Synopsis
Assess neuropathy, arterial perfusion, tissue loss and infection together so that a deceptively painless diabetic foot is triaged safely and investigated without delay.
- Treat ulceration with suspected limb ischaemia as limb-threatening: refer immediately to acute services and alert the multidisciplinary foot care service rather than waiting for clinic tests.
- A normal or high ABPI does not exclude PAD in diabetes because medial arterial calcification can make ankle vessels incompressible; combine Doppler waveforms, ABPI and toe-based measurements.
- Loss of protective sensation removes pain as a reliable warning signal, so inspect the whole foot, footwear, wound depth, infection signs and perfusion even when the person reports little discomfort.
Key red flags
Rapidly spreading erythema, systemic toxicity, haemodynamic instability, crepitus, bullae or severe pain out of proportion suggests sepsis or necrotising infection.
A cool pale or mottled foot, rest pain, tissue necrosis, gangrene, absent Doppler signals or abrupt deterioration suggests critically impaired perfusion.
A deep or chronic ulcer, exposed bone, purulent tracking, fluctuance or unexplained metabolic deterioration raises concern for deep infection or osteomyelitis.
New warmth, swelling and deformity with intact skin, especially with neuropathy or renal failure, can be acute Charcot arthropathy and needs prompt protection and specialist assessment.
Diagnose infection clinically when at least two local inflammatory findings are present, counting purulent discharge as one, rather than from bacterial growth alone. Define erythema extent, tenderness, warmth, swelling, discharge, fluctuance and systemic features; ischaemia or neuropathy can blunt inflammation.
Investigation priorities
Identify PAD using complementary bedside measures rather than relying on pulse palpation or one pressure ratio.
Management branches
Ulcer with ischaemia, gangrene, deep infection concern, fever, sepsis or rapidly deteriorating tissue.
- Refer immediately to acute services and notify the multidisciplinary foot care service; institute sepsis assessment and resuscitation when systemic illness is present.
- Remove constricting footwear, protect the limb, document neurovascular status and wound extent, and obtain urgent senior surgical, vascular and infection assessment without delaying transfer.
New ulcer, blister, unexplained swelling, redness or suspected Charcot change without immediate limb- or life-threatening features.