Centralized pain

While your pain may start as a result of endometriosis, bladder pain, or pelvic floor myalgia the pain impulses that originate at these peripheral sites travel to the spinal cord where they are initially processed within the portion of the spinal cord called the dorsal horn. The impulses travel up the spinal cord into your brain where the final step of processing occurs, and you recognize the pain you are experiencing.  When pain is severe or prolonged, or if you are predisposed to developing central sensitization (there are many predispositions including genetics, family history, narcotic use emotional factors) the processing of sensory information within the dorsal horn becomes disrupted and pain signals are amplified.  Signals also can spontaneously originate within the dorsal horn even when the original cause of pain has been removed.  This concept of centralized pain has been applied to pelvic pain in the last 25 years since I and a handful of other authors introduced the idea.  Patients who have chronic pain will often develop a centralized hypersensitivity that not only generates pain originating from the original source of pain but also develop abnormal reflexes that results in nearby organs becoming hypersensitive through a process often referred to as neurogenic inflammation.  This is why patients that have IC often have vulvodynia.  This is why patients with endometriosis often develop irritable bowel syndrome.  This is referred to as “cross talk”.  Each of these new sources of pain sends impulses to the same area of the spinal cord.  This further amplifies the dis-regulation of sensory processing that is occurring in the dorsal horn, resulting in persistent and self-perpetuating pain.  This is the key to understanding what chronic pelvic pain is.