Lecture Notes: Nociplastic Pain

Introduction

• Nociplastic Pain (NcplP): A type of pain distinct from nociceptive and neuropathic pain.
• First introduced in 2016.
• Defined by the International Association for the Study of Pain (IASP) as pain arising from altered nociception without clear evidence of tissue damage or a somatosensory system lesion.
• Often related to central sensitization, but not identical.

Pathophysiology

• Mechanisms:
  • Supraspinal: Hyperresponsiveness, increased connectivity in pain perception areas (e.g., mPFC, ACC, thalamus).
  • Spinal: Signal convergence, spinal cord reorganization, immune activation.
  • Peripheral: Sodium channel proliferation.
• Possible biopsychosocial model influences: genetic, environmental, abuse history.
• Sex-related differences in pain regulation noted in studies.

Diagnosis

• Complexity in diagnosing due to lack of standard criteria.
• IASP Criteria (2021): Characteristics, hypersensitivity, comorbidities.
• Mnemonic RATE: Recognize, Assess, Treat, Evaluate.
• No specific laboratory markers identified.
• Imaging and sensory profiling are being explored for diagnosis.

Associated Diseases

• NcplP is linked with multiple conditions:
  • Fibromyalgia: Often used as a synonym for NcplP.
  • Musculoskeletal Disorders: Including low back pain, complex regional pain syndrome type 1.
  • Rheumatic Diseases: Osteoarthritis, rheumatoid arthritis.
  • Chronic Visceral Pain Syndromes: Irritable bowel syndrome, chronic pelvic pain.
• Psychological and cancer-related factors are also associated.

Treatment

• Non-Pharmacological Approaches:
  • Emphasis on physiotherapy, cognitive behavioral therapy (CBT), exercise, and emotional awareness therapies.
• Pharmacological Approaches:
  • TCAs, SNRIs, gabapentinoids have shown some efficacy.
  • NSAIDs, opioids less effective compared to other pain types.
  • Experimental use of cannabis-based medicine and ketamine.

Clinical Trials

• Ongoing research exploring various treatments and pathophysiological mechanisms.
• Trials have studied drugs like acetyl-L-carnitine and interventions like cognitive therapies.

Conclusion

• Nociplastic pain is a newly recognized pain phenotype linked with various diseases.
• Diagnosis is challenging due to the lack of specific criteria.
• Treatment involves a combination of non-pharmacological and pharmacological methods.
• Further research is critical to understanding and managing NcplP effectively.

References

• The lecture cites various studies and reviews, emphasizing the evolving understanding of nociplastic pain.