Peripheral neuropathy is most commonly associated with diabetes but is also found in relation to other disease states including vitamin deficiencies, thyroid dysfunction, chemical and metal toxicities, viral infections, inherited disorders or idiopathic (“no identifiable cause”). Peripheral neuropathy can also involve the functions of movement and strength as well as feeling or sensation. The change in normal neurological functioning in your body depends on the severity and form of neuropathy.
The outermost nerves are actually composed of motor, sensory and autonomic nerves. Since our nerves are not visible with normal observation, we must rely on a thorough history and physical exam along with appropriate diagnostics to evaluate both the severity and type of neuropathy. Testing can include screening for glandular dysfunction, vitamin deficiencies, inflammatory gammopathies, genetic aberrancies, immunological dysregulation, viral triggers, and other toxicities. Testing for “friendly fire” or auto-antibodies against angliosides, glyoproteins and RNA-binding proteins can also be done. Each potential cause has its own detailed list of sub-catagories. Studies to diagnose the problem may also include electromylography and nerve conduction studies or a specialized nerve biopsy. In many cases, the presenting symptom is usually pain, but identifying the underlying cause can be very important in slowing disease progression as well as implementing an appropriate course of action. Neuropathies can be acute, subacute or chronic and associated with previously identified systemic disease or, as of yet, undiagnosed disease. Thus the history, even the smallest detail, is quite important in helping the practitioner to accurately diagnose the patient.
Destruction of the outermost nerves cell (neuron) can be due to damage of the cell body (soma), the dendrites, or the axons. The axons connect one nerve cell body to the next and are the framework of nerve conduction. Nerve conduction is the process of transmitting signals, allowing many important body functions to occur at the same time. Each axon sends an impulse toward the presynaptic space which causes various neurotransmitters to continue conduction across to the postsynaptic space. This process, much like the electrical wiring in our homes, must be intact to function in a safe and effective manner. Thusly, just as faulty insulation on electrical wiring will cause problems with conduction and ultimately result in a dysfunctional electrical device, sometimes even permanently damaging the TV, light or appliance, our nerves can have similar problems. Nerves are covered by a coating called a myelin sheath. This sheath moves or conducts the impulses along the nerve. Parts of the myelin coating can become affected by one of the above mentioned processes which cause the disruption in the nerve’s ability to conduct – which in turn can cause the above symptoms. Peripheral neuropathy is a wide ranged complex set of both progressive and self-limiting disease states with varied outcomes.
Although every system in our body is complex, our nervous system is even more so, tying together our emotions with thought, digestion, movement, fight or flight, pleasure and pain. Therefore, diagnosis and an initial evaluation may start with your primary care physician then proceed to a specialist in neurology or pain medicine. In allopathic medicine, treatment is often based more on relief of symptoms once the more common disease states or toxicities have been either identified or ruled out. Treatments may include use of medications to reduce neuropathic pain. Neuropathic pain is an unusual un-regulation of sodium channels and other types of regulatory “gates” that control chemicals that tend to excite causing a rush of both peripheral and central (brain) sensitization that heightens the patient’s perception of feeling to even normal stimuli such as clothing. This heightened sense of feeling is called allodynia. Neuropathic pain can also be quite pronounced at night, when other distracting “normal’ stimuli like walking are absent allowing the painful stimuli to take a prominent place in the patient’s perception.
As indicated above, treatment will vary depending upon the cause of the neuropathy. In Allopathic medicine, treatment is based on controlling pain signals going to and from the brain. This involves interrupting descending transmission of pain-related neurotransmitters such as norepinepherine. We now know that pain is quite complex and involves a multitude of “neuro biochemical “events. In neuropathic pain states such mechanisms include changes in your normal internal balance or balance of various regulatory channels and receptors including opioid receptors, sodium channels, NMDA receptors and even the dorsal root ganglion. What this means is that our nervous system can actually reorganize, reroute and change in a faulty manner. This brings us back to why; if possible, the underlying mechanism of the neuropathy should be identified and treated.
There are numerous medications advertised in the media aimed at achieving this goal. These generally fall under the category of anti-convulsants, antidepressants (specifically tricyclics), and opioids. These drugs have been proven as most effective in easing neuropathic pain. Newer drugs such as selective serotonin and norepinepherine reuptake inhibitors have also been proven to be effective, but have less of a “proven track record”. Topical treatments can also be helpful. These include both pharmaceutical grade and standardized patches and creams. Additionally, compounded “neuropathic“formulas that affect multiple receptors such as ketamine, clonidine , amitriptyline are helpful to the patient. Lastly, there are specific forms of peripheral neuropathies that respond favorably to intravenous immunoglobulin therapy or steroids. However, these are not generally used as empiric treatments and only as specific therapies.
From an Integrative Medicine perspective, identification of the underlying cause may include food sensitivities specifically, gluten. This is different from either acute food allergy or Celiac disease. The gluten-sensitive patient needs to avoid gluten in all forms, not just bread. Any intestinal issues need to be identified and treated as a supportive measure. Other sources of peripheral neuropathy include exposure to toxic metals or pesticides. Exposure is not usually picked up on a routine blood or urine test, but can only be found via a provoked test. This means an agent must be given to “challenge” the chemical or metal gently from where they are stored in the bone or fat. Mineral and vitamin balance is also important and often cannot be randomly implemented. Mineral balance is most accurately determined in testing the red blood cell, not the serum. Lymphocyte sensitivity testing can identify low levels of the above mentioned substances that can cause symptoms in some patients. Pain can also be treated with Class IV High Power Laser Therapy. This is a safe, focused treatment that stimulates healing at the cellular level and is not likely to conflict with other treatment recommendations.
As you can see, peripheral neuropathy is a complex disorder that can involve almost every body system. As a patient, your input and history is vital to the most accurate diagnosis which will affect your treatment options. The more you understand regarding this complex disorder, the better your ability to advocate for yourself will be!