PHANTOM SENSATIONS AND PAINS

Phantom sensations occur after loss of a part of the body, most commonly a limb.

The person feels that the part of the body is still there. If it is painful as well then it is known as phantom pain. This latter scenario is more likely to occur if the part of the body that has been lost was painful prior to its loss. Phantom pain is also more likely if the part is lost as a result of a painful, traumatic accident.

The symptoms given are neuropathic in nature and are often accompanied by sympathetic signs as seen in CRPS1 and 2.

More common than phantom pain with a lost limb is pain at the end of the stump. This is usually a result of the cut nerves giving off painful signals in the absence of an ongoing painful stimulus, but may also be due to the presence of infection or inadequate initial surgery and the stump may need to be refashioned by a surgeon in both scenarios.

Examination is important in stump pain to also rule out the presence of the overgrowths of the nerves in the stump. These overgrowths are called neuromas and can be cut out by a surgeon. They are a common cause of stump pain. Other common causes are ulceration of the skin and pain in the stump scar.

Phantom sensations and pains are thought to be due to a rewiring of the central nervous system which occurred while the now absent part was still attached. When this part is removed the memory of pain in the brain remains. This memory is subconscious and can not be controlled and is also thought to be recorded is more than one area of the brain and spinal cord at the same time. This makes treatment difficult but recent work has shown a good response in these patients to Gabapentin. In addition, other neuropathic agents may be just as successful in any individual, side-effects permitting. Some patients respond to TENS machines. Some people respond poorly to all the basic treatments and may need to be put forward for a trial of a spinal cord stimulator.

Phantom-like pains may also be described by patients where a limb is still attached but the major nerve supply to the limb has been permanently damaged. In this case the pains are called deafferent pains and again are neuropathic in nature.