Table of Contents
Introduction: The Universal Disorder
You know it at once. It may be the fiery sensation of a burn moments
after your finger touches the stove. Or it's a dull ache above your
brow after a day of stress and tension. Or you may recognize it as a
sharp pierce in your back after you lift something heavy.
It is pain. In its most benign form, it warns us that something
isn't quite right, that we should take medicine or see a doctor. At its
worst, however, pain robs us of our productivity, our well-being, and,
for many of us suffering from extended illness, our very lives. Pain is
a complex perception that differs enormously among individual patients,
even those who appear to have identical injuries or illnesses.
In 1931, the French medical missionary Dr. Albert Schweitzer
wrote, "Pain is a more terrible lord of mankind than even death
itself." Today, pain has become the universal disorder, a serious and
costly public health issue, and a challenge for family, friends, and
health care providers who must give support to the individual suffering
from the physical as well as the emotional consequences of pain.
A Brief History of Pain
Ancient civilizations recorded on stone tablets accounts of pain
and the treatments used: pressure, heat, water, and sun. Early humans
related pain to evil, magic, and demons. Relief of pain was the
responsibility of sorcerers, shamans, priests, and priestesses, who
used herbs, rites, and ceremonies as their treatments.
The Greeks and Romans were the first to advance a theory of
sensation, the idea that the brain and nervous system have a role in
producing the perception of pain. But it was not until the Middle Ages
and well into the Renaissance-the 1400s and 1500s-that evidence began
to accumulate in support of these theories. Leonardo da Vinci and his
contemporaries came to believe that the brain was the central organ
responsible for sensation. Da Vinci also developed the idea that the
spinal cord transmits sensations to the brain.
In the 17th and 18th centuries, the study of the body-and the
senses-continued to be a source of wonder for the world's philosophers.
In 1664, the French philosopher René Descartes described what to this
day is still called a "pain pathway." Descartes illustrated how
particles of fire, in contact with the foot, travel to the brain and he
compared pain sensation to the ringing of a bell.
In the 19th century, pain came to dwell under a new domain -
science - paving the way for advances in pain therapy.
Physician-scientists discovered that opium, morphine, codeine, and
cocaine could be used to treat pain. These drugs led to the development
of aspirin, to this day the most commonly used pain reliever. Before
long, anesthesia-both general and regional-was refined and applied
"It has no future but itself," wrote the 19th century American
poet Emily Dickinson, speaking about pain. As the 21st century unfolds,
however, advances in pain research are creating a less grim future than
that portrayed in Dickinsons verse, a future that includes a better
understanding of pain, along with greatly improved treatments to keep
it in check.
The Two Faces of Pain: Acute and Chronic
What is pain? The International Association for the Study of
Pain defines it as: An unpleasant sensory and emotional experience
associated with actual or potential tissue damage or described in terms
of such damage.
It is useful to distinguish between two basic types of pain, acute and chronic, and they differ greatly.
- Acute pain, for the most part, results from disease,
inflammation, or injury to tissues. This type of pain generally comes
on suddenly, for example, after trauma or surgery, and may be
accompanied by anxiety or emotional distress. The cause of acute pain
can usually be diagnosed and treated, and the pain is self-limiting,
that is, it is confined to a given period of time and severity. In some
rare instances, it can become chronic.
- Chronic pain is widely believed to represent
disease itself. It can be made much worse by environmental and
psychological factors. Chronic pain persists over a longer period of
time than acute pain and is resistant to most medical treatments. It
canand often doescause severe problems for patients.
From "Pain: Hope Through Research"
NIH Publication No. 01-2406
Last updated November 04, 2004