Diabetic foot
patients with diabetes are at increased risks of developing peripheral arterial disease and peripheral neuropathy, which commonly affects the feet causing secondary problems such as ulceration or joint deformities. Diabetic neuropathy is thought to affect 16-26% of patients with diabetes, 2.2% of diabetics will present with foot ulcers annually, increasing to 7.2% in patients with neuropathy. the incidence of amputations is around 0.5-5 per 1000 of people with diabetes.
Risk factors
Risk factors for developing peripheral neuropathy includes increased age, increased periods of poor glycaemic control, increasing time since hyperglycaemia first occured, smoking, hypertension and ischaemic heart disease.
Risk factors for peripheral ischaemia includes smoking, hypertension and hypercholestrolaemia.
There is an increased risk of foot ulcer formation in patients with either ischaemic or neuropathic changes. In addition the following factors may percipitate the formation of ulcers:
Presentation
Patients with neuropathy may be asymptomatic and only present on screening. Peripheral neuropathy may also present with with neuropathic pain, paraesthesia or numbness in a symmetrical 'stocking' distribution. Pain may be worse at night. Patients may present with changes to the foot from self inspection of their feet or with problems during annual reviews. Ulcers occuring in patients with neuropathy tend to affect pressure points on the sole of the foot and may occur under callouses. Patients with neuropathy are also prone to having feet deformities, including clawed toes, loss of foot arch and charcot joints.
Arterial ischamia may present with claudication (pain on excercise).
Patients with critical ischaemic limbs may present with pink , painful, pulseless, perishingly cold feet. Patient may have severe pain even at rest. Patients with critical ischaemia may have ulcers which tend to occur in the sides of the feet, and gangrenous changes. Critical ischaemia with or without ulceration and gangrene requires urgent surgical intervention.
Diabetic ulcers tend to be punched out, painless, with pus, swelling, erythema, malodour and
Red flag symptoms include:
Examination findings
Neuropathic foot:
There may be reduced or loss of sensation of light touch, pinprick (pain), proprioception, temperature and vibration senses. Seonsory loss may be patchy, and should be tested with a 10g monofilament. Loss of ankle jerk may occur in severe neuropathy. Diabetic neuropathy can affect muscles as well but tend to predominately affect senses. Involvement of the hands only occur in severe/late disease. In a neuropathic foot the foot tends to have bounding pulses, with dialated veins. Neuropathic feet tend to be warm and dry, with callous formation. Feet deformities are caused by loss of pain and proprioception perception and is therefore usually seen in neuropathic feet.
Ischaemic foot:
The key sign in ischaemic feet is reduced pulses. However artherosclerotic arteries may also feel 'bounding'. In ischaemic feet, the feet may be pink and cold with atrophic skin and there is often little callous formation. There may be reduced sensation in ischaemic feet.
Differential diagnoses:
Diabetes is the most common cause of peripheral neuropathy although alternative causes may be considered.
Key diagnostic issues include:
differentiating between a neuropathic or ischaemic limb.
If an ulcer is present it is important to rule out infections, abscesses and osteomyelitis.
General management
Patients with diabetes should be reviewed at least annually for foot problems, and be educated about foot care. This includes self inspection of the feet, using appropriate footwear, avoiding activities which may increase the risk of trauma such as walking bare foot and sitting near heat or using hot water bottles on the feet. Patients should also have access to appropriate foot care and should be discouraged from removing callouses themselves. Patients should be educated to report their symptoms to healthcare professionals if pain, swelling, colour changes or breaks in the skin of their feet occur.
Neuropathy and ischaemia can also be prevented by good glycaemic control and managing co-morbidities such as high blood pressure and dyslipidaemia.
Neuropathy
Bloods to rule out alternative causes of peripheral neuropathy (eg. TFTs, B12) and nerve conduction studies may be necessary to diagnoses diabetic peripheral neuropathy.
Patients with neuropathy should be especially careful with their feet. In addition, patients with neuropathic pain should recieve psychological support for the condition. In terms of medical treatment, paracetamol is used first line, followed by tricyclics. Gabapentin, duloxetine, and pregabalin could be used if tricyclics inadequately control pain.
Ischaemic limbAnkle brachial index and angiography may be used to diagnose limb ischaemia. Angiography may cause renal failure so care should be taken to minimise this risk.
the management of the ischaemic limb is primarily surgical through balloon angioplasty, vascular reconstruction and stenting. Opioids may be used to relieve pain.
Ulcers
Diabetic foot ulcers are managed by removing the overlying callus, treating any underlying infection and by relieving pressure on the area with bed rest and appropriate foot support and foot wear. The ulcer should be swabbed for microscopy, culture and sensitivities. Patients should be given oral antibiotics for the period the ulcer heals if they are being managed in the community, and IV antibiotics if they are in hospital. Patients who are admitted may need an insulin pump during treatment to control blood glucose. The most common organisms to affect ulcers include staphylococcus, streptococcus and anaerobes. A combination of amoxicillin/benzylpenicillin, flucoxacillin and metronidazole is therefore frequently used empirically initially, which is then adjusted according to sensitivities. Ulcers should be dressed daily and washed with saline.
Osteomyelitis should be ruled out through foot radiograph where an ulcer is deep, where the lesion fails to heal or recurs.
Ulcers may require surgical debridement. Necrotic digits may require amputation.
Charcot's foot
Often presents as a unilateral warm swollen neuropathic foot. Charcot's foot is diagnosed by bone scan and gallium white cell scanning and MRI may be used to rule out infection.
Charcot's foot is managed with rest and use of non weight bearing crutches. A total contact plaster can also be used to allow injury to repair. This usually takes 2-3 months. Special shoes and insoles should be used after the foot has healed to prevent ulceration.
Complications:
Osteomyelitis - treated with surgical debridement and antibiotics. Additional antibiotics to standard antibiotics may be required.
abscess - requires surgical intervention.
Prognosis:
Patients with foot ulcers are at a high risk of amputation and recurrence of ulcers. Good foot care can reduce this risk. Patients with amputations have a poor survival rate.
http://www.bmj.com/content/326/7396/977?goto=reply
http://www.patient.co.uk/doctor/diabetic-foot
http://www.patient.co.uk/doctor/Limb-Embolism-and-Ischaemia.htm
http://www.patient.co.uk/doctor/diabetic-neuropathy
http://geekymedics.com/2010/10/10/diabetic-foot-examination-osce-guide/
Longmore M, Wilkinson IB, Davidson EH, Foulkes A, Mafi AR. Oxford handbook of clinical medicine, 8th ed. oxford, oxford university press, 2010
http://upload.wikimedia.org/wikipedia/commons/8/8f/Neuropathic_heel_ulcer.jpg
http://fc03.deviantart.net/fs38/f/2008/342/3/f/sch__feet_contour_drawing_by_tengwan.jpg
Risk factors
Risk factors for developing peripheral neuropathy includes increased age, increased periods of poor glycaemic control, increasing time since hyperglycaemia first occured, smoking, hypertension and ischaemic heart disease.
Risk factors for peripheral ischaemia includes smoking, hypertension and hypercholestrolaemia.
There is an increased risk of foot ulcer formation in patients with either ischaemic or neuropathic changes. In addition the following factors may percipitate the formation of ulcers:
- Poor fitting shoes/friction
- Untreated/self treated callus
- Using corn plasters
- trauma to the feet - eg. when walking barefoot
- Thermal trauma to the feet - eg. when sitting near fire
- Nail infections
- Heel damage in patients who are bed bound
- Feet deformities such as charcot's foot, clawed toes or oedema.
Presentation
Patients with neuropathy may be asymptomatic and only present on screening. Peripheral neuropathy may also present with with neuropathic pain, paraesthesia or numbness in a symmetrical 'stocking' distribution. Pain may be worse at night. Patients may present with changes to the foot from self inspection of their feet or with problems during annual reviews. Ulcers occuring in patients with neuropathy tend to affect pressure points on the sole of the foot and may occur under callouses. Patients with neuropathy are also prone to having feet deformities, including clawed toes, loss of foot arch and charcot joints.
Arterial ischamia may present with claudication (pain on excercise).
Patients with critical ischaemic limbs may present with pink , painful, pulseless, perishingly cold feet. Patient may have severe pain even at rest. Patients with critical ischaemia may have ulcers which tend to occur in the sides of the feet, and gangrenous changes. Critical ischaemia with or without ulceration and gangrene requires urgent surgical intervention.
Diabetic ulcers tend to be punched out, painless, with pus, swelling, erythema, malodour and
Red flag symptoms include:
- Red swollen foot with Pain and discomfort despite neuropathy.
- Cellulitis, discoloration of the foot, or crepitations.
- Pink, painful, pulseless foot.
- symptoms of systemic infection
Patients with red flag symptoms should be admitted to hospital.
Examination findings
Neuropathic foot:
There may be reduced or loss of sensation of light touch, pinprick (pain), proprioception, temperature and vibration senses. Seonsory loss may be patchy, and should be tested with a 10g monofilament. Loss of ankle jerk may occur in severe neuropathy. Diabetic neuropathy can affect muscles as well but tend to predominately affect senses. Involvement of the hands only occur in severe/late disease. In a neuropathic foot the foot tends to have bounding pulses, with dialated veins. Neuropathic feet tend to be warm and dry, with callous formation. Feet deformities are caused by loss of pain and proprioception perception and is therefore usually seen in neuropathic feet.
Ischaemic foot:
The key sign in ischaemic feet is reduced pulses. However artherosclerotic arteries may also feel 'bounding'. In ischaemic feet, the feet may be pink and cold with atrophic skin and there is often little callous formation. There may be reduced sensation in ischaemic feet.
Differential diagnoses:
Diabetes is the most common cause of peripheral neuropathy although alternative causes may be considered.
Key diagnostic issues include:
differentiating between a neuropathic or ischaemic limb.
If an ulcer is present it is important to rule out infections, abscesses and osteomyelitis.
General management
Patients with diabetes should be reviewed at least annually for foot problems, and be educated about foot care. This includes self inspection of the feet, using appropriate footwear, avoiding activities which may increase the risk of trauma such as walking bare foot and sitting near heat or using hot water bottles on the feet. Patients should also have access to appropriate foot care and should be discouraged from removing callouses themselves. Patients should be educated to report their symptoms to healthcare professionals if pain, swelling, colour changes or breaks in the skin of their feet occur.
Neuropathy and ischaemia can also be prevented by good glycaemic control and managing co-morbidities such as high blood pressure and dyslipidaemia.
Neuropathy
Bloods to rule out alternative causes of peripheral neuropathy (eg. TFTs, B12) and nerve conduction studies may be necessary to diagnoses diabetic peripheral neuropathy.
Patients with neuropathy should be especially careful with their feet. In addition, patients with neuropathic pain should recieve psychological support for the condition. In terms of medical treatment, paracetamol is used first line, followed by tricyclics. Gabapentin, duloxetine, and pregabalin could be used if tricyclics inadequately control pain.
Ischaemic limbAnkle brachial index and angiography may be used to diagnose limb ischaemia. Angiography may cause renal failure so care should be taken to minimise this risk.
the management of the ischaemic limb is primarily surgical through balloon angioplasty, vascular reconstruction and stenting. Opioids may be used to relieve pain.
Ulcers
Diabetic foot ulcers are managed by removing the overlying callus, treating any underlying infection and by relieving pressure on the area with bed rest and appropriate foot support and foot wear. The ulcer should be swabbed for microscopy, culture and sensitivities. Patients should be given oral antibiotics for the period the ulcer heals if they are being managed in the community, and IV antibiotics if they are in hospital. Patients who are admitted may need an insulin pump during treatment to control blood glucose. The most common organisms to affect ulcers include staphylococcus, streptococcus and anaerobes. A combination of amoxicillin/benzylpenicillin, flucoxacillin and metronidazole is therefore frequently used empirically initially, which is then adjusted according to sensitivities. Ulcers should be dressed daily and washed with saline.
Osteomyelitis should be ruled out through foot radiograph where an ulcer is deep, where the lesion fails to heal or recurs.
Ulcers may require surgical debridement. Necrotic digits may require amputation.
Charcot's foot
Often presents as a unilateral warm swollen neuropathic foot. Charcot's foot is diagnosed by bone scan and gallium white cell scanning and MRI may be used to rule out infection.
Charcot's foot is managed with rest and use of non weight bearing crutches. A total contact plaster can also be used to allow injury to repair. This usually takes 2-3 months. Special shoes and insoles should be used after the foot has healed to prevent ulceration.
Complications:
Osteomyelitis - treated with surgical debridement and antibiotics. Additional antibiotics to standard antibiotics may be required.
abscess - requires surgical intervention.
Prognosis:
Patients with foot ulcers are at a high risk of amputation and recurrence of ulcers. Good foot care can reduce this risk. Patients with amputations have a poor survival rate.
http://www.bmj.com/content/326/7396/977?goto=reply
http://www.patient.co.uk/doctor/diabetic-foot
http://www.patient.co.uk/doctor/Limb-Embolism-and-Ischaemia.htm
http://www.patient.co.uk/doctor/diabetic-neuropathy
http://geekymedics.com/2010/10/10/diabetic-foot-examination-osce-guide/
Longmore M, Wilkinson IB, Davidson EH, Foulkes A, Mafi AR. Oxford handbook of clinical medicine, 8th ed. oxford, oxford university press, 2010
http://upload.wikimedia.org/wikipedia/commons/8/8f/Neuropathic_heel_ulcer.jpg
http://fc03.deviantart.net/fs38/f/2008/342/3/f/sch__feet_contour_drawing_by_tengwan.jpg
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