Complex Regional Pain Syndrome

One of the more striking disease entities we see is complex regional pain syndrome, a name that always frustrated me because it seems to describe the disease but doesn't really say that much. Although some cases of CRPS have a clear inciting event, many don't even have an identified trigger. All of a sudden, the nociceptive and sympathetic nerves to a limb go wild, wreaking havoc. Because of nerve injury or inflammation or dysregulation or changes in sensitization, the normal pain pathways become completely disfigured. Touching a leg may cause excruciating pain. An area that feels numb may simultaneously burn and throb. The leg swells and becomes red. It sweats. The difference between the limbs is remarkable, as shown in the picture above. And because everything's gone haywire, there's no healing. The picture above is six months after an injury, and the left leg has gotten worse and worse in the absence of any ongoing injury. Seeing a few cases of CRPS really taught me how important nerves are. Even though we think of them as tiny wires relaying information, when they get out of control, they can take over a leg and ruin someone's quality of life.

Image shown under GNU Free Documentation License, from Wikipedia.