Pain amplification syndromes

When we experience pain, we tend to link it to an injury to our body.

This is usually true. When our bodies sustain damage, damaged cells release chemicals. Nerves sense the chemicals and send a signal to the brain, which causes us to feel pain.

However, this is only sometimes the case.

There are a group of conditions called pain amplification syndromes.

Conditions within this group include:

• Fibromyalgia

• Temporomandibular disorders

• IBS

• Pelvic pain syndromes

• Tension-type headaches

These conditions have minimal tissue damage compared to the pain experienced.

This is because the central nervous system amplifies the pain experienced in these conditions.

There may be some tissue damage or inflammation feeding into the pain pathway; however, this is then amplified by the pain pathway itself, giving the disproportionate pain levels.

The pain pathway begins in our tissues (muscles, tendons, ligaments, skin, and joints), passes through local nerves in the area, reaches the spinal cord level responsible for the nerves in that area, ascends the spinal cord to the brain, and then travels throughout the brain to give us the pain experience.

Another point is that no single pain centre exists within the brain.

When a pain signal reaches the brain, it is separated into a medial and lateral pathway.

The lateral pathway is involved in the sensation component of pain, producing information on the pain's location, characteristics and intensity.

The medial pathway projects to the front of the brain and generates the unpleasantness and suffering of pain.

Combining these two brain pathways gives the complete pain experience, and an increase in either will increase the pain experience.

In the pain amplification syndromes, the pain experienced is enhanced and may even be generated in the pain pathway.

This may be in one area, such as the spinal cord, or from multiple regions.

Furthermore, these conditions are vulnerable to pain flair-ups, a temporary increase in the pain experience.

Again, we tend to associate an increase in pain with an increase in damage; however, in pain amplification syndromes, the increase in pain can come from the central nervous system.

This includes the brain, which is why occasionally flare-ups may occur after psychological stress, such as exerting ourselves cognitively, experiencing emotional distress, or having an intense sensory experience.

When we manage these conditions, our aim should be the local areas generating pain and the whole pain pathway from tissues to the brain.

The first step should be to reduce any damage to our tissues that may contribute to the pain experience.

Whilst pain amplification syndromes have a significant central nervous system component, they may still have input from our tissues that helps sustain the pain experience.

Therefore, the first step is identifying any peripheral tissue issues that can be addressed.

Once we have done all we can to address peripheral issues, we move to the central nervous system.

We do not yet have the diagnostic clarity to identify precisely where in the pain pathway pain is amplified or in what percentage each contributes.

Therefore, currently, we have to treat the pain pathway holistically, working on all areas simultaneously.

The medications which are often used in these conditions include serotonin-norepinephrine inhibitors such as duloxetine, anticonvulsants such as gabapentinoids and low-dose naltrexone.

These medications attempt to change the pain signals in the pain pathway.

These are often coupled with physical activity, psychology work and diet.

Physical activity is often done in a start-low, go-slow style, where activities are performed at a low intensity to prevent the pain from worsening.

They also include physical rehabilitation exercises to help improve any biomechanical issues which may be contributing.

The psychology work is often an adapted anxiety program.

This is not necessarily because the individuals have an anxiety disorder, but the brain areas involved in generating the unpleasantness and suffering of pain overlap with those involved in generating anxiety.

Therefore, by performing an anxiety-targeting therapy program, the brain areas involved in pain generation are targeted.

Finally, the diets deployed in pain amplification syndromes improve overall metabolic health and gut bacteria.

The two most commonly cited diets are the Mediterranean and FODMAP diets.

The Mediterranean diet is high in fruits and vegetables, moderate in healthy fats and protein, and minimal in processed foods and foods high in sugar.

The FODMAP diet is a diet low in foods that may be poorly digested and ferment in the digestive tract, producing gas and discomfort.

In summary, pain amplification syndromes are conditions characterised by a disproportionate level of pain compared to the level of evident tissue damage.

The pain experienced in these conditions is amplified and occasionally generated by the pain pathway.

Due to the pain occurring from the pain pathway, traditional treatments which target tissues and inflammation are often unsatisfactory.

Therefore, management should focus on targeting the whole pain pathway.