Brain abscess

Background

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

Clinical Features

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

Diagnosis

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

Work-Up

1. Head CT w/ contrast
2. Blood cx

DDX

1. CVA
2. Meningitis
3. Malignancy

Treatment

1. Abx
   1. Otogenic source
      1. Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr
   2. Sinogenic or odontogenic source
      1. Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr
   3. Penetrating trauma or neurosurgical procedures
      1. Vancomycin 15mg/kg IV q12hr + ceftazidime 2gm IV q8hr
   4. Hematogenous source
      1. Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr
   5. No obvious source
      1. Cefotaxime 2gm IV q6hr + metronidazole 500mg IV q6hr

Disposition

• Neurosurgery consultation

Source

Tintinalli