What is the management of a subphrenic abscess?

Management of Subphrenic Abscess

The definitive management of subphrenic abscess requires drainage (either percutaneous or surgical) combined with appropriate antibiotic therapy, with percutaneous drainage being the first-line approach in carefully selected patients. 1, 2

Diagnostic Approach

• Diagnosis of subphrenic collections is typically made with sonography, which can identify the location and characteristics of the abscess 2
• CT scanning provides additional information about the extent, complexity, and relationship to surrounding structures 3
• Approximately 55% of subphrenic abscesses are located on the right side, 25% on the left, and 20% are multiple 3

Treatment Algorithm

First-Line Approach: Percutaneous Catheter Drainage (PCD)

• PCD is safe and effective with success rates of 85-87% when properly performed 2, 4
• Key technical considerations for successful PCD:
  • Use an angled subcostal approach (used in 90% of cases) to avoid pleural complications 2
  • Employ large-bore drainage catheters (12F or larger) 4
  • Utilize a combination of sonography and fluoroscopic guidance for accurate placement 2
  • Expect longer drainage times (>10 days in 60% of cases) 2

Antibiotic Therapy

• Empiric broad-spectrum antibiotic therapy should cover Gram-positive, Gram-negative, and anaerobic bacteria 5
• Therapy should be tailored based on culture results from the drained abscess fluid 1

Surgical Drainage Indications

• Multiple or complex multiloculated abscesses 1
• Unfavorable access routes for percutaneous drainage 1
• Failed percutaneous drainage 2
• Underlying conditions requiring surgical intervention (e.g., perforated ulcer, acute cholecystitis) 2
• Presence of enteric, biliary, or pancreatic fistulas may require surgical management 4

Alternative Approaches

• Endoscopic ultrasound-guided transmural drainage (EUS-TD) has emerged as a feasible option for subphrenic abscesses when percutaneous routes are challenging 6
• For EUS-TD, both internal and external drainage catheters should be placed into the abscess cavity 6
• The transesophageal route should be avoided due to risk of mediastinitis and pneumothorax 6

Complications and Pitfalls

• Mortality from subphrenic abscess ranges from 11-31% due to uncontrolled infection, malnutrition, and complications of prolonged hospitalization 3
• Potential complications of improper drainage technique:
  • Pneumothorax can occur if using an intercostal approach through the parietal pleura 2
  • Extension to thoracic cavity can lead to empyema, lung abscess, or pneumonia 3
  • Inadequate drainage of underlying fistulas can lead to persistent infection 4

Follow-up

• Monitor clinical improvement after catheter insertion 4
• Drainage catheters typically require longer placement (>10 days) compared to other intra-abdominal abscesses 2
• Consider follow-up imaging to confirm resolution of the collection 1
• Address any underlying pathology that may have caused the abscess 1, 4