Management of Stage 1 Diabetic foot

 

Assessment of Diabetic foot

The stage 1 foot has no risk factors for diabetic foot problems and is a normal foot. Neither neuropathy nor ischaemia, nor the other major risk factors which would make ulceration more likely, namely deformity, callus and oedema, are present. These five factors have to be excluded in order to diagnose a foot at stage 1.

The screening assessment consists of five parts:

  • Enquiring as to any previous history of ulceration or other serious foot problems
  • Testing for neuropathy (we use 10 g monofilament or a tuning fork)
  • Palpation of foot pulses to ensure that ischaemia is not missed. (It is so important not to miss ischaemia that we perform palpation of pulses on every diabetic patient at every clinic visit)
  • Inspection of the foot to look for the following abnormalities:

Deformity

Callus

Oedema

Ulceration

Signs of infection

Necrosis

  • Limited joint mobility can be assessed by a simple biomechanical assessment to detect hallux rigidus and a reduced range of movement at the ankle joint.

 

The aims of management are to ensure that:

  • The development of patients’ risk factors for diabetic foot ulceration is prevented or delayed
  • If risk factors do develop, they are detected early and patients placed in stage 2
  • Common foot problems that can occur in the general population are efficiently treated and do not lead to tissue breakdown even in the absence of neuropathy and vascular disease.

Mechanical control

Mechanical control is achieved by wearing the correct footwear and also by the recognition and treatment of common foot problems.

Footwear

Advice on buying shoes

For everyday wear, house shoes and for when the patient is on his feet a lot, selection should be made according to the following principles.

  • The shoe should be ‘foot-shaped’
  • Toe box should be roomy to avoid pressure on toes and borders of foot
  • Heel cup should fit snugly
  • Heels should be low (under 5 cm high)
  • Shoe lining should be smooth Sole should be sufficiently thick to prevent puncture wounds
  • Shoe should fasten with lace or strap to hold foot back in shoe
  • Court or slip-on shoes should be avoided except for special occasions
  • Wearing socks reduces friction within shoes
  • Socks should be non-constricting with no tight band around ankle or calf
  • Socks should be made of absorbent materials such as cotton
  • If shoes cause pain, callus, red marks or blisters then they do not fit properly and should be discarded
  • In hot climates, sandals may be worn; however, they give little protection against trauma and the foot is not held firmly in place, resulting in excessive shear.

 

Common foot problems

In maintaining mechanical control, it is important to

diagnose foot problems including:

Nail problems

Fungal infections

Corynebacteria infections

Fissures

Verrucae

Bullae

Malignancy

Inflammatory skin diseases

Hyperhydrosis and bromodrosis

Insect bites

Traumas

Fractures

Gout.

 

Nail problems

Many people in stage 1 will be able to cut their own nails. They should be taught the correct techniques for cutting normal nails as follows:

  • Nails should be cut straight across or in a gentle curve
  • The corners should not be cut out: a piece may be left behind and lead to an ingrowing toenail
  • The nail plate should not be cut in one piece: a gentle ‘nibbling’ technique should be used to avoid splitting the nail plate
  • The nail should not be cut so short that the seal between nail and nail bed is broken
  • The nails should not be left so long that they can catch on the socks, risking trauma
  • The nails should be cut regularly: even normal nails can cause problems if neglected
  • The nails should be cut after the bath, when the nail plate will be softer, more flexible and easy to cut
  • If nail cutting is difficult or painful, patients should seek professional help.

 

Onychauxis

Onychauxis is thickening of the nail without deformity. It follows an insult to the nail bed and is common. Regular filing will reduce the thickness of the nail. Without regular reduction onychogryphosis will develop.

Onychogryphosis (ram’s horn nail)

This is thickening of the nail with deformity. The cause is an insult to the nail bed. Treatment can be palliative or surgical. Palliative treatment consists of regularly cutting and thinning the nail plate at 3-monthly treatment intervals and can result in a normal appearance of the nail. If only one nail is affected and the patient dislikes the need for regular treatment, the nail plate can be removed under ring block local anaesthesia. If the exposed nail bed is treated with topical phenol the nail will be replaced by a fibrous plate which does not need regular reduction and has a cosmetically acceptable appearance. However, this procedure is invasive and should not be carried out on ischaemic feet.

Onychocryptosis (ingrowing toe nail)

This is frequently caused by improper nail-cutting technique, when a spike of nail is left behind at the side of the nail. As the nail plate grows forward the spike is pushed laterally into the nail sulcus (the groove of flesh at the side of the nail) and penetrates the soft tissues. Other causes of onychocryptosis include pressure on the side of the nail from tight shoes or tight socks, antithrombotic stockings or support hose, a trauma to the side of the nail, as when the toe is stubbed, and a patient who pulls and picks at the nail. Hypergranulation tissue is often present but resolves after treatment.

Treatment of onychocryptosis involves removal of the offending splinter (nail spicule), and the ragged edge of the nail is then filed smooth with a Black’s file (a small file specially designed to fit into the sulcus and under the nail). Unless the splinter is removed quickly, the spike of nail will penetrate the flesh, and in these circumstances infection rapidly supervenes. Proprietory remedies are useless unless the nail splinter is removed. Where onychocryptosis is recurring or chronic it can be treated very successfully with partial nail avulsion under local anaesthetic (without adrenaline). This procedure should not be performed on ischaemic feet. Unless revascularization is possible, palliative care is best.

 

 

Fungal infections (tinea pedis)

Tinea pedis infection is caused by a dermatophyte fungus.It can present in several ways:

  • Dry, scaly, often in a ‘moccasin-like’ distribution on the sole and borders of the foot
  • Acute vesicular
  • Interdigital, with moist, cracked areas which may be sore, itchy and sometimes malodorous, and are associated with whitish, rubbery, macerated skin, and can undergo erosion and cracking.

Scrapings can be taken and sent to the laboratory for identification of the infective organism but usually a clinical diagnosis is made.

Treatment of tinea pedis

Topical anti-fungal cream is usually sufficient. Clotrimazole 1% in isopropyl alcohol applied topically is best for interdigital areas. For other parts of the foot Lotrimazole cream can be applied. Treatment should be continued for at least 2 weeks after resolution of symptoms to avoid relapse. Nystatin cream, terbinafine cream and Whitfield’s ointment (benzoic acid) may  also be useful.

Verrucae

Warts may occur anywhere on the foot and may be single or multiple, and appear as round flattened papules or plaques. They are whitish or grey in colour with a rough surface. If they are on the plantar surface and thus subjected to pressure from walking, they may be difficult to distinguish from corns. However, warts are painful when they are squeezed while corns are painful when they are pressed. Skin striations are interrupted by warts but not by corns. Removal of a verruca by scalpel debridement reveals tiny reddish brown dots. Dots are not visible following removal of corns.

Small speckles of black (thrombosed blood vessels) can be a sign that the verruca is resolving spontaneously. Accumulation of hyperkeratosis may cause pain on walking: excess keratin can be pared with a scalpel or the patient may use a pumice stone. However, warts do not need to be treated unless they are painful or spreading: most will resolve within 2 years without treatment and they are less infectious than is commonly thought.

Bullae (blisters)

These are superficial accumulations of clear fluid within or under the epidermis which develop following trauma to the skin. Common causes include unsuitable shoes, failure to wear socks and walking in wet footwear. Pedal bullae are sometimes associated with hypoglycaemic episodes. Several serious lesions, including early neuropathic and early ischaemic ulcers, pressure ulcers, burns, puncture wounds and infections complicating ulceration, may first present as a bulla. Unless bullae are small, superficial and containing clear fluid, they should be regarded as stage 3 lesions. Small, flaccid bullae can be cleaned and covered with a sterile non-adherent dressing. Large bullae (over 1 cm in diameter) and all tense bullae should be lanced with a scalpel and drained before dressing. Aspiration with a syringe is less useful because the hole frequently seals, fluid accumulates again and unrelieved hydrostatic pressure causes extension of the blister. The cause of blisters should always be ascertained  and addressed. Bullosis diabeticorum is a rare condition where diabetic patients present with intraepidermal blisters which are not associated with trauma and heal without scarring. Treatment of bullosis diabeticorum is as for bullae.

Metabolic control

This should follow principles of modern diabetic management. Tight control of blood glucose, blood pressure,blood cholesterol and triglycerides, as well as stopping smoking and giving antiplatelet therapy when indicated, is extremely important at stage 1 in order to preserve  neurological and cardiovascular function. Diabetic patients are at a high risk of developing atherosclerotic disease and it is appropriate to manage such patients to the same targets of blood glucose, blood pressure and serum lipids

as those patients with established cardiovascular disease. Furthermore, the incidence of neuropathy is associated with potentially modifiable cardiovascular risk factors, including a raised triglyceride level, body mass index, smoking, and hypertension. Hypoglycaemia is an important metabolic complication of diabetic treatment. It is defined as blood glucose less than 3.5 mmol/L (63 mg/dL). The incidence of hypoglycaemia is 10% per year in type 1 diabetes on twice daily insulin and 30% in those with multiple injections. There is less risk in type 2 diabetes: 0.5% per year if taking sulphonylureas and 2–3% in those taking insulin.

 

Blood lipid control

Patients with diabetes have an increased prevalence of lipid abnormalities which contribute to high rates of  cardiovascular disease, especially in type 2 diabetes, and are also associated with neuropathy. Lipid management aimed at lowering low-density lipoprotein (LDL) cholesterol, raising high-density lipoprotein (HDL) cholesterol and lowering triglycerides has been shown to reduce macrovascular disease and mortality in patients with type 2 diabetes, particularly those who have had prior cardiovascular events. Reduction of saturated fat and cholesterol intake, weight loss and increased physical activity has been shown to improve the lipid profile in patients with diabetes.

Statins have been used as first-line pharmacological therapy for LDL lowering. Indeed, statins are now recommended for all diabetic patients greater than 40-years-old (or younger if there is evidence of cardiovascular disease) and for all patients with microalbuminuria above 20-years-old. High serum triglycerides should be treated with improved glycaemic control, statins and, if necessary, fibrates to achieve recommended targets.

In type 2 diabetes, modern targets are LDL cholesterol < 2.5 mmol/L, HDL cholesterol > 1.0 mmol/L and fasting triglycerides < 1.5 mmol/L. These are also applicable to patients with type 1 diabetes in view of their high morbidity from cardiovascular disease.

Reduction of smoking

Smoking is a very significant risk factor for peripheral vascular disease and is also associated with peripheral neuropathy. Clear, unequivocal advice should be given to stop smoking, but it is a very difficult habit to break. Patients may be helped by the prescription of nicotine replacement therapy or the administration of smoking cessation drugs such as bupropion, an antidepressant, or more recently varenicline.

Antiplatelet therapy

Patients with diabetes who are 50 years of age or more, or who are younger but have had diabetes for more than 10 years, should take aspirin 75 mg daily. If aspirin cannot be tolerated, then clopidogrel 75 mg daily should be prescribed.

Hypoglycaemic unawareness

Sympathetic responses decrease with increasing duration of diabetes, and patients may become unaware that they are hypoglycaemic: they develop hypoglycaemic unawareness. It occurs in 25% of patients with type 1 diabetes and in about 50% of patients who have had type 1 diabetes for more than 20 years. There is a change in the glucose threshold for activation of physiological responses to low glucose. The threshold is reduced to 2.5 mmol/L (45 mg/dL) from 4.0 mmol/L (72 mg/dL). Warning signs develop late and the brain does not recognize them because cognitive function diminishes below a glucose level of 3.0 mmol/L (54 mg/dL). Capillary blood glucose measurement should be available as well as first aid treatment. A stock of glucose drink and biscuits should be available

Warning signs of hypoglycaemia are due to sympathetic overactivity and cerebral impairment because of reduced glucose availability.

Sympathetic overactivity

  • Trembling
  • Paraesthesiae around the mouth
  • Shakiness
  • Anxiety
  • Hunger
  • Sweating.

Cerebral dysfunction

  • Confusion or altered behaviour
  • Slurred speech
  • Irritability
  • Loss of consciousness.

PRACTICE POINTS

  • All diabetic patients should have their feet screened annually
  • Although stage 1 patients are at low risk compared with any other stage of diabetic foot, they should still be regarded as vulnerable patients when compared with the non-diabetic population.
  • Diabetic patients should be advised to wear suitable footwear so as to prevent subsequent deformity
  • Common foot problems should be diagnosed early and treated appropriately
  • It is important to achieve good metabolic care with control of blood glucose, blood pressure, blood lipids, smoking cessation and taking antiplatelet therapy when indicated
  • All diabetic patients should be educated in good foot care, told why good diabetes control is important and warned about foot complications.