The Neurological Diseases known as the PNS Neuropathies

Author: Les Abrams
Published on: Dec 15, 1998

Disclaimer: Please check with your doctor before trying any procedure or program of nutrition regarding the treatment of any of these neurological diseases. If you do not have a competent and neurologically aware doctor, then you must find one. These diseases are serious and must neither be self-diagnosed nor self-treated and certainly not by a doctor not competent to do so.

Author's opening note: While the intent is to discuss the entire set of PNS Neuropathies, it is sufficient to cite examples referring to reflex sympathetic dystrophy (RSD). This is due to the great similarities between the neuropathies, with respect to the secondary and tertiary effects of the diseases as a group.

INTRODUCTION

The neurological diseases of the peripheral nervous system have many similarities. While each one has a different set of etiologies (causes) and in some cases, concurrent physiological problems (as blood sugar regulation in diabetic neuropathy, Raynaud's syndrome, carpal tunnel syndrome, and others), the symptoms due to the major secondary cause are similar across the entire family. There are three categories of triggering incidence that are responsible for the onset or cause of these neuropathies: trauma to a nerve, trauma to other tissue, and idiopathic (unknown).

There is a growing consensus and anecdotal evidence, that there is a possible genetic predisposition to some of these diseases. While such genetic linkage has not been proven for this particular set of diseases, there are other neurological (central nervous system) diseases for which it has.

The common underlying problem of these neuropathies is an aberration of the vasomotor function, which controls the blood flow throughout the vascular system. Subsets of the peripheral nervous system - the sympathetic and the parasympathetic nervous systems - are solely responsible for the control of the vasomotor function which is a system wide mechanism - that is, it serves the entire body.

Usually, the onset of a neuropathic disease, say RSD, occurs in a single area or region. Note: I choose the word region here because of the newer designation for RSD as complex regional pain syndrome (CRPS I). While each of these neuropathies have their own, and often unique etiologies (causes), they do share a common secondary problem - vasoconstriction. From vasoconstriction, the tertiary effects follow. These are cell necroses of the tissues attached at the ends of the affected capillaries. These are nerve, bone, muscle, skin, and the vascular system - including the capillaries. These cell necroses are due to hypoxia (oxygen starvation) and trophic (nutrient) starvation that result from curtailed blood flow to the affected region.

DESCRIPTION of the DISEASES

The following documents covering two of the Neuropathies are informative in that they are very descriptive of the disease and of its proscribed treatment. The links to these descriptions provide you the opportunity to view the documents without having to include them here.

This web page has a very detailed description of Algoneurodystrophy, or Sudek's Syndrome and its treatment. These are alternative names for reflex sympathetic dystrophy that are widely used in Europe Algoneurodystrophy. This page was co-opted from the Belgian National Health web site and with the help of a Belgian, we translated the text from Nederlands into English.

This document labeled A Multidisciplinary Approach to the Treatment of Diabetic Neuropathy, is a detailed description of the mechanics of Diabetic Neuropathy and a plan for its treatment Diabetic Neuropathy.

It is generally the case that the neuropathic diseases are not properly diagnosed in the early stages. This is due to most doctors being unfamiliar with these diseases. Early detection is important. If treatment is begun quickly, the damage is minimized and full recovery is more likely.

MANIFESTATION

Usually, the initial onset of RSD occurs in a very localized region proximal (near to) the site of the triggering trauma. The typical characterization of a localized region is: localized vasoconstriction and the resulting hypoxia (oxygen starvation) of the blood vessels and capillaries which in turn, produces cell necroses (cell death, due to constricted blood flow) of the bone, muscle, nerves, and skin, and the vascular system itself. For sake of argument, let us define RSD to be primarily an aberration of the sympathetic nervous system which in turn produces a vasomotor dysfunction for a given region. The vasomotor function is governed by both the sympathetic (increases the heart rate, blood pressure and constricts the vessels and capillaries), and the parasympathetic (lowers the heart rate, blood pressure and dilates the vessels and capillaries) nervous systems. The sympathetic and parasympathetic nervous systems, and the vasomotor control function are system-wide or body-wide global functions. But, RSD usually manifests in just one region (initially). RSD then seems to spread, in many cases to a new region, either proximal (near) to or distal (far) from the site of the original region.

As the disease progresses - it either spreads to an adjacent area (proximal to the most recent area) or it shows up elsewhere (distal to the most recent area). As the disease continues, this manner of spreading (proximal or distal) also continues. Now, as to where it may or may not next manifest - it seems that anywhere there are vasomotor functions and sympathetic and parasympathetic nerves, it is a potential location for a new RSD region.

This regionalization is currently thought (possibly) to be a defect in the cortical mapping function of the brain. The brain seems not to know exactly where to respond to the afferent nerves that report pain. This results in the "randomness" of RSD manifesting in some new region. (As reported in current research reports). This means, that RSD can affect any area within the body, eyes, heart, where ever. I am not yet certain about the domain of the central nervous system - the brain and the spine, but if such nerves and vasomotor function and its attendant capillarial delivery system exist, then RSD may spread there. It seems a reasonable assumption that it can spread to the brain and spine, since all areas, especially the brain - have capillaries and a well-defined vascular system.

Note: that not all cases of RSD spread. Some remain localized to the site of the original trauma or affect only the limb of the original site. It is the nature of this particular disease to be so varied in its manner of affliction that it makes characterization difficult.

STRESS and PAIN MINIMIZATION

The pain associated with these diseases is often very severe and intense. The patient is often caught in a cyclical situation, where the pain produces stress, which in turn produces more neurotoxins, which stimulate the afferent nociceptors and produce more pain. It is an important part of the treatment that first the pain is alleviated and second the stress be minimized or better, eliminated. Any stress will exacerbate the disease and the pain.

The pain stems from the cell necroses of the tissues that are affected by the curtailed blood flow within the affected region. As the nerves are attacked, the first sensation experienced is tingling. Usually in an extremity or proximal (near) to the affected area. As the nerve cells continue to suffer endoneural hypoxia (oxygen starvation) and trophic (nutrient) starvation, they begin to die. The patient then experiences severe burning pain. In the last stage, as the nerves continue to die an intense and numbness is experienced.

At the same time, cell necroses of the bones, muscles, and the vascular system also experience oxygen and nutrient starvation. As the bone cells die, a deep ache is produced. The bones in the affected area then become subject to attack by osteoclasts resulting in the loss of bone material (demineralization). This is not unlike osteoporosis. As the muscle cells die the patient experiences dystrophy or shrinking and distortion of the muscle. The skin is affected and changes color, texture, and temperature control, and is either too hot or too cold. The skin becomes hypersensitive to both temperature and touch. The skin and nails thicken and the follicles are affected and the hair falls out.

TREATMENT and NUTRITION

It is important to eat the correct foods and to avoid strong stimulants. Further, it is important to follow a dietary regime with vitamins and supplements that are similar to the Nutritional Treatment section of the Diabetic Neuropathy document. This subject will be covered more completely in a later article.

ETIOLOGIES (CAUSES)

Currently, the etiologies (causes) of many of the PNS neuropathies, including RSD are idiopathic (unknown). In most cases that are eventually diagnosed as for example, RSD, the onset of the disease usually begins with a minor trauma, usually to an extremity or limb. It is this incidence of "minor trauma" that bears investigation.

These minor traumata range from repetitive stress injuries (RSI) to the breaking of a bone, the cutting of the skin, the crushing of a limb, or injury to a nerve. It is believed that in these instances of minor trauma that result in RSD, that the trigger was nerve damage. But is this always the case?

Is it not most curious that a normal, healthy, robust individual sustains a minor trauma, which then results in RSD?

In the extreme, within a matter of months or at most two years, this formerly healthy individual is reduced to the state of a near quadriplegic. Furthermore, this individual has most likely suffered other trauma before this triggering incident, with no such consequences. In a few cases, the disease does not progress much beyond the original region.

What change in the physiology of this individual has occurred? Why did this change in the physiology permit such a minor trauma to result in a neurological disease like RSD?

The unknown primary cause almost always results in a dysfunction of the vasomotor control. This dysfunction is usually vasoconstriction. The sympathetic and the parasympathetic nervous systems control the vasomotor functions. Thus vasoconstriction may be due to the aberrant actions of the sympathetic nervous system. It is convenient to refer to this aberrant behavior as "sympathetic hyperactivity." This represents that the sympathetic nervous system appears to be triggering vasoconstriction, when there is no apparent reason to do so.

The parasympathetic nervous system causes the vasomotor function to dilate the blood vessels and capillaries. This is called vasodilation. However, the parasympathetic control seems to be absent in this case. Vasoconstriction is the underlying secondary cause of most RSD symptoms. Vasoconstriction reduces the blood flow, thus denying nutrients and oxygen to the tissues that are connected to the capillaries of the affected area. This in turn leads to the tertiary effects of tissue necroses (cell death).

At this time, it would be illustrative to present some questions that are raised by the information presented so far. Questions about the cause, how the diseases manifest, how they are treated and how the pain may be managed.

QUESTIONS IN SEARCH OF THE ETIOLOGIES (CAUSES)

• What needs to be understood is the underlying mechanism that is referred to as sympathetic hyperactivity. What exactly is this sympathetic hyperactivity?
• Is it that the potentiation rate of the "firing" nerves has increased? Is it constant? Does it vary?
• Is it that the voltage of the potentiation has increased from normal? Is it constant? Does it vary?
• Is there an up-regulation of nociceptors in the affected area by the release of neurotoxins - thus giving rise to and increased number of "pain pathways"?
• Is the number of nociceptors constant? Does it vary? One would think that if engendered by the release of neurotoxins, then yes there would be either an increase or a variance, according to the amount of neurotoxin available..
• Is there possibly a misunderstanding between the brain and the sympathetic nervous system?
• Or is this a very complex relationship that also involves the limbic system?
• Or can there be more complications than this?
• Does Cortical Mapping (or miss-mapping) play a role here?
• Is confusion on the part of the cortex or any other region of the brain responsible for the random appearance of the RSD regions?
• That is - is the appearance of a new region that is affected in the same or a different limb?
• And if so, is the choice of the new location (same side, symmetric or not) a clue to the workings of the disease? Or of the failure in the brain functions?

QUESTIONS IN SEARCH OF EFFECTIVE TREATMENT OF THE DISEASE

• If vasodilators are given to the patient, the problems due to vasoconstriction may be abated - or reduced. Given enhanced blood flow, the necroses of nerve, bone, muscle and vascular cells is halted. In the case of nerve and bone and vascular tissues, these cells may be regrown by the natural processes of the body. In the case of muscle damage, this is reversible only by surgery.
• If the cause of the pain that triggers the sympathetic hyperactivity is reduced then would the cycle of pain broken?
• It seems logical to think that it would be. But the pain may reduced and the disease abated by enhancing the blood flow and along with pain management. Yes it is important to manage the pain throughout the treatment of the disease, but the treatment of the disease must be continuous.
• The treatment of diabetic neuropathy has been studied to such an extent that it is possible to render the disease into remission or nearly "cure" it. Diabetic neuropathy is practically identical to RSD, save for the diabetes - which is treated separately.

QUESTIONS ABOUT PAIN MANAGEMENT

• Has intervention by pain management doctors been effective in pain alleviation - in the reduction of sympathetic hyperactivity? Effective in a few cases? Effective in all cases? Not at all effective?
• Pain management has been proven to be effective in the short term. But has pain management been effective in the long run? Does it contribute to the remission or "cure" of the disease?
• Evidence shows that by and large, pain management works only if the underlying disease is treated at the same time. If not, the disease progresses to the point where effective pain management is no longer possible. Thus the patient is reduced to taking ever-larger quantities of narcotic drugs in the hope of avoiding the pain which is now becoming infinite.

Author's closing note: This is a large topic in that there are many issues to be discussed and questions raised. The goal is to present what is currently known, to solicit input from the readership at large and to feed back the resulting questions and ideas to the research effort in the search for the causes and effective treatment of this group of diseases.

Regards

Les Abrams