Chronic
pain, on the other hand, is defined as pain which occurs on
most days and last for anything from 3 months to many years. AS is associated
with the experience of chronic pain. In AS, the intensity of chronic
pain varies within and between people. For example, many people
report that they have good days where the pain is minimal, and ‘flare
up’ days or weeks where the pain is at its most severe.
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Chronic
Pain
Now you
understand the difference between chronic and acute pain we will describe
the two different types of chronic pain.
Nociceptive
pain occurs when there is clear damage to tissue. Nociceptive simply
means ‘causing pain’. AS is an example of nociceptive pain.
Neuropathic
pain is the other type of chronic pain and results from damage to the
nerves, spinal cord or the brain. A common example of neuropathic pain
is shingles, which occurs after an infection with the chicken pox virus.
The pain experienced is often described as a burning sensation,
a sharp pain or tingling feeling.
In reality,
many pain conditions can involve a combination of nociceptive and neuropathic
pain.
How
do we feel pain
Structures
There are
a number of structures within the body which contribute to our sensations
of pain. Within our bodies there are millions of sensors called nocireceptors.
- Nocireceptors
are, simply, sensory receptors which respond to pain and painful stimuli.
When tissue has been damaged, messages are sent along the nerves to
the spinal cord.
- The
spinal cord plays a very important part in our perception
of pain. The spinal cord is a collection of specialised nerves and
cells that lie within the spine. At the base of the skull the spinal
cord is connected to an area we call the brain stem,
which is the lower part of the brain. Not every pain message reaches
the brain, however, all messages reach the spinal cord which is where
some messages may be blocked.
- The
brain is the main structure involved in the way we try to
make sense of pain. The brain helps us to judge where the pain is
coming from, which reaction to take towards the brain and how we experience
pain. The brain is also the structure where thoughts, anxieties and
emotions about pain may start.
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Pain
theory
In 1965
two scientists called Professor Melazack and Professor Patrick Wall,
suggested that there was a ‘gate’ within the spinal cord
which allowed messages to pass through to the brain. However, this
‘gate’ could close in response to other messages sent through
the spinal cord. An example is messages sent by the nerves that respond
to pressure or touch. Once the ‘gate’ is closed pain messages
will not reach the brain and the sensation of pain will not be experienced.
It is easier to understand with an example.
If
we bang our elbow we tend to rub it. This is almost an automatic response.
The sensation of rubbing our throbbing elbow takes away or lessens the
sensation of pain by striking other nerves which results in the gate
closing.
A key thing
to remember is that we cannot make the ‘gate’ open or close.
However, when the brain receives other messages or signals, as in the
above example, the pain becomes less intense.
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