They provide both an insight and an overview into best practice concerning neuropathic pain, both its cause and its treatment. As a neuropathy patient, you should be entitled to the sensible and sympathetic approach that is advised here. It's refreshing to see that its starting premise is that your pain must be taken seriously!
The fact that the information both today and tomorrow is meant for other professionals and medical students does not mean that you're not entitled to read it. Not all of it will apply to your particular case but at least you will have an excellent source of information and alternatives, from which your treatment should emerge.
Treating Neuropathic Pain And The Neuropathic Pain Patient - PART ONEPART TWO tomorrow (How neuropathy is treated)
John T. Farrar, MD, MSCE - Last Modified: Monday, 16-May-2011
Departments of Anesthesiology, Neurology, and Epidemiology, the Center for Clinical Epidemiology and Biostatistics, the University of Pennsylvania Cancer Center, Philadelphia, Pennsylvania.
Neurologists have the option of choosing from among numerous drugs and drug classes when treating neuropathic pain. The challenge, therefore, lies not in having limited options for treatment, but in the art of practicing medicine, i.e., of identifying neuropathic pain and empathizing with the patient without the benefit of either an objective test or a complete understanding of pain pathophysiology, and providing the best evidence-based options for therapy. The International Association for the Study of Pain definition of pain - a sensory and emotional experience, signaling actual or potential tissue damage - illustrates the dual nature, both objective and subjective, of this condition. The neurologist's unique understanding of the complex interactions that occur in the nervous system can provide a significant contribution to the care of patients with pain.
Additionally, we must remember that many patients, unable to quantitatively describe their pain and witnessing the medical community's lack of codified remedies, leave the physician's office thinking that the practitioner views their pain, even when incapacitating, as psychosomatic. An equally important role of the practicing neurologist, therefore, is to acknowledge the patient's experience of pain without attempting to validate its source. This article includes strategies for approaching a neuropathic pain patient, useful methods to treat the whole patient, and a discussion of why a holistic approach is important. An overview of the pharmacotherapies available for the treatment of neuropathic pain and their role in treating the whole patient is also provided.
Copyright 2001 Galen Publishing, LLC. First published in the September 2001 issue of Advanced Studies in Medicine, New Developments in the Management of Migraine and Neuropathic Pain (Volume 1, Number 6: 241-247), www.ASIMCME.com.
Treating neuropathic pain means treating the neuropathic pain patient by first understanding what the patient is experiencing. This can be difficult, as there are no empirical tests for pain. Yet, the pain is completely real to the patient, and may even be incapacitating. The primary role of the physician is to make the appropriate diagnosis and focus treatment on the most important features of the patient's pain as reported by the patient. This should always include the presumed underlying pathophysiologic mechanism but must also focus on other contributing factors, some of which may be more amenable to treatment than the primary process.
What Is Pain?
The International Association for the Study of Pain (IASP) defines pain as: "The unpleasant sensory and emotional experience of actual or potential tissue damage or an experience expressed in such terms."1 Since pain is both a sensory and an emotional experience (i.e., it affects the whole person), the whole person must be treated. The degree of pain intensity can be affected by the patient's attitude and perceptions of his surroundings. A broken toe will seem less painful if injured on the way to the airport to start one's vacation than if this takes place on the way to an Internal Revenue Service audit. Similarly, a cancer patient with back pain will experience a lessening of pain when assured by the physician that the pain is not indicative of metastasis or recurrence of the cancer. In fact, the use of environmental factors for managing pain intensity, known as distraction therapy, is widely used by practitioners and patients to help patients perform daily activities in spite of pain and other discomforts. The popularity of distraction therapies is the result of its demonstrated effectiveness in both the laboratory and the clinical setting.2
Despite the exponential growth of our knowledge about the brain in recent years, we do not yet understand the intricate pathophysiological mechanisms of neuropathic pain. We do, however, know that the brain, through the production of hormones and direct nerve connections from the brain to the pain fibers, is capable of far more control over the pain system than was previously thought. Yet since we have not identified a means to specifically harness this descending control system, a physician's best hope for providing effective treatment is to present patients with the various pain-management strategies and to support them in their search for the one or ones that work, remembering that efficacy is subjective and patient specific, much like in the treatment of psychiatric illness. Similarly, the success of treatment can be assessed only by individual patients reporting on changes in their symptoms.
The IASP definition of pain also includes the phrase "actual or potential tissue damage or an experience expressed in such terms." Acute pain is experienced immediately upon injury and notifies the individual of tissue damage. Neuropathic pain is caused by nerve damage proximal to the sensory nerve endings in the skin. Neuropathic pain has no protective or predictive value, because it persists long after tissue (i.e., nerve) damage has occurred. In essence, the lack of a specific measure of tissue damage does not preclude the sensation of pain.
Patients with neuropathic pain may also report fatigue, difficulty in concentrating, depression, and insomnia, and the severity of these symptoms may seem disproportionately high relative to the initial injury. Again, the most effective approach is to acknowledge the patient's discomfort and make a commitment to treat the pain. The hope gained from knowing that the physician will attempt to treat one's pain provides an effective distraction.
Types of Pain
The 3 types of pain (somatic, neuropathic, and visceral) are often co-occurring or comorbid as a mixed syndrome, so treating the neuropathic component may only treat part of the patient's symptoms. Most pain patients, especially those with chronic pain, have a mixed syndrome (neuropathic and somatic pain). Unlike somatic pain, which comes from specialized nerve endings and warns of tissue damage, neuropathic pain comes directly from nerve dysfunction and does not imply ongoing damage. It is important for physicians to explain this distinction to patients, who will be reassured when they learn that their pain does not signal continuous damage and may not be the harbinger of a more serious illness.
A common example of this mixed somatic/neuropathic syndrome is compression of a small nerve in the spine (neuropathic), which leads to muscle spasm (somatic). The body responds to the pain of compression by protecting the area through spasms, which create muscle pain in the area as well as other inflammatory responses. While the patient feels the muscle pain, the underlying pathology can be neuropathic. In treatment, therefore, residual pain after treating somatic pain should be considered an indication of possible neuropathic pain, even if the symptomatic features of the neuropathic pain are not predominant.
There are several neuropathic pain syndromes, outlined in Table 1, that are the result of ectopic generators, nerve trunk pain, microenvironmental changes, central alterations, and changes in the balance of nociceptor and nonnociceptor fibers. At this time, it is not yet possible to determine which of these factors specifically cause an individual's neuropathic pain. However, all of these factors can result in sensory loss, paresthesias (positive numbness or tingling), dysesthesias (painful or unpleasant burning, tingling or electric shock phenomenon), hyperesthesia (increased perception of mildly painful stimuli), hyperpathia (subthreshold stimuli producing pain), or allodynia (nonpainful stimuli producing pain).
Table 1. Common Types of Neuropathic Pain*
Examples of peripheral neuropathic pain
•Carpal tunnel syndrome
•Complex regional pain syndrome
•Human immunodeficiency virus (HIV) sensory neuropathy
•Painful diabetic neuropathy
•Phantom limb pain
Examples of central neuropathic pain •Central poststroke pain
•Multiple sclerosis pain
•Parkinson's disease pain
•Spinal cord injury pain
Examples of cancer-associated neuropathic pain •Chemotherapy-induced polyneuropathy
•Neuropathy secondary to tumor infiltration or nerve compression
•Phantom breast pain
•Postradiation plexopathy and myelopathy
*Reprinted with permission from A Clinical Guide to Neuropathic Pain. Galer BS, Dworkin RH, eds. Minneapolis, MN: McGraw-Hill Healthcare Information; 2000.