Body cavity infections

1. Big picture

Body cavity infections are infections inside normally sterile anatomical spaces, especially the peritoneal cavity, pleural cavity, mediastinum, pericardial cavity, joint spaces, and deep postoperative spaces.

They are surgically important because antibiotics alone often fail if there is:

• pus under pressure,
• perforation,
• anastomotic leak,
• infected necrosis,
• foreign body,
• loculated collection,
• obstruction,
• ongoing contamination.

The key surgical principle is:

Body cavity infection = infection in a closed or semi-closed space
        ↓
Antibiotics may control spread
        ↓
But source control is often required:
drain pus, repair perforation, resect necrosis, remove foreign body, relieve obstruction

In the oral exam, always answer in this order:

Recognize sepsis → localize the cavity → identify the source → image the cavity → start antibiotics → perform source control.

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