A client who is admitted with an above-the-knee amputation tells the nurse that his foot hurts and itches. Which response by the nurse indicates an understanding of phantom limb pain?
A. “The pain will go away in a few days.”
B. “The pain is due to peripheral nervous system interruptions. I will get you some pain medication.”
C. “The pain is psychological because your foot is no longer there.”
D. “The pain and itching are due to the infection you had before the surgery.”
Correct Answer: B. “The pain is due to peripheral nervous system interruptions. I will get you some pain medication.”
Pain-related to phantom limb syndrome is due to a peripheral nervous system interruption. A recent study estimated that there were about 1.6 million people with limb loss in the USA in 2005 and this number was projected to increase by more than double to 3.6 million by the year 2050. Vascular problems, trauma, cancer, and congenital limb deficiency are among the common causes of limb loss.
Option A: Phantom limb pain can last several months or indefinitely. The phantom pain and sensation may have its onset immediately or years after the amputation. There are reports of two peak periods of onset, the first within a month and the second a year after amputation. The prevalence is reported to decrease over time after amputation.
Option C: The explanation of phantom limb pain is not psychologically related. PLP was once thought to be primarily a psychiatric illness. With the accumulation of evidence from research over the past decades, the paradigm has shifted more towards changes at several levels of the neural axis, especially the cortex. Peripheral mechanisms and central neural mechanisms are among the hypotheses that have gained consensus as proposed mechanisms over the recent years.
Option D: Pain and itching are not symptoms of an infection due to surgery. During amputation, peripheral nerves are severed. This results in massive tissue and neuronal injury-causing disruption of the normal pattern of afferent nerve input to the spinal cord. This is followed by a process called deafferentation and the proximal portion of the severed nerve sprouts to form neuromas. There is an increased accumulation of molecules enhancing the expression of sodium channels in these neuromas that results in hype-excitability and spontaneous discharges. This abnormal peripheral activity is thought to be a potential source of stump pain, including phantom pain.