Chapter 1 Definitions

Question 1

What is pain?

Answer 1

The International Association for the Study of Pain defines pain as: ‘‘An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in
terms of such damage

Question 2

What is the difference between pain and suffering?

Answer 2

Pain is a sensation plus a reaction to that sensation.

Suffering is a more global concept—an overall negative feeling that impairs the sufferer’s quality of life.

Question 3

What is the difference between impairment and disability?

Answer 3

Impairment is a medical concept; disability is a legal or societal concept. Impairment is any loss or abnormality of psychological, physiologic, or anatomic structure or function.

According to WHO definition, disability results from impairment; it is any restriction or lack of ability to perform an activity in the manner or within the range
considered normal for a human.

Another definition of disability is a disadvantage (resulting from an
impairment or functional limitation) that limits or prevents the fulfillment of a role that is normal for an individual (depending on age, sex, and social and cultural factors).

Question 4

What is meant by inferred pathophysiology?

Answer 4

implies that we understand the basic mechanisms underlying a pain
syndrome, and leads to the pathophysiologic classification of pain syndromes

Question 5

neuropathic pain

Answer 5

a pain

syndrome is more likely due to nerve injury

Question 6

somatic nociceptive pain

Answer 6

a pain syndrome is more likely due of muscle or bone

Question 7

visceral nociceptive pain

Answer 7

a pain syndrome is more likely due of the internal organs

Question 8

What is the definition of nociception?

Answer 8

Nociception is the activation of a nociceptor by a potentially tissue-damaging (noxious) stimulus. It is the first step in the pain pathway.

Question 9

What is a nociceptor?

Answer 9

A nociceptor is a specialized, neurologic receptor that is capable of differentiating between
innocuous and noxious stimuli. In humans, nociceptors are the undifferentiated terminals of
A-delta fibers and C fibers, which are the thinnest myelinated and unmyelinated fibers,
respectively. A-delta fibers are also called high-threshold mechanoreceptors. They respond
primarily to mechanical stimuli of noxious intensity.

Question 10

Pain threshold

Answer 10

the lowest intensity at which a given stimulus is perceived as painful.

Question 11

Pain tolerance

Answer 11

the greatest level of pain that a subject is prepared to endure. pain tolerance is of much more importance than pain threshold

Question 12

allodynia

Answer 12

an abnormal circumstance in which an innocuous stimulus is perceived as painful. It is common in many neuropathic pain conditions, such as postherpetic neuralgia, complex regional pain syndrome, and certain other neuropathies.

Question 13

Two different types of allodynia are described

Answer 13

thermal and mechanical.
In thermal allodynia, an innocuous warm or cold breeze may be perceived as painful.
With mechanical allodynia, a very light touch (such as the clothes rubbing against the skin) may be extremely painful, while
firmer pressure is not.

Question 14

Analgesia

Answer 14

the absence of pain despite the presence of a normally painful stimulus

Question 15

Analgesia can be produced peripherally and centrally

Answer 15

Analgesia can be produced peripherally (at the site of tissue damage, receptor, or nerve) or centrally (in the spinal cord or brain). In general, the nonsteroidal antiinflammatory drugs and other minor analgesics act primarily at the site of tissue damage, whereas opioids and so-called adjuvant
drugs act primarily at the spinal cord or cerebral level.

Question 16

Anesthesia

Answer 16

Anesthesia implies loss of many sensory modalities, leaving the area ‘‘insensate.’’

Question 17

Analgesia

Answer 17

Analgesia refers specifically to the easing of painful sensation.

Question 18

Paresthesia

Answer 18

A paresthesia is any abnormal sensation. It may be spontaneous or evoked.

Question 19

Dysesthesia

Answer 19

A dysesthesia is a painful paresthesia. By definition, the sensation is unpleasant.
Examples: burning feet that may be felt in alcoholic peripheral neuropathy or the spontaneous
pain in the thigh felt in diabetic amyotrophy

Question 20

Hypoesthesia

Answer 20

decreased sensitivity to stimulation. Essentially, it is an area of relative numbness and may be due to any kind of nerve injury. Areas of hypoesthesia are created intentionally by local infiltrations of anesthetics.

Question 21

Formication

Answer 21

a form of paresthesia in which the patient feels as though bugs are crawling on his or her body. It is a common hallucinatory sensation in patients with delirium tremens.

Question 22

Anesthesia dolorosa

Answer 22

a syndrome in which pain is felt in an area that is otherwise numb or
desensitized. It commonly occurs after partial nerve lesions and is a typical complication of
radiofrequency coagulation of the trigeminal nerve

Question 23

Neuralgia

Answer 23

a clinically descriptive term that refers to pain in the distribution of a nerve or nerves.

Question 24

Trigeminal neuralgia

Answer 24

characterized by a jabbing pain in

one or more of the distributions of the trigeminal nerve.

Question 25

Neuralgic pain

Answer 25

fairly characteristic:

it is an electrical, shocklike pain.

Question 26

Hyperpathia

Answer 26

refers to an abnormally intense pain response to repetitive stimuli. Usually the hyperpathic area of skin is not sensitive to a simple stimulus but overresponds to multiple stimuli. Hyperpathia is sometimes called summation dysesthesia

Question 27

Algogenic substances

Answer 27

when released from injured tissues or injected subcutaneously, activate
or sensitize nociceptors (algos ¼ pain). Histamines, substance P, potassium, and prostaglandins are examples of algogenic substances.

Question 28

Sensitization

Answer 28

Sensitization is a state in which a peripheral receptor or a central neuron either responds to
stimuli in a more intense fashion than it would under baseline conditions or responds to a stimulus to which it is normally insensitive. Sensitization occurs both at the level of the
nociceptor in the periphery and at the level of the second-order neuron in the spinal cord

Question 29

What is a ‘‘lancinating’’ pain? What does its presence imply?

Answer 29

Lancinating literally means ‘‘cutting.’’ It is a sharp, stabbing pain that is often associated with
neuropathic syndromes

Question 30

Deafferentation

Answer 30

implies the loss of normal input from primary sensory neurons. It may occur after any type of peripheral nerve injury. Deafferentation is particularly common in postherpetic
neuralgia and in traumatic nerve injuries. The central neuron on which the primary afferent
was to synapse may become hyperexcitable.

Question 31

gate control theory of pain

Answer 31

are that activity in large (nonnociceptive) fibers can inhibit the perception of activity in small (nociceptive) fibers and that descending activity from the brain also can inhibit that perception. Given this construct, it is easy to
understand why deafferentation may cause pain. If the large fibers are preferentially injured, the
normal inhibition of pain perception does not occur.

Question 32

‘‘breakthrough’’ pain

Answer 32

If a patient has good pain control on a stable analgesic regimen and suddenly develops an acute
exacerbation of pain, this is referred to as breakthrough pain. It often occurs toward the end
of a dosing interval because of a drop in analgesic levels.

Question 33

‘‘Incident’’ pain

Answer 33

a type of breakthrough pain that occurs either with a maneuver that would normally exacerbate pain (weight bearing on an extremity with a bone metastasis) or with sudden disease exacerbation (hemorrhage, fracture, or expansion of a hollow viscus).

Question 34

Pain resulting from falling analgesic levels is best controlled by

Answer 34

increasing the dose or

shortening the intervals between doses.

Question 35

Incident pain, on the other hand, is usually best handled by

Answer 35

administering an extra dose of an analgesic before the exacerbating activity.

Question 36

Tabetic pain

Answer 36

a complication of syphilis. It is a sharp, lightning type of pain. Also called lancinating pain,

Question 37

central pain

Answer 37

applied when the generator of the pain is believed to be in the
spinal cord or the brain. The original insult may have been peripheral (nerve injury or
postherpetic neuralgia), but the pain is sustained by central mechanisms. Central pain also may occur after central injuries, such as strokes or spinal cord injuries. The pain tends to be poorly localized and of a burning nature.

Question 38

referred pain

Answer 38

Pain in an area removed from the site of tissue injury is called referred pain. The most
common examples are pain in the shoulder from myocardial infarction, pain in the back from
pancreatic disease, and pain in the right shoulder from gallbladder disease

Question 39

presumed mechanism of referred pain

Answer 39

afferent fibers from the site of tissue injury enter the spinal cord at a similar level to afferents from the point to which the pain is referred. This conjoint area in the spinal cord results in the mistaken perception that the pain arises from the referral site.

Question 40

Phantom pain

Answer 40

pain felt in a part of the body that has been surgically removed.

Question 41

Meralgia paresthetica

Answer 41

syndrome of tingling discomfort (dysesthesias) in an area of nerve
injury, most commonly the lateral femoral cutaneous nerve. It is characterized by a patch of
decreased sensation over the lateral thigh; this area is dysesthetic. Meralgia paresthetica may be caused by more proximal nerve compression.

Question 42

difference between fast pain and slow pain

Answer 42

Fast pain is a relatively localized, well-defined pain that is carried in the neospinothalamic tract.
Slow pain is more diffuse and poorly localized and presumed to be carried in the
paleospinothalamic tract. In the periphery, C fibers generally subserve slow pain and A-delta
fibers subserve fast pain.

Question 43

difference between primary and secondary pain syndromes

Answer 43

In primary pain syndromes, the pain itself is the disease. Examples include migraine, trigeminal neuralgia, and cluster headache. A secondary pain syndrome is due to an underlying
structural cause—for example, trigeminal neuralgia due to a tumor pressing on the cranial
nerve

Question 44

One of the major diagnostic issues in any primary pain syndrome is to

Answer 44

exclude an underlying destructive cause (tumor or infection).

Question 45

palliative care

Answer 45

The WHO defines palliative care as ‘‘the active total care of patients, controlling pain and
minimizing emotional, social, and spiritual problems at a time when disease is not responsive to
active treatment.

Question 46

addiction

Answer 46

‘‘a primary, chronic neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving.’’

Question 47

According to the WHO, addiction is

Answer 47

‘‘a state, psychic and sometimes also physical, resulting
from the interaction between a living organism and a drug, characterized by behavioral and
other responses that always include a compulsion to take the drug on a continuous or periodic
basis in order to experience its psychic effects, and sometimes to avoid the discomfort of its
absence. Tolerance may or may not be present.

Question 48

Physical dependence

Answer 48

a state of adaptation that is manifested by a drug class–specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction,
decreasing blood level of the drug, and/or administration of an antagonist.

Question 49

Drug tolerance

Answer 49

a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug’s effects over time.

Question 50

Pseudoaddiction

Answer 50

an iatrogenic syndrome of abnormal behavior developing as a direct consequence of inadequate pain management. Treatment strategies include establishing trust between the patient and the health care team and providing appropriate and timely analgesics to control the patient’s level of pain.