Evaluation of the diabetic foot
- David K McCulloch, MD
David K McCulloch, MD
- Clinical Professor of Medicine
- University of Washington
Foot problems are an important cause of morbidity in patients with diabetes mellitus. The lifetime risk of a foot ulcer for diabetic patients (type 1 or 2) may be as high as 25 percent . A potentially preventable initiating event, most often minor trauma that causes cutaneous injury, can often be identified. Foot amputations, many of which are preventable with early recognition and therapy, may be required . These observations illustrate the importance of frequent evaluation of the feet in patients with diabetes to identify those at risk for foot ulceration . Systematic screening examinations for neuropathic and vascular involvement of the lower extremities and careful inspection of feet may substantially reduce morbidity from foot problems.
Evaluation of the diabetic foot is provided here. A discussion of diabetes-related foot infections (cellulitis and osteomyelitis) and the management of diabetic foot ulcers are found elsewhere. (See "Clinical manifestations, diagnosis, and management of diabetic infections of the lower extremities" and "Management of diabetic foot ulcers".)
Several risk factors are predictive of ulcers and amputation. Early recognition and management of risk factors is important for reducing morbidity of foot ulceration. Most risk factors are readily identifiable from the history or physical examination. The most important are previous foot ulceration, neuropathy (loss of protective sensation), foot deformity, and vascular disease [1-4]. The significance of these risk factors was confirmed by the results of a community-based study of 1300 type 2 diabetic patients . The incidence of lower extremity amputation was 3.8 per 1000 patient-years. Predictors of amputation were foot ulceration (hazard ratio [HR] 5.6, 95% CI 1.2-25), ankle brachial index <0.9, elevated glycated hemoglobin (A1C), and neuropathy.
Neuropathy is present in over 80 percent of patients with foot ulcers; it promotes ulcer formation by decreasing pain sensation and perception of pressure, by causing muscle imbalance that can lead to anatomic deformities, and by impairing the microcirculation and the integrity of the skin. Once ulcers form, healing may be delayed or difficult to achieve, particularly if infection penetrates to deep tissues and bone and/or there is diminished local blood flow.
Risk classification — There are several risk classification systems designed to predict foot ulcer in patients with diabetes [6,7]. Risk categorization can be used to design preventive and monitoring strategies (table 1). One system, developed by the International Working Group on the Diabetic Foot, stratifies patients as follows :
- Boulton AJ, Armstrong DG, Albert SF, et al. Comprehensive foot examination and risk assessment: a report of the task force of the foot care interest group of the American Diabetes Association, with endorsement by the American Association of Clinical Endocrinologists. Diabetes Care 2008; 31:1679.
- Pecoraro RE, Reiber GE, Burgess EM. Pathways to diabetic limb amputation. Basis for prevention. Diabetes Care 1990; 13:513.
- Singh N, Armstrong DG, Lipsky BA. Preventing foot ulcers in patients with diabetes. JAMA 2005; 293:217.
- Cheer K, Shearman C, Jude EB. Managing complications of the diabetic foot. BMJ 2009; 339:b4905.
- Davis WA, Norman PE, Bruce DG, Davis TM. Predictors, consequences and costs of diabetes-related lower extremity amputation complicating type 2 diabetes: the Fremantle Diabetes Study. Diabetologia 2006; 49:2634.
- Frykberg RG, Zgonis T, Armstrong DG, et al. Diabetic foot disorders. A clinical practice guideline (2006 revision). J Foot Ankle Surg 2006; 45:S1.
- Apelqvist J, Bakker K, van Houtum WH, et al. International consensus and practical guidelines on the management and the prevention of the diabetic foot. International Working Group on the Diabetic Foot. Diabetes Metab Res Rev 2000; 16 Suppl 1:S84.
- Peters EJ, Lavery LA, International Working Group on the Diabetic FOot. Effectiveness of the diabetic foot risk classification system of the International Working Group on the Diabetic Foot. Diabetes Care 2001; 24:1442.
- Pham H, Armstrong DG, Harvey C, et al. Screening techniques to identify people at high risk for diabetic foot ulceration: a prospective multicenter trial. Diabetes Care 2000; 23:606.
- 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.
- Al-Delaimy WK, Merchant AT, Rimm EB, et al. Effect of type 2 diabetes and its duration on the risk of peripheral arterial disease among men. Am J Med 2004; 116:236.
- Young MJ, Boulton AJ, MacLeod AF, et al. A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population. Diabetologia 1993; 36:150.
- Kenny SJ, Smith PJ, Goldschmid MG, et al. Survey of physician practice behaviors related to diabetes mellitus in the U.S. Physician adherence to consensus recommendations. Diabetes Care 1993; 16:1507.
- Peters AL, Legorreta AP, Ossorio RC, Davidson MB. Quality of outpatient care provided to diabetic patients. A health maintenance organization experience. Diabetes Care 1996; 19:601.
- Perkins BA, Olaleye D, Zinman B, Bril V. Simple screening tests for peripheral neuropathy in the diabetes clinic. Diabetes Care 2001; 24:250.
- McNeely MJ, Boyko EJ, Ahroni JH, et al. The independent contributions of diabetic neuropathy and vasculopathy in foot ulceration. How great are the risks? Diabetes Care 1995; 18:216.
- Boulton AJ. The diabetic foot. In: Diabetes: Clinical management, Tattersall R, Gale EAM (Eds), Churchill Livingstone, Edinburgh 1990.
- Young MJ, Breddy JL, Veves A, Boulton AJ. The prediction of diabetic neuropathic foot ulceration using vibration perception thresholds. A prospective study. Diabetes Care 1994; 17:557.
- Liniger C, Albeanu A, Bloise D, Assal JP. The tuning fork revisited. Diabet Med 1990; 7:859.
- Sosenko JM, Kato M, Soto R, Bild DE. Comparison of quantitative sensory-threshold measures for their association with foot ulceration in diabetic patients. Diabetes Care 1990; 13:1057.
- Mayfield JA, Sugarman JR. The use of the Semmes-Weinstein monofilament and other threshold tests for preventing foot ulceration and amputation in persons with diabetes. J Fam Pract 2000; 49:S17.
- Boyko EJ, Ahroni JH, Cohen V, et al. Prediction of diabetic foot ulcer occurrence using commonly available clinical information: the Seattle Diabetic Foot Study. Diabetes Care 2006; 29:1202.
- Ganda OP. Pathogenesis of accelerated atherosclerosis in diabetes. In: Management of diabetic foot problems, Kozak GP, Hoar CS (Eds), Saunders, Philadelphia 1984. p.17.
- Sammarco GJ. Examination of the foot and ankle. In: The foot in diabetes, Lea & Febiger, Philadelphia 1991. p.33.
- Fowkes FG. The measurement of atherosclerotic peripheral arterial disease in epidemiological surveys. Int J Epidemiol 1988; 17:248.
- Rosenblum BI, Pomposelli FB Jr, Giurini JM, et al. Maximizing foot salvage by a combined approach to foot ischemia and neuropathic ulceration in patients with diabetes. A 5-year experience. Diabetes Care 1994; 17:983.
- Grayson ML, Gibbons GW, Balogh K, et al. Probing to bone in infected pedal ulcers. A clinical sign of underlying osteomyelitis in diabetic patients. JAMA 1995; 273:721.
- Armstrong DG, Lavery LA, Harkless LB. Validation of a diabetic wound classification system. The contribution of depth, infection, and ischemia to risk of amputation. Diabetes Care 1998; 21:855.
- O'Neal, LW, Wagner, FW. The Diabetic Foot, Mosby, St Louis 1983. p.274.
- Crawford F, Inkster M, Kleijnen J, Fahey T. Predicting foot ulcers in patients with diabetes: a systematic review and meta-analysis. QJM 2007; 100:65.
- Smieja M, Hunt DL, Edelman D, et al. Clinical examination for the detection of protective sensation in the feet of diabetic patients. International Cooperative Group for Clinical Examination Research. J Gen Intern Med 1999; 14:418.
- Litzelman DK, Marriott DJ, Vinicor F. The role of footwear in the prevention of foot lesions in patients with NIDDM. Conventional wisdom or evidence-based practice? Diabetes Care 1997; 20:156.
- Uccioli L, Faglia E, Monticone G, et al. Manufactured shoes in the prevention of diabetic foot ulcers. Diabetes Care 1995; 18:1376.
- Lavery LA, Vela SA, Fleischli JG, et al. Reducing plantar pressure in the neuropathic foot. A comparison of footwear. Diabetes Care 1997; 20:1706.
- 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.
- Lavery LA, Higgins KR, Lanctot DR, et al. Home monitoring of foot skin temperatures to prevent ulceration. Diabetes Care 2004; 27:2642.
- Armstrong DG, Holtz-Neiderer K, Wendel C, et al. Skin temperature monitoring reduces the risk for diabetic foot ulceration in high-risk patients. Am J Med 2007; 120:1042.
- American Diabetes Association. Standards of medical care in diabetes--2013. Diabetes Care 2013; 36 Suppl 1:S11.
- RISK FACTORS
- Risk classification
- PHYSICAL EXAMINATION
- Physical signs of neuropathy
- Screening tests for peripheral neuropathy
- - Vibration sensation
- - Pressure sensation
- - Pain and temperature sense
- Physical signs of peripheral artery disease
- Foot ulceration
- - Wound evaluation
- - Signs of infection
- - Imaging
- - Wound classification
- SCREENING FOR RISK OF FOOT ULCERATION
- Preventive foot care
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS
- High risk for future ulcer