L'hermitte's Phenomenon - The sensation of a very sudden pain like an electric shock
that spreads from the neck and down the arms, spine and legs. It's usually triggered
by flexing the neck - that is, bending your head down, chin towards chest. The sensation
is short-lived, usually no more than a second.
The sign is named for a French neurologist, Jean Lhermitte (1877-1959) who originally
described it in a patient with multiple sclerosis (MS). It is a classic sign of MS.
How often the symptom occurs, and what other symptoms develop along with it, depends
on the underlying cause, of which there are several.
L'hermitte's Phenomenon is a sign that something may be damaging the spinal cord.
This damage is usually in the neck or region of the spine known as the cervical spine.
The symptom is very non-specific and says nothing about exactly where in the spinal
cord the problem is, or what is damaging it.
Causes include:
Cervical Spondylosis.
Multiple sclerosis.
Vitamin B12 deficiency (pernicious anaemia).
Tumours.
Compression of the discs in the cervical spine following trauma.
Radiotherapy to the neck.
However, in many cases a specific cause can't be found.
