Central Pain Syndrome – It’s not in your head (kinda)

Fibromyalgia, IBS, unrelenting limb pain, chronic penile pain, pelvic floor syndrome, interstitial cystitis, and reflex sympathetic dystrophy are central pain syndromes (CPS).  All of them are conditions sufferers are told they must live with and hopefully control with medication.

Central pain syndrome is caused by damage or malfunction in the central nervous system (brain and spinal cord).  This is the patient that has unrelenting pain in, let’s say, their leg that won’t go away and all testing is “normal”.  Instead of looking to the central nervous system for the cause the practitioners then attempt to treat the peripheral location of the pain or dysfunction.  For example, if the urinary bladder “hurts” (as in interstitial cystitis) practitioners are trained to first look at the bladder itself.  MRI’s, CAT scans, etc.  Then they would perform a urinalysis and blood panel to look for bacteria.  If your penis hurts the PCP will look at it and do testing to determine if you have a sexually transmitted disease.  Mouth burning?  Let’s look in there and determine if you have herpetic lesions or a vitamin deficiency causing the mouth problem and so on.

This approach is appropriate as part of a “complete” evaluation, but all pain is transmitted by nerves and perceived by the brain.  So, if the nerves are not evaluated when all tests are “normal” then a complete evaluation has not been performed.  It almost never is.  If nothing is found at the pain site with standard non-neurological testing that’s the end of the search for the cause and treatment is to offer the patient partial relief through pain medications – which do what?  They alter nerve function to reduce the pain.

When the diagnosis is not clear to the practitioner it will often be told to the patient “there is nothing wrong with you” this can cause significant psychological ramifications for the patient.  This puts most patients into an immediate stress response causing stress hormone production which creates a vicious cycle by inflaming the system and further perpetuating their pain.  To understand all of this let’s get a tiny bit scientific for a moment and discuss the gating theory of pain.

If someone pinches the skin on your hand nerve cells in the area send a signal to your spinal cord, then up to the brain.  Your brain, at the same time, is trying to shut off other pain signals that are happening all the time all over the body.  To accomplish this feat there are “gates” in your spinal cord that open and close to stop the pain or let it flow through from the affected body part to the brain.  In central pain disorders the “gating” mechanism breaks down.  When it breaks down “escape” of pain takes place from one area of the body to another area instead of going to the brain to be “blocked” (i.e. your pelvic floor, bladder, penis, mouth, bowels, or involvement of entire body as in fibromyalgia).  So a “small” pain in the shoulder could become full blown fibromyalgia.  This is the basic mechanism of central pain syndrome.

Stress hormones can instigate or fluctuate CPS in other ways.  If you once again pinch a person’s hand who already has CPS the pain signals will facilitate stress hormones to travel to the spinal cord and up to the brain.  Thus even more pain is perceived.  The more the pain increases stress hormones the more this vicious cycle creates pain.

Poor sleep is a factor that affects brain function in CPS.  Patients with CPS don’t sleep well.  When you don’t sleep well areas of brain cells in your brain stem don’t send the proper signals down the brain stem to help the spinal gating mechanism to stop the pain.

Lastly there is a high percentage of autoimmunity found in the CPS patient population.  Recently autoimmunity relative to its relationship in fibromyalgia has been well documented.  So not only can CPS patients not shut off pain from their bodies and not only do they not sleep so that their brain doesn’t shut off pain signals, but most also have autoimmune responses which increase inflammation in their body.  The immune inflammation promotes further pain signals coming to their brain even though there’s nothing wrong in their target tissues (areas of pain) throughout the body.

So much of the time when the patient is told it’s “in their head” it’s only sort of in their head – and spinal cord.

Next month – What’s the solution?