Visceral pain means pain in the hollow organs, such as gut or bladder.
Visceral pain is not uncommon as part of central pain. It is not one of the identifying features of CP–that role goes to 1) burning dysesthesia, 2) the increase centripetally of any touch or themal pain; and 3)atopoesthesia (comparative loss of perception of the location of the body surface). Lancinating pain is also very common as is visceral pain.
Visceral pain seems to have some anatomic footing. A person may have very severe burning in the bladder, but only a mild sense of discomfort in the gut, or vice versa. Some have terrible bloating in the stomach, but little pain in the rectum, while in others this is reversed.
It is now known than sensory activity in viscera is affected primary by the local nerves and whatever material is present in the viscera. For example, in the gut, food passing activates the small network known as the enteric nervous inputs. However, this is coordinated with the central nervous system. When those controls are lost, the patient may experience symptoms such as “nausea, pain, diarrhea, constipation and bloating” See eg. Beglinger, Ther Umsch. 2007 Apr;64(4):191-3.
Similarly, the appearance of bladder burning is induced by the presence of urine in the bladder. These observations appear to make visceral pain an EVOKED pain. Because evolving theory presupposes that evoked central pain requires peripheral input, new methods of minimizing evoked pain have been considered. For example, resiniferatoxin infused by catheter into the bladder may kill the TRPV-1 receptors in the bladder cells and prevent evocation. We have also invited researchers to inject resiniferatoxin into the successive dorsal root ganglia in order to blod evoked pain. This has not been done, but some researchers report that it is working in the bladder.
Evoked pain is so much more severe than spontaneous burning that we need not wait until the spontaneous is cured before we direct some hits at evoked pain. Lancinating pain, being carried in the posterior columns, is regarded as treatable by most doctors. Dysesthesia, carrried in the anterior spinothalamic tracts, is not regarded as particularly treatable. However, the evoked portion of the pain circuit may be amenable ot medication or other therapy. We await further studies.
