Brain abscess

Background

• Caused by one of three methods:
  • Hematogenous spread (33%)
  • Contiguous infection from middle ear, sinus, teeth (33%)
  • Direct implantation by surgery or penetrating trauma (10%)
• Microbiology
  • Anaerobes and Gram-negative rods are typical pathogens
  • Staph is involved with direct implantation cases

Clinical Features

• Pts rarely appear acutely ill
• Classic traid of HA, fever, AND focal neuro deficit is present in <33%
  • Headache is most common symptom (present in almost all cases)
  • Fever (~50% of pts)
• Focal neuro symptoms or seizure (~33% of pts)
• Neck stiffness (<50% of pts)
• Signs of increased ICP: vomiting, confusion, obtundation (50% of pts)

Differential Diagnosis

• CVA
• Meningitis
• Malignancy

Intracranial Mass

• Intracranial hemorrhage
  • Intra-axial
    • Hemorrhagic stroke (Spontaneous intracerebral hemorrhage)
    • Traumatic intracerebral hemorrhage
  • Extra-axial
    • Epidural hemorrhage
    • Subdural hemorrhage
    • Subarachnoid hemorrhage (aneurysmal intracranial hemorrhage)
• Brain tumor
• Brain abscess
• Subdural empyema
• Epidural abscess (intracranial)

Diagnosis

Workup

• Head CT with contrast
• Blood cultures

Evaluation

• CT with contrast
  • Ring enhancing lesion surrounding low-density center surrounded by white matter edema
  • Early in course ring may be less defined; CT may only show area of focal hypodensity

Treatment

Antibiotics

Otogenic source

• Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr

Sinogenic or odontogenic source

• Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr

Penetrating trauma or neurosurgical procedures

• Vancomycin 15mg/kg IV q12hr + ceftazidime 2gm IV q8hr

Hematogenous source

• Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr

No obvious source

• Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr

Disposition

• Neurosurgery consultation