Management of Abdominal Abscesses

Causes of Abscess Expansion

• Incomplete drainage of the abscess cavity can lead to ongoing infection, according to the World Journal of Emergency Surgery guidelines 1, 2
• Multiloculated abscesses with multiple compartments that aren't fully accessed during drainage can cause treatment failure, as reported by the World Journal of Emergency Surgery 2
• Persistent underlying disease, such as Crohn's disease or diverticulitis, can contribute to abscess expansion, as noted by the World Journal of Emergency Surgery 2
• Enteric fistulae can allow continuous bacterial seeding, leading to abscess growth, as described by the World Journal of Emergency Surgery 2
• Risk factors for fistula formation include bowel wall thickness, disease length, and bowel dilation, according to the World Journal of Emergency Surgery 2
• Resistant organisms, such as ESBL-producing E. coli and resistant Bacteroides fragilis, can emerge and contribute to treatment failure, as reported by Clinical Microbiology and Infection 3
• Candida species can be an overlooked component in polymicrobial abscesses, as noted by Critical Care 4
• Inadequate antifungal therapy can lead to disseminated infection and abscess expansion, as reported by Critical Care 4
• Risk factors for fungal infection include prior antibiotic use, immunosuppression, and disruption of gastrointestinal microbiome, according to Critical Care 4

Abscess Characteristics and Treatment Outcomes

• Larger abscesses (> 6 cm) are more difficult to drain completely, as reported by the World Journal of Emergency Surgery 2
• Drainage catheter issues, such as malposition, occlusion, or premature removal, can lead to treatment failure, as noted by the World Journal of Emergency Surgery 2
• Multiple drainage procedures may be required in 8-20% of patients due to initial failure, according to the World Journal of Emergency Surgery 2
• Poor drug penetration and underdosing can impede antibiotic effectiveness, as reported by Critical Care 4
• Volume of distribution changes can significantly increase in intra-abdominal disease, especially in critically ill patients, as noted by Critical Care 4

Diagnostic Evaluation

• The World Journal of Emergency Surgery recommends using CT scan with IV contrast as the preferred imaging modality to assess abscess size, location, and complexity, identify the presence and characteristics of the fistula, and evaluate surrounding structures 5, 6
• Laboratory evaluation should include complete blood count, inflammatory markers, serum creatinine and electrolytes, and blood cultures if sepsis is suspected, as recommended by the World Journal of Emergency Surgery 5, 7

Treatment Guidelines

• For abscesses <4-5 cm without fistula, antibiotic therapy alone may be sufficient, according to the World Journal of Emergency Surgery 8
• For abscesses >4-5 cm or any abscess with fistula, drainage is essential, as recommended by the World Journal of Emergency Surgery 5, 6
• Initial empiric therapy should cover gram-negative bacteria and anaerobes, with piperacillin/tazobactam 4.5g IV every 6 hours as the first-line option, as recommended by the World Journal of Emergency Surgery 5
• Alternative options include ertapenem 1g IV daily and eravacycline 1 mg/kg IV every 12 hours, as recommended by the World Journal of Emergency Surgery 5
• For septic shock, meropenem 1g IV every 6 hours by extended infusion or continuous infusion, and imipenem/cilastatin 500 mg IV every 6 hours by extended infusion are recommended, as per the World Journal of Emergency Surgery 5
• For documented beta-lactam allergy, eravacycline 1 mg/kg IV every 12 hours or tigecycline 100 mg loading dose, then 50 mg IV every 12 hours are recommended, as per the World Journal of Emergency Surgery 5
• Fluconazole is appropriate for small, uncomplicated abscesses with susceptible Candida albicans, with a recommended standard dosing of 400mg daily (6-12 mg/kg) 9
• First-line therapy for Candida albicans includes echinocandins (caspofungin, micafungin, or anidulafungin) for critically ill patients, as recommended by the Infectious Diseases Society of America and the International Society for Antimicrobial Chemotherapy 9, 10
• Penicillin VK is appropriate for Lactobacillus infections, as Lactobacillus is generally susceptible to penicillins 9

Abscess Size and Treatment

6, 2

Surgical Intervention

• Surgical intervention may be considered for complex or recurrent abscesses, as reported by the World Journal of Emergency Surgery 1
• Fistula management may involve placing a loose draining seton for fistulas involving sphincter muscle, as described by the World Journal of Emergency Surgery 7
• Consider surgical intervention for enteric fistulae, as noted by the World Journal of Emergency Surgery 2
• For low anal fistula not involving sphincter muscle, consider fistulotomy at the time of abscess drainage, as recommended by the World Journal of Emergency Surgery 7
• For fistula involving sphincter muscle, place a loose draining seton, as recommended by the World Journal of Emergency Surgery 7

Duration of Therapy and Follow-up

• The duration of therapy should be 4 days in immunocompetent, non-critically ill patients if source control is adequate, and up to 7 days in immunocompromised or critically ill patients, as recommended by the World Journal of Emergency Surgery 5
• With adequate source control, 4-7 days of antimicrobial therapy after drainage may be sufficient, but therapy should continue until clinical signs of infection have resolved, as noted in the Clinical Infectious Diseases guidelines 9
• Without adequate source control or in immunocompromised patients, a longer duration of therapy (up to 14 days or more) may be necessary, with regular reassessment using imaging to confirm resolution, according to the World Journal of Emergency Surgery guidelines 2
• Close clinical monitoring is mandatory, and patients who have ongoing signs of infection beyond 7 days warrant diagnostic re-investigation, as recommended by the World Journal of Emergency Surgery 5
• Follow-up imaging should be considered to confirm resolution of the abscess, and patients should be informed about warning signs that would necessitate re-evaluation 2
• Identifying and addressing any underlying cause of the abscess is crucial for preventing recurrence, as recommended by the World Society of Emergency Surgery (WSES) 6
• Higher recurrence rates (up to 44%) have been reported for certain types of abscesses, with patients having enteric fistulae at particularly high risk of recurrence and may require surgical intervention, as noted in the World Journal of Emergency Surgery 2
• Failure to treat fungal components can lead to disseminated infection and fungemia, emphasizing the importance of antifungal therapy in polymicrobial abscesses containing Candida, as recommended by the Infectious Diseases Society of America 9
• Inadequate source control can render antimicrobial therapy ineffective, highlighting the need for proper drainage of abscesses >3 cm, as recommended by the World Journal of Emergency Surgery guidelines 2
• Premature discontinuation of therapy can lead to treatment failure, and overlooking the fungal component can result in disseminated infection, emphasizing the importance of comprehensive treatment, including antifungal therapy, as noted in the Clinical Infectious Diseases guidelines 9