Nociceptive Pain

This article is still missing information.

Nociceptive pain is the most frequently encountered type of pain in clinical practice, arising from the body's natural response to harmful or potentially harmful stimuli affecting non-neural tissues. Understanding its definition, the physiological processes involved, and its various subtypes is fundamental to pain medicine.

Definition

Definition

Nociceptive Pain

Pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors

The International Association for the Study of Pain (IASP) defines nociceptive pain as “pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors”. The careful wording in the IASP definition of nociceptive pain—emphasising "activation of nociceptors" in "non-neural tissue" with a "normally functioning somatosensory system" clearly delineates it from the other two major mechanistic pain categories.

Neuropathic pain by contrast involves damage to the somatosensory nervous system itself, while nociplastic pain involves altered nociception without clear peripheral tissue damage or nerve lesion. A key characteristic of nociceptive pain is that it occurs with a normally functioning somatosensory nervous system. This tripartite classification, though recognizing that mechanisms can coexist, forms a cornerstone of modern pain taxonomy, guiding both diagnosis and mechanism-based treatment strategies.

Clinical Features

Core characteristics of nociceptive pain often include:

• Stimulus-Response Relationship: A clear and proportionate relationship to the degree of ongoing tissue damage or intensity of the noxious stimulus. Pain has a direct relationship with aggravating and/or easing factors.  
• Localization: Pain is typically localized to the area of injury or pathology, although some somatic referral can occur.  
• Resolution: A tendency to resolve as the underlying tissue damage heals or the noxious stimulus is removed.
• Pain Quality: Qualities can vary depending on the tissue involved and the nature of the stimulus. It is often described as sharp, aching, throbbing, or dull.  
• Response to Analgesics: Responsiveness to conventional analgesics, such as non-steroidal anti-inflammatory drugs (NSAIDs) and opioids, especially in the acute phase.
• Psychological Features: Minimal or absent psychological features are typically associated with nociceptive pain.  
• Physical Examination Findings:
  • Mechanical testing demonstrates a clear, consistent, and proportional pattern of pain or symptom reproduction.  
  • Neurological testing typically shows an absence of abnormal findings.
  • There is an absence of remote tenderness or pain on palpation.  
• Quantitative Sensory Testing (QST): Normal local and remote pain and detection thresholds are characteristic, along with normal conditioned pain modulation and temporal summation.  
• Imaging: Imaging studies (e.g., X-ray, CT, MRI) may show evidence of localized tissue injury or pathology that is proportional to and related to the pain experience.  
• Pain-Type Questionnaires: Individuals with nociceptive pain typically have normal scores on questionnaires designed to detect neuropathic pain (e.g., painDETECT, DN4, LANSS).

Challenges

A challenge in the identification of nociceptive pain is that it is often identified by a process of exclusion, meaning it's considered when features of other pain mechanisms are absent. For instance, the absence of signs typically associated with neuropathic pain (like dermatomal sensory loss) might help exclude neuropathic pain but doesn't definitively differentiate nociceptive pain from nociplastic pain.

The boundaries are very blurred In inflammatory pain. Consider conditions like Gout and Vertebrogenic Pain (with Modic 1 change). In these conditions there will often be localised allodynia, which is due to the normal peripheral sensitisation process from inflammation.

Furthermore, some tests used to identify nociceptive pain have limitations. For example, while imaging evidence of structural damage is often argued to infer a nociceptive mechanism, its absence does not entirely rule out a tissue origin for nociceptive information (e.g. facet joint injuries in whiplash). Conversely, pain relief achieved through local anesthetic blocks, sometimes used to confirm a peripheral nociceptive source, may not definitively exclude nociplastic pain due to potential placebo effects.  

Nociception

Main article: Nociception

Nociceptive pain is the perceptual correlate of nociception, which is the neural process of encoding and processing noxious stimuli. Nociception involves a series of four physiological stages: transduction, transmission, perception, and modulation. This process is described in the article on nociception.