What is the proper evaluation of an anal abscess before incision and drainage (I&D)?

From the Guidelines

Proper evaluation of an anal abscess before incision and drainage (I&D) should include a thorough history and physical examination, focusing on symptoms, duration, associated conditions, and risk factors, as suggested by the WSES-AAST guidelines 1. The physical exam should assess the perianal region for swelling, erythema, fluctuance, and tenderness, with digital rectal examination to evaluate for deeper abscesses when appropriate. Some key points to consider in the evaluation include:

• Collecting a focused medical history and performing a complete physical examination, including a digital rectal examination 1
• Checking serum glucose, hemoglobin A1c, and urine ketones to identify undetected diabetes mellitus 1
• Requesting complete blood count, serum creatinine, and inflammatory markers in patients with signs of systemic infection or sepsis 1
• Considering imaging investigations such as MRI, CT scan, or endosonography in cases of atypical presentation or suspicion of occult supralevator abscesses, complex anal fistula, or perianal Crohn’s disease 1
• Evaluating patients with significant comorbidities like diabetes, immunosuppression, or inflammatory bowel disease more carefully 1
• Considering preoperative antibiotics in patients with systemic signs of infection, valvular heart disease, or immunocompromise 1 The rationale for thorough evaluation is to ensure appropriate surgical planning, identify underlying conditions that may affect healing, and reduce the risk of recurrence or complications such as fistula formation. In terms of management, incision and drainage is recommended for anorectal abscesses, with the timing based on the presence and severity of sepsis 1. Additionally, antibiotics may be considered in patients with drained anorectal abscess and signs of sepsis, surrounding soft tissue infection, or disturbances of the immune response 1. Overall, a thorough evaluation and appropriate management are crucial to reduce morbidity, mortality, and improve quality of life in patients with anal abscesses.

From the Research

Evaluation of an Anal Abscess

Before incision and drainage (I&D) of an anal abscess, several factors should be assessed and evaluated, including:

• The presence of a fistula, as anal abscesses are often associated with fistulas, with a reported incidence of up to 40% 2, 3
• The location and size of the abscess, as well as the presence of any signs of sepsis or systemic infection
• The patient's medical history, including any previous anal surgery or conditions that may affect healing, such as diabetes or immunosuppression
• The patient's symptoms, including pain, discharge, and any changes in bowel habits

Assessment and Evaluation

The assessment and evaluation of an anal abscess should include:

• A thorough physical examination, including a digital rectal examination (DRE) to assess for any masses, tenderness, or fistulas
• Imaging studies, such as ultrasound or MRI, to confirm the diagnosis and evaluate the extent of the abscess
• Laboratory tests, such as complete blood count (CBC) and blood cultures, to rule out systemic infection

Considerations for I&D

Before proceeding with I&D, the following considerations should be taken into account:

• The risk of recurrence and fistula formation, which can be reduced with adequate drainage and treatment of any associated fistula 4, 5
• The potential for antibiotic use to reduce the risk of fistula formation, although the evidence is still limited and controversial 6
• The importance of careful patient selection and tailored treatment approaches to minimize the risk of complications, such as fecal incontinence 5, 3

Key Factors to Evaluate

Key factors to evaluate before I&D of an anal abscess include:

• The presence of a fistula and its location and complexity
• The patient's overall health and medical history
• The size and location of the abscess and any signs of sepsis or systemic infection
• The potential benefits and risks of antibiotic use and fistula treatment
• The need for careful patient selection and tailored treatment approaches to minimize complications and optimize outcomes 4, 2, 6, 5, 3