23 Oct Diabetic Foot Infections
Foot infections are the most complications of diabetes mellitus that lead to hospitalization. It is the most common cause of nontraumatic lower-extremity amputation. Diabetic foot infections, both involving the skin (cellulitis) and the bone (osteomyelitis) are very common in patients with poorly controlled DM.
These infections are diagnosed clinically as they typically present with symptoms and signs of inflammation – pain, redness, swelling, and likely purulence (pus formation). These infections are polymicrobial, which means a number of bacteria or pathogens cause it, such as aerobic gram-positive cocci, mainly Staphylococcus species. When these infections run deep to involve bone, the condition is called osteomyelitis. It is a serious complication of diabetic foot infection and often requires surgical treatment.
Treatment is based on the extent and severity of the infection. Mild infections are treated conservatively with oral antibiotics, wound care, and pressure off-loading. Moderately severe and severe infections require hospitalization and may require surgical intervention. It is critical to assess the vascular status as many of these patients have peripheral arterial disease, which can severely hamper post-surgical healing.
The focus of diabetic care should be on the prevention of foot infections, not cure. This requires a holistic approach, which includes patient education, dietary modification, lifestyle changes such as exercise, and routine health visits so that key tests and examinations can be performed. In addition to monitoring blood glucose levels routinely, diabetics should undergo a systematic foot examination at least once a year. These exams should be more frequent if there are risk factors for diabetic foot ulcers. Key preventive measures include strict glycemic and blood pressure control, proper diet, regular exercise, smoking cessation, use of prescription footwear, and podiatry care (to screen for and address early signs of infection).
Major factors that contribute to the development of diabetic foot infections include peripheral neuropathy, peripheral vasculopathy, and impaired immunity. Whenever there is a suspicion for a diabetic foot infection, a thorough clinical assessment needs to be performed, including a thorough assessment of the wound, the limb, and the patient’s overall health status. Telltale signs of infection include redness, warmth, induration/swelling, pain/tenderness, and pus formation. It is also important to look for signs of impaired wound healing. Osteomyelitis is a serious complication of diabetic foot infection. It requires aggressive systemic antimicrobial treatment and still entails a high risk of treatment failure and lower extremity amputation.
It is seen in up to 20% of mild and moderate infections, and almost half of severe infections. It is especially common if the foot ulcers are large (> 2 cm) or deep (> 3 mm), or if they are close to an underlying bone. Poorly healing chronic ulcers with bone showing has a very high likelihood of developing osteomyelitis. X-ray imaging is performed if osteomyelitis is expected, although it may be negative in the first several days. In those cases, MRI or a nuclear bone scan may be performed to assess the extent of infection.