detailed list of pain, related terms and definitions

Pain is an unpleasant sensation in the body that is triggered by the nervous system. The onset of body pain can occur suddenly or slowly, depending on many factors, (e.g. environmental, biological, emotional, cognitive, etc.)

For your convenience, a list of pain terms with definitions have been aggregated from a variety of online resources, including the Cleveland Clinic Foundation, Mayo Clinic and the National Pain Education Council.

Abstinence syndrome – A syndrome that may occur with abrupt cessation or diminution of chronic drug administration; the nature and time of onset of this syndrome vary with drug actions and half-life.

Arcuplasty – Arcuplasty is a minimally invasive method of treating vertebral compression fractures. The procedure shares its roots with other cement augmentation procedures such as, vertebroplasty and kyphoplasty. Arcuplasty represents the latest refinement in the stabilization of compression fractures. Through a single 3 millimeter incision a working channel is established into the vertebral body. Through this tiny access port a variety of instruments can access the fractured bone. An arc shaped osteotome allows the creation of a cavity within the injured bone. This cavity can then be expanded further to restore some of the shape of the fractured bone. After the cavity is prepared, bone cement is gently advanced into the space while under the guidance of live x-rays, or fluoroscopy. This bone cement will cure within minutes, and cure the bone pain associated with the fractured vertebrae. The procedure can often be performed in less than minutes. Patients frequently awaken to immediate relief, and some are able to return home the same day.

Activation – Excitation of a neuron sufficient to generate a nerve impulse (action potential).

Acupuncture – A traditional Chinese medical practice of insertion and manipulation of fine needles into specific exterior body locations (acupuncture points) to relieve pain, to induce surgical anesthesia, and for therapeutic purposes. This process is believed to adjust and alter the body’s energy flow into healthier patterns, and is used to treat a wide variety of illnesses and health conditions This alternative is often included in pain management programs (NIPC 2005).

Acute pain – Warning pain, the discomfort or signal that alerts of something physically wrong in the body. Pain may result from any condition that stimulates the body’s sensors, such as inflammation, infections, injuries, hemorrhages, tumors, and metabolic or endocrine problems. Acute pain usually abates as the underlying problem is treated. Early management of acute pain may hasten the recovery of the causative problem and reduce the length of treatment.

Addiction –  A primary, chronic, neurobiological 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. Sometimes called “dependence,” addiction should not be confused with physiologic dependence — eg, tolerance, withdrawal — that may naturally occur with opioid analgesics.

Adjuvant analgesic – A medication that is not primarily and analgesic but that has independent or additive pain relieving effects.

Agonists – Agents that exert pharmacologic effects by binding to and activating specific receptors.

Algogenic – Pain-inducing. (Not to be confused with Allogenic, meaning from individuals of the same species. Tissue transplanted from one person to another is said to be allogenic.)

Allodynia – Pain caused by a stimulus that normally does not provoke pain, such as the light touch of a finger or feather.
Analgesia – Absence of pain in response to a normally painful stimulus, typically without loss of consciousness (NPEC 2006).

Analgesics – medications designed to relieve pain. Analgesics used for back pain include those that are available by prescription or over-the-counter and those made to be taken orally or rubbed onto the skin.

Ankylosing spondylitis – a form of arthritis that affects the spine, the sacroiliac joints, and sometimes the hips and shoulders. In severe cases, the joints of the spine fuse and the spine becomes rigid.

Analgesic ceiling – A dose of an analgesic beyond which no additional analgesia is obtained.

Anesthesia – Generally, a loss of sensation resulting from pharmacologic depression of nerve function or from neurological dysfunction.

Antagonists – Agents that competitively bind with the binding sites of agonists and thereby inhibit the agonist actions.
Antidepressant – An agent that stimulates the mood, generally relieving symptoms of depressive disorders (unipolar or bipolar) by increasing levels of excitatory neurotransmitters. The main types of antidepressant drugs in use are: tricyclic, selective serotonin reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAOIs). Although adverse effects may be seen as early as the first dose, significant therapeutic improvement is delayed (3-5 weeks). Similarly, the effects of antidepressants will continue for a similar length of time after the drugs have been discontinued.

Antiemetics – Agents that prevent or alleviate nausea and vomiting. They are typically used to treat motion sickness and the side effects of opioid analgesics and chemotherapy.

Antiepileptic Drug (AED) – An agent that combats epilepsy and also may be used in the treatment of chronic pain. AEDs may alter pain transmission by interacting with specific neurotransmitters and ion channels. The agents differ in neuropathic and non-neuropathic pain, and agents within each medication class have varying degrees of efficacy.
Arachnoiditis – Painful inflammation and thickening of the arachnoid membrane (one of three membranes covering the central nervous system) around nerve roots.

Arthritis  – An inflammation of one or more of your joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. The two most common types of arthritis are osteoarthritis and rheumatoid arthritis.

Behavioral therapy or behavioral modification – Therapy that is concerned with the treatment or modification of observable behaviors rather than underlying psychological processes. Behavioral therapy applies learning principles to substitute desirable responses and behavior patterns for undesirable ones.

Beta-blockers – A class of drugs that combine with and block the activity of the beta-receptor to decrease the heart rate and force of contractions and lower blood pressure. Beta-blockers are used to treat hypertension, angina pectoris, and ventricular and supraventricular arrhythmias by controlling cein hormones (catecholamines) released by the body as part of its response to heart failure. Beta-blockers are also used to prevent migraines, treat tremors, and control anxiety.

Bioavailability – The rate and extent to which an active drug or metabolite enters the general circulation, thereby permitting access to the site of action.

Biofeedback – The process of training a person (or animal) to regulate physiologic responses by providing feedback (typically sounds or light patterns) about those responses. Clinically, patients are typically taught to control finger temperature, perspiration, muscle tension, and other responses.

Biopsychosocial – Relating to the biological, psychological, and social aspects in contrast to the strictly biomedical aspects of disease or chronic pain. This is a way of looking at the mind and body of a patient as two important, interlinked systems (the mind-body connection).

Board-certification in Pain Medicine – The physician should be board-certified in Pain Medicine* by the American Board of Anesthesiology. Only physicians who have completed a 1-year fellowship approved by the  American Board of Medical Specialties  are eligible  for this Certificate of Additional Qualifications in Pain Medicine. While there are other organizations that issue certificates in pain management, none of these require a physician to complete an additional year of training. *Approved ABMS Member Board General and Subspecialty Certificate

Botulinum toxin type A (Botox) – A purified botulinum toxic, used by injection to relax muscles. It is often used to treat certain eye conditions, severe sweating of the armpits, in cosmetic dermatology and plastic surgery to minimize wrinkles, and in pain management to treat migraines.

Buprenorphine – A semi-synthetic opioid agonist-antagonist used as an analgesic for moderate to severe pain and as an anesthesia adjunct. It can be administered sublingually or by intramuscular or intravenous injection, and is increasingly used (sublingually) rather than oral methadone for treating opioid abuse.

Breakthrough pain – Pain that overwhelms or “breaks through” any pain relief afforded by ongoing analgesics.

Complementary and Alternative Medicine (CAM)– a group of diverse medical and healthcare systems, practices, and products that are not presently considered to be part of conventional medicine as practiced in the United States. Conventional medicine is practiced by holders of MD (medical doctor) or DO (doctor of osteopathy) degrees and their allied health professionals, such as physical therapists, psychologists, and registered nurses. Some healthcare providers practice both conventional medicine and CAM, including a variety of techniques (eg, massage, acupuncture), agents (eg, nutritional supplements), or other therapies (eg, aromatherapy).

Capsaicin – A component of certain plants (cayenne, red pepper), used topically to relieve minor arthritis and neuralgia pain. Capsaicin, when applied to the skin, causes a burning sensation; it is believed that this burning depletes the nerve cells of a chemical (substance P), which has a role in transmitting pain messages.

Cauda equina syndrome — Impairment of the nerves in the cauda equina, the bundle of spinal nerve roots that arise from the lower end of the spinal cord. The syndrome is characterized by dull pain in the lower back and upper buttocks and lack of feeling (anesthesia) in the buttocks, genitalia, and thigh, together with disturbances of bowel and bladder function.

Causalgia – A burning pain and sensitivity to vibration or touch, usually in the hand or foot, at a site removed from an injury of a peripheral nerve that has healed.

Celiac plexus – A network of nerve fibers in the abdomen that conducts pain sensation from the abdominal organs, including the liver, spleen, stomach, and pancreas.

Central nervous system (CNS) – Consists of the brain and spinal cord.

Central pain – Pain associated, initiated, or caused by a lesion in the central nervous system.

Central sensitization – Enhanced excitability and responsiveness of spinal neurons producing long-lasting changes.

Cerebral cortex – Gray cellular “mantle” of the brain, which includes the sensory cortex, motor cortex, and association cortex.

Cervical spine – the upper portion of the spine closest to the skull. It is composed of seven vertebrae.

Chronic non-cancer pain (CNCP) – Persistent pain that is not associated with cancer.

Chronic non-malignant pain (CNMP) – Persistent pain that is not attributable to a life-threatening condition; some prefer to use alternate terms, such as: chronic noncancer pain, chronic non-cancer–related pain.

Chronic pain – A long-term pain state that is persistent (usually defined as three months or longer) and in which identifying, treating, and/or removing the underlying cause poses a clinical challenge. Chronic pain sometimes may be associated with a long-term incurable or intractable medical condition or disease.

Chronic pain syndrome (CPS) – Psychosocial disorder that occurs in some patients with chronic non-cancer pain in which symptoms of the pain consume the attention of the patients and becomes incapacitating.

Continuous dysesthesia – A continuous type of neuropathic pain that manifests as burning, electrical, or other abnormal sensations.

Controlled Substance Agreement – This is a consensual, written contract, promise, or accord between the patient and the healthcare provider intended to enhance therapeutic adherence to opioids. Also known as an Opioid Agreement, Opioid Contract or Narcotics Agreement.

Corticosteroid – Anti-inflammatory drug created from, or based on, a naturally occurring hormone produced by the cortex of the adrenal glands (cortisone) ( 2005).

COX-2 inhibitor – A nonsteroidal anti-inflammatory drug (NSAID) that specifically inhibits the enzyme cyclooxygenase-2 (COX-2), which contributes to inflammation. COX-2 inhibitors are used to treat pain and are less likely to cause gastrointestinal bleeding than other NSAIDs.

Complex regional pain syndrome (CRPS), also known as reflex sympathetic dystrophy (RSD) and causalgia, has been recognized for the past 2,500 years and believed in for the past 150, but it has yet to be understood. These syndromes can be characterized by discrete sensory, motor, and autonomic findings, but many patients with CRPS continue to suffer for years without a diagnosis. The role of the sympathetic nervous system in maintaining these syndromes and its appropriateness as a target for treatment continue to be subjects of controversy.

Cyclooxygenase (COX) – Enzyme involved in prostaglandin synthesis; there are two isoforms: COX-1 and COX-2.

Deafferentation – Temporary or permanent loss of primary afferent fibers due to injury or disease.
Deep somatic pain – A type of somatic pain associated with ongoing activation of nociceptors in muscles, tendons, joint capsules, fasciae, or bones.

Deep tissues – Tissues including bone, muscle, tendons, joint capsules, and fasciae.

Dermatomes – Cutaneous sensory pathways that are defined by sensation; each dermatome corresponds to the area of skin that is supplied by the dorsal roots of a particular sensory nerve.

Disc – circular pieces of cushioning tissue situated between each of the spine’s vertebrae. Each disc has a strong outer cover and a soft jelly-like filling.

Discectomy – the surgical removal of a herniated disc. A discectomy can be performed in a number of different ways, such as through a large incision in the spine or through newer, less-invasive procedures using magnifying microscopes, x rays, small tools, and even lasers.

Discography/Discogram – A discogram is a test used to evaluate back pain. A discogram may help your doctor determine if your back pain could be caused by an abnormal disk in your spine. During a discogram, dye is injected under low pressure into the center of several of your spinal disks. Then an X-ray or CT scan is performed to see if the disks are damaged. Because a discogram is an invasive procedure, it’s typically reserved for patients whose back pain persists despite repeated attempts at treatment. Your doctor may use the results of a discogram to help determine a new treatment plan for your back pain or in preparation for spinal fusion surgery.

Dorsal horn (DH) – The posterior gray matter of the spinal cord, which contains cell bodies (neurons). The spinal cord consists of 10 laminae (segments) and laminae I-VI comprise the dorsal horn.

Dorsal horn neurons – Neurons in the dorsal horn of the spinal cord, including interneurons and second order (projection) neurons.

Dysesthesia – An unpleasant abnormal sensation, which may be

spontaneous or evoked, experienced by patients with neuropathic pain; distinct from pain in the classical sense.

Electromyography (EMG) – Electromyography (EMG) is a diagnostic procedure used to assess the health of muscles and the nerves that control them. Electrical signals travel along the nerve and cause the muscles to contract. An EMG translates these signals into waveforms, sounds and numerical values that a physician will interpret to diagnose conditions that can cause numbness, tingling or weakness.

Endogenous opioids – Natural opioid compounds produced by the body; also referred to as enkephalins and endorphins.

Enkephalins – Naturally occurring molecules in the brain that attach to certain receptors in the brain and spinal cord to stop pain messages. These receptors respond to morphine and other opioid analgesics ( 2005, MedlinePlus 2006).

Epidural – Situated on the outside of the dura mater (a tough lining that surrounds the spinal cord).
Epidural Blood Patch – An epidural blood patch is used to relieve headaches caused by lumbar puncture (spinal tap).  Sometimes, after a lumbar puncture, spinal fluid can leak, decreasing the pressure of the spinal fluid.  This low pressure causes a headache.  A headache after a lumbar puncture can cause severe pain with standing or sitting, and no pain with lying flat.  If you think you have a low-pressure headache, your doctor may first instruct you to rest, lie flat, and drink plenty of fluids.  If this does not help, your doctor may refer you for an epidural blood patch. An epidural blood patch places your own blood in the spinal canal close to the same site where the lumbar puncture was performed.  This should seal the leak of spinal fluid and relieve the headache.

Equianalgesic – Having an equivalent analgesic effect.
Equianalgesic dose chart – A chart that is used to convert from one analgesic or route of administration to another. Such charts typically describe the dose of an opioid required to produce the same degree of pain relief provided by a standard oral or parenteral dose of morphine.

Ergotamine – An alkaloid derived from ergot (fungus in the genus Claviceps), which narrows blood vessels (vasoconstriction). They sometimes relieve pain by reducing pressure on pain-sensitive structures that may be associated with cluster and/or migraine headaches. It may also affect certain brain chemicals that affect how a person feels pain.

Excitatory amino acids (EAAs) – These include the neurotransmitters glutamate and aspartate, which mediate most excitatory transmission in the central nervous system.

Facet joints – the joints where the vertebrae of the spine connect to one another. Arthritis of the facet joints is believed to be an uncommon cause of back pain.
Fellowship training – Since 1993, physicians have been able to complete one-year Pain Management fellowship programs. Interventional Pain Management who completed their residency after 1993 should have also completed a one-year fellowship at a program accredited by the Accreditation Council for Graduate Medical Education. All Valley Pain Consultants physicians who completed anesthesiology residency after 1993 are fellowship -trained at ACGME-accredited institutions.
Field block injection – A procedure used to relax a tender muscle, or to reduce muscle pain and inflammation. The targeted muscle is injected with a local anesthetic (for example, Lidocaine) and corticosteroid. Also called trigger point injection.
Fibromyalgia – A syndrome described as inflammation of the fibrous or connective tissue of the body. Symptoms include diffuse musculoskeletal aching, chronic pain, stiffness, and tenderness of muscles, tendons, and joints. Diagnosis is difficult and frequently missed because symptoms of fibromyalgia are vague and generalized. It does not cause body damage or deformity; however, undue fatigue (and depression) plagues the large majority of patients, and sleep disorders are common.
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Glutamate – An excitatory amino acid neurotransmitter responsible for much of excitatory transmission in the central nervous system.
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Headache – A pain in the head above the eyes or ears, behind the head (occipital), or on the back of the upper neck. All headaches are grouped into primary headaches and secondary headaches. Primary headaches are not associated with other diseases and include migraine, tension, and cluster headaches. Secondary headaches are caused by other diseases, which may be major or minor.
Headache, cluster – A headache syndrome also called migrainous neuralgia. There are two main types of cluster headache: episodic and chronic. Episodic is the most common pattern, characterized by 1 to 3 short attacks of pain around the eyes per day. The attacks are clustered over a stretch of 1 to 2 months followed by an approximate remission of a year. Chronic cluster headache is characterized by the absence of sustained periods of remission and may start with no past history of cluster headaches or it may emerge several years after an episodic pattern of cluster headaches .
Headache, rebound – This type of headache is experienced by those who have taken analgesics or ergotamines for migraines or other health issues, and who have built up a tolerance. The headache frequently occurs immediately after the medication wears off. Using the medication less frequently or switching to a different medication may treat the headache. Some patients find relief from acute ergotamine rebound with injected phenothiazine or long-acting steroid medication..
Headache, sinus – Caused by pressure within the sinus cavities of the head, usually in connection with infection of the sinuses. Symptoms include pain and tenderness in the sinus area, discharge from the nose, and sometimes facial swelling.
Headache, tension – This headache type manifests with mild or moderate pain of variable duration. It affects both sides of the head and typically is accompanied by contraction of neck and scalp muscles.
Herniated disc – a potentially painful problem in which the hard outer coating of the disc is damaged, allowing the disc’s jelly-like center to leak and cause irritation to adjacent nerves.
Herpes zoster virus (related to shingles) – An acute viral inflammation of the sensory ganglia of spinal and cranial nerves. Caused by reactivation of the virus causing chicken pox, herpes zoster, resulting in vesicular eruption and neuralgic pain, usually on one side of the body.
Hyperalgesia – An abnormally painful response to a normally painful stimulus.
Hyperesthesia – Increased sensitivity to stimulation.
Hyperpathia – A syndrome characterized by an abnormally painful and exaggerated reaction to a stimulus, especially a repetitive stimulus.
Hypersensitivity Pain Disorder (HPD) – A suggested category (possibly transient) denoting chronic pain with signs/symptoms typical of neuropathic pain mechanisms; however, due to limitations of currently available diagnostic tools, it does not achieve the level of a clinical definition of neuropathic pain.
Hypoalgesia – Diminished pain in response to a normally painful stimulus.
Hypoesthesia – Decreased sensitivity to stimulation.
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Iatrogenic – A response, usually unfavorable, to a medical or surgical treatment induced by the treatment itself.
Inflammation – A pathologic process involving complex chemical and cellular reactions that occurs in tissues in response to injury or abnormal stimulation. Its cardinal signs— rubor (redness), calor (heat or warmth), tumor (swelling), and dolor (pain)—reflect processes directed at destroying/removing injurious material and at promoting repair and healing.
Inflammatory mediators – These may include prostaglandins, bradykinin, serotonin, histamine, and other agents.
Imagery – A method for relieving pain by using mental images from memory or imagination .
Intermittent claudication – This condition, generally found in older people, is marked by cramping and pain in a muscular area. This pain, typically in the legs, is produced by exercise and relieved by rest (NPEC 2006).
Interventional pain management – Blocking of the body’s production and/or transmission of pain signals to the brain by use of a neurological procedure, nerve block, spinal cord stimulation, implantation of a drug delivery system, or injection of an anesthetic.
Intra-articular injection – the injection of a medication into a joint space, usually to reduce inflammation, such as in bursitis or fibromyositis. With the same technique abnormally excessive fluid may be withdrawn from the joint space. The fluid may be a result of trauma or inflammation.
Intradiscal Electrothermal Therapy (IDT) – a treatment for herniated discs in which a wire is inserted into the disc through a small incision in the back. An electrical current is then passed through wire to modify and strengthen the collagen fibers that hold the disc together.
Intractable pain – Intense, usually chronic and unremitting, pain for which no accepted medical intervention has provided relief..
Intrathecal – Within either the subarachnoid or subdural space .
IPN – Inflammatory pain, resulting from tissue response to disease or injury (pathological process involved in tissue destruction).
Ischemia – A reduction in local blood flow due to obstruction of the blood supply.
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Joint – In anatomy, the place of contact, generally moveable, between two or more bones. There are three structural types of joints: fibrous (connective tissue); cartilaginous (cartilage); and synovial (cavity).
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Ketamine – A parenterally administered anesthetic that produces catatonia, profound analgesia, increased sympathetic activity, and little relaxation of skeletal muscles. Can be used for minor surgical procedures in which muscle relaxation is not required. It is chemically related to phencyclidine (PCP) and can produce hallucinations; therefore, its use is not as prevalent as it was when originally used during the Vietnam War.
Kyphoplasty – a procedure for vertebral fractures in which a balloon-like device is inserted into the vertebra to help restore the height and shape of the spine and a cement-like substance is injected to repair and stabilize it.
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Lancinating pain – A type of neuropathic pain that manifests as an episodic shooting, stabbing, or knifelike pain.
Lidocaine – An anesthetic that produces pain relief by blocking signals at nerve endings in the skin. Lidocaine can be administered topically, as a patch or oral gel, or injected as a local anesthetic. It is used for pain and discomfort of, for example, infections of the skin. It also is used in the management of certain cardiac arrhythmias.
Local anesthetic – An anesthetic that reversibly blocks pain and/or movement nerve signals in a specific part of the body (see Lidocaine).
Limbic system – The limbic system includes structures such as the amygdala, hippocampus, septal nuclei, hypothalamus, and transitional cortical regions (e.g., cingulate gyrus). This part of the brain is involved with emotional responses.
Lumbar spine – the lower portion of the spine. It is composed of five vertebrae.
Lumbar spondylosis – Degeneration and/or deformity of the lumbar spine (pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum (pelvis), or degenerative disc disease. This may lead to spinal stenosis (narrowing of the spinal canal), vertebral instability, and/or malalignment, which may be associated with back pain and/or leg symptoms.
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Migraine – A vascular symptom complex of periodic headache, usually temporal and unilateral in onset. It is typically associated with irritability, nausea, vomiting, constipation, or diarrhea. Migraine headaches may occur with or without aura (prodrome of neurologic symptoms, often visual in nature) (NPEC 2006, NIPC 2006).
Migraine, menstrual – Refers specifically to migraines that occur within the first two days of the onset of menstruation.
Morphine – The principle and most active alkaloid of opium. Morphine acts directly on synapses of the arcuate nucleus and the CNS. The soluble salts are used in medicine as an analgesic, anesthetic, or sedative. It is available in oral preparations and as rectal suppositories. It may also be given via subcutaneous, intramuscular, intravenous, or intrathecal injection. Tolerance, and physical and psychological dependence may develop (NIPC 2006, NPEC 2006).
Mu agonists – Opioids that bind to m1 and m2 receptors in the brain, spinal cord and, under certain conditions (e.g., inflammation), the periphery to exert their effects.
Multimodal analgesia – Also known as “balanced analgesia,” this approach to pain management involves the use of more than one method or modality of controlling pain (e.g., drugs from two or more classes, drug plus nondrug treatment) to obtain additive beneficial effects, reduce side effects, or both.
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Nerve block – A form of regional anesthesia, in which an anesthetic agent is injected near a nerve to block pain.
Neuroablation – Destruction of tissue, typically by surgical, chemical (e.g., phenol), or heat (e.g., radiofrequency) lesions. The goal of neuroablative procedures is to interrupt signal flow between peripheral sources of pain and the brain or to remove neural structures that contribute to pain.
Neurolysis – A technique for destroying neural tissue that involves injection of a destructive chemical or use of cold (cryotherapy) or heat (radiofrequency coagulation).
Neuralgia – Pain that extends along the course of one or more nerves. It is a form of chronic pain that can be difficult to diagnos.
Neuritis – Inflammation of a nerve that can include pain, tenderness, anesthesia and paresthesia, paralysis, wasting, and loss of reflexes (NPEC 2006).
Neuroablative therapy – Use of various injectable substances, for example alcohol or phenol, or the use of controlled heat or cold, to render the nervous system unable to transmit a pain signal. The nerve destruction may be permanent or the nerves may grow back in time; this is usually employed only when other therapies have failed (NPEC 2006, WebMD 2006).
Neuropathic pain – Pain arising from disease or injury to the thermo-nociceptive component of the nervous system at any level (peripheral, central, or both). Peripheral neuropathic pain syndromes include HIV sensory neuropathy, postherpetic neuralgia (PHN), and diabetic neuropathy. Central neuropathic pain includes poststroke pain, spinal cord injury pain, trigeminal neuralgia (5th cranial nerve, one of the largest nerves in the head), and multiple sclerosis pain (NIPC 2006, MedlinePlus 2006).
Nociceptive pain – Common but misused term (means “painful pain”), which might be replaced by “physiological pain.” This may result from activity in neural pathways caused by potentially tissue-damaging stimuli, including postoperative pain, arthritis, mechanical low back pain, sickle cell crisis, sports/exercise injuries, and others .
Nociceptors – Sensory receptors that are preferentially sensitive to tissue trauma or a stimulus that would damage tissue if prolonged.
Non-pharmacologic therapy – Alternative pain management approach that includes biofeedback, relaxation therapy, cognitive/behavioral strategies, acupuncture, and others types of treatments.
Nonsteroidal anti-inflammatory drug (NSAID) – This type of drug, commonly prescribed for the treatment of arthritis or other conditions, for example bursitis or tendinitis, reduces inflammation and pain. NSAIDs block the production of certain body chemicals that can cause inflammation; they also may relieve the pain of bruises or headaches. NSAIDs include aspirin, ibuprofen, naproxen, and many other agents.
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Occipital Nerve Block – An occipital nerve block is done when there is inflammation of the occipital nerves (located in the back of the head) that is causing headaches.   Local anesthetic and steroid are injected into the occipital region in order to reduce inflammation of the nerves and provide pain relief.  Local anesthetic is used in combination with the steroid.  The local anesthetic may provide pain relief for the first few hours after the injection, but then wears off.   You may be sore for a day or so.  Pain relief from the steroid is typically experienced a few days after the injection.  This injection may provide pain relief for several weeks or months.
Onset of action – The length of time it takes for a medication to begin working.
Opiate – A drug directly derived from opium, for example, morphine (a natural substance extracted from opium poppies) and codeine. Pain is relieved by binding primarily to mu-opioid receptors in the brain and spinal cord..
Opioid – A more inclusive term for naturally derived opiates and synthetic or semisynthetic agents with analgesic properties similar to opiates.
Opioid-Induced Hyperalgesia OIH  – This condition occurs when the use of opioids reduces the pain threshold and can manifest as opioid tolerance. The patient’s pain can in fact become worse despite an increase in dose or escalation of use. The physiology behind this condition is not clearly understood and many medical personnel were initially skeptical of its origin. This paradoxical phenomenon poses a challenge for doctors, pain management specialists, anesthesiologists and other medical professionals trying to treat patients. It is often hard for people to wrap their heads around the idea that medication prescribed to relieve pain is having the opposite effect. It creates an issue for doctors who may not be sure whether an increase in pain is related to hyperalgesia or if the injury, disease or condition has worsened.
Opioid, long-acting – Agents with a half-life of many hours or in extended release formulation, and typically used for persons with chronic pain, for example in cancer, and for management of non-cancer pain associated with arthritis, back disorders, fibromyalgia, and multiple sclerosis .
Opioid rotation – Strategy of switching opioids, thereby allowing any opioids causing toxicity or no longer helping to manage pain to be eliminated while still maintaining the analgesic effect. The optimal dose should avoid under-dosing or overdosing, both associated with negative outcomes for the patient. This requires the use of equianalgesic dose tables, to determine new dosage, ensuring that pain is well controlled.
Opioid, short acting – Agents typically with a half-life of but a few hours and most commonly used for the treatment of acute (sudden onset) or breakthrough pain, for example, post-operative, dental, or trauma-associated pain.
Osteoarthritis – a disease in which the cartilage that cushions the ends of the bones at the joints wears away, leading to pain, stiffness, and bony overgrowths, called spurs. It is the most common form of arthritis and becomes more likely with age.
Osteoporosis – a condition in which the bones become porous and brittle, and break easily.
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Pain flares (flare ups) – pain that suddenly erupts or emerges with or without a specific aggravating event or activity.
Pain intensity scales – Systems of rating pain for adults, children, and infants. Some pain scales are: Numeric Rating Scale, Wrong-Baker Faces, COMFORT Scale, CRIES Pain Scale, FLACC Pain Scale, and the Checklist of Nonverbal Indicators.
Pain management – The systematic study of clinical and basic science and its application for the reduction of pain and suffering. Pain management emphasizes an interdisciplinary approach to treatment, and combines tools, techniques, and principles from a variety of the healing arts to create a holistic paradigm for the reduction of pain and suffering.
Pain management physicians – A pain medicine specialist should possess the training and certification listed below:
• ACGME-accredited fellowship in Pain Medicine
• American Board of Medical Specialties (ABMS) board certification  and subspecialty certification in Pain Medicine from the American Board of Anesthesiology (ABA)
Pain pump – A  surgically implanted device in the lower abdomen that provides a steady stream of medication (typically an opioid) to the cerebrospinal fluid.
Pain scales — self-report tools that can help a patient describe the intensity of pain to assist healthcare providers in measuring the level of pain for diagnostic and treatment purposes. Three common types of scales include numeric (eg, 1 to 10 scale), verbal (eg, words describing extent of pain), and visual (eg, expressive pictures of faces).
Pain threshold – The least amount of pain which a patient can recognize.
Pain tolerance level – The greatest level of pain which a patients is prepared to withstand.
Palliative care (hospice) – Comfort and/or medical care that reduces the severity of an incurable disease or slows its progress rather than providing a cure. Typically used to preserve the patient’s quality of life by avoiding aggressive end-of-life treatment, these programs can assist the family or caregiver(s) in making the patient as comfortable as possible; assistance is usually available around the clock, seven days a week.
Parenteral administration – Administration of a drug via a route other than the gastrointestinal system, such as by intravenous, intramuscular, or subcutaneous injection.
Paresthesia – An abnormal sensation (e.g., “pins and needles” from a foot “going to sleep”), which may be spontaneous or evoked, and often experienced by patients with neuropathic pain.
Patient-controlled analgesia (PCA) – The self-administration of analgesics by a patient; often involves an intravenous, subcutaneous, or epidural opioid administered via a pump mechanism.
Perioperative pain – Pain that is present in a surgical patient because of preexisting disease, the surgical procedure (e.g., associated drains, chest or nasogastric tubes, complications), or a combination of disease-related and procedure-related sources.
Peripheral neuropathy – A disease or degenerative state in which motor, sensory, and/or vasomotor nerve fibers may be affected. This condition may manifest as muscle weakness and atrophy, pain, and numbness.
Peripheral sensitization – A lowering of the stimulus (pain) threshold for nociceptor activation and an increase in the frequency of nerve impulse firing (hyperexcitability). Peripheral sensitization can contribute to pain hypersensitivity found at the site of tissue damage/inflammation .
Phantom pain – Pain or discomfort following amputation that feels to the patient as if it comes from the missing limb.
Postherpetic Neuralgia (PHN) –   Postherpetic neuralgia is a painful condition affecting your nerve fibers and skin. The burning pain associated with postherpetic neuralgia can be severe enough to interfere with sleep and appetite.
Postherpetic neuralgia is a complication of shingles, which is caused by the chickenpox virus. Most cases of shingles clear up within a few weeks. But if the pain lasts long after the shingles rash and blisters have disappeared, it’s called postherpetic neuralgia.
Physical dependence – A physiologic state of adaptation that often includes tolerance and is manifested by a drug class-specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood levels of the drug, and/or administration of an antagonist. This should not be confused with “addiction.”
Physiological pain – Pain arising from a stimulus (e.g., pinprick, heat pulse) that activates the temperature- and pain-transmitting (thermonociceptive) nervous system. (Term sometimes replaces nociceptive pain.)
Polypharmacy – The administration of multiple drugs sometimes resulting in excessive medication (NIPC 2006).
Potency – The dose or concentration of a drug required to produce a particular effect (e.g., pain relief).
Preemptive analgesia – A pharmacologic intervention performed before a noxious event (e.g., surgery) that is intended to minimize the impact of the stimulus by preventing peripheral and central sensitization.
Prialt® (Ziconotide) – A calcium channel blocker with analgesic and neuroprotective effects that has been used to help relieve chronic intractable pain. It is a synthetic analog of a constituent of the venom from a tropical marine snail of the genus Conus (C. magus).
Primary afferent (nerve) fibers – Axons of primary afferent (or “first order”) neurons that transmit impulses from the periphery toward the central nervous system. Each neuron has a cell body that resides in sensory ganglia (e.g., dorsal root ganglia) and a bifurcated axon. One branch extends along a peripheral nerve and ends in a sensory receptor; the other branch projects to the spinal cord, where it synapses with a spinal neuron (e.g., interneuron, projection neuron).
Projection neurons – Neurons in the dorsal horn of the spinal cord with nerve fibers that project to the brain in tracts. These neurons are responsible for transmitting nociceptive information from the spinal cord to higher centers.
Prolotherapy – a treatment for back pain in which a practitioner injects a sugar solution or other irritating substance into trigger points along the periosteum (tough, fibrous tissue covering the bones) to trigger an inflammatory response that promotes the growth of dense, fibrous tissue. The theory behind prolotherapy is that such tissue growth strengthens the attachment of tendons and ligaments whose loosening has contributed to back pain.
Pruritus – Severe itching; sometimes a side effect of opioid therapy.
Pseudoaddiction – An iatrogenic syndrome that may be created by the undertreatment of pain. It is characterized by patient behaviors such as anger and escalating demands for more or different medications. Apparent “drug seeking” can be mistaken for addiction and result in suspicion and avoidance by staff. Pseudoaddiction can be distinguished from true addiction in that the behaviors normally resolve when pain is effectively treated.
Pseudo-opioid resistance – patients with adequate pain control may continue to report pain or exaggerate its presence, as if they have become resistant to opioid analgesic effects, to prevent reductions in their currently effective doses of medication.
Pseudotolerance – The need to increase analgesic dosage that is not due to tolerance, but due to other factors such as: disease progression, new disease, increased physical activity, lack of compliance, change in medication, drug interaction, addiction, or deviant behavior. When a once-fixed opioid dose is no longer effective, the above conditions should be reviewed to exclude pseudotolerance.
Psychogenic pain – Sometimes pejorative and usually unhelpful term related to unclassified pain experienced by psychiatric patients.
Psychological dependence – Generally refers to the mental/cognitive manifestations of substance dependence or abuse whereby the patient believes there is a need for the drug to maintain comfort or stability, possibly in the absence of any physiologic benefit.
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Radiculopathy – Caused by compression, inflammation, and/or injury to a spinal nerve root in the lower back. Also known as radicular pain or sciatica, the causes of this type of pain include herniated disc with nerve compression, foraminal stenosis, diabetes, nerve root injuries, and scar tissue from previous spinal surgery
Referred pain – Pain felt in a part of the body other than where the cause is situated. As different nerve networks converge to common neurons, which relay information to higher never centers, the brain is not always able to distinguish where activity initiated..
Reflex sympathetic dystrophy (RSD) – Also known as CRPS (complex regional pain syndrome) this disorder has been recognized for the past 2,500 years and accepted as valid for the past 150, but it has yet to be understood. These syndromes can be characterized by discrete sensory, motor, and autonomic findings, but many patients with CRPS continue to suffer for years without a diagnosis.
Regional anesthesia – This type of anesthesia interrupts the sensory nerve conductivity to a specific region of the body. When produced by injection of an anesthetic agent close to the specific nerve, it is called a nerve block.
Responsiveness – The probability of achieving adequate pain relief with an analgesic without encountering unmanageable side effects.
Rheumatism – Any of a variety of disorders marked by inflammation, degeneration, or metabolic derangement of the connective tissue structures of the body. It is attended by pain, stiffness, or limitation of motion in joints and related structures, including muscles, bursae, tendons, and fibrous tissues.
Rheumatoid arthritis (RA) – This is an inflammatory disorder, considered an autoimmune disease that causes pain, swelling, stiffness, and loss of function in the joints. It has several features that make it different from other kinds of arthritis, for example, RA generally occurs in a symmetrical pattern, meaning that if one knee or hand is involved, the other one also is. While the disease often affects the wrist joints and the finger joints closest to the hand, it can also affect other parts of the body besides the joints. Many people with RA develop anemia, or a decrease in the production of red blood cells. In addition, people with rheumatoid arthritis may have fatigue, occasional fevers, and a general sense of malaise .
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Sciatica (see also Radiculopathy) – A syndrome characterized by pain radiating from the back into the buttock and lower extremity along its posterior or lateral aspect. It is most commonly caused by protrusion of a low lumbar intervertebral disk, but the term can be used to refer to pain anywhere along the sciatic nerve .
Scoliosis – a condition in which the spine curves to one side as a result of congenital malformations, neuromuscular disorders, injury, infection, or tumors.
Selective Nerve Root Block – A selective nerve root block is an injection of a local anesthetic along a specific nerve root. Along the spine, there are several “holes” or “foramina” through which nerve roots emerge. If these foramina are partially closed from bulging disks, bone spurs, misalignment of vertebrae, etc., the nerve root can also be pinched. This typically causes a shooting or radiating pain along that nerve root. In a selective nerve root block, a small needle is placed in the foramen alongside the nerve root and the medication is injected.
Selective serotonin reuptake inhibitors (SSRIs) – Medications used to relieve depression by increasing the availability of serotonin in the brain. By increasing this chemical’s availability, these drugs modify neuronal pathways involved in regulating mood ( 2005, MedlinePlus 2006).
Shingles – An acute viral inflammation of the sensory ganglia of spinal and cranial nerves caused by reactivation of the virus causing chicken pox, herpes zoster, and resulting in dermatitis with vesicular eruptions and neuralgic pain, usually on one side of the body.
Sicca syndrome — An autoimmune disease, also known as Sjögren syndrome, that classically combines dry eyes, dry mouth, and another disease of connective tissue such as rheumatoid arthritis (most common), lupus, scleroderma, or polymyositis. About 90% of Sjögren syndrome patients are female, usually in middle age or older. Inflammation of the the lacrimal glands leads to decreased tears and dry eyes. Inflammation of the salivary glands leads to dry mouth. The syndrome can consequently be complicated by infections of the eyes, breathing passages, and mouth.
Sjögren syndrome — see Sicca syndrome (above).
Somatic pain – Pain arising from tissues such as skin, muscle, tendon, joint capsules, fasciae, and bone.
Spinal cord stimulator – As a therapy for certain types of chronic neuropathic pain, the spinal cord is electrically stimulated to cause a new sensation, for example, tingling, to block pain from being perceived by the brain..
Spinal stenosis – Narrowing of the vertebral canal, nerve root canals, or intervertebral foramina of the lumbar spine, usually resulting from soft tissue and bony encroachment of the spinal canal and nerve roots. Symptoms include pain, paresthesias, and neurogenic claudication (non-specific limb symptoms).
Spondylitis – Name given to a group of chronic diseases that are forms of inflammatory arthritis primarily affecting the spine (NPEC 2006, MedlinePlus 2006).
Spinothalamic tract (STT) – Major pathway by which nociceptive information travels from the dorsal horn of the spinal cord to the thalamus.
Stellate ganglion block – A procedure to relieve pain caused by overactivity of the sympathetic nervous system (automatic regulation system, operating without the intervention of conscious thought) in the upper extremities, head, or neck. A local anesthetic is injected in the front of the neck; sympathetic nerves are blocked, while sensory pathways are not.
“Stress hormone” response – A series of responses to an acute injury or stress that leads to an increase in the metabolic rate, blood clotting, and water retention; impaired immune function; and a “fight or flight” alarm reaction with autonomic features. These responses minimize further damage and blood loss, promote healing, prevent or fight infection, and reduce blood flow to vital organs, among other functions.
Spinal fusion – the surgical joining of two more vertebrae together, usually with bone grafts and hardware. The resulting fused vertebrae are stable but immobile. Spinal fusion is used as a treatment for spondylolisthesis, scoliosis, herniated discs, and spinal stenosis.
Spondyloarthropathy – a form of arthritis that primarily affects the spine and sacroiliac joints.
Spondylolisthesis – a condition in which a vertebra of the lumbar (lower) spine slips out of place.
Substance P – A neuropeptide that activates spinal neurons and enhances their responsiveness to excitatory amino acids, thus facilitating nociception.
Superficial (cutaneous) somatic pain – A type of somatic pain associated with ongoing activation of nociceptors in the skin, subcutaneous tissue, or mucous membranes.
Sympathetic (nervous system) hyperactivity – Symptoms and signs of sympathetic (autonomic) nervous system hyperactivity include increased heart rate, blood pressure, and respiratory rate; sweating; pallor; dilated pupils; nausea; vomiting; dry mouth; and increased muscle tension.
Sympathetic nerve block – Injection of anesthetic to relieve pain resulting from abnormal activity in the sympathetic nervous system.

Temporomandibular Joint (TMJ) Disorder – A condition causing pain and dysfunction in the lower jaw joint and muscles that control jaw movement. It is often associated with restricted jaw movement, clicking or popping sounds, muscle spasms, and grinding of teeth. Trauma to the jaw or temporomandibular joint plays a role in some TMJ disorders but in most cases the exact cause of the condition is not clear .
Thalamus – A portion of the brain that relays impulses from the sensory nerves, which, in turn, enables people to feel objects they touch as well as pain.
Therapeutic dependence – sometimes patients exhibit what is considered drug-seeking because they fear the reemergence of pain and/or withdrawal symptoms from lack of adequate medication therapy; their ongoing quest for more analgesics is in the hopes of insuring a tolerable level of comfort.
Thermonociceptive – Relating to the temperature- and pain-sensing components of the nervous system.
Tolerance – A state of adaptation in which repetitive exposure to a drug induces changes that result in a diminution of one or more of the drug’s effects over time.
Topical agents – Medication applied to the skin rather than ingested or injected.
Transcutaneous Electrical Nerve Stimulation (TENS) – a treatment designed to relieve pain by directing mild electrical impulses to nerves in the painful area of the body.
Transdermal – Medication absorbed into the bloodstream via the skin.
Tricyclic antidepressants (TCAs) – Any of a group of antidepressant drugs that contain three fused benzene rings, which increase the effectiveness of norepinephrine or serotonin by inhibiting their uptake by nerve endings, but do not inhibit monoamine oxidase. TCAs were the most popular antidepressants until the advent of SSRIs. They are still prescribed for certain types of severe depression that do not respond to SSRIs.
Trigger point injection – A procedure used to relax a tender muscle, or to reduce muscle pain and inflammation. The targeted muscle is injected with a local anesthetic (for example, Lidocaine) and corticosteroid. Also called field block injection.
Trigger zone/point – Hypersensitive area on the body where touch or pressure elicits pain.
Triptans – A class of drugs for the treatment of migraine that act as agonists for 5-hydroxtryptamine (5-HT) receptors. The triptans also help relieve other migraine symptoms, such as nausea, vomiting, and sensitivity to light, noise, and motion. While triptans can be effective in relieving migraine for some patients, they do not prevent future attacks or lessen their frequency.

Vertebrae – the individual bones that make up the spinal column.
Vertebroplasty – a minimally invasive surgical procedure that involves injecting a cement-like mixture into a fractured vertebra to relieve pain and stabilize the spine.

Wind-up pain – Nerve cells in the spinal cord may release chemicals that intensify the pain, affecting the strength of the pain signal that reaches the brain. Also known as sensitization.
Withdrawal – The uncomfortable physical or psychological state experienced when certain substances or medications are discontinued suddenly in an habituated individual. Therapeutic medication withdrawal is done gradually over time to minimize uncomfortable symptoms.

Ziconotide – A calcium channel blocker with analgesic and neuroprotective effects that has been used to help relieve chronic intractable pain. It is a synthetic analog of a constituent of the venom from a tropical marine snail of the genus Conus (C. magus). The brand name for the drug is Prialt®.