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RBCs of vascular surgery The Diabetic Foot.Diabetics present with a myriad of problems. Of these, none is more challenging or demanding of resources than the diabetic foot. It is the commonest major end point among diabetic complications. The diabetic foot presents as three clinical problems: ulceration (neuropathic or ischaemic), peripheral gangrene and infection. These may often co-exist.
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Diabetic neuropathy and neuropathic ulcers Clinical Aspects. The neuropathic ulcer is located over a pressure point (e.g. matatarsal head), is painless, deep and often surrounded by skin callus. The foot itself is warm with bounding pulses. Treatment. The 'foot at risk' should be recognised early. Such patients should be instructed in daily foot examination, avoiding foot trauma from ill fitting shoes or walking barefoot and reminded to carefully dry between the toes after bathing. Those with major foot deformities should be referred to an orthotist to have cutomised shoes made to avoid pressure ulcers. Regular podiatry relieves callus which reduces pressure. For established ulcers, the best treatment is a modified pressure relieving slipper or, in advanced cases, a total contact cast which transfers wieght from the metatarsal heads to the heel and leg. This can heal up to 90% of ulcers. For persistently relapsing ulcers, we have resorted to excision of the metatarsal heads, thus removing the pressure areas, allowing overlying ulcers to heal. Treatment. The 'foot at risk' should be recognised early. Such patients should be instructed in daily foot examination, avoiding foot trauma from ill fitting shoes or walking barefoot and reminded to carefully dry between the toes after bathing. Those with major foot deformities should be referred to an orthotist to have cutomised shoes made to avoid pressure ulcers. Regular podiatry relieves callus which reduces pressure. For established ulcers, the best treatment is a modified pressure relieving slipper or, in advanced cases, a total contact cast which transfers wieght from the metatarsal heads to the heel and leg. This can heal up to 90% of ulcers. For persistently relapsing ulcers, we have resorted to excision of the metatarsal heads, thus removing the pressure areas, allowing overlying ulcers to heal. 2.
Ischaemic ulcers and gangrene Clinical Aspects. The ischaemic ulcer is often shallow and painful with surrounding erythema. There is no surrounding callus. The foot is cool with absent pulses. The ABI may be high due to medial calcification of the vessel wall but often the wave form is monophasic rather than triphasic - easily heard with a hand-held Doppler. Gangrene usually involves tips of the toes. Treatment. Ischaemic ulcers or gangrene present some of the most challenging problems in vascular surgery. Gangrenous tissue must be removed. Where gangrene is well demarcated, a local amputation may succeed. If not, a bypass is required to salvage the limb. A full angiogram showing vessels from groin to foot is needed. It may be possible to do something relatively simple like an angioplasty or femoro-popliteal bypass. Often, however, one is faced with occluded or diseased femoral, popliteal and infracrural vessels with only a single vessel patent in the foot. Here, a bypass from the groin to a single cural vessel in the calf or at the ankle, is required. These bypasses can give gratifying results allowing healing of a distal amputation site (digit or ray amputation). Failure to achieve adequate revascularisation will result in a major amputation.
3. Infection Clinical Aspects. Failure to recognise infection can have devastating effects leading to major amputation. Infections are more often than not worse than they seem. Systemic signs of infection (fever / leulocytosis) are frequently absent. A good examination of the foot is essential. This may show an ulcer or gangrene with surrounding erythema. It is important to look between the toes for any sisuses. The presence of pus here or from an ulcer confirms severe infection. I find it useful to squeeze over the metatarsal heads or plantar surface of the foot. Eliciting fluctuance or pain often indicates a deep collection of pus. Gas forming bacteria can cause crepitus which can be easily felt. An x-ray of the foot is essential to look for underlying osteomyelitis and gas in soft tissue. Treatment. I have a very low threshold for admitting patients with an infected diabetic foot to hospital. After a foot x-ray and swap, I start broad spectrum antibiotics to cover gram +ve cocci and gram -ve bacilli. Infected and neurotic tissue and bone needs aggressive debridement. This may require repeated visits to theatre. Once infection has been controlled, revascularisation may be necessary to improve blood supply to facilitate healing. At times, infection is so severe and deep seated that a below knee ampuation is the only solution. In recognition of the difficulties of providing good care for patients with diabetic feet, we now run a special diabetic foot clinic which can be accessed by phoning one of the numbers listed on this publication. the RBCs byNeil Browning, FRCSPublished By: The Julie Andrews Vascular Unit
Ashford & St. Peter's Hospitals
NHS Trust
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