Understanding Pain

Pain is something we all experience at some point and it can vary greatly in intensity and duration. Musculoskeletal pain affects bones, muscles, ligaments, tendons, and nerves. It can be localised or widespread.

Why am I in pain?

Acute Pain vs. Chronic Pain

Pain is categorised as either acute or chronic depending on how long it has been present. These terms have nothing to do with its severity or intensity.

ACUTE PAIN is pain that comes on suddenly, typically after an injury. It’s usually short-lived and resolves as the body heals.

  • Example: Spraining your ankle.
  • What happens:
    • Nerve endings, known as nociceptors, detect injury and send signals to the brain, which the brain interprets as pain.
    • This immediate pain provides a warning to encourage you to protect the injured area and prevent further damage.
    • Pain may persist if there is tissue damage, but it should eventually subside once the injury heals.

Key Message: Acute pain serves to protect the injured area and promote healing by encouraging rest.

CHRONIC PAIN is pain that lasts longer than 3 to 6 months.

  • Cause: Often, chronic pain continues even after the initial injury has healed or sometimes due to ongoing disease processes like osteoarthritis. Chronic pain can result in pain sensitisation. This happens when, as a result of persistent pain signals, the nervous system becomes oversensitive. It can then amplify pain signals even when any original injury has healed. This process is known as “wind-up” where nerves and pain receptors grow and adapt abnormally.
  • Secondary Effects: There can be secondary effects to chronic pain such as:
    • Deconditioning: i.e. lack of movement due to pain can lead to muscle weakening and a decrease in cardiovascular health.
    • Compensatory Changes: To avoid pain, the body may adopt abnormal postures or movements, which can lead to further muscle imbalances and pain elsewhere in the body.

Key Message: Chronic pain is often more difficult to treat because of nervous system changes and the potential for compensatory movement patterns.

Impact of Chronic Pain

Chronic pain can drastically affect:

  • Daily Function: Impacts ability to perform everyday tasks. or to enjoy hobbies
  • Work: Can lead to difficulty or inability to work.
  • Sleep: Disrupts sleep patterns, leading to further complications.
  • Emotional Well-being: Can contribute to anxiety, depression, and stress.
  • Relationships: Affects interactions with family, friends, and coworkers.

Key Message: Chronic pain can severely reduce quality of life and create a vicious cycle of distress.

Acute vs. Chronic Pain: Why the Distinction Matters

  • Acute pain usually resolves with time and/or appropriate treatment.
  • Chronic pain, due to its complex nature (involving changes in the nervous system), is harder to treat. It is therefore better to seek early intervention before your pain becomes chronic in nature. Remember, pain is classed as chronic once it has been present for around 3 to 6 months.

Imaging and Diagnosis: Do I Need a Scan?

People who experience musculoskeletal pain often think the answer to a diagnosis lies in a scan. Imaging modalities (e.g., x-ray, MRI, ultrasound) look for structural issues in the body. However, not all musculoskeletal pain is caused by structural abnormalities. Some types of pain can arise from functional issues, such as poor posture or muscle imbalances. Functional issues like these don’t show up on radiological imaging but they can still be a significant source of pain.

Imaging can be useful to rule out serious conditions or narrow down a diagnosis, but it doesn’t always give an accurate picture of what is causing the pain and it may not change how the condition is managed.

Pain Perception: Biological and Emotional Factors

It is a mistake to think that the severity of pain is always related to the severity of a condition or injury. Pain perception is much more complex than this and it can influenced by several factors:

  • Competing Sensations: If your brain is processing other sensations (like heat or cold), it can influence how much pain you feel.
  • Emotions: Emotional states can alter pain perception. For instance, someone in a high-stress situation may experience less pain due to adrenaline, while someone who is already anxious, depressed or perhaps going through a bereavement may perceive pain more intensely.
  • Memory: Past experiences can influence how pain is perceived. For example, if you’ve previously had a serious injury, your brain may amplify the pain signal in a similar situation to ensure you take action.

An interesting experience relayed in a TED Talk

The speaker describes how he was trekking abroad and was passing through a forest. He was brushing past fallen twigs and branches when he suddenly felt a scratch on his leg. He didn’t feel any intense pain. His brain had registered the twigs and branches and had processed the signal as a harmless scratch, so it decreased the amount of pain he felt.

A few days later, the man awoke from a coma in hospital. He had not been scratched by harmless tree debris. He had been bitten by a poisonous snake!

Some years later, he was trekking through a similar forest again. This time he felt an intense pain on his leg and fell to the ground in agony. His brain had again registered the fallen twigs and branches, but it also remembered that the last time he was in a similar environment, he had been bitten by a poisonous snake and had nearly died. So his brain wasn’t going to take any chances this time!

It amplified the pain signal so that the pain was unbearable. This was a protective mechanism that would cause him to seek immediate help. However, when his fellow trekkers rushed to help him all that they found was a mild scratch caused by a fallen twig.

This experience illustrates the power of memory in the perception of pain.

Key Message:

Pain is influenced by both biological factors (such as nerve sensitivity) and psychological/emotional factors (such as stress and past experiences).

Summary:

  • Acute pain is short-term and serves a protective function, usually resolving once the injury heals.
  • Chronic pain can last for months or years and is harder to treat due to nervous system changes and compensatory movements.
  • Imaging can help identify structural issues but is not always necessary, as pain can arise from functional problems too.
  • The perception of pain can be a complex mix of biological, psychological and emotional factors.

To conclude: It is better to seek early intervention when you have musculoskeletal pain rather than allowing it to carry on for months and become chronic. And knowing that the perception of pain can be about more than simply biological disease or injury can help you to identify and address other possible factors which might just be preventing that pain from fully resolving.