Acute & Chronic Pain

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What Do We Mean by
Acute & Chronic?

Getting the language right from the start. Both are real, both involve genuine suffering — but they are different, and treating them the same way causes harm.

Acute

Less than 3 months

Recent, usually tied to tissue damage. Expected to resolve.

3 MONTHS

Chronic

Beyond 3 months

Its own biology, its own drivers. Needs a different way of thinking.

The 3-month mark is not a magic line. It is a useful guide, not a fixed rule. Some people transition earlier, some later. Duration alone does not tell the whole story.

Pain + Time ≠ Chronic Pain

How the person has been managed matters enormously. Poor clinical interactions can accelerate and cement chronic pain.

Why Does Chronic
Pain Develop?

Understanding the pathways from acute to chronic — and the role the healthcare system plays in that transition.

The Majority

  • Started as acute pain that didn't resolve
  • Often made worse by unhelpful healthcare interactions
  • Fear avoidance begins in the acute phase
  • Poor explanations create lasting fear

The Minority

  • Autoimmune conditions
  • Post-surgical complications
  • Genetic predisposition
  • Simply bad luck

The healthcare system itself can be a contributing factor — through poor communication, excessive imaging, unhelpful explanations, or creating fear and dependency. This is called iatrogenic harm.

Fear Avoidance is relevant at both stages. It can start in the acute phase and carry through into chronic pain if not addressed early. Never underestimate the power of a poorly chosen word.

The Biology
Sensitisation

What is actually happening in the nervous system when pain becomes chronic.

1
Peripheral Sensitisation

After injury, nerves at the tissue level become more sensitive and fire more easily. Normal in the short term — but can persist beyond tissue healing.

2
Central Sensitisation

Over time, the brain and spinal cord become amplified. Less input produces more pain output. The volume is turned up — and stays up.

3
Inflammation

Drives pain in the acute and early chronic phase. A normal healing response — but when it persists, it feeds sensitisation and keeps the alarm ringing.

Key insight: Chronic pain can exist without ongoing tissue injury. The system has become sensitised — it is not just damaged tissue sending signals. This is why imaging often shows "nothing" but the person is still in real pain.

Pain Is Not
Just Physical

Pain is shaped by far more than tissue damage. Every person brings an entire universe of context to their pain experience.

Personal Factors

  • Beliefs about pain
  • Age & identity
  • Personal history
  • Education level
  • Genetic makeup

Social Factors

  • Culture & community
  • Socioeconomic status
  • Family environment
  • Work context
  • Social support

Clinical Factors

  • Previous healthcare
  • Diagnoses received
  • Imaging history
  • Explanations given
  • Trust in clinicians

The patient is the expert on their own experience. Clinicians must listen and not assume they already know the answer. Self-awareness in practice matters — you are also a complex human being walking into that room.

No Two People Experience Pain The Same Way
The Hardwired
Trap

Human brains are wired for cause-and-effect stories. This is useful — but in chronic pain, it leads us dangerously astray.

The Simple Story We Default To

Forceful Incident → Tissue Insult → PAIN ✓

Feels logical. Makes sense. We have experience. This is the model that is hardwired.

The Reality in Chronic Pain

Every Other Bloody Thing → Last Thing You Did → PAIN ✓

The brain fills in the gap with the most recent activity — even when it is completely unrelated to the actual cause.

Clinical risk: This leads clinicians to over-attribute pain to the last movement, position, or activity — and leads patients to unnecessarily avoid things that are actually safe.

Rule 4 — Don't confuse a model for reality. Clinical frameworks are useful tools — not the truth. Stay humble about what you think you know. The map is not the territory.

Common Clinical
Mistakes

How treating acute and chronic pain as completely separate categories creates new problems in both directions.

Problematic Beliefs

Problems Created in Both

Mistakes With Acute

  • Ignoring external stressors
  • Overusing imaging and scans
  • Creating catastrophic narratives
  • Building passive dependency

Mistakes With Chronic

  • Ignoring tissue states entirely
  • Assuming "all in the head"
  • Thinking information alone cures
  • Confusing research averages with individuals
What Patients
Experience

After seeing many clinicians and receiving many explanations, patients with chronic pain often still don't understand why they hurt. This is a system failure.

"I Have No Idea Why It Hurts"

Signals That Something Went Wrong

Dismissal Pathway

  • "They didn't even touch me"
  • "They just talked to me for an hour"
  • "They said it was all in my head"

Over-Medicalisation Pathway

  • "I've seen 10 people, no one knows"
  • "CT and MRI showed nothing — must be bad"
  • "Machines 3 times a week for 6 weeks"
  • "One tight muscle, one not working"

Negative imaging does not mean pain is not real. Patients need this explained clearly and confidently. "Nothing on the scan" is not the same as "nothing is wrong."

Poor, inconsistent, or alarming explanations increase fear, increase sensitisation, and increase chronicity. Your words are a clinical intervention — choose them carefully.

The Rules for Not Being
A Bad Clinician

A practical framework for doing better — in every consultation, with every patient, regardless of whether their pain is acute or chronic.

1
Use Words Carefully

Language shapes how patients understand their pain. The words you choose can heal or harm. There is no neutral explanation.

2
KISS — Keep It Simple

Don't overcomplicate explanations. Clear, honest, simple communication is almost always more therapeutic than complex narratives.

3
Don't Make Things Up

If you don't know why someone is in pain, say so. Inventing explanations destroys trust and increases fear. Uncertainty is honest. Fabrication is dangerous.

4
Don't Confuse a Model for Reality

Frameworks are useful guides — not the truth. Stay humble about what you think you know. Every model is a simplification.

5
Don't Overpromise

Only commit to what you can actually deliver. False hope followed by disappointment is worse than honest uncertainty.

Key Terms &
Summary
Term Simple Definition
Acute Pain Pain present for less than 3 months, usually linked to tissue damage or injury
Chronic Pain Pain persisting beyond 3 months, often involving nervous system changes rather than ongoing damage
Peripheral Sensitisation Nerves at the injury site become more sensitive and reactive over time
Central Sensitisation The brain and spinal cord amplify pain signals beyond what tissue damage alone explains
Fear Avoidance Avoiding movement due to fear of pain — worsens outcomes in both acute and chronic stages
Iatrogenic Harm Harm caused unintentionally by the healthcare system or clinician, not the original condition
KISS Principle Keep It Simple — clear communication is more effective than complex explanations
Natural History The expected course of a condition without treatment — useful context, but not a cure for everything
The Best Clinical Tool Is How You Communicate

Evidence base: This module draws from peer-reviewed work by Hoegh, Loeser, Kiverstein, Wand, Stilwell, Nijs, Gifford, and others across pain neuroscience, central sensitisation, fear avoidance, exercise therapy, and patient-centred care.