It is well known that having uncontrolled diabetes puts many diabetics at high risk for complications including foot infections. Foot infections are caused by harmful micro-organisms growing inside the foot. These micro-organisms feed on the tissue and multiply to many numbers. The body’s (immune) defense system starts to fight against these organisms and inflammation results causing pain, redness, swelling and a rise in the temperature in the area.
The amount of damage to the tissues depends on the strength or number of micro-organisms, and how healthy the person is. Some of the conditions that can make the infection worse are:
• Diseases that affect the health of the person – malnutrition, diabetes mellitus, HIV infection, cancer or people on immunosuppressive drugs.
• Reduced sensation in the foot can also lead to foot infection, as trauma to the foot goes unnoticed because there is no pain. This is commonly seen in diabetes mellitus and neurological disorders after a stroke.
• A poor blood supply to the foot causes a delay in healing of wounds leading to persistence and extension of infection. This is usually seen in diabetes mellitus, vascular disease and even lupus.
Foot infection can be classified into two types based on how they got the wound – those that result from trauma or an injury like stepping on a nail or getting a cut or laceration to the foot, or those where no trauma is involved. Traumatic infections are more common with people who may have a weakened immune system, have loss of feeling or have poor blood flow to the foot. Traumatic infections can happen to anyone and occur by many different ways according to the injury – for example, industrial accidents, road traffic accidents, lawn mower injuries, gunshot injuries, puncture injuries, etc.
Infections are also classified by the location on the foot – on the toenail, heel, arch, etc. Infection can also be on the skin in soft tissues like tendons or in the bone, and are called cellulitis or infection of skin and subcutaneous tissues, fasciitis or infection of the fascia and tendons and osteomyelitis when infection is in the bone and joints. The deeper the infection and the greater the trauma, leads to deeper infections.
Puncture injuries can also cause infections usually caused by stepping on nails, wood, glass, etc. Infection can develop over a few hours or days and cause increase in the pain followed by the swelling or even pus out of the foot. A part of the object may have remained inside and may be seen on an x-ray, ultrasound or MRI scan. This would have to be removed by the doctor.
The most common cause of foot infections is the bacteria Staphylococcus aureus. However, most diabetic foot infections have more than one bacteria at the same time.
The usual symptoms of foot infection include the following:
• Pain that can be moderate to severe or throbbing if pus is present.
• Redness of the skin around the wound or injury site.
• Fever and a local increase in temperature at the site of infection.
Remember, because of the diabetes, the immune system is not working at its best, so it may not produce all these classic signs of infection. In diabetes, pain and fever may be absent, but a good sign of infection may be an increase in blood sugar readings.
Diagnosis of infection is based mostly on signs and symptoms and a clinical exam when you go to the doctor. Blood investigations and foot x-rays are also a part of the work-up to make the diagnosis and rule out other conditions that may look like a foot infection such as Charcot foot. A wound culture is often sent to the lab to find out what bacteria is causing the infection. Other studies such as an ultrasound, CT scan and MRI may also be done to see the extent of the infection before planning any surgery.
Treatment of foot infection depends on the extent and severity of the infection. How well your diabetes is controlled and your overall health affects the success of the treatment. Because of the high blood sugar, the neutrophils – “immune fighters” are not as effective at killing bacteria. Blood flow to the foot may also be affected, which will decrease the amount of antibiotics that can actually get to the infection site to kill the bacteria.
General principles of foot infection treatment
• Rest and elevation of the foot on one or two pillows to reduce swelling and pain
• Take the antibiotics ordered by your doctor to kill the bacteria causing the infection
• If the infection is deep or in a large area, surgery may be needed to drain the area if present
• Debridement or removal of all the dead tissue present will be done in the office at every visit. Dead tissue serves as food for bacteria and antibiotic concentration is poor in dead tissue. All dead tissue has to be removed as early as possible as healing can only begin once the dead tissue has gone.
• Cleaning of the wound with saline and surrounding normal skin is done with each dressing change. Wounds are covered because it helps to keep them clean and they heal faster when covered rather than staying open.
It may be difficult for you to determine if a wound is infected and you may have some concerns about going to the doctor at this time with COVID-19. It is not a good idea to stay home with a diabetic foot infection. It must be treated by the doctor. It is best to have it evaluated as soon as possible by your podiatrist or primary care doctor.
• For more information on foot conditions, visit www.apma.org, healthcentral.com, or email us at email@example.com. To see a podiatrist, visit Bahamas Foot Centre, Rosetta Street, or telephone 325-2996 for an appointment at Bahamas Surgical Associates Centre, Hilltop Medical, or call 394-5820 for an appointment. You can also visit Lucayan Medical Centre in Freeport, Grand Bahama, or telephone 373-7400 for an appointment.