Strategies and Methods for the Treatment of Diabetic Neuropathy Using Integrative Chinese and Western Medicine

Author: Heng Xianpei

Diabetic neuropathy (DN) is the most common metabolic neuropathy in clinics, not only in diabetes patients (>60%), but also in pre-diabetic (8%) and normal persons (5%)(1). Its pathogenesis has not been fully understood up to now. It is generally believed that it is related to the increase in glycation endoproducts (AGEs) caused by hyperglycemia, and the activation of the polyalcohol pathway, protein kinase C and the amidohexose pathway. Some scholars believe that neurotrophic disturbance is also one of the pathogeneses of DN. Recently it has been found that oxidative stress and free radical injury play key roles in the pathology of vascular and neural complications in diabetes. The disorders of blood and oxygen supply may cause and/or promote nerve injury, respectively. Another research found that hyperosmosis was also important in the process of nerve injury (2)

Western Medicine Treatment

Anyhow, the pathologic treatment should be prioritized first, and this involves controlling the metabolic disorder. The benefits of comprehensive and scientific intensive treatment focused on controlling blood glucose for preventing complications have been confirmed by researches in evidence-based medicine, such as the UK Prospective Diabetes Study (UKPDS), the Diabetes Control and Complications Trial (DCCT), etc. The studies show that the results of treatment aiming at the pathological mechanism of DN are more effective than those aiming at symptoms. Moreover, the former could reduce visit frequency and expenses(3). If without contraindications, improving blood and oxygen supply is important in treating chronic complications of diabetes. As to oxidative stress, the ideal treatment is eliminating the source which produces it, but realistically it is very difficult to achieve. Currently, we could try only to eliminate the product of oxidative stress: free radicals. Unfortunately, the effectiveness of free radical scavengers has been verified only with difficulty until now. Currently, the general suitability and effectiveness of inhibitors of protein glycation and aldose reductase depressors are very limited. Drugs aiming at protein kinase C and the passageway of amidohexose have not yet been used in clinical practice. Another treatment method is symptomatic, especially to stop pain. As the first line treatment, anti-epileptic drugs such as carbamazepine, topiramate and Lamotrigine are usually applied. If they are not effective, antidepressant such as Tricyclic imipramine and inhibitors of 5-HT reuptake such as Paroxetine or Venlafaxine, as well as the antianxietic Gabapentin could be used. Externally applied capsicine and nitrate have short-term effects on some symptoms of superficial nerves. It is unsuitable to alleviate pain in DN with non-steroidal analgesics and narcotic analgesics, especially for diabetes patients often complicated with high risks of hypertension or cardiocerebral vascular diseases, but these drugs relieve pain remarkably in a few patients. Mexiletine and Lidocaine are effective in relieving mild pain, but it should be noticed that their effective pain-killing dosage brings about risk of increasing side effects. Vitamin D may alleviate the pain of DN. Decompression of the common peroneal, the posterior tibial, and the deep peroneal nerves might be feasible for severe pain. There is no drug aiming directly at relieving numbness, but the above systemic treatments could relieve numbness in some DN patients. Other symptoms, such as functional disorders involving balance and movement, formication, burning sensation and so on, mostly may only be expected to be treated with systemic therapies. The effects of neurotrophy drugs such as mecobalamine, benfotiamine and promoting nerve recovery drugs are very limited, and even considered similar to the placebo.

Traditional Chinese Medicine Treatment

According to clinical reports, there are many effective traditional Chinese medicine (TCM) treatments, but we do not think we should completely copy any one of them. Guided with TCM diagnosis and treatment based on syndrome differentiation, systemic treatment is the key point to get a satisfactory effect. Summarizing the experiences taken from long-term practice regarding the diagnosis and treatment of DN, we find common pathogeneses of DN, including: a combination of phlegm and blood stasis, stagnation of the Gan (Liver)-qi, deficiency of the Pi (Spleen)-qi, retention of phlegm and dampness in the Pi, insufficiency of yang-qi and stagnation of collaterals, deficiency of yin and insufficiency of essence. Among them, blood stasis and phlegm stagnation are the most common pathogeneses, but the level of visualization of the sign of blood stasis and phlegm stagnation in clinical practice is incompletely identical due to different degrees of impatency of blood stasis and phlegm stagnation. As collaterals are hindered by blood stasis and phlegm stagnation leading to incomplete smoothing of the cycling of qi and blood combined with stagnation of collaterals-qi, the result is a functional disorder of skin apertures and collaterals. Stagnancy of phlegm and blood stasis is often the direct reason for pain and numbness. If DN patients are treated with smoothing the stagnation of Gan-qi, nourishing and strengthening Pi-qi, invigorating the Pi to clear out turbid fluid, warming yang to dredge the collaterals, and nourishing yin and essence, etc.,

Traditional Chinese Medicine Treatment
It is important that these be appropriately combined with removing blood stasis and resolving the phlegm to open collaterals, which can improve the efficacy(4). One study showed that the prescription of dissolving blood stasis and resolving phlegm has a regulatory function in the nerve metabolism of sugar alcohol. Such a prescription, for example, the Dan Gua prescription, reduced ROS concen