What is central sensitization?

Central sensitization: the back story to just about every story I tell on this blog. I’ve written the phrase a million times, but always in passing, always with a link to an article somewhere else. I think it’s high time the topic gets its own post.

Practice Makes Perfect

We’ve all heard the phrase “practice makes perfect,” right? When you want to get better at something, you practice. Want to learn how to play the piano? Practice. Want to learn how to ride a bike? Practice.

Our nervous systems are always changing and growing, in response to the things we do. Our brains form new connections all the time.

This is how we learn how to control our fingers, and move them more quickly and in more complicated patterns, when we practice the piano. It’s how we learn to balance when riding a bike. It becomes second nature.

Unfortunately, the same thing can happen when you give your nervous system enough changes to “practice” sending pain signals.

It sounds crazy, but basically, our nervous systems get better at sending these signals. It doesn’t happen automatically– you won’t develop central sensitization if you stub your toe, or get stung by a bee.

But it can happen if the pain goes on for long enough. For example, central sensitization can happen to someone who’s hurt their back, and has been in pain for a few months. The nervous system has been sending these pain signals over and over again, and now– just as if the person had been practicing the piano for a few months– the task has gotten easier.

Central sensitization can also occur in someone who has suffered a larger degree of physical trauma in a shorter time period. For example, it can happen to someone who’s had surgery– even if they were under anesthesia at the time.  Consciousness isn’t required for central senstization to occur.

This is because central sensitization involves nerves, your spinal cord, and the parts of your brain that process pain without conscious thought. They are still learning how to process all those pain signals, even if you are under anesthesia. (Of course, I’m not saying this will happen to everyone who has surgery. It is, however, a possibility).

In a nutshell, central sensitization means the central nervous system becomes more sensitive.

There are many different ways in which central sensitization can manifest itself– the symptoms are not always the same from person to person.

The differences have to do with the person’s individual genetic makeup, what the original illness or injury was, and other health issues the person may have. (And yes– the person’s beliefs and perspective on pain can have an impact on how they respond to central sensitization, but they do not cause it. More on this later– I have very strong feelings on the subject!).

Invisible Illness

Scientific research has shown that central sensitization tends to be present in patients suffering from many of the conditions people generally refer to when they talk about “invisible illness.” These conditions include fibromyalgia, chronic regional pain syndrome, migraine, temporal-mandibular joint disorder, chronic pelvic pain, and irritable bowel syndrome.

Sometimes central sensitization is the root of the problem: for example, researchers now generally believe it to be the cause of fibromyalgia (please, please don’t believe the other things you read!).

In other cases, central sensitization is one of several contributing factors (still playing an important role, however). This is more likely to be the case in conditions such as irritable bowel syndrome, which can also be influenced by food intolerances/imbalances in gut bacteria, and temporal-mandibular joint disorder, which involves the physical pathology of the joint. In these cases, central sensitization perpetuates the problem and causes additional pain and discomfort, but is not necessarily the primary cause.

The Common Link

Because central sensitization is the common cause, it makes sense that so many patients with fibromyalgia also suffer from other “invisible illnesses.” For example, studies have shown that significant numbers of fibromyalgia sufferers also have irritable bowel syndrome.

I have so much more to say on this topic– more research to tell you about, the history of how it was discovered, as well as my own personal stories.

But…. as I have to keep reminding myself, I’m writing a blog, not a textbook… so all of that will have to come in future posts!

Citations:

I think it’s important to always post links to scientifically-valid articles when I talk about scientific/medical concepts.

Here is a great plain-English overview on central sensitization, written by Christina Lasich, M.D., for HealthCentral.net.

Next, an incredible overview of the science on central sensitization from Paul Ingraham of PainScience.com, which is an amazing website.

Ingraham’s article is actually a “jargon-to-English” summary of this important review of the scientific literature on central sensitization written by Clifford Woolf, the researcher who first discovered central sensitization back in 1983.

Finally, check out this equally important article from Muhammad Yunus, who has done vital work exploring the common links between central sensitization and the invisible illnesses (he calls them central sensitivity syndromes in this article).

I realize that the average reader might not be able to understand all of the scientific terms in these articles (I know I struggle), but I want you to know that legitimate and credible information is out there, and this is what it looks like.

A Note to My Readers:

I am always happy to answer any questions that you might have.  I think that all of this information is so important for us to be aware of as chronic pain sufferers!  It can really be life-changing, once you start to truly understand the roots of your condition.

I am always so curious to know what you think! Did you already know that central sensitization is believed to be the cause of fibromyalgia?  Does the common link between fibro and other invisible illnesses make sense to you? Let me know!