Diabetic Foot: Abscess Characteristics and Causes

Wound Management and Diabetic Foot

Characteristics of an Abscess

• Presents with calor (heat), rubor (redness), dolor (pain), and tumour (swelling)
• May also exhibit functio leasa (loss of function) and damage to the infected part

Causes and Composition of an Abscess

• Caused by pyogenic organisms, mainly Staphylococcus aureus
• Composed of pus, dead and dying white blood cells, and damaging cytokines, oxygen-free radicals, and other molecules

Formation and Resolution of an Abscess

• Surrounded by an acute inflammatory response and a pyogenic membrane
• Granulation tissue forms later around the suppuration, leading to collagen deposition
• May spontaneously discharge through a surgical incision, but most take 7-9 days to form after surgery
• May need debridement and curettage with exploration to resolve

Complications of Chronic Abscesses

• May lead to sinus or fistula formation
• Persistent chronic abscesses may exhibit lymphocytes and plasma cells, sequestration, and calcification
• Certain organisms, such as mycobacteria, are related to chronicity, sinus, and fistula formation

Diagnostic Tools

• Plain or contrast radiographs may not be helpful
• CT scan, MRI, and isotope scans are usually accurate and may allow guided aspiration without surgical intervention

Surgical Site Infections

Classification of Surgical Wounds

• Class I or clean wounds: low risk of infection (1-4%)
• Class II clean contaminated wounds: slightly higher risk of infection (3-6%)
• Classified based on potential risk of microbial contamination and whether a hollow viscous is entered