Treatment of Hemipelvis Abscess
Surgical drainage is the primary intervention for hemipelvis abscesses, accompanied by appropriate antibiotic therapy covering Staphylococcus aureus, Streptococcus species, and anaerobic organisms. 1
Diagnostic Evaluation
- Obtain blood cultures prior to initiating antibiotics (positive in approximately 28% of abscess cases)
- MRI is the preferred imaging modality for detailed assessment
- Serial imaging (every 2 weeks) is recommended to monitor treatment response
Treatment Algorithm
1. Surgical Management
- Surgical drainage provides definitive source control and allows collection of samples for microbiological analysis
- Options include:
- Percutaneous catheter drainage under CT or US guidance (success rates of 67-82% for retroperitoneal/pelvic abscesses) 2
- Open surgical drainage for complex, multiloculated abscesses or those with fistulous communications
- Collect specimens for aerobic and anaerobic cultures during drainage procedure
2. Antimicrobial Therapy
Initial Empiric Therapy:
- 3rd-generation cephalosporin plus metronidazole 1, 3
- Metronidazole is specifically indicated for intra-abdominal abscesses caused by Bacteroides species, Clostridium species, Eubacterium species, Peptococcus species, and Peptostreptococcus species 3
- For immunocompromised patients: Add trimethoprim-sulfamethoxazole and voriconazole 1
Targeted Therapy:
- Adjust antibiotics based on culture and sensitivity results
- Metronidazole is effective against Bacteroides fragilis infections resistant to clindamycin, chloramphenicol, and penicillin 3
Duration:
- Typically 6-8 weeks total 1
- Initial intravenous therapy followed by oral antibiotics once clinical improvement is observed
Monitoring and Complications
Monitor for signs of treatment failure:
- Persistent fever
- Worsening pain
- Spread of infection to adjacent structures
Potential complications:
- Spread to adjacent structures or retroperitoneal space
- Sepsis
- Neurological deficits due to nerve compression
- Progression to life-threatening infection requiring more extensive surgery 4
Important Considerations and Pitfalls
- Multiloculated abscesses and those with fistulous communications have higher failure rates with percutaneous drainage 2
- Delayed or inadequate surgical debridement can lead to uncontrolled spread of infection, potentially requiring more extensive procedures 4
- Premature discontinuation of antibiotics can lead to treatment failure 1
- In cases where the abscess is related to a prosthetic joint infection, removal of the prosthesis may be necessary to control the infection 4
- For abscesses extending along muscle planes (e.g., psoas, iliacus), drainage may need to address both the primary pelvic focus and the extension 5
Remember that prompt and aggressive treatment is essential, as delayed diagnosis and inadequate treatment can lead to significant morbidity and mortality.