Neuropathic pain 'haunting' those with amputated limbs

According to neurologists (experts dealing with disorders of the nervous system), people whose limbs (or body appendages) have been surgically removed because of diseases or accidents are more likely to be diagnosed with phantom limb syndrome.

David Lim (not his actual name), a 36-year-old trader, injured his little finger badly in a road accident earlier this year.

As a result, surgeons were forced to amputate the injured finger to prevent infection from spreading and affecting other fingers on Lim's left hand.

Today, several months after the surgery, the wound is healed, but Lim still experiences episodes of excruciating pain.

At times, the pain is so severe that even strong painkillers do not work.

PAIN FROM SEVERED NERVES

"At first, I thought I was experiencing pain because of my wound. However, when my doctor mentioned that my wound had healed, I realised that the source of the pain was from deep withinmy nerves.

"This is the reason why painkillers had not worked earlier," explained Lim when met at a hospital here.

According to physicians, such pain is termed as neuropathic pain.

The nerve fibres in your body had become dysfunctional when they were severed during the accident, said a surgeon, who wished to be known as Dr A Raman.

"As a result, fibres send incorrect signals to the brain, and you perceive the signal as pain," he explained.

Dr Raman added that neuropathic pain usually follows a tissue injury, and those affected may feel it as either 'pins and needles,' burning sensations, or electric shocks.

"Neuropathic pain occurs when nerves that usually respond to an injury become active for no reason.

"When a person is diagnosed with neuropathic pain, the function of these nerves is compromised and nerve activity increases. If left unchecked, this activity may cause other nerves to become ultra-sensitive, and it leads to pain in the body," he explained.

PHANTOM LIMB SYNDROME

Neuropathic pain can last for a very long time, forcing the sufferer to constantly look for ways to relieve the pain.

According to Dr Raman, painkillers are not effective in reliving neuropathic pain. Phantom limb syndrome is a type of neuropathic pain.

It occurs when an arm or a leg is amputated because of an illness or injury. In this case, the brain continues to receive signals from nerves that originally carried impulses from the missing limb, and the brain interprets these signals as pain.

"These nerves now misfire and cause pain to the sufferer," he said. What causes neuropathic pain?

According to Dr Raman, there is no definite cause of neuropathic pain, but some of the common causes include alcoholism, amputation, chemotherapy, diabetes, and spinal cord surgery.

"Symptoms of neuropathic pain include shooting and burning pain as well as tingling and numbness," he explained.

PAIN MANAGEMENT

Neuropathic pain is defined by the International Association for the Study of Pain (IASP) as pain arising from a lesion or disease affecting the somatosensory system.

Dr Raman said the sufferer experiences discomfort for long periods of time, often described as burning sensations, a sharp, stabbing, or shooting pain, or 'similar to electric shocks.

Studies have shown that this type of pain can be relieved by taking drugs such as Aleve and Motrin.

According to Dr Raman, anti-convulsion drugs such as Neurontin (Gabapentin), in doses of 100mg to 300mg, are effective in a number of cases.

However, he mentioned that the side effects of this drug include drowsiness, and one should not take this drug before operating machinery or driving a vehicle.

"For complicated cases, surgeons may have to perform invasive therapy or insert implants for effective treatment," he said, adding that normal painkillers are not effective in eliminating phantom pain (limb) syndrome.