Lhermitte’s sign describes a distinct sensation, often likened to an electric shock, that travels down the spine and into the limbs. This phenomenon is a symptom, not a disease, indicating an underlying nervous system issue. Understanding this sensation is important for those who experience it.
The Sensation Described
Lhermitte’s sign often begins with a sudden, intense jolt, similar to a brief electrical shock. This feeling typically originates in the neck or upper back and can rapidly propagate downwards, extending through the spine and often into the arms, legs, fingers, or toes. Individuals might also describe it as a buzzing, tingling, or vibrating sensation, varying in intensity.
This distinctive sensation is transient, meaning it usually lasts only for a few seconds. Despite its brief duration, the intensity can be quite startling and uncomfortable. The feeling is often compared to hitting one’s “funny bone” or touching a live wire. It can occur unexpectedly, even multiple times throughout a day.
What Triggers the Sensation
Lhermitte’s sign is most commonly triggered by specific movements of the head and neck. The primary action that elicits this sensation is flexing the neck forward, such as bending the head towards the chest. This movement can stretch or compress the spinal cord in the neck region, leading to the electrical sensation.
Other movements can also sometimes trigger Lhermitte’s sign, including extending the neck backward, coughing, sneezing, or yawning. The sensation usually resolves quickly once the triggering movement ceases. Factors like fatigue, stress, or exposure to heat can sometimes make individuals more susceptible.
Conditions Associated with Lhermitte’s Sign
Lhermitte’s sign is a neurological symptom associated with various underlying medical conditions, rather than being a standalone diagnosis. It often arises from damage or irritation to the nerves within the cervical spinal cord, particularly the myelin sheath. When this protective covering is compromised, nerve signals can become disrupted, leading to the electrical sensation upon movement.
Multiple sclerosis (MS) is one of the most common conditions linked to Lhermitte’s sign, with many individuals experiencing it. However, it is not exclusive to MS and can appear in other demyelinating disorders, such as neuromyelitis optica. Spinal cord compression, which can result from issues like a herniated disc, tumors, or cervical spondylosis, is another frequent cause.
Other conditions that can lead to Lhermitte’s sign include severe vitamin B12 deficiency. Radiation myelopathy, a side effect of radiation therapy to the head or neck, can also cause this symptom. Spinal cord injury or inflammation, and even discontinuation of certain antidepressant medications, have also been associated with Lhermitte’s sign.
When to Seek Medical Guidance
If you experience Lhermitte’s sign, it is advisable to consult a healthcare professional. While the sensation itself is not dangerous, it indicates a potential underlying issue that warrants investigation. A medical evaluation is necessary to determine the specific cause of the symptom and to rule out any serious conditions.
A doctor can conduct examinations and tests, such as imaging studies, to identify the origin of the sensation. Self-diagnosis is not recommended, as professional medical advice is essential for proper management and to address any health concerns. Early evaluation can help in understanding the cause and discussing potential management strategies.