Diabetic Foot Complications- A Diabetic’s Worst Nightmare

Diabetes is a growing epidemic in our nation and globally. The prevalence of diabetes among Singapore residents (Singapore citizens and Permanent Residents) has increased over the decade. In Singapore, it is estimated that 1 in 9 adults has diabetes¹. Today, there are over 450,000 Singaporeans living with diabetes. This number is projected to go up to 1 million by 2050, if nothing is done². The Ministry of Health (MOH) launched the War on Diabetes in 2016, in response to the significant health and societal burden posed by diabetes. The cost burden of diabetes, including loss to productivity, is anticipated to double from S$940 million in 2014 to S$1.8 billion in 2050³.

People with diabetes are at high risk of developing a range of serious complications, including heart disease, kidney failure, blindness, and lower-extremity complications. The most disabling of these is the lower limb complications. It is the leading cause of diabetes-related reason for hospitalization and lower limb amputation. In addition to high healthcare costs, it is also associated with significant reduction in quality of life^4-5.

Approximately 25% of diabetics will develop a foot wound or ulcer in their lifetime. Amputation in people with diabetes is 10 to 20 times more common than in people without diabetes⁶. Every year, more than one million of leg amputations are performed globally because of diabetes, which is equivalent to one leg amputation every 30 seconds⁷.

In a person with diabetes, higher than normal sugar levels in the body will over time damage nerves (neuropathy)⁸ and cause blood vessels of the leg and foot to narrow and harden (atherosclerosis) leading to reduced blood flow down to the feet (Peripheral Arterial Disease (PAD))⁹.
 

a) Diabetic neuropathy⁸- This can result in:

1. Poor sensation in the feet- Minor injuries to the foot can be left undetected because of poor sensation and may consequently lead to foot ulceration and infection.
2. Foot deformities- Structural changes in the foot such as hammer toes, claw toes, collapse of the midfoot (Charcot foot) and limited joint mobility can result in focal areas of high pressure on the sole. Skin can break down over pressure points leading to ulceration.
3. Decreased sweating- Nerves supplying the sweat glands stop functioning, leading to dry, flaky and cracked skin. Cracked skin in the foot may allow bacteria to enter and cause infection.

b) Peripheral Arterial Disease (PAD)⁹ – People with diabetes are at increased risk of atherosclerosis which narrows and harden the blood vessels of the leg and within the foot. Poor blood supply to the foot will lead to poor healing and gangrene as well as reduced ability to fight infection.

It is important to recognize that most diabetic foot complications are manageable and amputation can be prevented if treatment is sought early. Delayed in treatment of diabetic foot complications is common. The main reasons are underestimation of the severity of foot problems and lack of recognition of poor circulation¹². Management of diabetic foot problems is often complex and experts from other specialties may need to be involved, including vascular/ endovascular surgery, diabetology and podiatry.

Successful management of diabetic foot ulcers/wounds hinges on addressing the following treatment modalities:

1) Ensure adequate blood supply to the foot- Every foot ulcer/wound should be examined for the presence of ischaemia. If poor circulation of the foot is suspected, investigations such as ultrasound scan or CT angiogram are required to assess the nature of the blockage in the leg arteries. The procedures to improve blood supply to the leg include surgical bypass or endovascular techniques (balloon angioplasty with or without stent)¹³. The treatment of choice depends on the specific type of blockage and which artery is involved and the general health condition of each patient.

2) Control of infection- Signs of wound infection may include:

 a) Peri-wound redness/ swelling
 b) Foul smelling wound
 c) Pus
 d) Pain

Systemic signs of infection may include fatigue, fever, tachycardia (increased in heart rate), and general malaise. When infection is present clinically, cultures should be obtained. Antibiotics that are shown to be effective against the offending bacteria through sensitivity testing should be given either orally or intravenously, depending on the severity of the infection.

For severe wound infection with significant tissue destruction involving muscle, tendon and bone; urgent surgical intervention will be needed to control the spread of infection.

3) Wound care

a) Debride all non-viable tissue (e.g. callus, foreign bodies and necrotic tissue) that may impede wound healing
b) Appropriate dressing choice to ensure moist wound environment for healing.
c) Antimicrobial dressings need to be considered to treat and prevent wound from infection

4) Offloading- redirecting weight (or pressure) off and away from the wound with proper footwear. Some patients may require wheelchair or crutches to achieve effective offloading.

1) Management of risk factors

a. Blood sugar level- High blood sugar, the hallmark of diabetes, injures nerves and blood vessels throughout the body.
b. High blood pressure- high blood pressure damages blood vessels, leading to atherosclerosis
c. High cholesterol level- accumulation of cholesterol-rich fatty deposits in arteries can result in atherosclerosis.

2) Lifestyle modification

a. Smoking cessation- Smoking interferes with blood circulation, and so compounds the effects of nerve and blood vessel damage.
b. Exercise- naturally improves circulation while working to lower cholesterol and improve heart function.
c. Healthy diet- Steering clear of excessive amounts of salt and saturated fats can help you manage your body weight, blood pressure and cholesterol.
d. Weight loss- losing weight improves the body’s ability to control blood sugar and it also takes some pressure off the feet.

3) Foot Care

a. Check your feet and toes every day for cuts, sores, corns or blisters
b. Never go barefoot. Choose shoes that are comfortable and fit well. Ill-fitting shoes can cause corns and calluses, ulcers and nail problems.
c. Wash feet daily. Apply moisturising skin lotion to feet to prevent dryness and cracks.
d. Cut or file your toenails regularly.
e. Yearly foot screening by podiatrist, doctor or trained nurse- Early identification of those at risk of diabetic foot ulcers will prevent development of foot complications and thus reduce the number of amputations. Education on proper foot care and good glycaemic (blood sugar level) control

Finally, if there are symptoms of unusual pain, redness in the foot, swelling, injury to the foot, infection or ulcer; make sure this is checked by your doctor or diabetic nurse as soon as possible. There is a clear need to recognise decreased perfusion or vascular impairment as an indicator for the need for revascularisation in the diabetic foot in order to achieve and maintain healing and to avoid or delay a future amputation. Early identification of the problem and treatment before the problem becomes severe is CRITICAL in preventing limb loss.

This article was contributed by Dr Tan Yih Kai, AIA Quality Healthcare Partner, and Consultant Vascular and Endovascular Surgeon of Farrer Vascular Vein and Wound Centre. Clinic. To request an appointment with Dr Tan, please click here.

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