A 35-year-old man presents with a surgical wound that has failed to heal for 8 weeks following an elective abdominal surgery. The wound shows persistent drainage, erythema, and induration. Clinical examination reveals a fluctuant mass beneath the wound. Which investigation is most appropriate to confirm the suspected diagnosis and guide management?

## Diagnosis of Wound Complications: Imaging Approach ### Clinical Scenario Analysis The patient presents with classic signs of a **post-operative wound abscess**: persistent drainage, erythema, induration, and a fluctuant mass. The 8-week timeline indicates a **delayed complication** beyond simple infection. ### Why Ultrasonography is the Investigation of Choice **Key Point:** Ultrasonography is the **first-line imaging modality** for suspected wound abscess because it: - Confirms the presence of a fluid collection (abscess) - Determines the size, depth, and loculation of the abscess - Is **non-invasive, real-time, and cost-effective** - Can be performed at the bedside - Guides percutaneous drainage if needed **Clinical Pearl:** A **hypoechoic or anechoic collection** on ultrasound with **posterior acoustic enhancement** is pathognomonic for abscess. The absence of vascularity on Doppler helps exclude hematoma. ### Role of Other Investigations | Investigation | Indication | Limitation | |---|---|---| | **Wound culture** | Identifies organism after drainage; guides antibiotic therapy | Does NOT diagnose abscess; requires drainage first | | **CT scan** | Reserved for deep/intra-abdominal extension or complex anatomy | Expensive, not first-line for superficial wound abscess | | **CBC with differential** | Supports diagnosis of infection (elevated WBC) | Non-specific; does not localize the problem | ### Management Algorithm ```mermaid flowchart TD A[Suspected wound abscess] --> B[Ultrasonography] B --> C{Fluid collection confirmed?} C -->|Yes| D[Percutaneous/open drainage] C -->|No| E[Reconsider diagnosis] D --> F[Send pus for culture] F --> G[Targeted antibiotics] ``` **High-Yield:** Ultrasound has **>90% sensitivity** for detecting fluid collections >2 cm and is the **gold standard first-line imaging** in resource-constrained settings. **Tip:** Always perform ultrasound **before** culture—you need to drain the abscess first to obtain a meaningful culture specimen.