Diabetic foot infection

Diabetic foot infection
Gas gangrene due to diabetes
Symptoms	Pus from a wound, redness, swelling, pain, warmth[1]
Complications	Infection of the bone, tissue death, sepsis, amputation[2]
Causes	Diabetic foot ulcer[2]
Diagnostic method	Based on symptoms[1]
Differential diagnosis	Phlegmasia cerulea dolens, ischemic limb[2]
Prevention	Appropriate shoes[2]
Treatment	Wound care, antibiotics, hyperbaric oxygen therapy[2]
Frequency	Common[2]

Diabetic foot infection is any infection of the foot in a diabetic person.^[2] The most frequent cause of hospitalization for diabetic patients is due to foot infections.^[3] Symptoms may include pus from a wound, redness, swelling, pain, warmth, tachycardia, or tachypnea.^[4] Complications can include infection of the bone, tissue death, amputation, or sepsis.^[2] They are common and occur equally frequently in males and females. Older people are more commonly affected.

They most often form following a diabetic foot ulcer, though not all foot ulcers become infected. Diabetic foot ulcers can be caused by vascular disease or neuropathy and its prevalence occurs in approximately 25% of diabetics throughout their lifetime.^[4] Some risk factors for developing diabetic foot infections include history of repeated foot ulcers, foot ulcers lasting for longer than 30 days, poor control over blood glucose levels, peripheral neuropathy, renal impairment, peripheral artery disease, injury or trauma to foot, walking barefoot frequently, and history of amputation in lower limbs.^[4][5][6] Most diabetic foot infections are polymicrobial (contain multiple infective organisms), and bacteria that are commonly involved include staphylococcus, including methicillin resistant staphylococcus aureus (MRSA), streptococci, pseudomonas, and gram-negative bacteria.^[2][5] Previously, MRSA infections were usually acquired from hospital settings, however, recently MRSA infections acquired from the community are becoming more prevalent and are linked to poor treatment outcomes for diabetic patients.^[6] Some risk factors for developing MRSA infections include use of antibiotics that cover a broad spectrum of pathogens for a long duration of time, prolonged hospital stay, or certain surgical procedures.^[6] The underlying mechanism of diabetic foot infections often involves poor blood flow and peripheral neuropathy. Diagnosis is based on symptoms and may be supported by deep tissue culture.^[2]

Treatment involves proper wound care and antibiotics. Pseudomonas aeruginosa empiric therapy is not warranted unless the patient had a previous infection with a culture identifying the organism, or if the patient has risk factors for it such as frequent use of wet dressings or living in hot climates.^[5][4] MRSA empiric therapy is also not warranted unless the patient has a critical infection such as sepsis, if the rate of MRSA infections are particularly high in a local area, or if the patient had a previous MRSA infection.^[5] The duration of antibiotics depends on the severity of infection, ranging anywhere from 1–12 weeks. Treatment of mild-moderate infections should last 1–2 weeks and typically requires oral antibiotics that cover staphylococci and streptococci.^[4] Severe infections typically require IV antibiotics that cover more pathogens, such as gram positive organisms, gram negative organisms, and obligate anaerobes to allow for better treatment outcomes.^[4] Total antibiotic treatment of severe infections should be approximately 2–3 weeks or more, depending on how extensive the infection is.^[5] Prevention includes wearing appropriate shoes, regular foot examinations, and control of risk factors.