Understanding The Causes of Pain and Pain Management

Summary

This educational video delves into pain management, distinguishing between acute and chronic pain and emphasizing the importance of following local guidelines and consulting specialists. It covers the sensory and affective aspects of pain, the physiology of pain transmission, and the complexities of pain perception. The script also discusses methods for measuring pain, the WHO analgesic ladder, side effects of analgesics, opioid use in palliative care, and strategies for managing chronic and neuropathic pain, including the DN4 questionnaire and first-line treatments.

Takeaways

• 💊 The International Association for the Study of Pain defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.
• 🩹 Pain is categorized into acute (new onset) and chronic (lasting more than three months), with management guided by local protocols and specialist advice.
• 🧠 Pain consists of sensory (physical sensation) and affective (emotional reaction) components, and it is subjective, meaning that individual experiences of pain must be respected.
• 🔍 Pain can be measured using the Visual Analog Scale (VAS) or Numerical Rating Scale (NRS), with chronic pain being defined as pain persisting or recurring for more than three months.
• 📉 The WHO analgesic ladder suggests starting with non-opioids for mild pain, progressing to weak opioids for moderate pain, and strong opioids for severe pain.
• 💥 Neuropathic pain arises from nerve damage or abnormal nerve function and can present with burning, tingling, or electric shock sensations.
• 🧪 Chronic pain is multifactorial, influenced by biological, psychological, and social factors, and can be primary (without an identifiable cause) or secondary (with an underlying condition).
• 🧬 Treatment for neuropathic pain includes medications like amitriptyline, Duloxetine, Gabapentin, and Pregabalin, with other options like Tramadol for flares and Capsaicin cream for localized pain.
• 💉 Post-operative analgesia is critical for patient recovery, often involving a combination of regular paracetamol, NSAIDs, and opioids, with analgesia started in theater by the anesthetist.
• 🔄 Opioid conversion is essential for safe dosing, with approximate conversions provided in the script (e.g., 10 mg oral morphine ≈ 100 mg oral codeine).

Q & A

What is the definition of pain according to the International Association for the Study of Pain (IASP)?

The IASP defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.

What are the two main categories of pain?

The two main categories of pain are acute pain, which is a new onset of pain, and chronic pain, where the pain has been present for three months or more.

Why is it important to distinguish between acute and chronic pain when managing it?

It is important to distinguish between acute and chronic pain because different management strategies and approaches may be required for each type, and the duration and nature of the pain can influence treatment options.

What are the two aspects of the experience of pain?

The two aspects of the experience of pain are the sensory experience, which refers to the sensory signal transmitted from the pain receptor, and the affective experience, which is the emotional reaction to the pain.

What is the difference between pain threshold and pain tolerance?

Pain threshold refers to the point at which a sensory input is reported as painful, while pain tolerance refers to a patient's response to pain, including how much pain they can endure before seeking relief or altering their activities.

What are the two groups of nerve fibers that transmit pain signals?

The two groups of nerve fibers that transmit pain signals are C fibers, which are unmyelinated and transmit signals slowly, producing dull and diffuse pain sensations, and Delta fibers, which are myelinated and transmit signals fast, producing sharp and localized pain sensations.

What is referred pain and how does it occur?

Referred pain is pain experienced in a location away from the site of tissue damage. It can occur due to shared nerve pathways, amplification of spinal cord sensitivity to signals from other areas, and activation of the sympathetic nervous system in response to pain.

What are the two common methods used to measure pain?

The two common methods used to measure pain are the visual analog scale (VAS) and the numerical rating scale (NRS), both of which ask the patient to self-report their pain on a scale.

What is the World Health Organization's analgesic ladder and how is it used?

The WHO analgesic ladder is a stepwise approach to managing pain, starting with non-opioid medications for mild pain and progressing to weak and then strong opioids for more severe or unresponsive pain. It can be used for acute, chronic, and cancer-related pain.

What are some side effects of NSAIDs and opioids?

NSAIDs can cause gastritis, dyspepsia, stomach ulcers, exacerbations of asthma, hypertension, renal impairment, and coronary artery disease. Opioids can cause constipation, pruritus (itching), nausea, sedation, cognitive impairment, confusion, and respiratory depression.

How is patient-controlled analgesia (PCA) different from other forms of pain management?

PCA involves a patient administering a bolus of a strong opioid medication through a pump when they feel pain, rather than receiving medication on a fixed schedule. It requires patient activation of the pump and is designed to provide more immediate and personalized pain relief.