- Jan 7, 2002
- 12,755
- 3
- 0
Pain study points to a mirror image
By Carey Goldberg, Globe Staff, 4/2/2004
For more than a century, doctors have reported cases of a mysterious phenomenon: When a patient's arm or leg was injured, the opposite limb would sometimes feel chronic pain, as well.
Now, Massachusets General Hospital research on rats suggests that such opposite-limb symptoms may stem from a previously unrecognized connection of pinpoint accuracy between the nerves on one side of the body and the mirror-image spot on the other side.
The research provides the "first conclusive proof" that trauma on one side of the body can cause opposite-side nerve damage, said Dr. Gary J. Bennett of McGill University in Montreal, a leading pain specialist who was not involved in the research. "There's no precedent for this; it's a completely out-of-the-blue discovery."
After all, he added, "if you break your left foot, you don't expect any change in the bones of your right foot."
The study in rats is to be published in the Annals of Neurology as researchers have been making great progress in understanding pain and finding biological evidence that it is not just in patients' heads.
But the mechanism of the mirror-image injury remains a riddle, said Dr. Anne Louise Oaklander, the study's lead author and head of Mass. General's nerve injury unit. But she said her findings could already help patients get their opposite-side pain taken seriously.
"So many patients notice that they have symptoms in the area immediately opposite a one-sided injury, and typically these are dismissed by the physician or the patient is told that because one limb is injured, it puts extra stress or strain on the opposite side," she said.
"But in fact," she said, "some patients -- and we do not yet know how many -- may be experiencing consequences of this type of crossover injury."
Oaklander used a relatively new method to make her discovery, performing a biopsy on a tiny patch of skin and then counting the nerves related to pain. Loss of such nerve endings has been linked to chronic pain after an injury.
She began applying some of the new biopsy methods to diagnose patients and do research several years ago. She wanted to figure out why some patients recover easily from shingles, an excruciating skin-and-nerve disease that tends to attack older people, while others suffer for years with post-shingles pain.
In the course of that work, she found, to her own surprise, that people with post-shingles pain not only lost most of their nerve endings at the spot where the shingles erupted, but also lost about half their nerve endings at the same spot on the opposite side of the body.
Text
By Carey Goldberg, Globe Staff, 4/2/2004
For more than a century, doctors have reported cases of a mysterious phenomenon: When a patient's arm or leg was injured, the opposite limb would sometimes feel chronic pain, as well.
Now, Massachusets General Hospital research on rats suggests that such opposite-limb symptoms may stem from a previously unrecognized connection of pinpoint accuracy between the nerves on one side of the body and the mirror-image spot on the other side.
The research provides the "first conclusive proof" that trauma on one side of the body can cause opposite-side nerve damage, said Dr. Gary J. Bennett of McGill University in Montreal, a leading pain specialist who was not involved in the research. "There's no precedent for this; it's a completely out-of-the-blue discovery."
After all, he added, "if you break your left foot, you don't expect any change in the bones of your right foot."
The study in rats is to be published in the Annals of Neurology as researchers have been making great progress in understanding pain and finding biological evidence that it is not just in patients' heads.
But the mechanism of the mirror-image injury remains a riddle, said Dr. Anne Louise Oaklander, the study's lead author and head of Mass. General's nerve injury unit. But she said her findings could already help patients get their opposite-side pain taken seriously.
"So many patients notice that they have symptoms in the area immediately opposite a one-sided injury, and typically these are dismissed by the physician or the patient is told that because one limb is injured, it puts extra stress or strain on the opposite side," she said.
"But in fact," she said, "some patients -- and we do not yet know how many -- may be experiencing consequences of this type of crossover injury."
Oaklander used a relatively new method to make her discovery, performing a biopsy on a tiny patch of skin and then counting the nerves related to pain. Loss of such nerve endings has been linked to chronic pain after an injury.
She began applying some of the new biopsy methods to diagnose patients and do research several years ago. She wanted to figure out why some patients recover easily from shingles, an excruciating skin-and-nerve disease that tends to attack older people, while others suffer for years with post-shingles pain.
In the course of that work, she found, to her own surprise, that people with post-shingles pain not only lost most of their nerve endings at the spot where the shingles erupted, but also lost about half their nerve endings at the same spot on the opposite side of the body.
Text
Facebook
Twitter