Chronic Pain in Primary Care: Overview and Pathophysiology Module 1

1. Chronic Pain in Primary Care: Overview and PathophysiologyModule 1 Frances Sonstein, MSN, RN, FNP, CNS Mary Lou Adams, PhD, RN, FNP-BC, FAAN Paula Worley, MSN, RN, FNP-BC Diane Tyler, PhD, RN, FNP-BC, FNP-C, FAAN Stephanie Key, MSN, RN, CPNP-PC The University of Texas at Austin School of Nursing Consultants: Yvonne D’Arcy, MSN, RN and JoEllen Wynne, MSN, RN, FNP-BC, FAANP

2. Objectives: • Relate impact of chronic pain in primary care settings • Identify barriers to optimal chronic pain management • Define different types of pain • Describe pathophysiology of pain Goal: provide NPs with a concise and easy to understand overview of pain.

3. Impact on Primary Care • Prevalence of chronic pain • Health care costs • Complexity of care • Impact on all dimensions of health

4. Prevalence and cost of chronic pain Common chronic pain conditions affect 116 million US adults at a cost of $560-635 billion annually in direct medical costs and lost productivity. Healthcare costs $261-300 billion Lost productivity $297-336 billion IOM: “Relieving Pain in America: A blueprint for transforming prevention, care ,education and research (2011)

5. Complexity of Care and Impact on all dimensions of health • Many providers refuse to see patients with chronic pain • Patients with inadequately managed chronic pain suffer unnecessarily • Have significant loss in overall functional status and productivity • High rate of depression • Strained social relationships • Poor quality of life.

6. Principles of Chronic pain Management • Effective pain management is a moral imperative • Chronic pain can be a disease in itself • Value of comprehensive treatment • Need or interdisciplinary approaches • Importance of prevention • Wider use of existing knowledge • The conundrum of opioids • Roles for patients and clinicians working together • Value of a public health and community health approach

7. Barriers • Patient-related barriers • Unwillingness to report pain or accept treatment • In older adults, the perception that pain is a part of aging • Beliefs • good patients don’t complain • Strong pain medication should be ‘last resort’ • Stigma of opioid use • Access and availability to treatment, since many providers refuse to treat chronic pain patients

8. Barriers • Provider-related barriers • Lack of knowledge • Lack of diagnostic precision • Difficulty in choosing the right analgesic • Lack of standardized approach to treating pain • Fear of doing harm • Legal and regulatory issues • Limited referral resources • Attitudes, beliefs, expectations

9. Types of Pain: • Pain • An unpleasant , sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage • Acute pain • Identifiable etiology • Self-limited, short duration • Objective autonomic features • Chronic pain • Persists > 6 months or beyond the normal healing period • Vague, poorly articulated characteristics

10. Nociceptive Pain • Physiologic response to noxious stimuli • Initiated by nociceptors • thermal, chemical, mechanical • Somatic pain • Superficial • Deep • Visceral pain

11. Neuropathic Pain • Disorder of neuromodulation • Etiology • Nervous system injury or dysfunction • Characteristics • Hyperalgesia • Hyperesthesia • Allodynia • Hyperpathia

12. Neuropathic Pain • Examples • Phantom limb pain • Complex regional pain syndrome • Diabetic neuropathy • Central pain syndrome • Trigeminal neuralgia • Post-herpetic neuralgia

13. Myofascial Pain • Muscle and connective tissue pain • Etiology • Hypertonic muscles • Myofascial trigger points • Arthralgias • Fatigue with muscle weakness • Example • Fibromylagia

14. Physiology of Pain • Gate Control Theory • Afferent nerve fibers transmit impulses to spinal cord and brain • Perception • Descending pathways • Modulation

15. Pain Physiology: Multiple Processes • Transduction • Transmission • Neuromodulation • Descending modulation systems • Sensitization • Pain modulation

16. Transduction • Noxious stimuli are converted to electrical signals on nociceptors • C-fibers and A- delta fibers • Do not respond normally to non-noxious stimuli • Do not adapt • Release of excitatory neurotransmitters increase sensitization • Opioid receptors activated by endogenous or exogenous opioids slow afferent firing.

17. Transmission • Periphery  spinal cord thalamus  cortex of the brain via afferent nerve fibers. • C-fibers are non-myelinatedand respond to mechanical, thermal and chemical stimuli • A-delta fibers are thinly myelinatedwhich respond to mechanical and thermal stimuli • Release of pain neurotransmitters, such as glutamate and substance P, in the spinal cord.

18. Modulation • Inhibitory nervous system response to noxious painful stimuli • Intermediate neurons • Descending neural tracts • Respond to exogenous and endogenous opioids • Open calcium channels • Release of Endorphins and enkephalins

19. Descending Modulation Systems • Stimulation of Opioid Receptors in the midbrain • Stimulated by serotonin (5HT) and norepinephrine (NE) cells • Inhibit transmission of pain stimuli • Prevent the release of Substance P and glutamate • Inhibit the activation of peripheral nociceptors

20. Sensitization • Sensitization • Neurohormonal transmitters such as Substance P, calcitonin gene peptide (CGRP) and adenosine triphophate (ATP) create an “inflammatory soup” even further lowering the pain threshold thus further sensitizing • Hyperalgesia- pain augmentation

21. Pain Pathway See diagram page 488 (permission to reproduce not authorized) McCance,K., Huether, S. et al. (2010). Pathophysiology: The biologic basis for disease in adults and children (6thed). Mosby: Philadelphia, PA. (permission to reproduce not authorized)

22. Pain Neurotransmitters Inflammatory Excitatory Inhibitory Mediators Transmitters Transmitters Bradykinin Glutamate Gama amino butyric acid Leukotrienes -NMDA (GABA) Prostagandins - AMPA Descending pain modulators Serotonin Tachykinins Norepinephrine – alpha 2 Substance P NeuronkininA & B receptors InterleukinsSubstance P Serotonin receptors Tumor necrosis Calcitonin geneOpioids receptors factorrelated peptides (mu, delta, kappa) Nitric Oxide SomatostatinsEndodorphins ATPBombesinsEnkephalins NeurokininsCholecystokinineDynorphins Calcitonin gene- related peptide

23. Implications • Summary statement • Treatment of chronic pain both pharmacologic and non-pharmacologic including Complementary Alternative Medicine are based on understanding of the various processes in the pain pathway • The goal is to enhance modulation of the painful sensation. • Basis for assessment and management • Determining the type of pain, intensity, etiology will direct effective management

24. References • Arnstein, P and St. Marie, B. (2010) Managing Chronic Pain with Opioids: A call for change. Executive Summary of a White paper by the Nurse practitioner Healthcare Alliance Foundation. AM J for Nurse Practititoners 14(11/12), 48-51. •  Committee on Advancing Pain Research, Care, and Education; Institute of Medicine. (2011) Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. National Academies Press. Available at http://www.nap.edu/catalog.php?record_id=13172 • D’Arcy, Y. (2008) Pain in the Older Adult. The Nurse Practitioner 33(3), March, 18- 24.  • Dipiro, J., Talbert, R., Yee, G., Matzke, G., Wells, B., and Posey, M. (2011) Pharmacotherapy: A Pathophysiologic Approach, 8th ed. NY: McGraw Hill, 1045-59. • Dobschra, S., Corson, K, Flores. J, Tansill, E and Gerrity, M. (2008) Veterans Affairs Primary Care Clinicians’ Attitudes toward Chronic Pain and Correlates of opioid prescribing rates. Pain Medicine, 9(5), 564-571. • errell, B, Fine , P and Herr, K. (2010) Strategies for Success: Pharmacologic Management of Persistent Pain in the Older Adult. Supplement to The Clinical Advisor October 2010. • Jackman, R and Malllett, B. Chronic Nonmalignant Pain in Primary Care. Am Fam Physician: 78(10) Nov 15, 2008, 1155-62. • Kaasalainen, S, Martin-Misener R., Carter, N., Disenso, A, Donald F.and Baxter, P (2010) The Nurse Practitioner Role in Pain Management in Long term care. Journal of Advanced Nursing 66(3), 542-551 • McCance,K., Huether, S. et al. Pathophysiology: The biologic basis for disease in adults and children, 6TH ED. MOSBY ELSEVIER PHILA 2010,PAGES 481-495, •  Spitz, A, Moore, A., Papaleontiou, M., Granieri, E., Turner, B. and Reid, M.C. (2011) Primary care providers’ perspective on prescribing opioids to older adults with non-cancer pain: a qualitative study. BMC Geriatrics, 11 (35). • Tarzian,A. and Hoffmann, D. (2004) Barriers to Managing Pain in the Nursing Home: Findings From a Statewide Survey. J Am Med Dir Assoc 5: 82–88. • Weidemer, N. Harden,P. Arndt, I. and Gallaghere, R. (2007) The Opioid Renewal Clinic: a primary care, managed approach to opioid therapy in chronic pain patients at risk of substance abuse. Pain medicine 8(7), 573-84. • Vanderah, T.  (2007): Pathophysiology of pain.  Medical Clinics of North America 91, (1) 1-12. WB Saunders. • Vijayaraghavan, et al.  (2012) Primary Care Providers Views on Chronic Pain Management among High-Risk Patients in Safety Net Settings.  Pain Medicine: 13:1141-48.

25. Post-Test Questions • According to the 2011 Institute of Medicine report, “Relieving Chronic Pain in America”, chronic pain healthcare costs and lost productivity ranges annually: a. 200-300 million dollars b. 560-635 million dollars c. 200-300 billion dollars d. 560-635 billion dollars 2. One of the factors leading to inadequate treatment of chronic pain is: a. Many healthcare providers refuse to see patients with chronic pain. b. Lack of reimbursement for chronic pain conditions. c. Lack of adequate treatment regimens. d. None of the above

26. Post-Test Questions 3. Patient related barriers include unwillingness to report pain and accept treatment, the stigma of opioid use, and decreased access and availability of treatment. a. True b. False 4. Chronic pain can be described as: a. pain with vague or poorly articulated characteristics b. pain persisting greater than 6 months c. pain lasting longer than the normal healing time for a specific condition d. all of the above 5. Deep somatic pain in ligaments, bones, joints, muscles and blood vessels is described as which type of pain? a. Nociceptive b. Neuropathic c. Myofascial

27. Post-Test Questions 6. A normally non-painful stimulus, such as light touch on sunburned skin, causing perception and sensation of pain is: a. Hyperpathia b. Hyperalgeaia c. Allodynia d. Hyperestheaia 7. Phantom limb pain, complex regional pain syndrome, diabetic neuropathy, central pain syndrome, trigeminal neuralgia and post-herpetic neuralgia are all examples of : a. Acute nociceptive pain b. Chronic nociceptive pain c. Acute neuropathic pain d. Chronic neuropathic pain

28. Post-Test Questions 8. The process of pain pathway described by Melizak in 1965 involving transmission, perception, descending pathways and modulation is called: a. Specificity Theory b. Gate Control Theory 9. The stage in the pain pathway in which C-fibers and A- delta fibers conduct the electrical impulses of the perception of pain from the periphery to the spinal cord, the thalamus, and eventually the cortex of the brain releasing pain excitatory neurotransmitters such as glutamate and Substance P is: a. Transduction b. Transmission c. Modulation d. Sensitization

29. Post-Test Questions 10. Which of the following statements apply to the effective management of chronic pain? a. Requires the clinician determining the etiology, type, intensity of pain. b. May involve pharmacologic, non-pharmacologic and complimentary alternative medical intervention. c. Is directed at enhancing the modulation of painful sensation. d. All of the above.