Exploring Phantom Limb Pain

[Christopher]

Another read on phantom limb pain. Nothing that new in this one, but still interesting...

http://www.psychiatrictimes.com/showArt ... =185303203

Exploring Phantom Limb Pain
By Steven A. King, MD, MS
New York University School of Medicine

April 2006, Vol. XXIII, No. 4
First described more than 500 years ago, phantom limb pain (PLP) is a common disorder today; as many as 50% to 80% of patients who undergo amputation report experiencing pain in the missing body part.1 Although it is easy to recognize and diagnose, its cause remains unclear and it can be difficult to manage successfully. Perhaps that's why health care professionals often do not address it. A survey by Hanley and associates,2 for example, found that 53% of patients with PLP and 38% with severe PLP had never been treated for the disorder.

Why this problem develops in certain patients remains unclear, although animal studies indicate that there may be a genetic predisposition to PLP.3 PLP most commonly occurs after the amputation of an extremity, but it also has been reported after surgical removal of other parts of the body, most notably after a mastectomy.

At one time, PLP was thought to be primarily a psychological problem that reflected both the patient's grieving over the loss of the limb and his or her desire to believe that the limb was still present; however, psychological factors do not appear to be the primary cause. Ephraim and colleagues4 did find the presence of depression to be a predictor of the severity of PLP, although it was similarly associated with residual limb and back pain in amputees.

Concepts of causation
Current concepts of causation center primarily around the role of the peripheral and central nervous systems.5 Amputation results in a disruption of normal peripheral nerve activity. The traumatic injury to the nerves may cause abnormal ectopic discharges that are perceived as pain at the level below which the nerves were severed. Formations of neuromas in the remaining portion of the limb may also play a role, although it has been noted that PLP frequently occurs before there has been sufficient time for neuromas to appear. Activation of the sympathetic nervous system is also a possible cause. Centrally, changes may occur in both the spinal cord and brain following amputation. Injuries to the peripheral nerves can result in changes in synaptic responsiveness in the dorsal horn that can lead to increased excitability of the neurons in the dorsal horn and decreased inhibitory processes.6 It appears that following amputations, there may be changes in the brainstem, thalamus, and cortex caused by abnormal peripheral input. However, it is unclear whether these changes are involved in the causation of PLP or are secondary to it.

Since there are no physical changes in PLP, the diagnosis is made solely on the basis of the patient's self-report. Because of fears that the presence of pain in a missing body part is irrational and may indicate that one is “losing one's mind,” it is important to assure patients that it is a very real phenomenon. It is also always important to differentiate PLP from stump pain, which commonly occurs after amputation and is often much easier to manage.

When describing PLP, patients report a variety of sensations, including burning, shooting, and aching pains as well as tingling and pins-and-needles sensations. The pain is usually intermittent and most often felt in the distal parts of the missing limbs.1

Managing the pain
There is no single best treatment for PLP. Multiple therapies have been used with mixed success, and there are a limited number of good controlled studies. Unfortunately, there are no factors for predicting which therapy is likely to benefit a particular patient.

Medications are usually the first course of action. The apparent neuropathic nature of PLP would suggest that antidepressants, anticonvulsants, and other medications used for neuropathic pain would be most efficacious. However, Ephraim and coworkers4 found that most patients are treated with acetaminophen, NSAIDs, and opioids.

As with any neuropathic pain, the antidepressants that affect both the serotonergic and noradrenergic systems appear to provide the strongest analgesic effects. In a recent randomized, placebo-controlled study, Wilder-Smith and colleagues7 reported that 25 of 30 patients with PLP responded to treatment with amitriptyline (Elavil), and 22 of 33 patients responded to tramadol (Ultram) (a drug that is a mixture of a serotonin/norepinephrine reuptake inhibitor and a weak opioid), compared with only 2 of 37 patients who responded to placebo. If tricyclic antidepressants cannot be tolerated or their use is contraindicated, venlafaxine (Effexor) or duloxetine (Cymbalta) (both of which, like the tricyclics, are serotonin/norepinephrine reuptake inhibitors) should be considered as an alternative. However, I am unaware of any published studies on their use for the treatment of PLP.

There are studies indicating that at least 2 anticonvulsants, gabapentin (Neurontin) and topiramate (Topamax), may be beneficial for PLP.8,9

Another medication for neuropathic pain that I have found useful at times for the treatment of PLP is the lidocaine patch (Lidoderm). This medication has the advantage of being without significant side effects and, therefore, can be used safely even in patients with severe medical problems.

Psychologically based modalities may also provide relief. Therapies such as biofeedback and hypnosis may directly affect the physiologic processes involved in the pain. Other therapies that may be beneficial include peripheral nerve blocks, epidural infusion of analgesic agents, transcutaneous electrical nerve stimulation, and acupuncture. Surgical interventions—including sympathectomy, rhizotomy, cordotomy, and most recently, deep brain stimulation—have also been used.10

Dr King is clinical professor of psychiatry at the New York University School of Medicine.
References
1. Nikolajsen L, Jensen TS. Phantom limb pain. Br J Anaesth. 2001;87:107-116.
2. Hanley MA, Ehde DM, Campbell KM, et al. Self-reported treatments used for lower-limb phantom pain: descriptive findings. Arch Phys Med Rehabil. 2006;87:270-277.
3. Seltzer Z, Wu T, Max MB, Diehl SR. Mapping a gene for neuropathic painrelated behavior following peripheral neurectomy in the mouse. Pain. 2001;93:101-106.
4. Ephraim PL, Wegener ST, MacKenzie EJ, et al. Phantom pain, residual limb pain, and back pain in amputees: results of a national survey. Arch Phys Med Rehabil. 2005;86:1910-1919.
5. Woodhouse A. Phantom limb sensation. Clin Exp Pharmacol Physiol. 2005;32:132-134.
6. Flor H. Phantom-limb pain: characteristics, causes, and treatment. Lancet Neurol. 2002;1:182-189.
7. Wilder-Smith CH, Hill LT, Laurent S. Postamputation pain and sensory changes in treatmentnaive patients: characteristics and responses to treatment with tramadol, amitriptyline, and placebo. Anesthesiology. 2005;103:619-628.
8. Bone M, Critchley P, Buggy DJ. Gabapentin in postamputation phantom limb pain: a randomized, double-blind, placebo-controlled, cross-over study. Reg Anesth Pain Med. 2002;27:481-486.
9. Harden RN, Houle TT, Remble TA, et al. Topiramate for phantom limb pain: a time-series analysis. Pain Med. 2005;6:375-378.
10. Bittar RG, Otero S, Carter H, Aziz TZ. Deep brain stimulation for phantom limb pain. J Clin Neurosci. 2005;12:399-404.

[Christopher]

Question to all amputees...

Did your pain change in any way after amputation?

If so, what kind of changes did you experiences from before to after (neuropathically, not so much from weight bearing changes)? And did you have all 5 nerves avulsed?

Thanks,
Chris

[jacko]

I managed to pretty well beat the pain before I had the amputation. I don't think that amping the arm would reduce the nerve pain, but it most definitely reduced the pain from subluxation, which made a huge difference to my life.

The biggest problem I get now and again is phantom itching. I'm not talking about a little itch here. I'm talking about something that takes over the vast majority of the stump. Like TENS, etc, the trick is to locate the correct nerve in the shoulder, or around the clavicle, and massage it to reduce the itching. Easier said than done, and if I hit the wrong nerve, I get a sharp reminder of what nerve pain is all about.

[jennyb]

When I spoke to the doctor about my proposed amputation and PLP, he said I already have PLP, that's what my pain is. So I'm not expecting any change in the electric pains in the palm of my bpi hand-that will probably continue after I get the chop (if I ever manage to get the chop!). I do look forward to not having the weight hanging off my shoulder.

Jen NZ

[marieke]

There is also another med now on the market, it works like Neurontin (gabapentin). It's called Lyrica (pregabalin). It is said to have less side effects and requires smaller doses for the same effect as Neurontin.
Marieke

[admin]

Great article. I have a question for anyone out there who knows meds. How does a Lidocaine patch work if the arm is paralyzed? It works locally on the spot you put it, but it is unknown where the pain is located in BPI so I can't understand how it would work. The pain Dr. at the Mayo offered it to my son. He hasn't tried it yet. Can anyone explain how it works??
Frank's mom

[marieke]

The nerves that control movement (ventral root/nerve tract) are not the same as those which control feeling/sensation (dorsal root/nerve tract).
So the patch is applied in the area where the pain is felt the most (or as close as possible) and the medication is absorbed through the skin and affects the nerves that control sensation, in this case pain.
Not sure what youu mean by "it is unknown where the pain is located in BPI". You feel the pain along the nerve tract. It's origin may not be known, but you do feel the location(s) where it hurts.
Hope this helps a little...
Marieke

[Christopher]

If you have all five nerve roots avulsed, nothing that is put on topically will effect the pain. I still have C8 & T1 and Lidocane did very very very little for me. I did try a Ketamine ointment that worked better (it partially works on the principle that after a few applications it circulates into the bloodstream) but it left my hand pasty & gooey so it was a hassle, but still a relief knowing that something kind of works w/out messing with my head (ie. all meds).

Chris

[jennyb]

That's the thing I found confusing about this article-it seems to say that the pain can be helped by topical applications, it even mentions nerve blocks. Not only PLP but tbpi pain from total avulsions can't be helped by things like that according to everything else I've read on it-and I've read a lot. I do get less attacks on SSRI antidepressants, proving to me the pain's in the brain , nowhere near the arm. For the record, in my and many other cases, the pain is felt felt mainly in the palm of the hand and fingers, nowhere near the site of any nerve damage. Because of this meds only work by messing with your head, as Chris says. This injury is long term, meds are not the answer.

One thing that's happened recently is a change in sensation in my arm, it used to flare up if I touched my chin, neck and face, now it twinges if I touch my chest. I know this is cortical remapping, I'm just interested that it changed. Also, for the first time in 26 years, I get pain in my hand if I touch the skin of my bpi arm. This is quite a breakthrough as I've had no feeling in my arm for decades, I still have no feeling but something is going on if I get a reaction in the hand. It also means my clothes are actually causing pain.....I hope this passes soon, it's bloody annoying!

[marieke]

Jenny b
I know what you mean about your clothes touching you and causing pain... I am LOBPI but have another neuro condition that paralyzed me from mid-chest down. Along with the paralysis (which is now limited to my left leg/foot, and part of my stomach I have been left with what falls under the category of PLP related to paralysis. I get the "itch" feeling, neurogenic pain = tingling, squeezing, really hot/cold... you name it. And the weird feeling like my foot is twisted around but it is in perfect position. I also have spasms/clonus in the left leg, stomach, bum... and at the begining while still in hospital I could not stand for the sheets to touch my toes, hurt like crazy!!! That did go away. But last month my socks hurt to wear, on the skin. Just touching my skin I wanted to die and I had to wear shoes too... I am in school (nursing school) and don't have the option of strong meds or not going (not unless I want to fail out). So I know what you mean. But it has gone away again, thankfully. So yes, that feeling should pass.
And I am on Neurontin and Lyrica and Elavil (the latter 2 at night only) for the "pain" and anti-spasmodics for the rest.
Marieke