Acute versus Chronic Pain

Overview: 
  • Acute pain is brought on by a particular injury or disease, is thought to serve a useful process, and should be self-limited.  Chronic pain, however, could be considered a pathological process, reflecting a mal-adaptive response or acute pain persisting beyond the “normal” duration of the healing process from injury or disease.  
  • Whether pain is acute or chronic, it must be viewed as a biopsychosocial process, although the following factors may play a more important role in the chronification of pain.  
  • Biological factors could include incompletely understood differences in pain processing related to age, sex, and the presence of sensitization (e.g., upregulation of the NMDA receptor)
  • Psychological factors could include maladaptive cognitive processes (e.g., anticipation of adverse outcomes, also sometimes referred to as catastrophizing), mood (e.g., depression), anxiety, history of trauma (e.g., PTSD)
  • Social factors could include cultural beliefs about pain, socio-economic / environmental stressors, and the presence or absence or social support systems

Challenges

  • Educating patients —and clinicians— about the multi-dimensional nature of pain is no easy task
  • Assessing the multiple facets of an individual’s pain experience is also challenging
  • Resources are limited, in particular in most inpatient settings, for addressing psychosocial and social needs, and even when such resources are available, addressing these elements is time-consuming.

Treatment Recommendations

  • “What are we treating?” should be one of the first questions asked when met with challenging acute or chronic pain.  
  • OLDCARTS: Onset, location, duration, character, alleviating / aggravating, radiation, temporal pattern, and symptoms associated is a time-honored guide, more helpful for acute than for chronic pain

Special Considerations

  • Pain severity is ultimately less valuable than the extent to which pain interferes with a given activity.  
  • There is no perfect assessment tool for acute or for chronic pain.  
  • Common assessment tools include PROMIS (patient-reported outcomes measurement information system) from the NIH, reporting on not just pain intensity but various aspects of physical, mental, and social health
  • Other simple tools include the PEG (Pain, Enjoyment, General Activity) screening tool, which inquiries about numerical average pain, extent to which pain interferes with enjoyment of life, and extent to which pain interferes with general activity
References: 

Fillingim RB. Individual differences in pain: understanding the mosaic that makes pain personal. Pain. 2017 Apr;158 Suppl 1: S11-S18.

Grichnik KP, Ferrante FM. The difference between acute and chronic pain. Mt Sinai J Med. 1991 May;58(3):217-20.

Krebs EE, Lorenz KA, Bair MJ, et al. Development and initial validation of the PEG, a three-item scale assessing pain intensity and interference. J Gen Intern Med 2009; 24:733.

Talbot K, Madden VJ, Jones SL, Moseley GL. The sensory and affective components of pain: are they differentially modifiable dimensions or inseparable aspects of a unitary experience? A systematic review. Br J Anaesth. 2019;123(2):e263-e272.