This is a video made by Dr Sletten of The Comprehensive Pain Rehabilitation Center at The Mayo Clinic about a condition called Central Sensitization Syndrome which can be a cause of chronic pain and discomfort. My notes follow the video.
In our peripheral nervous system, we have tiny sensors in every part of our body (aside from hair and fingernails). These sensors are in our skin, gut, muscles, joints, bones, vestibular system, nerves, vascular system, vision, hearing, taste, and smell. These sensors pass information on the the central nervous system about our safety and comfort so that we can respond appropriately (drink when we are thirsty, for example). There can be situations that cause the sensors to be up-regulated (to send a stronger signal), and once this happens they stay upregulated, continuing to send stronger signals. Sensory symptoms can become very problematic. This syndrome may start after an injury, illness or disease, surgery, hereditary, or some repetitive injuries.
Once the input from the peripheral sensors becomes upregulated, it sends increasingly stronger signals to the brain. The somatosensory cortex, which is where all of our sensory input into the brain goes to be analyzed, begins to react more strongly. Input that may have been mild and easily handled in the past, such as discomfort from clothing, can become much more distressing. Because the Somatosenosry Cortex is organized by body part, pain and discomfort in one part of the body can lead to other symptoms in the same area of the body. This leads to another group of symptoms that can be worse over time including pain, fatigue, dizziness, nausea, sensitivity to temperature, touch, tastes, sounds, smells, even barometric pressure. None of this is psychological, it is physiological. Patients don't bring this on themselves.
There are 4 reactive and maintaining factors which include physical, emotional, behavioral, and chemical. When patients are on many meds, it can cause confusion in the brain as they interact, they call this "polypharmacy". In this way "over-medicating" can make the problem worse. Behavioral reactions to pain such as avoidance can worsen the situation because the muscles can become deconditioned. The emotional distress about being sick and dealing with pain can itself also be overwhelming to the brain and can increase the overall stress on the brain. He is careful to point out that emotions are a response, NOT a cause in this condition.
Mayo treats this with The Pain Rehabilitation Program, which is a 3-week program (40 hours a week) in which they work with patients to alter those 4 factors that can amplify the sensory signals.
