ABPMR Pain Medicine key terms

A free nerve ending that detects tissue-damaging or potentially damaging stimuli and converts them into electrical signals. Nociceptors are found in skin, muscle, joints, and viscera and respond to mechanical, thermal, or chemical stimuli.

A thinly myelinated primary afferent nerve fiber that carries fast, sharp, well-localized pain signals from nociceptors to the spinal dorsal horn. Its conduction velocity is faster than that of unmyelinated C fibers.

An unmyelinated, slow-conducting primary afferent fiber that transmits dull, burning, poorly localized pain. C fibers are polymodal, responding to mechanical, thermal, and chemical stimuli, and contribute strongly to central sensitization after repeated activation.

The gray matter region of the spinal cord where primary afferent fibers synapse and where pain signals are modulated before ascending. It contains interneurons, projection neurons, and descending inhibitory inputs that shape nociceptive transmission.

An ascending pathway carrying nociceptive and temperature information from the spinal cord to the thalamus, with collateral projections to brainstem and limbic areas. It crosses the midline near the level of entry and is key to conscious pain perception.

An activity-dependent increase in central nervous system responsiveness to nociceptive input, producing hyperalgesia and allodynia. It involves enhanced synaptic efficacy, reduced inhibition, and glial activation, and explains pain persisting after tissue healing.

A progressive increase in dorsal horn neuron firing during repeated C-fiber stimulation at frequencies above 0.3 Hz. Wind-up is a short-lived form of synaptic plasticity that contributes to central sensitization and temporal summation of pain.

A top-down analgesic system originating in the periaqueductal gray and rostral ventromedial medulla that projects to the dorsal horn and suppresses nociceptive transmission. Its dysfunction is implicated in chronic pain states such as fibromyalgia.

A G-protein-coupled receptor concentrated in the dorsal horn, periaqueductal gray, and limbic system. Activation reduces neuronal excitability and neurotransmitter release, producing analgesia, euphoria, respiratory depression, and constipation.

A transient receptor potential vanilloid channel activated by heat, capsaicin, and acidic conditions. It is expressed on small nociceptive afferents and is a target for topical capsaicin therapy in neuropathic pain.

Pain caused by a lesion or disease of the somatosensory nervous system, rather than by ongoing tissue damage. It is often described as burning, shooting, or electric-like and may include allodynia, hyperalgesia, and sensory loss.

Pain evoked by a stimulus that normally does not produce pain, such as light touch or mild cooling. It reflects altered central processing or sensitization and is common in neuropathic pain and complex regional pain syndrome.

An increased pain response to a stimulus that is normally painful. Primary hyperalgesia occurs at the injury site due to nociceptor sensitization, while secondary hyperalgesia extends into surrounding uninjured tissue and reflects central sensitization.

A disorder of a spinal nerve root producing pain, sensory change, weakness, or reflex loss in a dermatomal or myotomal pattern. Common causes include disc herniation, foraminal stenosis, and degenerative spondylosis.

A hyperirritable taut band within skeletal muscle that is painful on compression and may produce referred pain, restricted motion, and autonomic symptoms. Trigger points are diagnosed clinically and treated with manual therapy, dry needling, or injection.

A chronic pain condition, usually after trauma, characterized by disproportionate pain, sensory changes, vasomotor instability, edema, and motor or trophic changes. Diagnosis uses Budapest criteria, and treatment combines rehabilitation, medications, and sympathetic or neuromodulatory procedures.

A set of eight clinical signs used during low back pain examination to identify nonorganic or illness-behavior components. They include tenderness, simulation, distraction, regional disturbance, and overreaction, and are not a test for malingering.

The area of skin supplied by a single spinal nerve root. Dermatomal maps guide examination of radicular pain, sensory loss, and the level of nerve root involvement.

Delivery of corticosteroid, often with local anesthetic, into the epidural space to reduce inflammation and pain from radiculopathy or spinal stenosis. Approaches include interlaminar, transforaminal, and caudal, with fluoroscopic guidance recommended.

Injection of local anesthetic around the medial branch of the dorsal ramus that innervates a facet joint. A positive response helps select patients for radiofrequency ablation of the same nerves.

A procedure that uses heat generated by radiofrequency current to destroy pain-transmitting nerves, most commonly medial branches for facet-mediated pain. It provides longer relief than local anesthetic blocks in carefully selected patients.

A neuromodulation technique in which electrical impulses delivered to the dorsal columns or dorsal root ganglia modulate pain transmission. It is used for persistent neuropathic pain such as failed back surgery syndrome or complex regional pain syndrome.

Injection of local anesthetic near the stellate ganglion at the C6 level to block sympathetic outflow to the head, neck, and upper extremity. It is used for complex regional pain syndrome, sympathetically maintained pain, and some vascular disorders.

Implantation of a pump that delivers small doses of analgesic medication, typically opioids or baclofen, directly into the cerebrospinal fluid. It is considered for refractory cancer pain or severe spasticity when systemic therapy is limited by side effects.

Percutaneous injection of bone cement into a compressed vertebral body to stabilize a fracture and reduce pain. It is considered for painful osteoporotic or pathologic compression fractures after conservative measures fail.

The combined use of two or more analgesic agents or techniques with different mechanisms to improve pain relief while reducing dose-dependent side effects. It is a cornerstone of perioperative and chronic pain management.

A state in which repeated opioid exposure reduces responsiveness, so that a higher dose is needed to produce the same effect. Tolerance develops at different rates for analgesia, respiratory depression, and constipation.

A paradoxical increase in pain sensitivity caused by opioid exposure, distinct from tolerance and withdrawal. It is suggested by worsening pain despite escalating doses and may improve with opioid reduction or rotation.

A short-acting opioid receptor antagonist used to reverse opioid-induced respiratory depression and overdose. It may precipitate acute withdrawal in opioid-dependent patients and often requires repeat dosing or infusion.

A drug class including gabapentin and pregabalin that binds the alpha-2-delta subunit of voltage-gated calcium channels, reducing excitatory neurotransmitter release. It is used for neuropathic pain and has sedative and renal-excretion considerations.

A serotonin-norepinephrine reuptake inhibitor approved for diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain. It may improve pain and function but can cause nausea, somnolence, and blood pressure elevation.

A cream or patch containing capsaicin, which activates and then defunctionalizes TRPV1-expressing nociceptors. High-concentration patches are used for postherpetic neuralgia and other localized neuropathic pain.

A nonsteroidal anti-inflammatory drug that inhibits cyclooxygenase enzymes and reduces prostaglandin synthesis, providing analgesic and anti-inflammatory effects. Risks include gastrointestinal bleeding, renal injury, and cardiovascular events.

A structured psychological treatment that helps patients identify and change maladaptive thoughts, beliefs, and behaviors related to pain. It improves coping, function, and distress in chronic pain and is a core component of interdisciplinary programs.

A sequential rehabilitation approach using laterality recognition, imagined movement, and mirror therapy to treat chronic pain and cortical reorganization. It is commonly used in complex regional pain syndrome and phantom limb pain.

Patient education that explains pain as a protective output of the nervous system influenced by biological, psychological, and social factors. It aims to reduce fear and catastrophizing and support active coping.

An interdisciplinary program combining physical conditioning, pain management, and psychological support to improve function and return to work. It emphasizes graded activity and self-management rather than passive treatments.

A maladaptive cognitive response to pain characterized by rumination, magnification, and helplessness. It predicts greater pain intensity, disability, and poorer treatment outcomes and is addressed in psychological therapy.

A psychological approach that encourages accepting pain-related experiences while committing to actions aligned with personal values. It reduces avoidance and improves functioning in chronic pain.

A self-management strategy that balances activity and rest to avoid symptom flares and gradual deconditioning. It helps patients with chronic pain increase function without the boom-bust cycle.