Lhermitte phenomenon, also called the barber chair phenomenon, is an uncomfortable "electrical" sensation that runs through the back and into the limbs. The sensation can feel like it goes up or down the spine. It is painful for some, although others might simply feel strange sensations. In many people, it is elicited by bending the head forward. It can also be evoked when a practitioner pounds on the

cervical spine In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sa ...

while the neck is flexed; this is caused by involvement of the posterior columns. Lhermitte phenomenon is named after the French neurologist Jean Lhermitte. __TOC__

Associated conditions

The sign suggests a lesion or compression of the upper cervical spinal cord or lower brainstem—usually dorsal columns of the cervical cord or caudal medulla. Although often considered a classic finding in multiple sclerosis, it can be caused by a number of conditions, including transverse myelitis,

Behçet disease Behçet is a Turkish name and may refer to: Given name * Behçet Cantürk, Turkish mob boss * Behçet Necatigil, Turkish author and poet * Behçet Uz, Turkish politician and doctor Surname * Hulusi Behçet, Turkish dermatologist and scientist Ot ...

osteogenesis imperfecta Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may b ...

, trauma, radiation

myelopathy Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, '' cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results from narrowing of the spina ...

vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...

deficiency (

subacute combined degeneration Subacute combined degeneration of spinal cord, also known as myelosis funiculus, or funicular myelosis, also Lichtheim's disease, and Putnam-Dana syndrome, refers to degeneration of the posterior and lateral columns of the spinal cord as a resul ...

), compression of the spinal cord in the neck from any cause such as cervical spondylosis, disc herniation, tumor, and

Arnold–Chiari malformation Chiari malformation (CM) is a structural defect in the cerebellum, characterized by a downward displacement of one or both cerebellar tonsils through the foramen magnum (the opening at the base of the skull). CMs can cause headaches, difficul ...

. Lhermitte's sign may also appear during or following high-dose

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...

. Irradiation of the

may also evoke it as an early delayed radiation injury, which occurs within 4 months of

radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Rad ...

. Delayed onset Lhermittes sign has been reported following head and/or neck trauma. This occurs ~2 1/2 months following injury, without associated neurological symptoms or pain, and typically resolves within 1 year. This sign is also sometimes seen as part of a " discontinuation syndrome" associated with certain psychotropic medications, such as selective serotonin reuptake inhibitors and serotonin norepinephrine reuptake inhibitors, particularly

paroxetine Paroxetine, sold under the brand names Paxil and Seroxat among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used to treat major depressive disorder, obsessive-compulsive disorder, panic disorder ...

and

venlafaxine Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin-norepinephrine reuptake inhibitor (SNRI) class. It is used to treat major depressive disorder, generalized anxiety disorder, panic di ...

. Typically, it only occurs after having taken the medication for some duration, and then stopped or withdrawn rapidly or after administering reduced dose.

Fluoxetine Fluoxetine, sold under the brand names Prozac and Sarafem, among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used for the treatment of major depressive disorder, obsessive–compulsive disorde ...

, given its very long half-life, can be given as a single small dose, and often avoid Lhermitte's sign and other withdrawal symptoms. In the dental field, three studies (Layzer 1978, Gutmann 1979, Blanco 1983) have identified Lhermitte sign among

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has ...

abusers. This is likely due to nitrous oxide depletion of vitamin B₁₂ leading to a very severe, rapid deficiency in the absence of supplementation.

Terminology

Lhermitte sign is not attributed to its discoverer. It was first described by Pierre Marie and Chatelin in 1917. Jean Lhermitte, a French neurologist and neuropsychiatrist, did not publish his first report until 1920. However, in 1924 he did publish the seminal article on the subject which resulted in it becoming well known.

References

{{DEFAULTSORT:Lhermitte's Sign Symptoms and signs: Nervous system Multiple sclerosis