Introduction to Pain Management

Introduction to Pain

• Pain is not uniform; different types of pain exist.
• This lecture will classify pain, outline approaches to classifying pain, and describe the role of pharmacists in pain management.
• Key features distinguishing acute and chronic pain will be identified.
• Four types of pain, based on their underlying mechanism, will be explained.

Aims of the Lecture

• Outline different approaches to classifying pain
• Identify key features distinguishing between acute and chronic pain
• Explain four types of pain by their underlying mechanism (aetiology): nociceptive, inflammatory, neuropathic, and nociplastic
• Describe the physical and emotional impacts of living with pain
• Outline pharmacological and non-pharmacological pain treatment options
• Describe the pharmacist's role in pain management

Main Types of Pain Classification

• Not all pain is the same
• Key considerations include duration, etiology (mechanism), cause, location, (e.g., headache, visceral, musculoskeletal) and whether it's cancer-related or not
• Pain is classified into acute and chronic, and further subdivided into nociceptive, inflammatory, neuropathic, and nociplastic pain

Pain Classification by Duration

• Acute Pain:*

• Recent onset, usually short-lived

• Linked to clear tissue injury (e.g., injury, surgery, burn)

• Severity varies with the extent of injury

• Predictable time course

• Generally, responds well to treatment

• Chronic Pain:*

• Lasting more than 3 months

• Can occur after expected healing

• May have no discernible cause or pathological process

• Intensity might not correlate with tissue injury

• Time course is unpredictable

• Often difficult to treat

Burden of Chronic Pain

• Chronic pain can negatively impact quality of life
• Associated with depressive feelings
• Sleep disturbances
• Fatigue
• Impaired physical functioning
• Difficulty concentrating
• Increased time off work
• Reduced activity levels

Pain Classification by Aetiology

• Adaptive pain:* Has a function

• Nociceptive pain

• Inflammatory pain

• Non-adaptive pain:* (maladaptive, pathological)

• Neuropathic pain

• Nociplastic pain ((dys)functional pain)

Aetiology: Nociceptive Pain

• 'Good' pain, protective function
• Sensation from potentially tissue-damaging noxious stimuli
• Example scenario: a 5-year-old child burns their hand on a hot kettle

Aetiology: Inflammatory Pain

• Obvious tissue injury or illness
• Associated with tissue injury and immune cell infiltration
• Adaptive, protective function
• Descriptors: sharp, dull, aching, throbbing, well-localised, characteristic case study (Ayaan Jessa)

Aetiology: Neuropathic Pain

• Caused by damage to or disease of the sensory nervous system
• Tissue injury may not be immediately obvious
• Does not have a protective function
• Descriptors: burning, shooting, pins and needles, numbness, less well-localised
• This type of pain can be caused by certain conditions or medications (e.g., stroke, chemotherapy, certain viral infections)

Neuropathic Pain Scenarios

• Peripheral: Drugs (e.g., chemotherapy), amputation (phantom limb), infections (e.g., shingles), trigeminal neuralgia, diabetes
• Spinal: Spinal injury, MS
• Brain: Stroke, tumour

Case study: Daphne Monta

• 61-year-old woman with type 2 diabetes
• Experiences constant tingling and burning pain in both feet
• Pain interferes with daily activities and sleep.

Aetiology: Nociplastic Pain

• Substantial pain without noxious stimuli or minimal peripheral inflammatory pathology
• No neuronal damage or injury
• Abnormal function of the pain axis; related to central sensitization and nerve memory
• Associated with various conditions (e.g., fibromyalgia, IBS, tension-type headaches)
• Case study: Carole Parkinson (chronic widespread pain, pain in various locations, fatigue, sleep disturbances)

Cancer v Non-cancer Pain

• Cancer pain:*

• Often progressive

• Might be a combination of acute and chronic pain

• Can be related to nerve compression, chemotherapy, or disease progression

• Non-cancer pain:*

• Various underlying causes

• Can be acute or chronic

• Examples include fractures, appendicitis, chronic back pain, or arthritis

• May be mixed nociceptive and neuropathic

Cancer Pain Examples

• Uterine cervical cancer, breast cancer, bone metastases (spread of cancer to the bones), due to nerve compression, chemotherapy

Non-cancer Pain Examples

• Fracture, appendicitis, myocardial infarction (heart attack), chronic back pain, arthritis

Goals of Treatment

• Acute pain:*

• Patient comfort and satisfaction

• Earlier mobilization

• Reduced hospital stay

• Minimize stress response and neuroendocrine effects

• Minimize adverse effects on various systems (respiratory, cardiovascular, etc.)

• Chronic pain:*

• Improved function

• Pain management

• Reduction in healthcare utilization

• Greater understanding of ongoing pain

• Less fear associated with physical activity

Management Strategies

• Pharmacological:*

• Paracetamol

• NSAIDs and coxibs

• Opioids

• Local anaesthetics

• Ketamine

• Corticosteroids

• Antidepressants (tricyclics, serotonin-norepinephrine reuptake inhibitors)

• Anti-epileptics (gabapentin, pregabalin, carbamazepine)

• Non-pharmacological:*

• Self-care (heat/cold, activity and exercise, pacing activities, sleep hygiene)

• Cognitive behavioural therapy

• Acceptance commitment therapy

• Acupuncture

• Transcutaneous electrical nerve stimulation (TENS)

• Pain management programs

• Invasive devices (spinal cord stimulation, deep brain stimulation)

Members of the Multidisciplinary Team

• Doctors
• Nurses
• Pharmacists
• Physiotherapists
• Psychologists
• Occupational therapists
• Person with pain

Pharmacist's Evolving Role

• Hospital pharmaceutical services aim to ensure the preparation, assembly, efficient procurement, and safe storage and distribution of quality medicines, facilitating safe and efficient medicine use.
• Pharmacists are integral to the multidisciplinary team managing pain, possessing knowledge of medicines, interactions and appropriate therapies, offering advice and support.

Summary

• Pain classification is essential, with consideration of acute/chronic, cancer/non-cancer, nociceptive/neuropathic types.
• Pharmacists are crucial members of the pain management team.
• Treatment varies depending on the type of pain.

This quiz covers various aspects of pain, including its classification into acute and chronic types. Key features and underlying mechanisms of different pain types will be explored, alongside the role of pharmacists in managing pain. Learn about both pharmacological and non-pharmacological treatment options.