Diabetic Foot

Pathophysiology & Risk Factors - Triad Trouble

• Core Pathophysiological Triad:
  • Neuropathy: Sensory (Loss Of Protective Sensation - LOPS), motor (muscle imbalance → deformities like claw toes, Charcot), autonomic (anhidrosis → dry, cracked skin).
  • Angiopathy (PAD): Atherosclerosis → ↓ blood flow, ↓ oxygen & nutrient delivery, impaired wound healing. Affects distal vessels.
  • Immunopathy: Impaired leukocyte function, ↓ chemotaxis & phagocytosis, blunted inflammatory response → ↑ infection susceptibility.
• Key Risk Factors:
  • Uncontrolled DM (HbA1c > 7%)
  • DM duration > 10 years
  • Previous DFU/amputation
  • Structural foot deformity
  • Limited joint mobility
  • Poor footwear, smoking
  • Visual impairment, nephropathy

⭐ Peripheral neuropathy is the primary factor in the development of diabetic foot ulcers.

Clinical Assessment & Diagnosis - Spotting the Signs

• History: DM duration, glycemic control, neuropathy symptoms (pain, numbness), claudication, prior ulcers.
• Examination:
  • Inspect: Deformities (Charcot, claw/hammer toes), calluses, ulcers (site, size, depth, base, discharge), skin (dry, fissures, hair loss, infection signs).
  • Palpate: Skin temperature, tenderness, pulses (DP, PT), Capillary Refill Time.
  • Neuropathy: 10g Semmes-Weinstein Monofilament (SWMT), 128Hz tuning fork (vibration).
  • Vascular: Ankle-Brachial Index (ABI).

    ⭐ An Ankle-Brachial Index (ABI) < 0.9 suggests Peripheral Arterial Disease (PAD).

• Key Investigations:
  • X-ray: Osteomyelitis, gas, foreign body, Charcot.
  • MRI: Gold standard for osteomyelitis, deep abscess.
  • Doppler Ultrasound: Assesses arterial flow.
  • Wound Culture: For targeted antibiotics.

Classification & Charcot Foot - Grading the Grief

Diabetic Foot Ulcer Classification:

• Wagner Classification: Key system for severity.
  • Grade 0: Intact skin, may have bony deformity (pre-ulcerative).
  • Grade 1: Superficial ulcer (skin only).
  • Grade 2: Ulcer extending to ligament, tendon, joint capsule, or deep fascia (no bone/abscess).
  • Grade 3: Deep ulcer with abscess, osteomyelitis, or septic arthritis.
  • Grade 4: Gangrene of a portion of the forefoot or heel.
  • Grade 5: Extensive gangrene of the entire foot.
• University of Texas (UT) Classification:
  • Matrix: Combines ulcer depth (Grades 0-III) with presence of Infection and/or Ischemia (Stages A-D).

Charcot Neuroarthropathy:

• Progressive, non-infectious, destructive process affecting bones, joints, and soft tissues, typically in individuals with neuropathy.
• Acute phase: Presents as a red, hot, swollen foot; often misdiagnosed as infection.
• Eichenholtz Classification (Modified):

⭐ Wagner Grade 3 ulcer involves deep infection with abscess, osteomyelitis, or septic arthritis.

Management & Prevention - Healing & Halting

• Multidisciplinary Team: Key.
• Wound Care:
  • Sharp debridement.
  • Moist wound dressings (hydrocolloids, alginates).
  • NPWT for select wounds.
• Infection Control:
  • Mild: Oral antibiotics.
  • Mod/Severe: IV Abx, surgical debridement.
  • Deep tissue cultures.
• Offloading (Key for Neuropathic Ulcers):

  ⭐ Total Contact Casting (TCC) is the gold standard for offloading neuropathic plantar ulcers.

  • Alternatives: Removable Cast Walkers (RCW), therapeutic shoes.
• Vascular Management:
  • Assess: ABI < 0.9 or > 1.3 (calcification) needs vascular studies.
  • Revascularization for PAD.
• Surgical Interventions:
  • Debridement, I&D.
  • Charcot reconstruction.
  • Amputations (minor/major) last resort.
• Prevention (Halting Progression):
  • Glycemic control (HbA1c < 7%).
  • Education: Daily foot inspection, hygiene, nail care.
  • Therapeutic footwear, orthotics.
  • Podiatric care.
  • 📌 Mnemonic: "FOOT CARE" (Footwear, Observe daily, Offloading, Test sensation, Control sugar, Annual check-up, Refer early, Educate).

High‑Yield Points - ⚡ Biggest Takeaways

• Diabetic Foot triad: neuropathy (sensory loss), angiopathy (poor circulation), and immunodeficiency.
• Charcot neuroarthropathy: progressive destruction causing rocker-bottom foot deformity.
• Wagner classification (Grades 0-5) is essential for ulcer staging.
• Management pillars: strict glycemic control, wound debridement, effective offloading (e.g., Total Contact Cast), and targeted antibiotics.
• Always assess for Peripheral Vascular Disease; revascularization may be needed.
• Osteomyelitis is a common, severe complication requiring prompt, aggressive treatment.
• Prevention is key: patient education, daily foot inspection, and appropriate footwear.