Foot gangrene
Gangrene - death and putrefaction of a body tissue.
- Dry
- Dry/desiccated
- Usually defined line of demarcation between dry and wet tissue
- Wet
- Affected tissue may still be partially perfused, retain some turgor
- No clear line of demarcation
- Gas
- Anaerobic bacteria (Clostridia) invade tissue and muscle and release gas and toxins
- Can be rapidly fatal
Essentially, it occurs because of inadequate blood flow to keep tissues viable. Therefore the goal of treatment is to increase blood flow.
- Most patients with gangrene in feet have some sort of arterial pathology
- Therefore entire vascular tree must be evaluated
Aetiology
[edit | edit source]- Atheroembolic
- Occlusive
- Myeloproliferative disorders
- Vasculitides
- Prolonged vasoconstrictors
History/exam
[edit | edit source]- Thorough history - look for vascular risk factors
- Exam - all pulses/bruits
- Try to distinguish between causes of gangrene - atheroembolisation vs occlusive disease
- ABI
- Toe pressures
Imaging
[edit | edit source]- Start with USS doppler
- CTA
Amputations
[edit | edit source]- If confined to tip of toe, partial toe amputation, preserving proximal phalanx
- Try to preserve first metatarsal head - important for gait/balance
- If forefoot gangrene, or multiple toe involvement, need to do transmetatarsal amputation
- If entire foot and heel involved, need to do leg