Diagnosis of PLP

Diagnosing phantom limb pain is a rather subjective endeavor.

There is no specific medical test to diagnose this disease, it is purely based on your medical history and the description of your pain (onset, pattern, location, etc).  Because of this, it is very important to document the characteristics of your pain and write them down.  Every time pain is felt, do your best to describe it in as much detail as possible.  Then, the next time you visit your PCP, give them or read them your pain log.  This will give them the best chance to diagnose your disease.

(http://www.bfe.org/protocol/pro05eng.htm)

Phantom Limp Pain Pathophysiology

While there are many theorized mechanisms for the existence of phantom limb pain (PLP), the exact 

mechanism is not known.  In this post, I will cover a few of the main theories and attempt to explain some possible origins of PLP.  However, as with most things in the human body, the mechanism that controls PLP is likely an amalgamation of mechanisms that work together to cause the symptoms of this disease.

(http://www.amazingsuperpowers.com/2012/08/en-garde/)

Three of the main theories are :

The peripheral theory, which assumes that PLP originates at the nerves around the injury.
When tissues are injured, chemicals and enzymes create an inflammatory process and sensitize the pain receptors.  Neurotransmitters are released around the site of damage, which then activates neighboring nerve endings.  This causes nerves not originally involved in the damage to become involved and expands the area of the body the pain perceives.  In normal tissue, this sensitization resolves spontaneously, but in damaged tissue it leads to neuropathic pain such as PLP.

The spinal theory, which attributes the cause to changes in the spinal cord.
Amputation damages the nerves which causes a hyperexcitability in the CNS, manifesting as an increase in neuronal firing, changes in the structure of the sensory neurons, and a reduction in the normal spinal cord inhibitory processes.
 
The central theory, which assumes that PLP is caused by some mechanism in the brain.
This theory is grounded in the idea of remapping of the somatosensory cortex of the brain.  Basically, when damage occurs and an area of the brain is no longer receiving impulses from a section (where the amputation was), the brain will "rewire" itself and interpret sensations from other parts of the body in the missing limb.  This is evident when a part of the body is touched, but the amputee feels it in their amputated limb.  


(http://kin450-neurophysiology.wikispaces.com/Phantom+Limbs+II)

References:

Chapman, S. (2011). Pain management in patients following limb amputation. Nursing Standard, 25(19), 35-40.

What do the numbers look like for Phantom Limb Pain?

In order to look at the prevalence of phantom limb pain, we obviously have to look through the numbers of amputations that occur.
Amputations that occur in the United States occur due to vascular disease, complications to diabetes, trauma and cancer.
According to a study conducted looking into the future projections of amputations, there were approximately 1.6 million in 2005 and a projected number of amputations greater that 3.6 million by 2050. The increase is attributable to the increasing numbers of older adults and the high number of older adults living with vascular disease.
In general, men are more likely than women to have a limb amputated for any reason.
Table 1 displays these values:

So why do these numbers matter and where do they fit with phantom limb pain?

According to one of the studies I researched, of the surgical amputations that occurred in the United States, approximately 70% of the patients experience phantom limb pain after the procedure.  Furthermore, and more significantly, 50% of the patients experience continued pain 5 years after the surgery.  

As we can see, the prevalence of phantom limb pain, and persistent limb pain, is a significant proportion of amputees, whose numbers are going to continue to grow into the future.  

References:
Bloomquist, T. (2001). Amputation and phantom limb pain: a pain-prevention model. AANA Journal, 69(3), 211-217.

Ziegler-Graham, K., MacKenzie, E., Ephraim, P., Travison, T., & Brookmeyer, R. (2008). Estimating the prevalence of limb loss in the United States: 2005 to 2050. Archives Of Physical Medicine & Rehabilitation, 89(3), 422-429.

Introduction

(http://www.contactmusic.com/phantom-limb/music/phantom-limb-live-in-bristol)

Over the course of the next 10 weeks, I will be writing about phantom limb pain.  I have quite a few friends who have been in the military. Luckily, they returned home from their tours with minimal injuries.  Many soldiers are not so lucky.
Phantom limb pain can be present in people who have had a limb amputated.  Most people with an amputation will experience some phantom limb symptoms, sometimes they still feel the limb and try to move it, other times they have severe pain where the limb used to be.  Studies have shown that as many as 70% of phantom limbs will be painful, even 25 years after the limb has been amputated.

(http://www.orangecountypainmanagement.net/693842/2013/05/09/what-is-phantom-limb-pain.html)

Phantom limb pain is a complicated phenomenon that is intensely grounded in neurology.  The symptoms of phantom limb pain are all neurological, and many of the treatments involve tricking the brain and training it to be able to control the phantom limb.   

(http://brain.oxfordjournals.org/content/126/3/579)

In the coming weeks, I will be delving into the various aspects of phantom limb pain, from incidence, treatments, to how it relates to nursing.  I am excited for the next 10 weeks where I will learn about this disease and chronicle the journey here. 

Until next week!