Understanding key types of pain

Assessing pain in practice

Acute pain and chronic pain can be different with acute pain typically related to injury or protection from injury, while chronic pain can have a less clear pathology.

Physicians need to be able to distinguish between nociceptive pain, pain related to inflammatory conditions, neuropathic pain and pain where there is no clear stimulus or damage associated with the experience of pain.


Assessing pain character & quality

Classification according to pathogenesis

Assessment and evaluation of the character and type of pain experienced by patients is important both for reaching a definitive diagnosis and to choose appropriate treatment options based on patient expectations.

Different types of pain suggest different pathological and biopsychsocial mechanisms and respond differently to treatment options.

  • Pain caused by actual or potential tissue damage and painful stimuli at nociceptors is termed nociceptive pain.
  • Pain due to disruption and change in the neural system is neuropathic pain. In some clinical syndromes such as chronic low back pain, both nociceptive and neuropathic pain may be involved.1
  • Chronic pain conditions often have a secondary psychological component resulting in psychosomatic pain.
Freynhagen R, Baron R, Gockel U, et al. painDETECT: a new screening questionnaire to identify neuropathic components in patients with back pain. Curr Med Res Opin. 2006;22:1911-20.


Chronic pain: multifactorial nature

Overlapping components in chronic pain

Importantly in diagnosis of chronic pain, the physician needs to be aware that pain can be multifactorial in nature – often involving nociceptive and neuropathic components. Typical examples are certain forms of back pain and cancer pain where a nerve injury is involved.

  • These overlapping components can be difficult to establish during diagnosis without a complex diagnostic work-up
  • However, establishing the nature of the patient’s pain is a key first step towards devising a suitable management plan

Influence of biopsychosocial factors on chronic pain

The biopsychosocial pain model

When assessing patients with chronic pain, the physician needs to consider at all times the interaction of physical, psychological and social factors.

  • The so-called biopsychosocial pain model acknowledges the interplay of these factors and is an important model to guide understanding, assessment and management of chronic pain.1
  • As pain becomes chronic, disease impairment is increasingly psychosocial.
  • Psychological factors within chronic pain include depression, fear of the future, anger and frustration and erosion of confidence. Patients may become inactive and withdrawn and consider themselves a burden
  • Cognitive factors are important and patients‘ attitudes to pain and their expectations of their ability to influence the course of their pain
  • The challenge for the physician and the patient is to work together to break the biopsychosocial pain cycle and empower patients to take control of their pain.
Gatchel RJ, Peng YB, Peters ML, et al. The biopsychosocial approach to chronic pain: scientific advances and future directions. Psychol Bull. 2007;133:581-624.


Clinical assessment of chronic pain patients

Diagnostic procedures for chronic pain1

Clinical assessment is a crucial first step in effective chronic pan management

  • A full history of patient pain, general medical history, treatment history and psychosocial assessment, along with physical examination and laboratory tests as required, are key to reaching a diagnosis
  • In reaching an assessment of the patient and their pain – the physician must begin the crucial process of engaging with the patient and developing a relationship of trust based on clear communication
American Pain Society. Pain Control in the Primary Care Setting. Glenview, IL: American Pain Society; 2006.


Pain case history and assessment

Key factors in chronic pain assessment

The table highlights the key factors that should be considered, explored and evaluated with the patient experiencing chronic pain.1

  • Pain is highly individual and subjective and many patients have difficulty describing their condition
  • They may be able to indicate location, frequency and type of pain but may have more difficulty describing pain intensity.
  • Estimates of pain intensity using pain evaluation tools are quite subjective. In clinical practice, such tools are not commonly used. However, establishing some feel for the patient’s concept of pain intensity gives insights into patient perception of pain.
  • Multidimensional tools should be used, in additional to numerical rating scales of pain, to determine the extent and effect of pain on physical function, mental status and quality of life.
American Pain Society. Glenview, IL: American Pain Society; 2006


Establishing individual therapeutic aims

Overcoming the communication barrier

At the end of a pain assessment and pain diagnosis, and before devising a management plan, it is important to establish the patient view on their pain by asking some key questions about what has to happen to make the patient more content with their treatment.

Key questions:

  • What has to happen that you are content with the pain treatment?
  • Regarding pain relief?
  • Regarding functional improvement?
  • Regarding tolerability?

Measuring pain and impact on quality of life


Since there are no practical objective methods of measuring pain, we must resort to scales and questionnaires to obtain information. Various tools can be used to assess pain intensity and the impact of pain on patient function, daily living and quality of life.

  • The simplest measure of pain intensity involves use of numerical (NRS) , visual (VAS) or verbal (VRS) rating scales in which the patient rates their pain or selects verbal descriptors that best describe pain intesity.

Since most of these scales are very much based on a subjective estimation of the severity of pain, the CHANGE PAIN Scale, a new user-friendly communication tool aimed at assessing pain via a more holitic approach, taking into account patients’ expectations on pain relief and quality of life.

Detailed questionnaires can be used to assess the impact on quality of life e.g. SF-36, WOMAC.


Quick check

Which of the following statements about the biopsychological pain model are not true?
The relative importance of biological, psychological, and social factors changes with the course of the disease.
In chronic pain, structural and functional changes in the CNS can occur.
Evaluation of the pain as threatening will lessen the sensation of pain.
Clinical assessment is a crucial step in effective chronic pain management. Which of the following items should be assessed by a physician accordingly:
Full history of patient pain, incl. medical and treatment history
Psychosocial assessment
All of them
Which of the following psychological or social factors can not occur in chronic pain patients?
Feeling of confidence


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