Causes
Many medical conditions or injuries can cause chronic pain. Some people
will continue to experience pain long after recovering from an initial injury
such as a back injury. Other chronic pain is caused by chronic diseases such
as arthritis or cancer. Some people have pain that does not have an identifiable
cause. This is not to say that the pain is not real. Whatever the cause, chronic
pain is real, and should be treated.
The following conditions may be associated with chronic pain:
- cancer
- fibromyalgia
- spinal injury
- headaches
- back injury
- arthritis
- nerve inflammation or damage
Sometimes pain can be felt in a part of the body that is no longer there. This
is called phantom limb pain, and develops as a result of amputation.
When pain in one part of the body is felt in another part of the body, it is
called referred pain.
Acute pain results when a disease or injury sends a signal to special sensory
nerve endings called nociceptors. Nociceptors are located in the
skin, as well as in other structures including blood vessels and tendons. The
internal organs are not very responsive to pain. Pain signals travel from the
nociceptors, through the sensory nerves, and up the spinal cord to the thalamus
in the brain. The signal is then sent to the cerebral cortex, the part of
the brain that processes thought. On the way to the brain, natural body chemicals
can change the pain signal. Substance P makes the pain signal stronger.
Endorphins make it weaker. Pain is not actually felt until the message
or signals get to the brain. Chronic pain can originate at many points in the
above pathway.
The cerebral cortex and the limbic system, which are the brain areas controlling
emotion, process pain signals. How much pain is felt depends on a number
of factors. Factors that increase how badly pain is felt include the following:
- previous bad experiences with pain
- insomnia
- anxiety
- depression
Anxiety can make pain much worse. Not knowing the cause of pain makes
people anxious. The pain often seems less severe once they have a diagnosis
of their medical condition. Worry about the seriousness of their condition can
often also increase the severity of the pain.