How should I diagnose and manage a patient with left upper quadrant pain, fever, leukocytosis and risk factors such as recent abdominal infection, endocarditis, trauma, immunosuppression, diabetes, or sickle‑cell disease suggestive of a splenic abscess?

Splenic Abscess: Diagnosis and Management

Immediate Diagnostic Approach

Obtain a contrast-enhanced abdominal CT scan immediately in any patient presenting with left upper quadrant pain, fever, and leukocytosis with risk factors for splenic abscess, as this imaging modality demonstrates 90-95% sensitivity and specificity for identifying abscesses as contrast-enhancing cystic lesions. 1

Key Clinical Features to Identify

• Fever is present in 82-92% of cases 2, 3
• Left upper quadrant abdominal pain occurs in 71-77% of patients 2, 3
• Leukocytosis (>10 × 10⁹/L) is found in 66-83% of cases 2, 3
• Clinical splenomegaly is present in only 30% of cases and should not be relied upon as a diagnostic indicator 4, 5

Imaging Strategy

• CT with IV contrast is the gold standard with 90-95% sensitivity/specificity 1, 4
• MRI provides equivalent diagnostic accuracy (90-95%) and can differentiate abscesses from bland infarcts 4, 5
• Ultrasound has lower sensitivity (93% detection rate) but can be used for initial screening 6

Initial Management: Antibiotics

Start immediate IV broad-spectrum antibiotics targeting Staphylococcus aureus and Streptococcus viridans as soon as splenic abscess is suspected, as these organisms account for approximately 40% each of culture-positive cases, particularly in endocarditis-associated abscesses. 1, 5

• Most non-endocarditis cases grow gram-negative enteric bacilli 2
• Empiric regimen should cover both gram-positive cocci and gram-negative organisms 5
• Monitor for clinical improvement within 72-96 hours 4

Treatment Algorithm Based on Abscess Characteristics

For Single Abscesses >4 cm or Symptomatic Abscesses

Proceed with percutaneous catheter drainage (PCD) under CT or ultrasound guidance as first-line treatment after antibiotic stabilization, with success rates of 90% for unilocular abscesses >4 cm. 1

• PCD achieves 80-90% overall success rates 1
• Maintain drainage until output is <10-20 mL/day, infection signs resolve, and imaging confirms abscess resolution 1, 4
• Success rate of 90% specifically for unilocular abscesses >4 cm 7

For Abscesses <4 cm

• Antibiotics alone may be considered for abscesses <4 cm in diameter 7
• Success rate of 75% with antibiotics alone in selected patients 6
• Close monitoring with repeat imaging is essential if symptoms persist beyond 4 days 4

For Multiple or Complex Abscesses

Proceed directly to splenectomy for multiple or multilocular abscesses, as percutaneous drainage demonstrates high failure rates of 14.3-75% in this setting. 1, 4, 5

• Multiple abscesses are present in 28-47% of cases 6, 3
• Splenectomy is the preferred definitive treatment for complex disease 4, 5

Absolute Indications for Immediate Splenectomy

Perform splenectomy immediately in the following clinical scenarios:

• Splenic rupture with hemorrhage and hemodynamic instability 1
• Failure of percutaneous drainage with persistent infection 1
• No safe percutaneous window available for drainage 1, 4
• Multiple complex or multilocular abscesses 1, 4, 5
• High bleeding risk contraindicating percutaneous intervention 1, 4
• Persistent or recurrent bacteremia despite appropriate antibiotics and drainage 1
• Failure of medical therapy after 4 days of appropriate treatment 4

Splenectomy demonstrates 100% survival rate compared to 45% for percutaneous drainage and 48% for antibiotics alone in one series 2

Special Population: Endocarditis Patients

In patients with infectious endocarditis requiring valve surgery, perform splenectomy before valve replacement to prevent prosthetic valve infection from splenic bacteremia. 1, 5

• Viridans streptococci and S. aureus each account for approximately 40% of endocarditis-associated splenic abscesses 1, 5

Post-Splenectomy Prophylaxis Protocol

Immediately institute post-splenectomy sepsis (PSS) prevention protocol:

• Administer pneumococcal, meningococcal, and Haemophilus influenzae type B vaccines ideally ≥14 days after splenectomy 1, 4, 5
• Prescribe lifelong antibiotic prophylaxis: amoxicillin 3 g initial dose then 1 g every 8 hours for acute febrile episodes 1
• For penicillin allergy: levofloxacin 500 mg/24h or moxifloxacin 400 mg/24h 1
• Revaccinate every 5-10 years 1
• Annual influenza vaccination for patients >6 months 1
• Provide Medic-Alert identification and patient education on PSS risk 1

Critical Pitfalls to Avoid

• Never rely solely on antibiotics for large abscesses (>4 cm), as this has high failure rates and risks untreated sepsis mortality 1
• Do not attempt percutaneous drainage for multiple abscesses due to failure rates up to 75% 4
• Do not rely on clinical splenomegaly as a diagnostic indicator, as it is present in only 30% of cases 4, 5
• Persistent fever, abdominal pain, or bacteremia days after aspiration should trigger immediate re-imaging 1
• Do not aspirate suspected hematomas after drainage, as this risks introducing infection into sterile blood collections 1
• Maintain increased vigilance in IV drug users for hematogenous seeding and persistent infection 1