This document discusses classifications of pain. It defines pain according to several organizations and researchers. It notes the historical understanding of pain from Greek, Latin, and early philosophers' perspectives. It then describes types of pain based on speed of onset and duration, including experimental, transient, acute, and chronic pain. It also discusses types based on stimulation level, including somatic and visceral pain. The document outlines specific pains such as headaches, toothaches, and trigeminal neuralgia. It concludes by defining abnormal pains including hyperalgesia, allodynia, hyperpathia, and phantom limb pain.

1. CLASSIFICATION OF
PAIN
By: Dr. Vahid Nikoui
Email:

2. DEFINITIONS OF PAIN
 International Association for the Study of Pain (IASP)
(WHO)
An unpleasant emotional experience associate with actual
or potential tissue damage or described in terms of such
damage.
 Bell
The subject‟s conscious perception of modulated
nociceptive impulses that generate an unpleasant sensory
and emotional experiences associated with actual or
potential tissue damage or described in terms of such
damage.
 Monheim
An unpleasant emotional experience usually initiated by
noxious stimulus and transmitted over a specialized
neural network to CNS where it is interpreted as such.
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 Mac bryde

3. HISTORICAL NOTE
 Greek - “Poin” meaning penalty.
 Latin -“Poena” meaning punishment from
God.
 Homer - Thought pain was due to arrows
shot by God.
 Aristotle - was the first to distinguish five
physical senses, and considered pain to be
“passion of the soul” .
 Plato - pain and pleasure arose from within
the body, an idea that perhaps gave birth to
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the concept that pain is an emotional
experience more than a localized body

4. Nociception
 Nociception (synonym: nocioception or nociperception) is
defined as "the neural processes of encoding and
processing noxious stimuli. "
Nociceptor
 A nociceptor is a sensory receptor that responds to
potentially damaging stimuli by sending nerve signals to
the spinal cord and brain.
Noxious
 Noxious stimulus, an actually or potentially tissue
damaging event, may be mechanical, chemical or
thermal.
Algesia
 Algesia, from the Greek word algesis, is the sensitivity to
pain.

5. TYPES OF PAIN
1. Based on speed of onset, quality & duration
(1) Experimental (2) Transient (3) Acute
(4) Chronic
1. Experimental:
 noxious stimuli causes a mild uncomfortable or
painful sensation.
2. Transient pain:
 Short duration
 Severe
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 Self limiting

6. 3. Acute pathological pain:
• Sharp, fast, pricking
• Occurs very rapidly
• Carried by large diameter myelinated Aδ fibers
• Usually alleviated with the help of professional
4. Chronic pathological pain:
• Burning, aching
• Gradually increases
• Carried by small diameter non-myelinated „C‟
fibers
• Experience of persistent pain that lasts many
months to years
• Little apparent cause & not self limiting
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• Pain often increases over time & is aggravated by

7. 2.Based on level of stimulation
SOMATIC PAIN VISCERAL PAIN
Associated with skin and Associate with viscera
musculo-skeletal region and internal organs
Superficial Deep
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8. • Inflammatory Pain
tissue injury Prostaglandins &
Bradykinin
Local vasodilatation
&
Capillary permeability
•Non Inflammatory
pain
poorly understood
Receptor noxious
psychic
stimuli
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chronic

9. Referred Pain
 Referred pain (sometimes referred to as
reflective pain) is a term used to describe the
phenomenon of pain perceived at a site
adjacent to or at a distance from the site of an
injury's origin.
 One of the best examples of this is during
ischemia brought on by a myocardial
infarction (heart attack) where pain is often felt
in the neck, shoulders, and back rather than in
the chest, the site of the injury.

10. SPECIFIC PAINS
 Headache
A headache or cephalgia is pain anywhere in the
region of the head or neck. It can be a symptom of a
number of different conditions of the head and neck.
 1- Headache of intracranial origin
Meningitis headache, Migraine, Alcoholic
headache, Headache due to low pressure of
CSF, Constipation headache
 2- Headache of extracranial origin
Headache due to muscular spasm, Headache due to
nasal irritation, Headache due to eye disorders

11.  Toothache
A toothache, also known as odontalgia or, less
frequently, as odontalgy, is a pain in or around a tooth.
In most cases toothaches are caused by problems in
the tooth or jaw, such as cavities, gum disease, the
emergence of wisdom teeth, infected dental pulp, jaw
disease, or exposed tooth root.

12.  Trigeminal neuralgia
Trigeminal neuralgia (TN), Tic Douloureux (also
known as prosopalgia, the 'Suicide Disease' or
'Fothergill‟s disease) is a neuropathic disorder
characterized by episodes of intense pain in the
face, originating from one of the three trigeminal
nerves.
It is, "one of the most painful conditions known to
humans, yet remains an enigma to many health
professionals."
This pain may be felt in the ear, eye, lips, nose,
scalp, forehead, cheeks, teeth, and/or jaw; some
patients also experience pain in their left index
finger.

13. ABNORMAL PAINS
 Hyperalgesia
Hyperalgesia is an increased sensitivity to pain, which may be
caused by damage to nociceptors or peripheral nerves.
 Allodynia
Allodynia, meaning "other pain", is a pain due to a stimulus
which does not normally provoke pain and can be either
thermal or mechanical.
 Hyperpathia
Hyperpathia is a clinical symptom of certain neurological
disorders wherein nociceptive stimuli evoke exaggerated
levels of pain.
 Phantom Limb Pain
A phantom limb is the sensation that an amputated or missing
limb is still attached to the body and is moving appropriately
with other body parts.

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