Clinical 01 - Pain Classification PDF

Clinical 01 Basics of Pain: Pain classification Lodewijk Dekker & Roger Knaggs  Aims of this lecture At the end of this lecture, you should be able to:- ▪ Outline different approaches to classifying pain ▪ Identify key features that distinguish between acute and chronic pain ▪ Explain four...

Clinical 01 Basics of Pain: Pain classification Lodewijk Dekker & Roger Knaggs  Aims of this lecture At the end of this lecture, you should be able to:- ▪ Outline different approaches to classifying pain ▪ Identify key features that distinguish between acute and chronic pain ▪ Explain four different types of pain by underlying mechanism (aetiology) ▪ Describe the physical and emotional impacts of living with pain ▪ Outline pharmacological and non-pharmacological treatment options for pain ▪ Describe the role of the pharmacist in pain management 2  Main types of pain classification ▪ Not all pain is the same! ▪ Main considerations ▪ Duration ▪ Acute v chronic ▪ Etiology (mechanism) ▪ Nociceptive, inflammatory, neuropathic, (dys)functional ▪ Cause ▪ Cancer v non-cancer ▪ Location ▪ Headache, Viscera, Musculoskeletal, Everywhere 3  Pain classification by duration Acute pain Chronic pain ▪ Pain of recent onset and probable ▪ Pain lasting for more than 3 months limited duration ▪ Pain lasting after normal healing ▪ Obvious tissue injury (e.g. injury, ▪ Sometimes no identifiable cause operation, burn) ▪ May be no obvious pathologic ▪ Varying severity process ▪ Intensity related to extent of injury ▪ Intensity unrelated to tissue injury ▪ Predictable time course ▪ Unpredictable time course ▪ Treatments usually successful ▪ Difficult to treat 4  Burden of chronic pain ▪ Depression ▪ Sleep disturbances ▪ Fatigue ▪ Impaired physical functioning ▪ Impaired concentration ▪ Time off work ▪ Less active 5  Pain classification by aetiology Non-Adaptive (maladaptive, Adaptive Pain has a function pathological) ▪ Nociceptive pain ▪ Neuropathic pain ▪ Inflammatory pain ▪ Nociplastic pain ((dys)functional pain) 6  Aetiology: nociceptive pain ▪ ‘Good’ pain ▪ Adam ▪ Sensation associated with the ▪ 5 years old detection of potentially tissue- ▪ Stretches out knocks kettle over damaging noxious stimuli spilling boiling water over his hand ▪ Protective 7 Woolf CJ. J Clin Invest. 2010; 120(11): 3742–3744.  Aetiology: inflammatory pain ▪ Obvious tissue injury or illness ▪ Associated with tissue damage and infiltration of immune cells and can promote repair by causing pain hypersensitivity/peripheral sensitisation until healing occurs ▪ Adaptive - Protective function ▪ Descriptors ▪ Sharp and/or dull ▪ Aching ▪ Throbbing ▪ Well-localised 8 Woolf CJ. J Clin Invest. 2010; 120(11): 3742–3744. Ayaan Jessa ▪ 36 years old ▪ Playing in a football match yesterday evening ▪ Went to tackle opponent ▪ Swollen and red knee ▪ Painful to move ▪ Stiff for 30 minutes in the morning and then improve 9  Aetiology: neuropathic pain ▪ Caused by damage to, a lesion or disease of the sensory nervous system ▪ Tissue injury may not be obvious ▪ Does not have a protective function ▪ Descriptors ▪ Burning, shooting, pins and needles, or numbness ▪ Less well-localised 10 Woolf CJ. J Clin Invest. 2010; 120(11): 3742–3744.  Neuropathic pain scenarios Peripheral Spinal Brain Drugs – e.g. Chemotherapy MS Stroke induced neuropathic pain Amputation – phantom pain Spinal injury MS Infections - Herpes zoster, HIV Tumour Tumour Trigeminal neuralgia Epilepsy Diabetes mellitus – diabetic neuropathy Toxins – inc. Ethanol 11  Daphne Monta ▪ 61-year-old married lady ▪ She has had type 2 diabetes mellitus for the last 15 years ▪ Daphne describes constant tingling and occasional burning pain in both feet ▪ It causes difficulty in walking and she was being woken several times each night due to the pain. ▪ She found it increasingly difficult to get out and about and has become more and more dependent on family 12  Aetiology: nociplastic pain ▪ Substantial pain but no noxious stimulus and no, or minimal, peripheral inflammatory pathology ▪ No neuronal damage (i.e. functional problem) but abnormal function of the pain axis ▪ Related to central sensitisation/ nerve memory ▪ Conditions include fibromyalgia, irritable bowel syndrome, tension type headache, temporomandibular joint disease, interstitial cystitis 13 Woolf CJ. J Clin Invest. 2010; 120(11): 3742–3744.  Carole Parkinson ▪ Constant pain all day ▪ Location varies each day; sometimes legs, arms and back ▪ Burning sensations and pins and needles ▪ Woken six times each night due to pain ▪ Fatigue ▪ Finds difficult to concentrate on tasks ▪ Worried about the future 14 Cancer v non-cancer pain ▪ Cancer pain ▪ Progressive ▪ May be mixture of acute and chronic ▪ Non-cancer pain ▪ Many different causes ▪ Acute or chronic 15  Cancer pain ▪ Examples ▪ Uterine cervical cancer, breast cancer ▪ Bone metastases ▪ Due to nerve compression ▪ Due to chemotherapy ▪ Features of acute and chronic pain ▪ May be acute or chronic ▪ Often mixed nociceptive and neuropathic pain ▪ Usually gets worse over time if untreated 16  Non-cancer pain Acute pain Chronic pain ▪ Examples ▪ Examples ▪ Fracture, appendicitis, MI ▪ Chronic back pain, arthritis ▪ Symptom of tissue injury or illness ▪ Cause may not be obvious ▪ Usually nociceptive ▪ Complex, may be mixed nociceptive ▪ Occasionally neuropathic (e.g. and neuropathic sciatica) ▪ Different treatments may be needed 17  Goals of treatment Acute pain Chronic pain ▪ Patient comfort and satisfaction ▪ Earlier mobilization ▪  hospital stay ▪  costs ▪ Minimise stress response/neuroendocrine effects ▪ Minimise adverse effects on respiratory, cardiovascular, gastrointestinal / urinary and musculoskeletal skeletal systems 18 Adapted from National Pharmaceutical Council and Joint Commission on Accreditation of Healthcare Organisations 2001.  Management strategies ▪ Paracetamol ▪ Antidepressants ▪ NSAIDs and coxibs ▪ Tricyclic antidepressants ▪ Serotonin noradrenaline reuptake inhibitors ▪ Opioids ▪ Anti-epileptics ▪ Local anaesthetics ▪ Gabapentin and pregabalin ▪ Carbamazepine ▪ Ketamine ▪ Corticosteroids 19  Management strategies Self-care Non-pharmacological ▪ Heat & cold ▪ Cognitive behavioural therapy ▪ Acceptance commitment therapy ▪ Activity & exercise ▪ Pacing activities ▪ Acupuncture ▪ TENS ▪ Sleep hygiene ▪ Pain Management Programmes ▪ Invasive devices ▪ Spinal cord stimulation ▪ Deep brain stimulation 20  Members of the multidisciplinary team ▪ Doctors ▪ Nurses ▪ Pharmacists ▪ Physiotherapists ▪ Psychologists ▪ Occupational therapists ▪Person with pain 21  The evolving role of the pharmacist in pain management ▪ The main objectives of the hospital pharmaceutical service are to:- ▪ Ensure preparation and assembly of medicines of the required quality ▪ Ensure economical and efficient procurement and supply of medicines ▪ Ensure safe and effective storage and distribution of medicines ▪ Facilitate safe, effective and economic use of medicines Royal College of Surgeons of England and the College of Anaesthetists. The Commission on the provision of surgical services. Report 22 on the Working Party. Royal College of Surgeons. London, 1990.  The evolving role of the pharmacist in pain management 1. All inpatient pain management services must have dedicated pharmacy resources. 2. Clinical pharmacists working as part of the multiprofessional inpatient or outpatient pain management services must be competent to provide the service. 3. A pharmacist working as part of pain management services must be registered with the General Pharmaceutical Council (GPhC) and adhere to the standards for pharmacy professionals published by the Council. 4. A pharmacist working as part of pain management services must keep up their knowledge and skills with demonstrable CPD activity. 5. There must be sufficient pharmacy technical staff to provide support functions. 6. A pharmacist working as a ‘practitioner with a special interest’ in pain management must be accredited and recognised to undertake the role.1 7. Sterile manufacturing facilities and experienced technical staff must be available in centres that provide epidural or intrathecal drug delivery for acute and persistent pain. 8. Pain services must have access to a medicines information service to provide expert advice on the use of analgesic medicines in special circumstances (e.g. pregnancy and breastfeeding, renal impairment, hepatic impairment) and potential interactions with other medication. 23 Faculty of Pain Medicine. Core Standards for Pain Management Services in the UK. 2021.  Summary ▪ Deciding on the type of pain is important ▪ Acute / chronic ▪ Cancer / non-cancer ▪ Nociceptive / neuropathic ▪ Treatment depends on the pain type ▪ Pharmacists are an essential part of the multidisciplinary team providing care for people with pain 24