Caesarean Wound Infection

Caesarean wound infection is infection of the skin and subcutaneous tissue (superficial) or the deeper fascia and muscle (deep) at the caesarean incision, with redness, swelling, pain and pus. It is more common after emergency surgery, labour and ruptured membranes. It matters because it prolongs admission, delays breastfeeding, and can progress to wound breakdown and necrotising fasciitis.

• Risk factors: obesity, diabetes, emergency caesarean section, long labour, ruptured membranes for 18 hours or more, chorioamnionitis, HIV, anaemia, smoking, poor skin preparation, lack of prophylactic antibiotics.
• Usually appears 4 to 7 days after surgery.
• Organisms include Staphylococcus aureus, streptococci, Escherichia coli and anaerobes.

Women have wound pain, spreading redness, swelling, warmth, purulent discharge and fever from day 3 to 7. The wound edges are tender and indurated.

• Fever above 38 degrees Celsius.
• Pus draining from the incision or fluctuance under the skin.
• Differential diagnosis: wound haematoma, wound seroma, endometritis, stitch abscess, necrotising fasciitis, deep abscess, cellulitis from other cause, mastitis.
• Complications: wound dehiscence, abscess, necrotising fasciitis, sepsis, incisional hernia, prolonged hospitalisation, delayed healing, maternal death.

The diagnosis is made by examination of the wound and general condition, with culture of any discharge.

• Inspect and palpate the wound for erythema, induration, tenderness, fluctuance and pus; measure the area of redness and mark the margin.
• Temperature, pulse, blood pressure, respiratory rate.
• Swab or aspirate pus for Gram stain and culture; full blood count, C-reactive protein, blood glucose, blood culture if febrile.
• Ultrasound for a deep collection; CT for suspected necrotising infection.

The principle is to open and drain pus, debride dead tissue and give antibiotics for spreading infection.

• Supportive: remove skin sutures or staples over the infected area and open the wound; irrigate with sodium chloride 0.9 percent; pack loosely with moist gauze changed once or twice daily; keep dry; control diabetes with insulin to keep glucose below 10 mmol/L; hydration; continue breastfeeding.
• Pharmacological: cellulitis with no pus or mild infection: flucloxacillin 500 mg oral 6-hourly for 7 days, or amoxicillin-clavulanate 625 mg oral 8-hourly for 7 days; moderate or severe infection: ceftriaxone 2 g IV once daily plus metronidazole 500 mg IV 8-hourly until afebrile for 48 hours, then amoxicillin-clavulanate 625 mg oral 8-hourly to complete 7 days; suspected methicillin-resistant Staphylococcus aureus: vancomycin 15 mg/kg IV 12-hourly or clindamycin 600 mg oral 8-hourly; necrotising fasciitis: meropenem 1 g IV 8-hourly plus clindamycin 900 mg IV 8-hourly plus vancomycin 15 mg/kg IV 12-hourly, continued until surgical control and clinical improvement; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: opening and drainage of the wound at the bedside; surgical debridement for necrotic tissue; urgent wide debridement in theatre for necrotising fasciitis; negative pressure dressing or delayed secondary closure after 5 to 7 days when the wound is clean.
• Special groups: diabetic women need insulin and strict glucose control; HIV positive women continue tenofovir 300 mg, lamivudine 300 mg and dolutegravir 50 mg oral once daily; breastfeeding is compatible with flucloxacillin, amoxicillin-clavulanate, ceftriaxone and clindamycin.
• Red flags: rapidly spreading redness, skin blistering or dusky colour, pain out of proportion, crepitus, fever above 39 degrees Celsius, hypotension, confusion.
• Follow-up: wound review every 2 days until healing; review at 1 week and 6 weeks; advise on hygiene and wound care; plan antibiotic prophylaxis for later caesarean sections.