What is the treatment for a necrotic toe?

Management of Necrotic Toe

The treatment of a necrotic toe requires urgent surgical intervention in most cases of deep abscesses, compartment syndrome, and virtually all necrotizing soft tissue infections, while allowing autoamputation may be appropriate for dry gangrene in poor surgical candidates. 1, 2

Assessment and Classification

• Determine whether the necrosis is dry (ischemic) or wet (infected) as this fundamentally guides management approach 2
• Evaluate for signs of spreading infection including erythema, crepitus, purulence, foul odor, and systemic symptoms 1
• Assess for features suggesting deeper tissue involvement: severe pain disproportional to findings, wooden feel of subcutaneous tissue, systemic toxicity, edema extending beyond erythema, crepitus, bullous lesions, and skin necrosis 1
• Check vascular status through clinical examination and appropriate studies to determine if ischemia is contributing to the gangrene 2
• Obtain wound cultures before starting antibiotics to guide targeted therapy 1

Management Based on Type of Necrosis

Dry Gangrene (Non-infected)

• For dry gangrene, especially in patients who are poor surgical candidates, consider allowing autoamputation of the necrotic portions 1
• Leave adherent eschar in place, particularly on the heel, until it softens enough to be more easily removed, provided there is no underlying infection 1
• Monitor closely for signs of infection development, which would change management approach 1

Wet Gangrene (Infected)

• Urgent surgical intervention is necessary for deep abscesses, compartment syndrome, necrotizing soft tissue infections, and gas gangrene 1
• Surgical debridement should include drainage of deep pus, decompression of foot compartments, and removal of devitalized and infected tissue 1
• Most patients with necrotizing fasciitis should return to the operating room 24-36 hours after initial debridement and daily thereafter until no further debridement is needed 1
• Infected tendons must be widely removed as infections often spread along tendons within compartments 1

Antibiotic Therapy

• Start empiric broad-spectrum antibiotics covering gram-positive, gram-negative, and anaerobic organisms 1
• For polymicrobial necrotizing fasciitis, include agents effective against both aerobes (including MRSA) and anaerobes 1
• Recommended regimens include vancomycin, linezolid, or daptomycin combined with one of the following: 1
  • Piperacillin-tazobactam
  • A carbapenem (imipenem-cilastatin, meropenem, or ertapenem)
  • Ceftriaxone plus metronidazole
  • A fluoroquinolone plus metronidazole
• Adjust antibiotic regimen based on culture results and clinical response 2
• Continue antibiotics until further debridement is no longer necessary, the patient has improved clinically, and fever has been absent for 48-72 hours 1

Vascular Assessment and Intervention

• If the infected limb appears ischemic, refer the patient to a surgeon with vascular expertise 1
• Consider early revascularization (within 1-2 days) for severely ischemic infected limbs rather than delaying for prolonged antibiotic therapy 1
• Revascularization options include endovascular procedures or open bypass 1
• Patients with non-critical ischemia (ABI 0.4-0.9) can sometimes be successfully treated without vascular procedures 1

Surgical Considerations

• Surgical procedures should be performed by a surgeon with thorough knowledge of foot anatomy and the ways infection spreads through fascial planes 1
• Consider the relationship between the point of entry of infection and the compartment in which it spreads: 1
  • Infections from the great toe/first metatarsal head spread through the medial compartment
  • Infections from second, third, and fourth toes/metatarsal heads spread through the central compartment
  • Infections from the fifth toe/metatarsal head spread through the lateral compartment
• Bone resection and amputation may be necessary with extensive soft tissue necrosis 1
• When amputation is necessary, aim for the most distal level that will heal to preserve function 2

Pitfalls and Caveats

• Delaying surgical intervention in progressive infections can lead to irreparable tissue damage 1
• Failure to assess and address vascular insufficiency can result in poor healing and increased risk of amputation 2
• Inadequate debridement of infected tissue can lead to persistent infection and progression of gangrene 2
• CT or MRI may help identify deep infections but should not delay definitive diagnosis and treatment 1
• The absence of fever or leukocytosis should not dissuade consideration of surgical exploration of a diabetic foot infection 1

Special Considerations for Warfarin-Associated Necrosis

• Warfarin can rarely cause skin necrosis and limb gangrene as a complication 1
• If warfarin-induced necrosis is suspected, restart warfarin at a low dose (e.g., 2 mg) under coverage of therapeutic doses of parenteral anticoagulants, and gradually increase over 1+ weeks 1
• This approach avoids an abrupt fall in protein C levels before reduction in factors II, IX, and X 1