Foot Care in the Diabetic

Introduction

Adults with diabetes have an annual mortality of about 5.4% (double the rate for non-diabetic adults), and their life expectancy is decreased on average by 5-10 years.22 Although the increased death rate is mainly due to cardiovascular disease, deaths from non-cardiovascular causes are also increased. A diagnosis of diabetes immediately increases the risk of developing various clinical complications that are largely irreversible and due to microvascular or macrovascular disease. Duration of diabetes is an important factor in the pathogenesis of complications, but other risk factors for example, hypertension, cigarette smoking, and hypercholesterolaemia interact with diabetes to affect the clinical course of microangiopathy and macroangiopathy.

Neuropathy

The diabetic neuropathies present in several ways. The commonest form is a diffuse progressive polyneuropathy affecting mainly the feet. It is predominantly sensory and often asymptomatic,. Reduced sensation can be detected with a monofilament, and patients with sensory neuropathy as well as other high-risk features need advice on foot care to minimise the risk of ulceration. Neuropathic foot ulcers can be distinguished from vascular ulcers, although a mixed aetiology is common.

Peripheral Neuropathy can be subtle in its presentation. It can present as a burning sensation in the feet or simply loss of sensation. In the latter case, the patient maybe unaware he/she has a problem and thus the effects of trauma such as such as loss of skin integrity, ulceration and infections can develop to a greater extent than usual before they are discovered. In addition the macro vascular complications of diabetes, if present, can aggravate this situation.

Prevalence

Usual Scenario

A cascade develops that starts with mild trauma to the foot. This minor trauma can be shoe pressure, a minor cut, for example form nail cutting, or thermal injury. Because of lack of sensation, the patient is sometimes unaware of this initiating trauma and makes no changes. The trauma may continue and now becomes more than mild. Skin changes occur and skin breakdown can occur. This breakdown can lead to infection and/or ulcers. If vascular compromise is present this aggravates the problem and impairs healing.^3-9

Risks:

• Impaired sensation (monofilament)
• Past or current ulcer
• Maceration
• Fungal or gryphotic (thickened or horny) toenails
• Biomechanical problems (corns or callus)
• Fissures
• Clawed toes²²

EXAMINATION

INSPECTION:

FEET:
Shiny skin and lack of hair can be clues to poor circulation. The morphology of the foot Morphologic changes of the feet include callosities, fissures, fungal infection, blisters, ulcers, claw toes, prominent metatarsal heads, and Charcot arthropathy.

FOOTWEAR:
These can give a clue as to wear and potential puncture problems

PALPATION:
This involves palpation of foot pulses, a sense of the temperature of the foot and measurement of foot sensation. Foot sensation can be measured by a 10 g. monofilament weight or vibration testing.

Monofilament measurements should be taken at 10 different sites on the foot at least once a year. The monofilament is pressed against the foot with enough pressure to bend it. Loss of protective sensation and risk of ulcer formation should be considered when the patient fails to feel the monofilament at four different sites.

If vibration of a 128 Hz tuning fork over the medial malleolus is perceived for < 5 seconds, the test is considered to be positive.

Assessment of the ankle jerk is helpful although it is less reliable in elderly people

Preventive and Therapeutic Intervention

Glycemic Control

Tight glycemic control is always a goal. A continuous relation exists between glycaemic control and the incidence and progression of microvascular complications. The UK prospective diabetes study of patients with type 2 diabetes, showed that an intensive glucose control policy that lowered glycated haemoglobin concentrations by an average of 0.9% compared with conventional treatment (median HbA1c 7.0% v 7.9%) resulted in a 25% reduction in the overall microvascular complication rate. It was estimated that for every 1% reduction in HbA1c concentration there is a 35% reduction in microvascular disease.³⁴

Prevention and Counselling

The 2003 CDA Guidelines state that people at high risk of foot ulcerations and amputation require foot care education, proper footwear, counselling to avoid trauma, smoking cessation and early referrals if problems occur.⁴⁷

Interventions can occur anywhere in the trauma cascade, but obviously the sooner the better. Earlier interventions can be preventative. Regular foot examinations down by a health care professional should be part of a diabetic patients' routine care. Good patient education on foot care has been shown to decrease the rate of ulcers and amputations. A study by Malone et al showed that foot education resulted in a 3 fold decrease in ulceration and amputation rates after 2 years.²⁰ CDA guidelines on footcare recommend that foot examinations be an integral part of diabetic care.⁴⁷

- John Axler

Thanks to Dr. Stewart Harris for reviewing the draft copy of this article. Dr. Harris is Associate Professor at the University of Western Ontario, London, Ontario with Joint Appointments in the Department of Family Medicine, Department of Epidemiology and Biostatistics and the Division of Endocrinology and Metabolism.

Journal Articles:

1. American Diabetes Association: clinical practice recommendations 1997. Diabetes Care. 1997;20(suppl 1):S1-S70.
2. Reiber GE, Boyko EJ, Smith DG. Lower extremity foot ulcers and amputations in diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:409-428.
3. Eastman RC. Neuropathy in diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:339-348.
4. Palumbo PJ, Melton LJ III. Peripheral vascular disease and diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:401-408.
5. Boyko EJ, Lipsky BA. Infection and diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:485-499.
6. Frykberg RG. Diabetic foot ulcerations. In: Frykberg RG, ed. The High Risk Foot in Diabetes Mellitus. New York, NY: Churchill Livingstone; 1991:151.
7. Frykberg RG, Veves A. Diabetic foot infections. Diabetes Metab Rev. 1996;12:255-270.
8. Gibbons G, Eliopoulos GM, Kozak GP, et al. Infection of the diabetic foot. In: Kozak GP, Campbell DR, Frykberg RG, eds. Management of Diabetic Foot Problems. Philadelphia, PA: WB Saunders; 1995:121.
9. Reiber GE, Pecoraro RE, Koepsell TD. Risk factors for amputation in patients with diabetes mellitus. A case-control study. Ann Intern Med. 1992;117:97-105.
10. Bild DE, Selby JV, Sinnock P, et al. Lower-extremity amputation in people with diabetes. Epidemiology and prevention. Diabetes Care. 1989;12:24-31.
11. Reiber G. Epidemiology of the diabetic foot. In: Levin ME, OÕNeal LW, Bowker JH, eds. The Diabetic Foot. 5th ed. St. Louis, MO: Mosby; 1993:1-5.
12. Ebskov B, Josephsen P. Incidence of reamputation and death after gangrene of the lower extremity. Prosthet Orthot Int. 1980;4:77-80.
13. Most RS, Sinnock P. The epidemiology of lower extremity amputations in diabetic individuals. Diabetes Care. 1983;6:87-91.
14. Assal JP, MŸhlhauser I, Pernet A, et al. Patient education as the basis for diabetes care in clinical practice and research. Diabetologia. 1985;28:602-613.
15. Litzelman DK, Slemenda CW, Langefeld CD, et al. Reduction of lower extremity clinical abnormalities in patients with non-insulin-dependent diabetes mellitus. A randomized, controlled trial. Ann Intern Med. 1993;119:36-41.
16. Malone JM, Snyder M, Anderson G, et al. Prevention of amputation by diabetic education. Am J Surg. 1989;158:520-523, 523-524.
17. Boyko EJ, Ahroni JH, Stensel V, et al. A prospective study of risk factors for diabetic foot ulcer. The Seattle Diabetic Foot Study. Diabetes Care. 1999;22:1036-1042.
18. Margolis DJ, Kantor J, Berlin JA. Healing of diabetic neuropathic foot ulcers receiving standard treatment. A meta-analysis. Diabetes Care. 1999;22:692-695.
19. McCabe CJ, Stevenson RC, Dolan AM. Evaluation of a diabetic foot screening and protection programme. Diabet Med. 1998;15:80-84.
20. Mayfield JA, Reiber GE, Saundes LJ et al. Preventative foot care in people with diabetes. Diabetes Care; 21: 2161-2177,1998
21. Shilling F. Foot care in patients with diabetes. Nursing Standard; 17#23 61-68,2002
22. Donnely R, Elmslie-Smith A. et al. ABC of arterial venous disease BMJ 2000;320:1062-1066 (15 April)
23. Partanen J, Niskanen L, Lehtinen J, et al. Natural history of peripheral neuropathy in patients with non-insulin-dependent diabetes mellitus. N Engl J Med. 1995;333:89-94.
24. The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329:977-986.
25. Singleton JR, Smith AG, Bromberg MB. Increased prevalence of impaired glucose tolerance in patients with painful sensory neuropathy. Diabetes Care. 2001;24:1448-1453.
26. Young MJ, Breddy JL, Veves A, et al. The prediction of diabetic neuropathic foot ulceration using vibration perception thresholds. A prospective study. Diabetes Care. 1994;17:557-560.
27. Reiber GE, Boyko EJ, Smith DG. Lower extremity foot ulcers and amputations in diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:409-428.
28. Perkins BA, Olaleye D, Bril V. Carpal tunnel syndrome in patients with diabetic polyneuropathy. Diabetes Care. 2002;25:565-569.
29. Perkins BA, Olaleye D, Zinman B, et al. Simple screening tests for peripheral neuropathy in the diabetes clinic. Diabetes Care. 2001;24:250-256.
30. Rith-Najarian SJ, Stolusky T, Gohdes DM. Identifying diabetic patients at high risk for lower-extremity amputation in a primary health care setting. A prospective evaluation of simple screening criteria. Diabetes Care. 1992;15:1386-1389.
31. Reichard P, Berglund B, Britz A, et al. Intensified conventional insulin treatment retards the microvascular complications of insulin-dependent diabetes mellitus (IDDM): the Stockholm Diabetes Intervention Study (SDIS) after 5 years. J Intern Med. 1991;230:101-108.
32. The Diabetes Control and Complications Trial Research Group. The effect of intensive diabetes therapy on the development and progression of neuropathy. Ann Intern Med. 1995;122:561-568.
33. Ohkubo Y, Kishikawa H, Araki E, et al. Intensive insulin therapy prevents the progression of diabetic microvascular complications in Japanese patients with non-insulin-dependent diabetes mellitus: a randomized prospective 6-year study. Diabetes Res Clin Pract. 1995;28:103-117.
34. UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet. 1998;352:837-853.
35. Max MB, Culnane M, Schafer SC, et al. Amitriptyline relieves diabetic neuropathy pain in patients with normal or depressed mood. Neurology. 1987;37:589-596.
36. Max MB, Kishore-Kumar R, Schafer SC, et al. Efficacy of desipramine in painful diabetic neuropathy: a placebo-controlled trial. Pain. 1991;45:3-9, 1-2.
37. Max MB, Lynch SA, Muir J, et al. Effects of desipramine, amitriptyline, and fluoxetine on pain in diabetic neuropathy. N Engl J Med. 1992;326:1250-1256.
38. Gomez-Perez FJ, Rull JA, Dies H, et al. Nortriptyline and fluphenazine in the symptomatic treatment of diabetic neuropathy. A double-blind cross-over study. Pain. 1985;23:395-400.
39. McQuay H, Carroll D, Jadad AR, et al. Anticonvulsant drugs for management of pain: a systematic review. BMJ. 1995;311:1047-1052.
40. Stracke H, Meyer UE, Schumacher HE, et al. Mexiletine in the treatment of diabetic neuropathy. Diabetes Care. 1992;15:1550-1555.
41. Backonja M, Beydoun A, Edwards KR, et al. Gabapentin for the symptomatic treatment of painful neuropathy in patients with diabetes mellitus: a randomized controlled trial. JAMA. 1998;280:1831-1836.
42. Harati Y, Gooch C, Swenson M, et al. Double-blind randomized trial of tramadol for the treatment of the pain of diabetic neuropathy. Neurology. 1998;50:1842-1846.
43. Yuen KCJ, Baker NR, Rayman G. Treatment of chronic painful diabetic neuropathy with isosorbide dinitrate spray. A double-blind placebo-controlled cross-over study. Diabetes Care. 2002;25:1699-1703.
44. Low PA, Opfer-Gehrking TL, Dyck PJ, et al. Double-blind, placebo-controlled study of the application of capsaicin cream in chronic distal painful polyneuropathy. Pain. 1995;62:163-168.
45. The Capsaicin Study Group. Treatment of painful diabetic neuropathy with topical capsaicin. A multicenter, double-blind, vehicle-controlled study. Arch Intern Med. 1991;151:2225-2229.
46. Bianco A, Pitocco D, Valenza V, et al. Effect of sildenafil on diabetic gastropathy. Diabetes Care. 2002;25:1888-1889.
47. Canadian Journal of Diabetes: 2003 27 (Suppl.2) Canadian Diabetes Association 2003 Guidelines for the Prevention and Management of Diabetes in Canada

Internet Resources for Diabetic Foot care

http://www.diabetes.ca/Section_Main/welcome.asp

http://www.diabetes.ca/cpg2003/recommendations.aspx

http://www.niddk.nih.gov/

http://www.ndep.nih.gov/resources/health.htm

You can search for abstracts of the above references by following this link: PubMed