Overview: Peripheral Neuropathy

• Peripheral neuropathy, or peripheral neuritis, is a common neurologic disorder resulting from damage to the peripheral nerves.

• It may be caused by diseases of the nerves or may be the result of systemic illnesses.

• It has various causes including toxic trauma, certain prescription medications and chemotherapeutic agents, and mechanical injury causing compression or entrapment, as with carpal tunnel syndrome. Even simple pressure on superficial nerves, such as from prolonged use of crutches or sitting in the same position for too long, can lead to the disorder.

• Nutritional deficiencies can cause peripheral neuropathy, as seen in B-vitamin deficiency (i.e., from alcoholism, pernicious anemia, isoniazid-induced pyridoxine deficiency, malabsorption syndromes).

• Despite a thorough history and physical examination, the origin remains a mystery in approximately 50% of cases.

• One of the most common causes is diabetes; peripheral neuropathy is estimated to be present in approximately 40% to 60% of persons with diabetes of 25 years' duration.

• Diabetic neuropathy is now thought to be the most common form of peripheral neuropathy that afflicts humans, and the incidence increases significantly with age.

• Although the exact pathophysiology of diabetic neuropathy has not yet been clearly identified, the origin is multifactorial.

• Persistent hyperglycemia and autoimmune and microvascular mechanisms are important factors.

Important Points to Consider

• Acupuncture has a positive effect on neuropathic pain and often results in the ability to reduce or stop pain medications.

• In prescribing B-complex vitamins, make sure you are not already taking another vitamin supplement that may contain B vitamins. Vitamin B3 (niacin) in doses greater than 300 mg/day may cause headache, nausea, skin tingling, and flushing. Vitamin B6 in doses greater than 250 mg/day may cause reversible nerve damage.

• Caution should be used with the combination of tramadol, antidepressants, and anticonvulsants, owing to increased seizure risk.

Prevention Prescription

• Eat a whole foods, low-fat, high-fiber, plant-based diet.

• ⁠Avoid environmental toxins such as heavy metals, cigarette smoke, alcohol, pesticides, and herbicides.

• Prevent adult-onset diabetes by maintaining ideal weight and staying physically fit and active.

• If possible, avoid specific toxins (see Table 11-1) and pharmaceutical agents known to cause neuropathy (see Table 11-2).

• ⁠Avoid doses of vitamin B, (pyridoxine) greater than 250 mg/day.

• If taking the chemotherapeutic medications cisplatin, paclitaxel (Taxol), or vincristine, consider acetyl-L-carnitine, 1 g three times daily for 8 weeks.

• Increased levels of androgens are produced not only by the adrenal glands and gonads but also by the sebaceousglands in the skin. Elevated androgenicity is a physiologic consequence of puberty and a pathophysiologic conse- quence of conditions such as polycystic ovary syndrome, congenital adrenal hyperplasia, Cushing syndrome, and androgen-secreting tumors.

• Proliferation and impaired desquamation of keratino- cytes lining the orifice of the follicle pore follow and lead to the development of a hyperkeratotic plug. This occurs within the follicular canal and causes the formation of a microcomedo.

• Increased sebum is produced within the sebaceous gland, also because of increased androgen production. This results in the evolution of a closed comedo (a whitehead) and, if the orifice of the pore dilates, an open comedo (a blackhead).

• The gram-positive anaerobic bacterium Propionibacterium acnes propagates in its sebum-rich growth medium. Although P. acnes is typically a normal component of skin flora, it thrives in an anaerobic environment abundant with lipids as a nutrient source.

• A local inflammatory process develops as neutrophils and other host immune cells accumulate. Papules form, and with the rupture of the pilosebaceous follicle into the sur- rounding dermis, more severe pustular, nodular, and cystic acne lesions may appear

Integrative Therapeutic Review

Lifestyle and Nutrition

• Daily exercise of walking at least 30 minutes per day three times per week should be implemented. If walking is not possible because of painful peripheral neuropathy, gentler forms of exercise such as yoga or tai chi three times a week for 30 to 90 minutes are therapeutic.

• A whole foods, low-fat, high-fiber, plant-based diet with strict glycemic control should be strongly advised. Environmental and other toxins such as heavy metals, cigarette smoke, alcohol, and pollution should be avoided.

⁠Mind-Body Therapy

• Biofeedback: Recommendation is for at least six 1-hr biofeedback sessions at approximately 1-week intervals.

• Relaxation biofeedback techniques can be performed at home with the use of biofeedback home-use programs (e.g., emWave Desktop or em Wave [Institute of HeartMath]), audio CDs, or guided imagery exercises (for 10 to 20 minutes each day).

Bioenergetics

• Infrared: Monochromatic near-infrared photo energy (MIRE), that is, the Anodyne Therapy System (ATS), which consists of therapy pads containing 60 near-infrared (890 nm) gallium aluminum arsenide diodes used three times a week for 40 minutes each visit.

• Four treatments of photostimulation using light-emitting diodes (LEDs) at wavelengths between 750 and 1500 nm may be beneficial.

• Bioelectromagnetics: Magnetic footpad insole devices (i.e., Magstep) with a range of 450 to 475 G steep field gradient can be worn for up to 24 hours of direct contact, and for up to 4 months, to obtain symptomatic relief.

• Acupuncture: Scalp points: upper one fifth sensory area, foot motor and sensory area; ear points: ShenMen, sympathic, foot; body points: GB-40, GB-34, SP-10, SP-6, ST-44, LR-3, and Bafeng (extra point). Electrical stimulation can be used for the ear and body points at a frequency of 100 Hz at low intensity for 10 to 15 minutes for enhanced response. Patients can receive 2 treatments per week for 10 weeks.

• Electroacupuncture: This treatment can be performed in two cycles of five sittings each (10 sessions) at 2-day intervals.

Botanicals

• Curcumin longa, Boswellia serrata, and ginger (e.g., Bosmeric-SR, two caplets twice daily) or Curcumin C3 Complex: 1000 mg three times daily.

• Geranium oil (Pelargonium spp.): For topical pain relief, apply a few drops (i.e., Neuragen PN) to the affected area several times a day.

• Evening primrose oil (EPO; Oenothera biennis): 360 mg orally daily of GLA from EPO. The dose may be increased up to 480 mg orally daily.

Supplements

• Acetyl-L-carnitine (ALC): 500 mg orally twice daily to 1000 mg orally three times daily. ALC is used for both chemotherapy-induced and diabetic peripheral neuropathy.

• Alpha-lipoic acid: 600 to 1800 mg orally daily; start with 600 mg orally daily and increase up to 1800 mg orally daily in divided doses if needed.

• Benfotiamine: Lipid-soluble vitamin B 150 to 300 mg twice daily specifically for diabetic peripheral neuropathy.

• Methylcobalamin or 5-adenosylcobalamin:

• Better-absorbed vitamin B 12 500 mcg three times daily or 1500 mcg daily.

• B-complex multivitamin (B-100): One tablet once or twice daily for peripheral neuropathy caused by deficiency syndromes.

• Fish oil (omega-3 fatty acids): Eicosapentaenoic acid (EPA), 1000 to 2000 mg/day, and docosahexaenoic acid (DHA), 500 to 1000 mg/day or a vegetarian plant-based option (i.e., Nutra Vege).

Pharmaceuticals

For topical relief:

• Capsaicin cream 0.075%: Apply to the affected area up to three or four times daily for at least 4 to 6 weeks.

• Capsaicin patch (8%): One patch to area for 1 hour (after preanesthetic applied) and then removed. It is applied in a doctor's office under supervision.

For acute pain management, consider:

• Analgesics: Nonsteroidal antiinflammatory drugs (NSAIDs) as usually prescribed for pain, as well as narcotics. All should be used very cautiously due to black box warnings.

For chronic pain management:

Antidepressants

• Amitriptyline or nortriptyline: 10 mg orally nightly; titrate the dose upward to 25 mg orally nightly as side effects allow (usual range: 50 to 300 mg/day).

  Anticonvulsants

• Gabapentin (first-line choice): 300 mg orally nightly for 2 days, then 300 mg orally twice daily for 2 days; can be increased to 300 mg orally three times daily as tolerated, with increases in 300-mg increments as side effects allow; maximum daily dose, 3600 mg.

• Pregabalin: 50 mg three times daily. After an initial daily dose of 150mg, it should be titrated with the patient's response and tolerability over 2 weeks to a maximum of 300 mg daily.

Biomechanical Therapy

• Transcutaneous electrical nerve stimulation (TENS): Use of a TENS portable unit for 30 minutes daily for 4 weeks is recommended.

• Percutaneous electrical nerve stimulation (PENS): This modality can be used three times a week; stimulation is delivered along the peripheral nerves innervating the region of neuropathic pain.

• Neural blockade: This provides only temporary therapeutic benefit.

• Surgery: Surgical decompression may relieve symptoms in carpal tunnel syndrome; with neuronal entrapment from cancer, removal of the tumor itself may also be helpful.