Overview of Lhermitte's Sign

You may have heard your doctor mention Lhermitte's sign. What is this sign and what does it mean?

People who have experienced nerve pain as a result of any injury or condition know the jarring discomfort it causes. Lhermitte's sign is a flare up of neuropathic pain that has unique features, causes and management.

Lhermitte's sign is a sense of electricity that shoots down the spine from the head towards the feet, and often out through the arms, legs and appendages. It is often brought on by flexing the neck so that the chin moves towards the chest. Also known as barber chair phenomenon, it is thought to indicate dysfunction of the dorsal columns of the cervical spinal cord, which are responsible for transmitting information about light touch, proprioception (the sense of where your body is in space), and vibration to the brain.

Despite being called "Lhermitte's sign," the first people who described this phenomenon were Pierre Marie and Chatelin in 1917. Jean Lhermitte was a French neurologist who published an article on the subject in 1924, which led to wider knowledge about the symptom.

Lhermitte's sign has classically been thought of as a sign of multiple sclerosis (MS) and, indeed, any patient presenting with Lhermitte's sign will most likely undergo a thorough workup to exclude that disease. In patients with MS, the immune system attacks the coatings of nerves, called myelin. When the myelin wears away, scar tissue can form, which blocks the nerve signals that travel throughout the brain and spinal cord. 

In addition to multiple sclerosis, Lhermitte's sign can be the result of many other problems. These may include:

• Vitamin B12 deficiency (myelinopathy from B12 deficiency)
• Transverse myelitis
• Cervical spinal cord tumors
• Spondylosis
• Nitrous oxide toxicity (with nitrous oxide toxicity there is often a "reverse Lhermitte's sign, in which the electrical sensation travels in the opposite direction, from the feet toward the head

While it isn't dangerous in and of itself, Lhermitte's sign can cause debilitating discomfort. Treatment should first be aimed at addressing any underlying conditions that are causing or exacerbating the problem. For patients with MS, ensuring they don't become overtired or overheated can help avoid triggering Lhermitte's sign.

Certain lifestyle and noninvasive approaches can help prevent an attack, including

• Spinal cord stimulation - Electrical stimulating devices that send low-voltage electricity to the nerves, either from outside the body or through an implantable device (TENS units) may help.
• Posture adjustment and alignment - It's important to have a therapist assist you in learning these measures as some exercise may actually worsen the symptoms.
• Neck braces or collars that prevent head movements that can trigger the pain.
• Acupuncture, massage and other relaxation techniques.
• Breathing exercises such as deep breathing exercises.
• Stretching

In addition, for patients with Lhermitte's sign, certain medications can help manage pain, including:

• Antiseizure drugs (anticonvulsants) - Medications such as Neurontin (gabapentin) and Lyrica (pregabaline) among others may help with neuropathic pain such as Lhermitte's sign.
• Antidepressants - The category of antidepressants referred to as tricyclic antidepressants may sometimes help with chronic pain. These are used not because pain is felt to be secondary to depression but due to a different mechanism of these drugs.
• Sodium channel blockers.
• Steroids - Oral steroids have significant side effects when used long term, but may be used for an acute flare of pain.

Coping with chronic pain of any type is more than difficult. In addition to often requiring a number of modalities to treat symptoms, chronic pain can cause psychological and social havoc as well.

Keeping a pain journal is extremely helpful in determining what may be working and what may not. Treatments, such as anticonvulsants can take a while to work, and it can be difficult to know if a change in your symptoms is due to a treatment or something else. A pain journal can be as simple as writing down a number every day (for example, a 1 for minimal pain and a 10 for the worst pain you can imagine), listing the medications you used, and outlining what activities you did that day. Standing back and looking at your journal later on can help you see the big picture and assess your treatment approach.

Seek out others who are coping with the same condition you are. If you have an uncommon condition, you may need to go online to find others with the same disease. Knowing that there are others out their coping with the same challenges can make you feel a little less alone with your symptoms and provides a source of support from those who can truly understand what you are facing.

Seek help for depression. There is a strong link between chronic pain and depression, and each of these conditions can also exacerbate the other. It's not a sign of weakness to seek out help for depression but rather a sign of strength in doing what you need to do to feel as good as possible.

Practice relaxation. Stress can make anything we face more difficult, and various relaxation exercises have been shown to diminish stress in our lives. Check out these relaxation tips for managing chronic pain.

_Sources:

_{Ko, H., Powers, A., Sheu, R. et al. Lhermitte’s Sign Following VMAT-Based Head and Neck Radiation—Insights into Mechanism. PLoS One. 2015. 10(10):e0139448.}

_{Lhermitte JJ, Bollak NM. Les douleurs à type décharge électrique consécutives à la flexion céphalique dans la sclérose en plaques. Un cas de la sclérose multiple. Revue neurologique 1924; 2:56-57.}

_{Yakovlev, A., and A. Parmentier. Resolution of Lhermite’s Sign with Spinal Cord Stimulation. Pain Medicine. 2014. 15(1):167-9.}