Acute Pain 
- The normal, predicted physiological response to an adverse chemical, thermal, or mechanical stimulus associated with surgery, trauma, and acute illness. It is generally time-limited and is responsive to Opioid therapy, among other therapies.
Addiction - A neurobehavioral syndrome with genetic and environmental influences that results in psychological dependence on the use of substances for their psychic effects and is characterized by compulsive use despite harm. Addiction may also be referred to by terms such as "drug dependence" and "psychological dependence". Physical dependence and tolerance are normal physiological consequences of extended Opioid therapy for Pain and should not be considered addiction.
Allodynia -
Pain due to a stimulus which does not normally provoke pain. Two main types exist:-
- Mechanical (Tactile)
- Static mechanical allodynia – pain in response to light touch/pressure
- Dynamic mechanical allodynia – pain in response to brushing
- Thermal (hot or cold) allodynia – pain from normally mild skin temperatures in the affected area
Allo means "other" in Greek and is a common prefix for medical conditions that diverge from the expected. Odynia is derived from the Greek word "odune" or "odyne," which is used in "pleurodynia" and "coccydynia" and is similar in meaning to words with -algia or -algesia in them. See also hyperalgesia and hyperpathia.
Analgesia -
Absence of pain in response to stimulation which would normally be painful.
Analgesic Tolerance - The need to increase the dose of opioid (pain killer or reliever) to achieve the same level of analgesia. Analgesic Tolerance may or may not be evident during opioid treatment and does not equate with addiction.
Anaesthesia Dolorosa - Pain in an area or region which is anaesthetic.
Causalgia -
A syndrome of sustained burning pain, allodynia, and hyperpathia after a traumatic nerve lesion, often combined with vasomotor and sudomotor dysfunction and later trophic changes.
Central Pain -
Pain initiated or caused by a primary lesion or dysfunction in the central nervous system.
Chronic Pain - A pain state which is persistent and in which the cause of the pain cannot always be removed or is difficult to treat. Chronic Pain may be associated with a long term incurable or intractable medical condition or disease.
Dysaesthesia -
An unpleasant abnormal sensation, whether spontaneous or evoked by touching or rubbing.
Hyperalgesia -
An increased response to a stimulus which is normally painful. Hyperalgesia reflects increased pain on suprathreshold stimulation.
Hyperaesthesia -
Increased sensitivity to stimulation, excluding the special senses. The stimulus and locus should be specified and may refer to various modes of cutaneous sensibility including touch and thermal sensation without pain, as well as to pain.
Hyperpathia -
A painful syndrome characterized by an abnormally painful reaction to a stimulus, especially a repetitive stimulus, as well as an increased threshold. It may occur with allodynia, hyperesthesia, hyperalgesia, or dysesthesia.
Hypoalgesia -
Diminished pain in response to a normally painful stimulus.
Hypoaesthesia - Decreased sensitivity to stimulation, excluding the special senses.
Neuralgia -
Pain in the distribution of a nerve or nerves. Common usage, especially in Europe, often implies a paroxysmal quality.
Neuritis -
Inflammation of a nerve or nerves. Not to be used unless inflammation is thought to be present.
Neurogenic Pain -
Pain initiated or caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or central nervous system.
Neuropathic Pain -
Pain initiated or caused by a primary lesion or dysfunction in the nervous system.
Neuropathy -
A disturbance of function or pathological change in a nerve: in one nerve, mononeuropathy; in several nerves, mononeuropathy multiplex; if diffuse and bilateral, polyneuropathy.
Nociceptor -
A receptor preferentially sensitive to a noxious stimulus or to a stimulus which would become noxious if prolonged.
Noxious Stimulus -
A noxious stimulus is one which is damaging to normal tissues.
Pain -
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. The inability to communicate verbally does not negate the possibility that an individual is experiencing pain and is in need of appropriate pain-relieving treatment. Notes: Pain is always subjective. Each individual learns the application of the word through experiences related to injury in early life. Biologists recognize that those stimuli which cause pain are liable to damage tissue. Accordingly, pain is that experience we associate with actual or potential tissue damage. It is unquestionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore also an emotional experience. Experiences which resemble pain but are not unpleasant, e.g., pricking, should not be called pain. Unpleasant abnormal experiences (dysesthesias) may also be pain but are not necessarily so because, subjectively, they may not have the usual sensory qualities of pain.
Pain Threshold - The least experience of pain which a subject can recognize.
Pain Tolerance Level - The greatest level of pain which a subject is prepared to tolerate. As with pain threshold, the pain tolerance level is the subjective experience of the individual.
Paraesthesia - An abnormal sensation, whether spontaneous or evoked. Compare with dysesthesia.
Peripheral Neurogenic Pain - Pain initiated or caused by a primary lesion or dysfunction or transitory perturbation in the peripheral nervous system.
Peripheral Neuropathic Pain - Pain initiated or caused by a primary lesion or dysfunction in the peripheral nervous system.
Physical Dependence - A controlled substance is a physiologic state of neuro-addiction which is characterized by the emergence of a withdrawal syndrome if drug use is stopped or decreased abruptly, or if an antagonist is administered. Physical Dependence is an expected result of Opioid use. Physical Dependence, by itself, does not equate with addiction.
Pseudo Addiction - A pattern of drug seeking behaviour of pain patients who are receiving inadequate pain management that can be mistaken for addiction.
Substance Abuse - The use of any substance(s) for non-therapeutic purposes or use of medication for purposes other than those for which it is prescribed.
Tolerance - A physiologic state resulting from regular use of a drug in which an increased dosage is needed over time to produce the same effect, or a reduced effect is observed with a constant dose. 
