Diabetic foot and its management

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Diabetes mellitus is one of those metabolic disorders that impedes normal steps of wound healing process. Diabetic foot ulcer is one of the major complications of this impairement. Diabetic foot ulcers (DFUs) precede 85% of nontraumatic lower extremity amputations (LEAs). Approximately 3-4% of individuals with diabetes currently have foot ulcers or deep infections. Among persons with diabetes, 15% develop foot ulcers during their lifetime.

Etiology

Peripheral neuropathy affects sensory, motor, and autonomic pathways. Sensory neuropathy deprives the patient of early warning signs of pain or pressure from footwear, from inadequate soft-tissue padding, or from infection. This neuropathy appears in a stocking-glove distribution, with many patients complaining of burning or searing pain. Autonomic neuropathy produces chronic venous swelling. Motor peripheral neuropathy or Charcot arthropathy can produce bony deformity, which, combined with the loss of protective sensation, can result in skin ulceration from pressure or from shear forces.

Pathophysiology

Pressure over a bony prominence has often been cited as the cause for skin breakdown in patients with diabetes. Skin breakdown occurs at far lesser loads when the pressure is applied by shear forces. This leads to blister formation and full-thickness skin loss. Thickened, hypertrophic nails increase pressure on the soft tissues surrounding the nails. Once the skin barrier is broken, wound healing can be impaired by abnormally functioning WBCs.

Diagnosis

  • The vascular examination will have the greatest effect on treatment choices. The qualitative measurements include palpation of the pulses and determination of skin temperature, capillary refill, and hair and nail growth. Evidence of vascular disease is commonly gained through palpating for the dorsalis pedis and posterior tibial pulses.
  • MRI has the highest diagnostic accuracy. When used by an experienced radiologist, MRI can detect bone infection (characterized by an altered bone marrow signal) with 90-100% sensitivity and specificity.

Staging

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Treatment

The goal of treatment is the preservation of function, not just the preservation of tissue. Amputation surgery should be the first step in the rehabilitation of the patient. Because most of these individuals are ambulatory, surgical planning should be directed at the creation of a load-bearing terminal end organ that can interface most easily with accommodative footwear, a prosthesis, or a combination of both (ie, prosthosis). The principles that direct construction of a residual limb for weight bearing with a prosthesis should be employed when performing debridement or partial foot amputation.