Diabetic Neuropathy

1. Diabetic Neuropathy

2. Diabetic Neuropathy • About 60-70% of people with diabetes have mild to severe forms of nervous system damage, including: • Impaired sensation or pain in the feet or hands • Slowed digestion of food in the stomach • Carpal tunnel syndrome • Other nerve problems • More than 60% of nontraumatic lower-limb amputations in the United States occur among people with diabetes.

3. Risk Factors • Glucose control • Duration of diabetes • Damage to blood vessels • Mechanical injury to nerves • Autoimmune factors • Genetic susceptibility • Lifestyle factors • Smoking • Diet

4. Pathogenesis of Diabetic Neuropathy • Metabolic factors • High blood glucose • Advanced glycation end products • Sorbitol • Abnormal blood fat levels • Ischemia • Nerve fiber repair mechanisms

5. Diagnostic Tests • Assess symptoms - muscle weakness, muscle cramps, prickling, numbness or pain, vomiting, diarrhea, poor bladder control and sexual dysfunction • Comprehensive foot exam • Skin sensation and skin integrity • Quantitative Sensory Testing (QST) • X-ray • Nerve conduction studies • Electromyographic examination (EMG) • Ultrasound

6. Classification of Diabetic Neuropathy • Symmetric polyneuropathy • Autonomic neuropathy • Polyradiculopathy • Mononeuropathy

7. Symmetric Polyneuropathy • Most common form of diabetic neuropathy • Affects distal lower extremities and hands (“stocking-glove” sensory loss) • Symptoms/Signs • Pain • Paresthesia/dysesthesia • Loss of vibratory sensation

8. Complications of Polyneuropathy • Ulcers • Charcot arthropathy • Dislocation and stress fractures • Amputation - Risk factors include: • Peripheral neuropathy with loss of protective sensation • Altered biomechanics (with neuropathy) • Evidence of increased pressure (callus) • Peripheral vascular disease • History of ulcers or amputation • Severe nail pathology

9. Treatment of Symmetric Polyneuropathy • Glucose control • Pain control • Tricyclic antidepressants • Topical creams • Anticonvulsants • Foot care

10. Essentials of Foot Care • Examination • Annually for all patients • Patients with neuropathy - visual inspection of feet at every visit with a health care professional • Advise patients to: • Use lotion to prevent dryness and cracking • File calluses with a pumice stone • Cut toenails weekly or as needed • Always wear socks and well-fitting shoes • Notify their health care provider immediately if any foot problems occur

11. Autonomic neuropathy • Affects the autonomic nerves controlling internal organs • Peripheral • Genitourinary • Gastrointestinal • Cardiovascular • Is classified as clinical or subclinical based on the presence or absence of symptoms

12. Peripheral Autonomic Dysfunction • Contributes to the following symptoms/signs: • Neuropathic arthropathy (Charcot foot) • Aching, pulsation, tightness, cramping, dry skin, pruritus, edema, sweating abnormalities • Weakening of the bones in the foot leading to fractures • Testing • Direct microelectrode recording of postglanglionic C fibers • Galvanic skin responses • Measurement of vascular responses

13. Peripheral Autonomic Dysfunction, cont. • Treatment • Foot care/elevate feet when sitting • Eliminate aggravating drugs • Reduce edema • midodrine • diuretics • Support stockings • Screen for CVD

14. Genitourinary Autonomic Neuropathy

15. Gastrointestinal Autonomic Neuropathy • Symptoms/Signs • Gastroparesis resulting in anorexia, nausea, vomiting, and early satiety • Diabetic enteropathy resulting in diarrhea and constipation • Treatment • Other causes of gastroparesis or enteropathy should first be ruled out • Gastroparesis - Small, frequent meals, metoclopramide, erythromycin • Enteropathy - loperamide, antibiotics, stool softeners or dietary fiber

16. Cardiovascular Autonomic Neuropathy • Symptoms/Signs • Exercise intolerance • Postural hypotension • Treatment • Discontinue aggravating drugs • Change posture (make postural changes slowly, elevate bed) • Increase plasma volume

17. Polyradiculopathy • Lumbar polyradiculopathy (diabetic amyotrophy) • Thigh pain followed by muscle weakness and atrophy • Thoracic polyradiculopathy • Severe pain on one or both sides of the abdomen, possibly in a band-like pattern • Diabetic neuropathic cachexia • Polyradiculopathy + peripheral neuropathy • Associated with weight loss and depression

18. Polyradiculopathy, cont. • Polyradiculopathies are diagnosed by electromyographic (EMG) studies • Treatment • Foot care • Glucose control • Pain control

19. Mononeuropathy • Peripheral mononeuropathy • Single nerve damage due to compression or ischemia • Occurs in wrist (carpal tunnel syndrome), elbow, or foot (unilateral foot drop) • Symptoms/Signs • numbness • edema • pain • prickling

20. Mononeuropathy, cont. • Cranial mononeuropathy • Affects the 12 pairs of nerves that are connected with the brain and control sight, eye movement, hearing, and taste • Symptoms/Signs • unilateral pain near the affected eye • paralysis of the eye muscle • double vision • Mononeuropathy multiplex

21. Mononeuropathy, cont. • Treatment • Foot care • Glucose control • Pain control

22. Other Treatment Options • Aldose reductase inhibitors • ACE inhibitors • Weight control • Exercise

23. References American Diabetes Association:Preventive Foot Care in Diabetes (Position Statement). Diabetes Care 27 (Suppl.1): S63-S64, 2004 Feldman, EL: Classification of diabetic neuropathy. In UpToDate. Wellesley, MA, UpToDate, 2003 National Diabetes Information Clearinghouse. Diabetic Neuropathies: The Nerve Damage of Diabetes. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), DHHS; 2002 National Diabetes Information Clearinghouse. Prevent Diabetes Problems: Keep Your Feet and Skin Healthy. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), DHHS; 2003

24. References, cont. Feldman, EL: Pathogenesis and prevention of diabetic polyneuropathy. In UpToDate. Wellesley, MA, UpToDate, 2003. Feldman, EL, McCulloch, DK: Treatment of diabetic neuropathy. In UpToDate. Wellesley, MA, UpToDate, 2003. Stevens, MJ: Diabetic autonomic neuropathy. In UpToDate. Wellesley, MA, UpToDate, 2003. Feldman, EL: Clinical manifestations and diagnosis of diabetic polyneuropathy. In UpToDate. Wellesley, MA, UpToDate, 2003.