spine or certain chemotherapy treatments can also lead to this symptom. For many individuals, Lhermitte’s sign can be a temporary symptom that resolves over time.
More serious neurological conditions are also associated with Lhermitte’s sign, including multiple sclerosis (MS), transverse myelitis, and spinal cord compression caused by tumors or herniated discs. In MS, Lhermitte’s sign is a common symptom, occurring due to demyelination in the spinal cord. While the sign itself is not harmful, these underlying conditions may require investigation and management.
When to Consult a Doctor
Experiencing Lhermitte’s sign, especially for the first time or without a known cause, warrants medical evaluation. It is important to seek professional advice to determine the underlying reason and rule out any serious conditions. A doctor can assess the symptom in the context of your overall health and medical history.
Medical attention is particularly important if Lhermitte’s sign is new, persistent, or worsening. Individuals should also consult a doctor if the sensation is accompanied by other neurological symptoms. These include weakness, numbness, balance issues, vision changes, or problems with bladder or bowel function. While no specific test exists for Lhermitte’s sign itself, a healthcare provider may recommend diagnostic imaging, such as an MRI of the cervical spine, or blood tests to identify the cause. This comprehensive evaluation helps assess the symptom’s significance and guide appropriate management.