Lhermitte’s Sign
Lhermitte’s Sign
Lhermitte’s sign, or the "barber’s chair syndrome", is a painless but unpleasant tingling or electric shock-like sensation in the back and spreading instantaneously down the arms and legs following neck flexion (active or passive). It is associated with pathology within the cervical spinal cord. Although most commonly encountered (and originally described in) demyelination, it is not pathognomonic of this condition, and has been described with other local pathologies, such as:
subacute combined degeneration of the cord (vitamin B12 deficiency); nitrous oxide (N2O) exposure
traumatic or compressive cervical myelopathy (e.g., cervical spondylotic myelopathy)
epidural/subdural/intraparenchymal tumor radiation myelitis
pyridoxine toxicity
inflammation, e.g., systemic lupus erythematosus, Behçet’s disease cervical herpes zoster myelitis
cavernous angioma of the cervical cord
Pathophysiologically, this movement-induced symptom may reflect the exquisite mechanosensitivity of axons which are demyelinated, or damaged in some other way.
A "motor equivalent" of Lhermitte’s sign, McArdle’s sign, has been described, as has "reverse Lhermitte’s sign", a label applied either to the aforementioned symptoms occurring on neck extension, or in which neck flexion induces electrical shock-like sensation traveling from the feet upward.
References
Lhermitte J, Bollack J, Nicolas M. Les douleurs à type de décharge electrique consécutives à la flexion céphalique dans la sclérose en plaques: un case de forme sensitive de la sclérose multiple. RevueNeurologique 1924; 39: 56-62
Pearce JMS. Lhermitte’s sign. In: Pearce JMS. Fragments of neurolog-ical history. London: Imperial College Press, 2003: 367-369
Smith KJ. Conduction properties of central demyelinated axons: the generation of symptoms in demyelinating disease. In: Bostock H, Kirkwood PA, Pullen AH (eds.). The neurobiology of disease: contributions fromneuroscience to clinical neurology. Cambridge: CUP, 1996: 95-117
Cross References
