Onset most commonly occurs between the ages of 25
and 40 years, but it can be earlier. First sign is usually paresthesias in
the upper limbs; then loss of pain and temperature sensation in a
characteristic distribution, usually “suspended,” involving arms and trunk
but not legs (because of lesion to the posterior horns and the fascicle of Lissauer
sensory fibers). The progression is very slow. Other clinical features can be
observed that involve neurological function: autonomic pathways such as
Horner Syndrome, skin trophic changes, neurogenic bladder, reduced or absent
reflex in arms, and bilateral Babinski signs. Spastic paraparesis can occur.
Scoliosis is frequent.