Pain is multidimensional and subjective

The definition of pain

Pain is...

  • defined as an “unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.”1
  • based upon a sensory event of the peripheral and central nervous system, but the experience and procession of pain is influenced by biological, psychological and social factors.
  • a highly subjective experience. Even when suffering from the similar disorders, the pain of two patients is not the same.1

Therefore comprehensive clinical assessment and effective physician-patient communication are essential.

Part III: Pain Terms, A Current List with Definitions and Notes on Usage (pp 209-214) Classification of Chronic Pain, Second Edition, ISAP Task Force on Taxonomy, edited by H. Merskey and N. Bogduk, IASP Press, Seattle, © 1994.


Acute pain may become chronic

Differentiating pain

Acute pain constitutes a signal to brain about the presence of noxious stimuli and/or ongoing tissue damage. It has an important biological and a distinct protective function.

Acute pain:

  • has a sudden onset and often lasts from days to weeks but it resolves during the healing process.
  • is useful as the individual is informed about danger and the need to escape or seek help.
  • is often experienced during trauma, surgery or illness.

Poorly controlled acute pain can be a factor leading to progression towards chronic pain. That's why early and efficient management of pain is important.


Chronic pain is a disease in its own right

Differentiating pain

Chronic pain persists after the damaged tissue is healed and has no biological function.

  • Chronic pain is associated with functional, structural or chemical changes in the pain detection system itself, thus putting it into the realm of a disease in its own right.
  • In addition chronic pain often sets the stage for the emergence of a complex set of physical and psychosocial changes.
  • In clinical practice acute and chronic pain often do not represent two clearly separate entities. They may constitute a continuum without a clear boundary.

Chronic pain has significant consequences

Impact of chronic pain

Chronic pain is a specific healthcare problem and a therapeutic challenge. The prevalence of chronic pain in the European populations was estimated to be around 20%1.

Poorly managed pain may present a debilitating burden.

  • People with chronic pain suffer not only from pain but also from a demoralising overall situation.
  • Chronic pain is affecting quality of life, social functioning and the ability to work.2, 3
  • Patients with chronic pain often demonstrate depression and anxiety.

These restrictions themselves can contribute to perpetuation of the pain.

Breivik H et al. Survey of chronic pain in Europe: prevalence, impact on daily life, and treatment. Eur J Pain. 2006; 10: 287-333
Becker N et al. Pain epidemiology and health related quality of life in chronic non-malignant pain patients referred to a Danish multidisciplinary pain center. Pain. 1997; 73: 393-400
McDermott AM et al. The burden of neuropathic pain: results from a cross-sectional survey. Eur J Pain 2006; 10: 127-135


Knowledge of mechanisms supports effective treatment choice

Treatment of pain

Although we tend to think of pain as a homogeneous sensory entity, several distinct types exist which require different treatment approaches.

Nociceptive Pain:

  • is caused by an inflammatory or non-inflammatory response of the body to a noxious stimuli.
  • is transient and informs the organism of tissue damage or injury.

Neuropathic pain:

  • is caused by a primary lesion in the central or peripheral nervous system.
  • has no adaptive purpose and is more likely to become chronic in nature and may escalate over time.

In a third category of pain, functional pain, there is no obvious tissue or nerve damage.

Davis MP et al. What is new in neuropathic pain? Support Care Cancer 2007; 15 (4): 363-372


Chronic pain requires individualiseD multimodal management

Nociceptive and neuopathic components

Pharmacological treatment remains a therapeutic challenge because:

  • is multifactorial in nature and requires often multimodal treatment including physical and psychological treatment as well as pharmacological therapy.
  • chronic pain is often a mix of nociceptive and neuropathic components (e.g. in chronic low back pain, cancer pain).
  • especially when nociceptive and neuropathic components are involved combination therapy becomes necessary.
  • dose increase as well as combination therapy may result in increased side-effects. The balance between sufficient pain relief and acceptable tolerability is difficult to achieve.
  • a broad-spectrum approach addressing both processes would be ideal.

Quick check

Chronic Pain...
...can be clearly located
...becomes a disease in its own right
...has a distinct warning and protective function
Why is knowledge about the different pathologies of pain important in clinical practice?
Because it is the only existing classification
Because this knowledge can help guide selection of appropriate therapies
Because it is the oldest existing classification
Which of the following is usually a treatment option for nociceptive and neuropathic pain?
Non-pharmaceutical pain control techniques
combination therapy


Thank you for participating in the first basic module “The Relevance of Pain Classification”. We hope you enjoyed it. The PAIN EDUCATION platform provides more eModules concerning pain therapy. If you like to, please continue with these eModules and check your knowledge.