63E. Lawson and M. “Misha” Backonja (eds.), Painful Diabetic Polyneuropathy: A Comprehensive Guide for Clinicians, DOI 10.1007/978-1-4614-6299-6_6, © Springer Science+Business Media New York 2013

Introduction

Patients suffering from diabetic peripheral neuropathy (PN) often report numbness and diminished sensation, with or without pain. Painful symptoms are mostly described as burning or “pins and needles,” shooting pain, or hyperaesthesia [ 1 ] . Besides pain there are several other complaints from which patients with PN suffer including decreased muscle strength, insensate feet [ 2 ] , and impaired postural control. Additionally an exaggerated body sway [ 3 ] leads to an increased risk of falling. These problems may negatively in fl uence the patient’s physical activity level and increase the risk of diabetic complications and decreased musculoskeletal function, with fur-ther negative consequences for physical activity [ 4 ] . Furthermore, diabetic PN is a known risk factor for increased mortality and cardiovascular diseases (CVD) [ 5 ] as well as foot ulcers, infection, and even amputation [ 6 ] .

Neuropathic ulcers frequently occur at the forefoot beneath the metatarsal heads [ 7 ] . PN is associated with hyperextension of the metatarsophalangeal joints, claw-ing of the toes, and reduced plantar tissue thickness [ 8 ] . This may increase foot pressure and lead to foot ulcers [ 9 ] . A multidisciplinary management of diabetic foot disease is necessary. The pathogenesis of diabetic PN seems to be multifacto-rial. Pathologic changes in the endoneural capillaries correlate with severity of neu-ropathy [ 10 ] . Ischemia may be an important factor in the pathogenesis of diabetic neuropathies [ 11 ] . Based on this hypothesis a great part of the treatment is focused on improving circulation and oxygenation. Fisher et al. found improvements in nerve function—evaluated by electrophysiological parameters—after 24 weeks of moderate exercise training in patients with type II diabetes mellitus [ 11 ] .

K. Pieber, M.D. (*) • M. Herceg, M.D. • T. Paternostro-Sluga, M.D. Department of Physical Medicine and Rehabilitation , Medical University of Vienna, General Hospital of Vienna , Waehringer Guertel 18-20 , 1090 Vienna , Austria e-mail: karin.pieber@meduniwien.ac.at ; malvina.herceg@meduniwien.ac.at ; tatjana.paternostro-sluga@meduniwien.ac.at

Chapter 6 Physical Therapy for Painful Diabetic Neuropathy

Karin Pieber , Malvina Herceg , and Tatjana Paternostro-Sluga

64 K. Pieber et al.

For conservative treatment of diabetic PN different types of physical therapy are available. Therapeutic interventions focus on different symptoms like pain, reduced muscle strength, impaired balance and physical functioning, or feet ulcers. Also different pathogenetic mechanisms like impaired circulation and oxygenation, increased plantar pressure, or reduced muscle mass and glycogen utilization are taken into account.

This book chapter is aimed to provide an overview on different therapy options in the fi eld of physical medicine and rehabilitation from both an evidence-based and empirical view.

Exercise Therapy and Medical Training Therapy

Exercise therapy includes gait training, sensorimotor training, and exercises to improve physical activity, muscular fi tness, and fl exibility. Medical training therapy consists of aerobic exercises and resistance exercises both performed with suf fi cient intensity and frequency to increase cardiorespiratory and muscular fi tness. Medical training therapy has positive effect on blood glucose regulation, muscle strength, and perceived limitations in functioning in patients with diabetic complications [ 12 ] . Exercise therapy can be provided in groups twice weekly for 60 min over sev-eral weeks. Such training can improve gait speed, balance, muscle strength, and joint mobility in diabetic patients [ 4 ] . The balance exercise program can improve balance and trunk proprioception [ 13 ] . A brief intense exercise regimen designed to improve distal lower extremity strength has proven to be safe and well tolerated in a group of older persons with PN [ 14 ] .

In the past only non-weight-bearing activities such as swimming, bicycling, or arm exercises were recommended for patients with diabetic PN due to fear of increasing risk of skin breakdown, infection, and foot ulcers [ 5 ] . However LeMaster et al. did not fi nd signi fi cant increases in foot ulcers due to promoting weight-bearing activity after an adequate assessment and counselling of patients with diabetic PN [ 15 ] .

Postural control can be improved by exercise therapy, especially balance training [ 16 ] . Additionally aerobic exercise training may prevent the onset, or modify the course, of diabetic PN [ 17 ] .

Electrotherapy and Magnetic Field Therapy

As a metabolic effect in patients with diabetic PN electrotherapy may improve microcirculation in the peripheral nerves and increase the muscle’s oxidative capac-ity [ 18– 20 ] . As a further effect, local release of serotonin [ 21 ] and endorphins, increased mitochondrial ATP production [ 22 ] , and/or anti-in fl ammatory effects may achieve pain reduction. Activation of the dorsal column and inhibition of C fi bers can also reduce pain sensation [ 23 ] .

656 Physical Therapy for Painful Diabetic Neuropathy

Different types of electrotherapy including transcutaneous electrical nerve stimulation (TENS), external muscle stimulation, constant galvanization, pulsed-dose electrical stimulation applied by stocking electrodes, and pulsed (electro-) magnetic fi elds or static magnetic fi eld therapy are used for treatment of diabetic PN. A review by Pieber et al. dealing with electrotherapy for the treatment of pain-ful diabetic PN showed generally poor results regarding evidence-based quality factors [ 24 ] . TENS may be recommended for the treatment of PN. A major advan-tage of this therapy is that it can be applied as home treatment with the use of a portable device. Typically, TENS is applied for at least 30 min daily for 6–12 weeks. The simulation can be performed with self-adhesive skin electrodes placed over the common peroneal nerve of both legs using the low-frequency mode (4 Hz). The intensity can be set individually between 5 and 70 mA.

External muscle stimulation is another promising option. As described by Reichstein et al., stimulating the quadriceps and triceps surae muscles with modu-lated frequencies between 4.096 Hz and 32.768 Hz reduces neuropathy-associated pain and sensory symptoms [ 25 ] . Application time is 30–60 min twice to three times a week over 4 weeks [ 24 ] .

Magnetic fi eld therapy applied with coils, mats, or insoles and constant galvani-zation applied with stocking electrodes or water bath, which is often successfully used to treat patients with PN in daily routine, were not recommended in the men-tioned review [ 24 ] .

Laser Therapy

Low-level laser therapy has been shown to change cell and tissue function, facilitate collagen synthesis, improve the function of damaged neurological tissue, reduce in fl ammation, and relieve pain [ 26– 28 ] . The effects are assumed to be secondary to direct effects of photonic radiation and do not result from thermal processes. In an examination using infrared thermography a signi fi cant increase in skin microcircu-lation was found in patients with diabetic microangiopathy after athermic laser irra-diation [ 29 ] . Zinman et al. [ 29 ] showed a trend to improvement but failed to demonstrate a signi fi cant effect in painful symptoms of diabetic PN with laser ther-apy. No signi fi cant adverse effects were reported. Another study demonstrated posi-tive effects of laser therapy on improvement of nerve conduction velocity on diabetic PN, which further supports the therapeutic potential of this treatment [ 30 ] .

Balneotherapy

The old-fashioned carbonic-acid bath is applied to the skin in the form of gas bub-bles and causes capillary, arterial, and venous vasodilatation [ 31 ] . This effect makes it suitable for the treatment of diabetic PN. Existing literature is only available in Russian or Polish language. Although evidence-based recommendations are lacking, this treatment is often used successfully in daily routine by the authors.

66 K. Pieber et al.

Tai Chi

Tai Chi is a traditional Chinese martial art technique with slow movements, breathing exercises, and meditation. All major muscle groups and joints are used. An increase of muscle strength, improvement of balance, fl exibility, range of motion, and coor-dination are known positive effects [ 32, 33 ] . Wang et al. reported higher skin blood fl ows in healthy elderly Tai Chi practitioners compared to sedentary individuals at rest and during exercise [ 34 ] . Tai Chi may also enhance endothelium-dependent dilation in the skin vasculature [ 35 ] . Furthermore Tai Chi training has shown to improve plantar sensation and balance in elderly adults with diabetes with a large plantar sensation loss [ 36 ] .

Acupuncture

Various types of acupuncture including wrist-ankle [ 37 ] or whole body acupuncture [ 38 ] can be applied. The treatment consists of 6 courses of acupuncture for a 10-week period. Studies reported that acupuncture may show positive effects for diabetic peripheral neuropathy [ 37– 39 ] .

Yoga

In a study with patients suffering from mild to moderate Type 2 diabetes with sub-clinical neuropathy Yoga had a bene fi cial effect on glycemic control and improved nerve function [ 40 ] .

Topical Capsaicin

Capsaicin is an alkaloid of the genus Capsicum. The stimulation of afferent C- fi bers initially results in burning and irritation and stimulates the release of substance P and other neuropeptides [ 41 ] . Repeated exposure can produce a long-lasting analge-sic effect [ 42 ] . A 0.075% capsaicin cream is available over the counter and is recom-mended for topical application three to four times daily for 4–8 weeks. The Capsaicin Study Group found pain reduction and improvements in walking, working, sleep, and participation in recreational activities [ 43 ] .

676 Physical Therapy for Painful Diabetic Neuropathy

Conclusion

Currently available pharmacologic treatments may have incomplete success and may subject patients to adverse side effects that limit their use. Therefore it is impor-tant to have additional treatment options with positive effects on pain, balance, walking, and strength. The correct application, intensity, and frequency of these physical modalities are necessary to avoid signi fi cant adverse effects. A combined individualized treatment with focus on the major complaints is required and mostly consists of exercise therapy, medical training therapy, and electrotherapy. A multi-disciplinary management of painful diabetic peripheral neuropathy is most bene fi cial.

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