Excerpted from "When the Pain Never Goes Away," Stroke Connection Magazine September/October 2003
It’s difficult to leap from peripheral pain, or motor pain to central pain syndrome, or CPS. With peripheral pain, the sensation is experienced immediately at the site of the injury. Central pain response may be delayed.
An injured motor nerve carries less current, but an injured pain nerve does exactly the opposite. Its signal increases, but it’s not a simple increase. Pain nerves eventually gain the power to influence uninjured neighbor neurons, which begin firing independently. The process can become so violent that the thalamus, the brain’s pain center, records “bursts” of impulses from these injured nerves.
After sufficient bombardment threatens neuron death in the thalamus, this pain center “shuts down.” Central pain apparently occurs at this point. It’s as if the entire pain system is acting like a nerve ending. These pain signals reach the cortex of the brain, causing unbearable suffering.
For many, intense episodes are stimulated by something as simple as a very light touch. Many who experience CPS have to wear light, abbreviated clothing because they simply can’t stand the touch of anything on their skin. Dr. McHenry is hardly able to sleep at night because the touch of the sheets causes pain.
Patients may not feel any sensation in a limb when touched, but can feel constant pain. Other survivors with CPS may report reduced sensation, the inability to feel normal stimuli, while feeling a constant burning.
“All the pain is central because you experience it in your central nervous system,” says Dr. Thomas Swift, president of the American Academy of Neurology, “Central pain syndrome is a convenient term doctors use to refer to a lesion in the brain or spinal cord. This pain has characteristics that are different: unrelenting, very severe, with peculiar qualities – the skin is coming off, boring into the bone marrow. There are people with CPS who commit suicide because of the pain.”
Although there is no official scale of pain intensity, there seems to be a continuum of CPS pain. Dr. McHenry and Robert are at the extreme end, at levels 9-10, while others report constant pain of less intensity and are capable of managing it to varying degrees.