We are equippedwith an intricate network to detect pain. Several miles of nerves send messages to the brain indicating when an injury is about to happen or when it has already happened. The brain receives nerve impulses conveying the painful messages.
Nerve painis different from tissue injury pain, such as a sprain or a more severe damage. If the nervous system that conveys information about pain to the brain is itself damaged, as in the peripheral neuropathies such as GBS, CIDP and "my" Paraproteinaemic Neuropathy, then the message will be flawed. A specific type of pain results, neuropathic pain. Several other disorders also affect the peripheral nervous system. In all of them there are disorganised, irregular firing patterns. Some changes result in increased firing and in others reduced firing. In this nerve injury pain, sensory nerve fibres increase their excitability and the spinal cord amplifies incoming painful messages. Drugs to ameliorate pain, by reducing the abnormal excitability, are available.
Treatment of neuropathic pain.The main goal is to reduce the pain as much as posssible and help the patient to improve coping with any remaining pain.Nerve pain does not typically respond well to available painkillers. It can be very difficult to treat. There are drugs with pain killing abilities but to date there are no true nerve painkillers on the market. Neither are there any drugs that are specific for neuropathic pain. So each form of pain demands its' own unique form of treatment. Some drugs can be used to ameliorate nerve pain. Anti-epileptic or anticonvulsant drugs and/or anti-depressants are logically used because the pain arises from the nervous systems. Yet they only work for about a third of patients who use them.
Anticonvulsants.These are useful drugs that were originally designed for the treatment of epilepsy. The older ones such as carbamazepine, phenytoin and sodium valproate all have a role. They have an inhibitory effect, reducing abnormal and excessive "electrical" excitability in the nervous system. There may be problems. Due to their side effect profile, they are becoming less popular. Sedation is a major concern, along with problems with concentration and memory at the dose levels required for controlling pain. They can cause dizziness, blurred vision, allergies, skin rashes and so on.
Gabapentin , a relatively new anti-epileptic drug, has become more popular among pain clinicians. Having fewer side effects than other anti-convulsants it is better tolerated by patients and does not interfere with other medication being taken.
Anti depressants,such as Amitriptyline, are also used but some people can not tolerate these, as is the case with the anti-convulsants. They work on the nerves dealing with the pain. Amitriptyline has been a first-line drug in this group but it is an old one with side effects, mainly sedation, dry mouth, fast heart rate, weight gain.
These anti-depressants, or tricyclics, increase the levels of neuro transmitter by blocking their re-absorption. Depressed people have fewer neuro transmitters than normal being released, thus leading to reduced stimulation. Other drugs such as imipramine, dothiepin, dofepramine may also be used.
Non-drug methods.I tried a TENS ("transcutaneous electric nerve stimulation") machine at home over two months. This had no noticeable beneficial effect, perhaps because the nerves are already over-stimulated or that the transmission of messages is damaged. Some people have found acupuncture to be helpful in easing the pain temporarily.
HOWEVER IT MUST BE REPEATED THATneuropathic pain may be very resistant to treatment. Various drugs may reduce the pain but not clear it completely.