Diabetic Foot

Endocrinology > Diabetic Foot

Summary

Description

• Foot complications are common in people with diabetes
• They occur in people with type 1 and type 2 diabetes, but usually arise much later after diagnosis in patients with type 1 diabetes
• Principal causative factors are peripheral neuropathy, vascular compromise, ulceration, and infection
• These factors, often associated with trauma or foot deformity, lead to an increased risk of lower limb amputation
• People with diabetes are 25 times more likely to lose a leg than people without the condition
• In many cases, foot ulceration can be prevented with appropriate healthcare and patient education
• All people with diabetes should have regular foot and footwear inspections
• Patients should be stratified by their risk of foot ulceration so that appropriate measures can be taken for prevention and/or treatment

Synonyms

Immediate action

The following actions should be taken immediately in cases of limb- or life-threatening infections:

• Carry out metabolic assessment
• Optimize glycemic control
• Initiate broad-spectrum antibiotics
• Arrange for immediate surgical consultation

Urgent action

In cases of deep ulcers, with or without osteomyelitis:

• Carry out metabolic assessment
• Optimize glycemic control
• Accurately describe and assess extent of lesion
• Establish vascular status
• Debride devitalized tissues
• Treat infection

Key points

• Foot problems are common in people with diabetes because of their increased risk of peripheral neuropathy, peripheral vascular disease, abnormal pressure on the foot, and impaired resistance to infection
• These factors frequently combine and result in ulceration and infection, progression to gangrene, and subsequent lower limb amputation
• Prevention of ulceration is extremely important and should involve regular foot inspection, identification of the foot at risk, rapid treatment of all foot problems, education of patients and healthcare professionals, and instruction concerning appropriate footwear
• Ulceration is largely a preventable complication, however <50% of diabetic patients, even those considered at high risk, receive an annual foot examination

Background

Cardinal features

• In diabetic patients, multiple factors may exist that increase the risk of ulceration
• Diabetic peripheral neuropathy is one of the major problems predisposing to foot problems; up to 50% of type 2 diabetic patients have peripheral neuropathy
• Neuropathy may affect sensory, motor, and/or autonomic nerves and can lead to deformity and an abnormal gait
• This can cause development of calluses over pressure points on the foot
• As the patient with neuropathy may not be aware of foot discomfort, they may continue to walk on an injured foot
• Eventually, the skin may break down and this may result in a chronic ulcer
• Another major complication is peripheral vascular disease: this may present with a classically painful ischemic ulcer following minor injury
• Lower limb ischemia also slows the healing process
• It is not uncommon for patients to have both peripheral neuropathy and vascular disease, and as a result any ulceration may not be painful
• In cases of deep ulceration, osteomyelitis may occur, which may result in the wound failing to heal
• Local infection can result in cellulitis, deep abscess formation, and gangrene. Systemic infection (sepsis) can also result

Charcot's joint

• Charcot's joint is a rare but serious complication in diabetic patients that almost always occurs in those with existing neuropathy
• Charcot's joint results in destruction and deformity of articulations in the foot which are often made worse by a defect in pain sensation due to peripheral neuropathy
• The foot is likely to be injured and become deformed if the patient continues to walk on it, which may lead to ulceration and possibly amputation
• Typical early signs of Charcot's joint include one foot or part of one foot being warmer than the other, swelling, and redness

Causes

Common causes

Foot problems in diabetic patients usually result from the interaction of a number of component causes:

• Peripheral neuropathy: loss of sensation in the feet results in injuries going unnoticed, which can lead to foot ulceration
• Foot deformity: this may result in the formation of calluses on weight-bearing areas
• Trauma: often minimal, repetitive, and not perceived
• Arterial insufficiency: poor blood flow to the feet slows the wound healing process and increases risk of infection
• Impaired resistance to infection: increases the risk of severe infection leading to amputation

Rare causes

Charcot's joint is a rare but serious complication and is frequently associated with underlying neuropathy.

Contributory or predisposing factors

• Poor vision, especially in older people, those with diabetic retinopathy, and those with other diabetes-related eye conditions, may result in falls and foot injury
• Poor vision also contributes to difficulty managing toenails: deformed, overgrown nails will result in skin trauma
• Comorbidities and hospitalization frequently results in reduced mobility, unsteadiness, and skin defects due to pressure or swelling
• Poor general healing and reduced immune function may be directly related to chronic hyperglycemia: risk of ulceration or amputation is increased in people who have had diabetes for >10 years or who have poor glucose control
• Risk is also increased in people with other diabetes-related complications including cardiovascular disease and renal complications
• Depression is more common in people with chronic disease and may result in lack of self-care leading to skin infection or injury

Epidemiology

Incidence and prevalence

• The American Diabetes Association (ADA) has reported that 15% of people with diabetes will experience a foot ulcer at some point in their lifetime, although recent research suggests this figure may be as high as 25%
• The ADA also state that 14-24% of people with a foot ulcer will require an amputation
• Approx. 15-20% of people with diabetes in the US will be hospitalized with a foot complication at some point during the course of their disease
• In the US, almost 70% of all lower leg amputations are carried out on people with diabetes
• People with diabetes are 25 times more likely to lose a leg than people without the condition

Incidence

In people diagnosed with diabetes:

• The annual population-based incidence of foot ulceration is 1000-4100/100,000 (1.0-4.1%)
• Lifetime incidence of foot ulceration may be as high as 25%

Prevalence

The prevalence of foot ulcers is 4000-10,000/100,000 (4-10%) in people diagnosed with diabetes.

Demographics

Age

Diabetic foot problems are unusual in patients <40 years of age. They increase with age >40 years, and occur most commonly in those aged 50 years and older. However, duration and control of diabetes are greater predictors of diabetic foot problems than chronological age.

Gender

Men with diabetes are at increased risk of foot ulcers or amputation compared with women with diabetes.

Geography

• In developed countries, 1 in 6 people with diabetes will have a foot ulcer during their lifetime
• In developing countries, foot problems are thought to be even more common

Socioeconomic status

• People in lower socioeconomic groups tend to be at increased risk for diabetic foot disorders
• They may find it more difficult to access preventive care and may have fewer resources to organize appropriate well-fitting footwear

Codes

ICD-9 code

250.8 Diabetes mellitus with ulcer, skin, foot.

Read more about Diabetic foot from this First Consult monograph:

Diagnosis | Differential diagnosis | Treatment | Summary of evidence | Outcomes | Prevention | Resources

More Key Resources

Overview

The diabetic foot (includes Images and Table)
Andersen CA - Surg Clin North Am - 01-OCT-2007; 87(5): 1149-77, x

Etiology

Pathogenesis of Diabetic Foot Ulceration
Melmed: Williams Textbook of Endocrinology, 12th ed.

Diagnosis

Clinical Features of Diabetic Foot Infections
Marx: Rosen's Emergency Medicine, 8th ed.

Treatment & Management

Management of Diabetic Foot Ulcers
Melmed: Williams Textbook of Endocrinology, 12th ed.

Treatment of Diabetic Ulcers
Mandell: Principles & Practice of Infectious Diseases, 7th ed.

Treatment of Diabetic Ulcers
Canale & Beaty: Campbell's Operative Orthopaedics, 12th ed.

Diabetic foot management in the elderly (includes Tables and Figure)
Plummer ES - Clin Geriatr Med - 01-AUG-2008; 24(3): 551-67, viii

Office-based screening, prevention, and management of diabetic foot disorders (includes Table)
Farber DC - Prim Care - 01-DEC-2007; 34(4): 873-85, vii-viii

Screening & Prevention

Prevention of Foot Ulceration and Amputation (includes Figure)
Melmed: Williams Textbook of Endocrinology, 12th ed.

Office-based screening, prevention, and management of diabetic foot disorders (includes Table)
Farber DC - Prim Care - 01-DEC-2007; 34(4): 873-85, vii-viii

Patient Education

Practice Guidelines

Comprehensive Foot Examination and Risk Assessment (2008)
Source: American Diabetes Association

Diabetic Foot Disorders: A Clinical Practice Guideline (2006)
Source: American College of Foot and Ankle Surgeons

Chronic Wounds of the Lower Extremity (2006)
Source: American Society of Plastic Surgeons

Guidelines for Diagnosis and Treatment of Diabetic Foot Infections (2012)
Source: Infectious Diseases Society of America

Inpatient Management of Diabetic Foot Problems (2011)
Source: National Institute for Health and Clinical Excellence (UK)

Drugs

Ampicillin; Sulbactam

Ciprofloxacin

Clindamycin

Cloxacillin

Vancomycin