Brain Abscess - Diagnosis and Management (ESCMID 2024)

Algorithm Steps

1. ▶

   Start

   Suspected Brain Abscess

   Ring-enhancing lesion on imaging with clinical signs of infection

   1. ●

      Action

      Assess Clinical Presentation

      Classic triad: headache, fever, focal neurological deficit (present in <50%)

      • Headache (most common symptom)
      • Fever (may be absent)
      • Focal neurological deficits
      • Altered mental status
      • Seizures (25-35%)
      • Signs of elevated ICP
      1. ●

         Action

         Diagnostic Imaging

         MRI is the imaging modality of choice (ESCMID Strong, High)

         • MRI with contrast preferred
         • DWI: restricted diffusion in abscess cavity
         • Ring-enhancing lesion with central necrosis
         • Surrounding vasogenic edema
         • CT if MRI not available
         1. ●

            Action

            Identify Source

            Search for primary infection source

            • Dental infection (examine teeth, panorex)
            • Sinusitis/otitis (CT sinuses/temporal bones)
            • Endocarditis (TTE/TEE, blood cultures)
            • Pulmonary source (chest imaging)
            • Direct spread from trauma/surgery
            • Hematogenous (multiple abscesses)
            1. ◆

               Decision

               Severity Assessment

               Assess for severe disease requiring urgent intervention

               1. ⚠

                  Warning

                  ⚠️ Severe Disease

                  GCS ≤12, herniation signs, rapid deterioration

                  • Large abscess (>2.5 cm)
                  • Significant mass effect
                  • Multiple abscesses
                  • Intraventricular rupture
                  1. ●

                     Action

                     Urgent Neurosurgical Intervention

                     Aspiration or excision within 24h (ESCMID Strong, Low)

                     • Stereotactic aspiration preferred
                     • Craniotomy if superficial/loculated
                     • Send pus for culture (aerobic, anaerobic, fungal, TB)
                     • Gram stain, cell count
                     • May need repeat aspiration
                     1. ●

                        Action

                        Empiric Antibiotic Therapy

                        Start immediately, adjust based on cultures

                        • Ceftriaxone 2g IV q12h + Metronidazole 500mg IV q8h
                        • Add Vancomycin if post-surgical or MRSA risk
                        • Consider Ampicillin if Listeria risk
                        • Duration: 6-8 weeks IV (ESCMID recommendation)
                        • May transition to oral after clinical improvement
                        1. ◆

                           Decision

                           Culture Results Available?

                           Tailor therapy to identified organism

                           1. ●

                              Action

                              Targeted Antibiotic Therapy

                              Adjust based on organism and sensitivities

                              • Streptococcus: Penicillin G or Ceftriaxone
                              • Staphylococcus: Nafcillin (MSSA) or Vancomycin (MRSA)
                              • Anaerobes: Metronidazole
                              • GNR: Based on sensitivities
                              • Nocardia: TMP-SMX
                              1. ●

                                 Action

                                 Monitoring and Follow-up

                                 Serial imaging and clinical assessment

                                 • Repeat MRI at 1-2 weeks, then monthly
                                 • Clinical response expected by 2 weeks
                                 • Complete 6-8 weeks IV antibiotics
                                 • Oral step-down controversial but used
                                 • Address source (dental, sinus, etc.)
                                 1. ✓

                                    Outcome

                                    Resolution vs Reintervention

                                    Repeat aspiration if no improvement; mortality ~10-15%

                           2. ●

                              Action

                              Continue Empiric Therapy

                              If cultures negative, complete empiric course

               2. ●

                  Action

                  Mild-Moderate Disease

                  GCS >12, no herniation, stable

                  1. ◆

                     Decision

                     Abscess Size?

                     Size guides management approach

                     1. ●

                        Action

                        Large Abscess (>2.5 cm)

                        Aspiration recommended for pathogen identification

                        • Stereotactic aspiration
                        • Obtain cultures before antibiotics if possible
                        • May withhold antibiotics <24h if surgery imminent
                        • Send comprehensive cultures
                     2. ●

                        Action

                        Small Abscess (≤2.5 cm)

                        May consider medical management alone

                        • Trial of empiric antibiotics
                        • Serial imaging q1-2 weeks
                        • Aspiration if no response
                        • Close monitoring required