Diabetic Foot Care

Definition

A foot with a constellation of pathologic changes affecting the lower extremity in diabetics, often leading to amputation and/or death due to complications; the common initial lesion leading to amputation is a nonhealing skin ulcer, induced by regional pressure, pathogenically linked to sensory neuropathy, ischemia, infection.

Objectives

• Define diabetic foot.
• Explain etiopathogenesis of diabetic foot ulcer.
• Wagner grades.
• Understand Charcot’s foot.
• Explain prevention strategies to patient.

Extent

• 20 million DM patients in India ( 2 Crore).
• DM largest cause of neuropathy.
• Half don’t know.
• Foot ulcerations is most common cause of hospital admissions for Diabetics.
• Expensive to treat, may lead to amputation and need for chronic institutionalized care.

• After amputation 30% lose other limb in 3 years.
• After amputation 2/3^rds die in five years.
• Type II can be worse.
• 15% of diabetic will develop a foot ulcer.

Pathophysiology

• Vascular disease
• Neuropathy
  • Sensory
  • Motor
  • Autonomic

Neuropathy

• Changes in the vasonervosum with resulting ischemia ? cause
  • Increased sorbitol in feeding vessels block flow and causes nerve ischemia
  • Intraneural accumulation of advanced products of glycosylation

Abnormalities of all three neurologic systems contribute to ulceration

Vascular Disease

• 30 times more prevalent in diabetics
• Diabetics get arthrosclerosis obliterans or “lead pipe arteries”

• Calcification of the tunica media
• Endothelial changes
• Often increased blood flow with lack of elastic properties of the arterioles
• Not considered to be a primary cause of foot ulcers

Autonomic Neuropathy

• Regulates sweating and perfusion to the limb
• Loss of autonomic control inhibits thermoregulatory function and sweating
• Result is dry, scaly and stiff skin that is prone to cracking and allows a portal of entry for bacteria

Autonomic Neuropathy

Motor Neuropathy

• Mostly affects forefoot ulceration
• Intrinsic muscle wasting – claw toes
• Equinus contracture

Sensory Neuropathy

• Loss of protective sensation
• Starts distally and migrates proximally in

“stocking” distribution

• Large fibre loss – light touch and proprioception
• Small fibre loss – pain and temperature
• Usually a combination of the two

Sensory Neuropathy

• Two mechanisms of Ulceration
  • Unacceptable stress few times
    • rock in shoe, glass, burn
  • Acceptable or moderate stress repeatedly
    • Improper shoe s
    • deformity

Patient Evaluation

• Medical
• Vascular
• Orthopedic
• Identification of “Foot at Risk”

Patient Evaluation

Semmes-Weinstein Monofilament Aesthesiometer

• 07 (10g) seems to be threshold
• 90% of ulcer patients can’t feel it
• Only helpful as a screening tool

Patient Evaluation

• Medical
  • Optimized glucose control
  • Decreases by 50% chance of foot problems

Patient Evaluation

• Vascular
  • Assessment of peripheral pulses of paramount importance
  • If any concern, vascular assessment
    • ABI (n>0.45)
      • Sclerotic vessels
    • Toe pressures (n>40-50mmHg)
    • TcO₂ >30 mmHg
      • Expensive but helpful in level

Patient Evaluation

• Orthopedic
  • Ulceration
  • Deformity and prominences
  • Contractures

Patient Evaluation

• X-ray
  • Lead pipe arteries
  • Bony destruction (Charcot or osteomyelitis)

Patient Evaluation

Patient Evaluation

• Nuclear medicine
  • Overused
  • Combination Bone scan and Indium scan can be helpful in questionable cases (i.e. Normal X- rays)
  • Gallium scan useless in these patients
  • Best screen – indium – and if Positive – bone scan to differentiate between bone and soft tissue infection

Patient Evaluation

• CT can be helpful in visualizing bony anatomy for abscess, extent of disease
• MRI has a role instead of nuclear medicine scans in uncertain cases of osteomyelitis

Ulcer Classification

Wagner’s Classification

• – Intact skin (impending ulcer)
• – superficial
• – deep to tendon bone or ligament
• – osteomyelitis
• – gangrene of toes or forefoot
• – gangrene of entire foot

Treatment

• Patient education
  • Ambulation
  • Shoe ware
  • Skin and nail care
  • Avoiding injury
    • Hot water
    • B’s

• off loading 

• Debridement and drainage

• wound dressing

• appropriate use of antibiotic

• revascularization

• limited amputation

 

Treatment

• Wagner 0-2
  • Total contact cast
  • Distributes pressure and allows patients to continue ambulation
  • Principles of application
    • Changes, Padding, removal
  • Antibiotics if infected

Treatment

Treatment

• Wagner 0-2
  • Surgical if deformity present that will reulcerate
    • Correct deformity
    • exostectomy

Treatment

• Wagner 3
  • Excision of infected bone
  • Wound allowed to granulate
  • Grafting (skin or bone) not generally effective

Treatment

• Wagner 4-5
  • Amputation
    • ? level

• 5 P’s
• 3D’s

Treatment

• After ulcer healed
  • Orthopedic shoes with accommodative (custom made insert)
  • Education to prevent recurrence

Charcot Foot

• More dramatic – less common 1%
• Severe non-infective bony collapse with secondary ulceration
• Two theories
  • Neurotraumatic
  • Neurovascular

Charcot Foot

• Neurotraumatic
  • Decreased sensation + repetitive trauma = joint and bone collapse
• Neurovascular
  • Increased blood flow → increased osteoclast activity → osteopenia → Bony collapse
  • Glycolization of ligaments → brittle and fail →

Joint collapse

Classification

• Eichenholtz
  • 1 – acute inflammatory process
    • Often mistaken for infection
  • 2 – coalescing phase
  • 3 – consolidation

Indications for Amputation

• Uncontrollable infection or sepsis
• Inability to obtain a plantar grade, dry foot that can tolerate weight bearing
• Non-ambulatory patient
• Decision not always straightforward

Conclusion

• Multi-disciplinary approach needed
• Going to be an increasing problem
• High morbidity and cost
• Solution is probably in prevention
• Most feet can be spared…at least for a while

Prevention

• Diabetic control
• Foot care

Diabetic foot successfully treated !!