Introduction to Chronic Pain
Chronic Pain: Chronic pain is pain that continues for three or more months. While acute pain is a normal function of living beings, chronic pain is considered to be pathophysiological, or associated with disease or injury.
1 in 4 Canadians live with Chronic Pain, with specific populations of people being more affected by chronic pain than others.
Reference link: View
Women
Pain may present differently in women than in men. Due to a bias in many studies that include only men, women’s pain may be underdiagnosed. Women may also have more limited access to healthcare.
Indigenous Peoples
Some Indigenous communities experience barriers limiting access to healthcare. In addition, racism, stigma, and the impacts of intergenerational trauma can further affect their experiences of and with pain.
Reference link: AFMC UGME module “The Public Health Perspective” and CEPPP
Older Adults
Older adults may also have difficulty accessing care. Concurrent medical conditions can limit options for pharmacological treatment. For example, non- steroidal anti-inflammatory drugs are not safe for patients with renal dysfunction.
Reference link: AFMC UGME module “The Public Health Perspective” and CEPPP
Veterans
Veterans may concurrently experience post-traumatic stress disorder (PTSD) or other mental health conditions, which further complicate their experience of pain
Reference link: AFMC UGME module “The Public Health Perspective” and CEPPP
Access to healthcare can be challenging as they transition from Department of National Defense / Canadian Armed Forces health care services to the provincial / territorial healthcare system.
People Who Use Recreational Drugs
People who use recreational drugs report difficulty accessing healthcare due to stigma.
People who use recreational drugs report difficulty accessing healthcare due to stigma. Recreational drug use can alter pain thresholds. For example, patients with Opioid Use Disorder may experience hypersensitization. Some people in chronic pain may self-medicate with substances like alcohol and cocaine.
Reference link: AFMC UGME module “The Public Health Perspective” and CEPPP
Chronic pain itself a disease which can have a considerable impact on the lives of individuals.
Patients need understanding from their family, support network and healthcare providers. Isolation is harmful and further impairs physical and psychological function.
Pain management is an active process. An individual’s attitude physical activity, psychological and social environment can directly impact their perception of pain.
Primer on Pain
The International Association for the Study of Pain defines Pain as, “An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage”. This definition links emotion to the sensory experience.
In general, pain can be broadly categorized based on its duration:
Reference link: AFMC UGME module “The Pathophysiology of Pain”
ACUTE:
Acute pain is pain lasting less than three months. It tends to result from an injury. Acute pain responds well to opioids. Some causes of acute pain are inflammation, surgery, broken bone, infection, and childbirth.
Reference link: View View
CHRONIC:
Chronic pain persists for three or more months. While acute pain is a natural response to injury, chronic pain is abnormal. Non-opioid medications should be used before opioids are prescribed for chronic non-cancer pain.
Reference link: View View
Other classifications and types of pain:
CANCER-RELATED PAIN: :
Cancer-related pain arises from cancer or tumors and their effects on the body.
Reference link: View View
NEUROPATHIC PAIN:
Neuropathic pain results from nerve damage due to injury or disease.
Reference link: View View
NOCICEPTIVE PAIN:
Nociceptive pain results from an injury or disease outside the nervous system.
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MIXED PAIN:
Mixed pain is a combination of neuropathic and nociceptive pain.
Reference link: AFMC UGME module “The Pathophysiology of Pain”
NOCIPLASTIC PAIN:
Nociplastic pain arises from altered perception of pain despite no clear evidence of actual or threatened tissue damage
Reference link: AFMC UGME module “The Pathophysiology of Pain”
Mythbusters
Myth #1: Pain always means harm.
Fact: We can experience pain even when there is no explicit harm.
We all have a sensory “pain alarm” set to protect us from danger. If you put your hand on a hot stove, you automatically remove it the moment you feel heat. However, a false pain alarm can “go off” when there isn’t danger.
Reference link: View
False pain alarms still cause real pain.
Chronic pain is thought to be caused by pain signals that fire out of control, even when there isn’t a real threat. By assuring yourself and your brain of safety, over time, you can learn to decrease the pain alarm. The alarm system is your brain and nervous system.
Reference link: View. The alarm system is your brain and nervous system.
Dealing with chronic pain is frequently about resetting the pain alarm system in order to restore regular function.
Reference link: View
Myth #2: Chronic pain treatment require pain medication.
Fact: There is no perfect medication for chronic pain.
There is no magic pill for chronic pain. The best way to manage pain is through exploring multiple avenues - a “multimodal approach”. Some examples of chronic pain treatment include:
- Physical activity
- Self-management programs
- Physiotherapy
- Counseling / Psychotherapy
Reference link: AFMC UGME module “Core Concept in the Management of Pain”
The goal is to take an active role in managing chronic pain and turning down each pain alarm.
Myth #3: Pain always means you need to stop physical activity.
Myth: Exercise can help.
When you are injured and experience acute pain, your pain alarm correctly tells you to stop and rest. However, when experiencing chronic pain, stopping any time you feel pain can be harmful. It can lead to loss of muscle mass, isolation, depression, and poor quality of life. Resting too much makes people feel worse, while moving can release endorphins (feel-good brain chemicals) that help with both pain and mood. Pacing yourself when exercising to minimize pain flare-ups and help to achieve pre-planned activity goals.
Reference link: View
Myth #4: People who are dependent on opioids simply need better willpower.
Fact: It’s more complicated than that.
Opioid Use Disorder is a loss of control over the use of opioids. The person continues to use opioids despite negative consequences, or is unable to stop using opioids despite wanting to stop.
Long term misuse of opioids can alter brain function and cause lasting changes in the brain reward system. Reference link: View
Myth #5: People with Opioid Use Disorder are “addicts” or “junkies.”
Fact: Words are powerful.
Negative terms such as “addict”, “user”, “junkie”, and phrases like “needs to get clean” stigmatize people with Opioid Use Disorder and create barriers to effective treatment, further damaging the individual. A person is not defined by the condition or status of their health.
Reference link: View
What are potential side effects of opioids?
Side effects of opioids can include:
- Sleepiness
- Constipation
- Nausea
Opioids can also cause more serious side effects that can be life-threatening.
The following might be symptoms of an opioid overdose and require immediate action.
- Shallow breathing
- Slowed heart rate
- Loss of consciousness
Call 911, go to an emergency department, administer naloxone.
Individual side effects vary. When considering a medication, discuss its risks and benefits with your healthcare provider.
If you suddenly stop taking opioids, you may experience withdrawal symptoms such as jittery nerves, upset stomach, vomiting, agitation, trouble sleeping and/or increased pain.
The body adjusts to opioid use as its normal state and thus increased doses may be needed to relieve the pain. This may lead to opioid use disorder.
Reference link: View
Opioid-induced hyperalgesia (OIH)
Hyperalgesia is an elevated pain response to a stimulus that usually causes minor pain. Some people taking opioids may become more sensitive to pain.When opioids are taken for a long time, the brain will create new pain signal pathways. The body does this to try to overcome blocked pain signals. People who take opioids are at greater risk of developing OIH. It varies patient-to-patient for how long someone can be on opioids before developing OIH. The period of time will depend on the individual.
To treat OIH, people should slowly and patiently wean from their dose of opioids. Tapering should be done with your healthcare provider. During this treatment, people should talk with their healthcare provider about whether to continue or add non- opioid treatments to manage pain, such as other medications, psychological therapy, self-help interventions, and physiotherapy.
Reference link: VIEW
What are the behavioural signs of Opioid Use Disorder?
People with Opioid Use Disorder may change their behavior. Possible signs can include:
- Spending time alone (avoiding family / friends)
- Losing interest in activities enjoyed previously
- Decline of personal hygiene
- Depression
- Change in appetite (eating less / more)
- Overly energetic (talking fast /being incoherent)
- Acting nervous or cranky
- Rapid mood changes
- Changes in sleeping patterns
- Missing appointments
- Criminal behaviour
- Ignoring responsibilities (work / school / family)
Reference link: VIEW
What are Risk Factors for Opioid Use Disorder?
Most people who take opioids as prescribed do not develop an opioid use disorder. When taken not as directed by a healthcare provider, opioids are risky. This can include taking opioids by crushing a pill, snorting or injecting.
“This life-threatening practice is more dangerous if the pill is a long- or extended-acting one. A rapid delivery of the drug into your body can cause an overdose.” It is also risky to take more than the prescribed dose of opioids or taking opioids more often than prescribed. “Risk increases with the length of time taking opioids. The risk of misusing opioids a year after starting a short course increases after only five days on opioids.”
Additional factors (e.g. genetic, psychological, and environmental) can also play a role.
Reference link: VIEW
"Known risk factors of opioid misuse include:
- Unemployment
- Family history of substance use
- Personal history of substance use
- Young age
- History of criminal activity or legal problems
- Regular contact with high-risk people or high-risk environments
- Heavy tobacco use
- History of severe depression or anxiety
- Stressful circumstances”
Reference link: VIEW
Pain Management
Pain is more than a physical sensation. It has biological, psychological, and emotional factors.
Chronic pain can cause anger, hopelessness, sadness, and anxiety.
Non-pharmacological methods of managing pain should be considered first in chronic non-cancer pain, then non-opioid medications.
Effective medical, surgical, rehabilitative, and physiotherapeutic treatment may be helpful. AFMC UGME module “Core Concept in the Management of Pain”
Psychological treatments can be an important part of pain management.
Understanding and managing thoughts, emotions and behaviours that accompany pain can improve coping skills and reduce the intensity of pain.
In collaboration with a healthcare provider, choose treatments that feel comfortable. Initiate, adapt, and evaluate a treatment plan as you implement it.
A 30% reduction in pain or improved function is significant. Even a smaller improvement may be meaningful in day-to-day life. ( AFMC UGME module “Core Concept in the Management of Pain” )
Non-pharmacological methods of managing chronic pain can include:
Sleep Hygiene
Sleep, or lack thereof, is a challenge for many Chronic Pain patients. For more information about improving sleep, please see:
- https://painhealth.csse.uwa.edu.au/pain-module/sleep-and-pain/
- American Academy of Sleep Medicine. Healthy Sleep Habits. 2021. https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/
- Sleepwell | It's no dream. Sleep well without sleeping pills. (mysleepwell.ca)
Physical Activity
- Physical activity is recommended for chronic pain conditions such as low back pain, fibromyalgia, and osteoarthritis.
- Group activities can increase engagement, commitment and decrease feelings of isolation.
- Home based physical therapy can also be explored as an option.
- After a good work-out, exercise can hurt, but it does not mean that it is dangerous. Most physical activity is safe and recommended as part of chronic pain management. Work with your healthcare provider to develop the most appropriate exercise program. Reference link: VIEW
- Be patient:
- A minimum of 30 minutes, five days per week is recommended, but people with pain may find this goal overwhelming.
- As little as 15 minutes per day has major benefits (If that's too much, start with 5 minutes of gentle movement. Every little bit helps.)
- Be patient:
- A little more intense activity than normal, repeated daily, can reap benefits. The goal is to retrain your nervous system to understand that movement is safe. As a result, you will gradually increase your activity and build strength.
- Track your progress to evaluate the effects of physical activity on pain and function.
- For more information, please see: https://painhealth.csse.uwa.edu.au/pain- module/movement-with-pain/
Physiotherapy
- Passive and active physiotherapies are recommended for low back pain, neck pain, and neuropathic pain.
- Passive therapies do not require active involvement. It is useful in short-term. Examples include massage therapy, TENS and laser therapy.
- Active therapies require “homework”, usually stretching or strengthening work in between treatments.
Self-Management Programs
- Self-management is on managing oneself and taking responsibility for one’s own behaviour and well-being.
- Self-management plays a key role in chronic pain management
- Self-management programs are primarily educational, using interactive and collaborative methods facilitated by trained peers or healthcare providers. Topics include goal-setting, self-monitoring, and psychological and exercise therapies.
- Programs can be provided individually or in groups, in person or virtually. Whatever the mode, take an active part in managing your pain!
Psychological Treatment and Counselling
- Cognitive behavioural therapy (CBT) is a well-recognized psychological treatment for chronic pain. The basic principle of CBT is that feelings, thoughts, and behaviours influence each other. The sensation of pain cannot be targeted directly but thoughts and behaviours can be modified, which will then affect the feeling.
- Changing beliefs (thoughts) about the perceived danger represented by pain changes the pain experience (feeling) thus, increasing confidence to exercise (behaviour) and improves the sensation of pain.
- Other types of psychological treatment include mindfulness-based interventions, acceptance, commitment therapy, and respondent behavioural therapies.
- Working with a psychologist/counsellor, involves discussions about physical and emotional health. The psychologist/counsellor may ask about the pain experienced, where and when it occurs, and what contributing factors may affect it. (In addition, they will likely ask about any worries or stressors, including those related to pain. You also may be asked to complete a questionnaire that explores thoughts and feelings about pain.)
- Understanding your concerns will help the psychologist develop a treatment plan.
- The plan often involves teaching relaxation techniques, changing old beliefs about pain, building new coping skills and addressing any anxiety or depression that may accompany your pain.
- A psychologist can help develop new ways to think about problems and support in finding solutions.
- Studies have found that psychotherapy can be as effective as surgery for relieving chronic pain. Psychological treatments for pain can alter how the brain processes pain sensations.
- A psychologist/counsellor can also help with lifestyle changes to permit continued participation in work and recreational activities. Pain often contributes to insomnia, a psychologist/counsellor may suggest sleeping methods that could improve overall sleep quality. AFMC UGME module “Core Concept in the Management of Pain”
Medications that can help with chronic pain
- Five classes of non-opioid medications can be used to manage non-cancer chronic pain: non- opioid analgesics (e.g. Acetaminophens, NSAIDs, Antidepressants, Anticonvulsants, Cannabinoids, and Transdermal compounds.)
Non-opioid analgesics
Acetaminophen
- Acetaminophen is a pain medication that you take by mouth. It is also used to prevent or reduce fever. In combination to NSAIDs, it is useful in pain caused by arthritis. The recommended dose of acetaminophen is 1000-4000 mg/day. The maximum dose (4000 mg per day) is for short term treatment (5 days or less). Many medications (such as over-the- counter cough, cold, and pain medications) contain acetaminophen. Take care to avoid accidentally ingesting over the maximum dose. At too high a dose, acetaminophen can be toxic to the liver. People with liver disease or who chronically use alcohol could experience liver toxicity with lower doses. AFMC UGME module “Core Concept in the Management of Pain”
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):
- NSAIDs, or non- steroidal anti- inflammatory drugs decrease inflammation, fever, and pain. They are indicated for chronic, nonspecific low back pain. AFMC UGME module “Core Concept in the Management of Pain”
Some examples include:
- Ibuprofen: 200 mg every 4-6 hours, maximum 1200 mg/day
- Naproxen: 220 mg 1-2 pills every 6-8 hours, maximum 660 mg/day
- Ketorolac: 10 mg every 6-8 hours, maximum 40 mg/day
- Celecoxib: 100-200 mg twice a day, maximum 400 mg/day
Some side effects include:
- "Non-aspirin NSAIDs can increase the chance of heart attack or stroke.” People who have heart disease, smoke, have high blood pressure, high cholesterol, diabetes or related risk factors, are at greater risk. “This risk can occur early in treatment and may increase with longer use".
"Other side effects can include:
- Heart failure
- Bleeding in the intestines or stomach
- Feeling bloated
- Heartburn
- Stomach pain
- Nausea, vomiting
- Diarrhea
- Constipation"
Reference link: AFMC UGME module “Core Concept in the Management of Pain”
Antidepressants
- While antidepressants are normally used to treat depression, some can also be used in the management of neuropathic pain.
Some examples of Antidepressants include:
- Tricyclic Antidepressants (TCAs):
- Amitriptyline can be used in neuropathic pain.
- Side effects include constipation, weight gain, and dry mouth and eyes. It can be sedating so should be used with caution in the frail and elderly.
- Desipramine and Nortriptyline can be considered if amitriptyline is not effective. They are less sedating. Reference link: AFMC UGME module “Core Concept in the Management of Pain”
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs):
-
- Venlafaxine can be used in Neuropathic pain.
- Duloxetine has been approved for painful diabetic neuropathy, Fibromyalgia, and low back pain, as well as Major Depressive Disorder and Anxiety.
- All SNRIs have similar side effects, including
- Heart palpitations
- High blood pressure or low blood pressure with position change
- Nausea or upset stomach
- Weight gain
- Fatigue
- Liver toxicity
- Sexual dysfunction
- All SNRIs have similar side effects, including
Reference link: AFMC UGME module “Core Concept in the Management of Pain”
Anticonvulsants
Anticonvulsants are commonly used to treat seizures. They can also help relieve neuropathic pain.
- Gabapentin can be considered for neuropathic pain but reduces pain by less than 1 point on a 10-point pain scale. Side effects include upset stomach, dry mouth, weight gain, dizziness, drowsiness, or confusion.
- Pregabalin is indicated in neuropathic pain and fibromyalgia. It is an option if gabapentin or amitriptyline are not effective or have side effects that are not tolerated.
- Carbamazepine: the first line treatment for trigeminal neuralgia.
- Lamotrigine tends to be hit and miss in the treatment of neuropathic pain.
- Topiramate lacks evidence of benefit in chronic pain, except for recurrent migraine. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Cannabinoids
Cannabinoids are found naturally in cannabis and are indicated for neuropathic pain. The two most notable cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD).
- THC is the only cannabinoid currently synthesized and approved for medical use. It is associated with the psychotropic effects of cannabis.
- CBD’s effects are much less known . It has fewer psychotropic effects than THC.
Cannabinoids are not as effective as antidepressants or anticonvulsants in treating chronic pian. Examples of cannabinoids used in neuropathic pain include nabilone, nabiximols, and dried cannabis. The long-term benefits and harms of cannabinoids for the treatment of chronic non-cancer pain are not well studied. Side effects of cannabinoids include mood changes, nausea, dry mouth and eye, drowsiness, and Cannabis Use Disorder. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Transdermal compounds
Transdermal compounds are applied on the skin. They are well tolerated but there is less evidence for their effectiveness than the other non-analgesic options noted above. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Examples of transdermal compounds or topical drugs are:
- Diclofenac
- Baclofen
Opioid Medications for Chronic Non-cancer Pain (CNCP)
While not the preferred treatment for chronic non-cancer pain (CNCP), opioids can be considered in some cases. If opioids are used, they should be combined with non-pharmacological treatments and non-opioid medications. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Diagnosis
Discuss your diagnosis with your healthcare providers to see if it meets the indication of opioids. Currently, there is not enough evidence to support the use of opioids in fibromyalgia or headaches. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Treatment
Before considering opioids for your chronic pain, you should consider non-opioid treatments. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Severity
Determine whether pain is severe enough to interfere with day-to-day activities. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
Risk
If you are at a high risk of developing an Opioid Use Disorder, you may benefit from seeing a specialist in addictions medicine. Reference Link: AFMC UGME module “Core Concept in the Management of Pain”
High risk factors include:
- Current anxiety, depression, post-traumatic stress disorder (PTSD)
- Current or past history of substance use (e.g. alcohol, opioids, cannabis)