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Lhermitte’s sign is a physical exam maneuver that is considered to have a positive result when a patient experiences an electric-like shooting pain that radiates from the back of the neck down the back when the neck is bent forward by a physician or other health care professional. When patients have this symptom sporadically at other times, it is called the barber chair phenomenon or Lhermitte’s phenomenon. Although the sign is most closely associated with a disease called multiple sclerosis, it can be caused by a variety of diseases that affect the part of the nervous system located in the region of the neck. There is no specific treatment for the condition, but patients might experience a reduction in the symptom with the treatment of its underlying cause.
Many patients who have a positive Lhermitte’s sign on physical exam describe the pain as a shooting, tingling, shock-like sensation. The pain typically starts in the back of the neck and spreads in a downward direction, affecting the back, arms, spine, and even the legs. Often the pain is present for only seconds. Some doctors or health care providers can also trigger the sensation by tapping on the back of the neck while the patient is bending his neck forward.
The disease most commonly associated with Lhermitte’s sign is multiple sclerosis (MS). This condition occurs when the parts of the nervous system that insulate the nerves are attacked and destroyed by cells of the body’s immune system. It can cause a variety of neurologic deficits that can come and go over time.
A variety of other conditions can also cause a patient to have Lhermitte’s sign. Any disease that affects the nerve roots exiting the spinal cord in the neck region or any disease that affects the spinal cord in this region could cause the symptom to occur. Conditions as common as osteoarthritis, which occurs with advancing age due to the chronic wear and tear of joints, can cause the symptom. Rarer causes can include vitamin B12 deficiency, administration of high-dose chemotherapy, and transverse myelitis.
There is no specific treatment for having a positive Lhermitte’s sign. It can improve, however, by determining the underlying cause for the sign and treating that underlying disease. Patients who present with this complaint might undergo a further medical workup, including radiologic imaging of the neck region or tests that measure the speed of conduction of signals through the nerves. If a full workup fails to recognize the cause of the pain, doctors can elect to continue to monitor the patient for further signs of disease. Some physicians might choose to treat the pain symptom with medications that decrease the patient’s sensitivity to pain originating in the nerves.