How should I diagnose and manage a patient with multiple splenic abscesses caused by melioidosis (Burkholderia pseudomallei)?

Diagnosis and Management of Multiple Splenic Abscesses Caused by Melioidosis

Diagnostic Approach

Obtain an abdominal CT scan with intravenous contrast immediately, as this is the reference standard with 90-95% sensitivity and specificity for identifying splenic abscesses as contrast-enhanced cystic lesions. 1, 2

Key Clinical Features to Recognize

• Diabetes mellitus is present in approximately 90% of patients with melioidosis-related splenic abscesses and represents a critical risk factor. 3
• Multiple abscesses are the predominant pattern, occurring in 90% of cases in endemic regions. 3
• Look for disseminated disease with concomitant hepatic abscesses, pulmonary involvement, or bacteremia. 4, 5
• Maintain high clinical suspicion in patients returning from endemic areas (Southeast Asia, Northern Australia) with fever and abdominal pain. 6

Microbiologic Diagnosis

• Blood cultures and abscess cultures (if drainage performed) are essential, as Burkholderia pseudomallei requires specific identification—it is often misidentified as Pseudomonas species. 7
• Alert the microbiology laboratory to consider melioidosis, as correct identification is critical for appropriate prolonged therapy. 7

Management Algorithm

Intensive Phase: Intravenous Antibiotic Therapy

Initiate IV ceftazidime or a carbapenem (meropenem or imipenem) immediately, with or without TMP-SMX, for 10-14 days or longer as clinically indicated. 8

• Meropenem and imipenem demonstrate universal sensitivity against B. pseudomallei isolates and are preferred for severe disease. 8
• Ceftazidime is equally effective and widely used. 8, 6
• Avoid ertapenem, azithromycin, moxifloxacin, and amoxicillin-clavulanate, as B. pseudomallei demonstrates resistance to these agents. 8
• For septic shock, consider meropenem plus G-CSF based on protocols from high-volume centers. 8

Critical Pitfall: Carbapenem Resistance

• Be aware that carbapenem resistance can emerge during therapy due to efflux pump overexpression; if clinical deterioration occurs despite appropriate antibiotics, consider switching to combination therapy with ceftazidime plus TMP-SMX. 5
• Combination therapy may limit resistance emergence in refractory cases. 5

Drainage vs. Conservative Management Decision

For multiple splenic abscesses caused by melioidosis, conservative management with prolonged antibiotics alone is the preferred approach, reserving splenectomy only for specific complications. 3

When to Use Antibiotics Alone (Preferred for Melioidosis)

• Multiple abscesses respond well to prolonged antibiotic therapy in melioidosis, with 90% of patients in endemic series managed conservatively without surgery. 3
• This contrasts with general splenic abscess management, where multiple abscesses typically require splenectomy. 1, 2

Absolute Indications for Splenectomy

Proceed to splenectomy only if:

• Splenic rupture with hemorrhage and hemodynamic instability occurs. 1, 2
• Persistent or recurrent bacteremia despite adequate antibiotics. 1, 2
• Clinical deterioration with ongoing sepsis despite appropriate therapy. 9
• Failure of conservative management with worsening abdominal pain or enlarging abscesses on repeat imaging. 9

Role of Percutaneous Drainage

• Percutaneous drainage is generally NOT recommended as first-line for multiple melioidosis abscesses, given the high success rate of antibiotics alone and the 14.3-75% failure rate of drainage for multiple complex abscesses. 1, 2, 3
• Reserve percutaneous drainage for single large abscesses (>4 cm) that fail to respond to antibiotics. 1

Eradication Phase: Oral Antibiotic Therapy

Following the intensive phase, transition to oral TMP-SMX for 12-20 weeks, with or without doxycycline, to prevent relapse. 8

• This prolonged eradication phase is mandatory to achieve disease resolution and prevent recrudescence. 4, 7
• One case series successfully used doxycycline plus TMP-SMX for eradication. 6
• Amoxicillin-clavulanate is much less effective and should only be used for pregnant women, children, or patients with intolerance to first-line agents. 8

Monitoring and Follow-Up

• Monitor hemodynamic stability with frequent vital signs and serial hematocrit measurements. 1, 2
• Watch for signs of persistent infection: ongoing fever, abdominal pain, or bacteremia. 1, 2
• Obtain repeat imaging if clinical deterioration occurs to assess for abscess enlargement, rupture, or new lesions. 9
• Continue antibiotics until complete clinical and radiologic resolution is achieved. 4, 7

Post-Splenectomy Prophylaxis (If Surgery Required)

If splenectomy becomes necessary:

• Administer pneumococcal, meningococcal, and Haemophilus influenzae type B vaccines ideally ≥14 days post-operatively. 1
• Prescribe lifelong antibiotic prophylaxis with amoxicillin 1g every 8 hours for febrile episodes (or levofloxacin 500mg/24h if penicillin-allergic). 1
• Revaccinate every 5-10 years and provide annual influenza vaccination. 1
• Educate patients about overwhelming post-splenectomy infection risk and need for immediate medical attention with fever. 1, 2

Key Pitfalls to Avoid

• Never rely on antibiotics alone for less than 12-20 weeks total duration, as premature discontinuation leads to relapse. 8, 4
• Do not pursue aggressive surgical intervention for multiple abscesses in stable patients with melioidosis, as conservative management is highly effective. 3
• Maintain heightened vigilance for disseminated disease involving liver, lungs, brain, or bones. 4, 5
• Ensure microbiology laboratory correctly identifies B. pseudomallei rather than reporting it as Pseudomonas species. 7