• Clinical science

Brain abscess


A brain abscess is a focal, suppurative lesion that may occur in one or more regions of the brain. It may be caused by the direct spread of sinus, ear, and/or dental infections, inoculation of pathogens following open skull fractures, and/or hematogenous spread from infective foci. During the course of the disease, the infected brain tissue softens and is subsequently encapsulated by granulation tissue. Clinical manifestations include headache, fever, neurological deficits, seizures, nausea, vomiting, and other features of raised intracranial pressure. Given these clinical findings, the main differential diagnosis is primary or metastatic brain tumor. Contrast CT reveals an intraparenchymal lesion with a hypodense center and peripheral ring enhancement. Treatment of brain abscesses involves surgical drainage of the abscess followed by systemic antibiotic therapy.



  • Initial infection: entry of pathogens via contiguous spread, direct inoculation, or hematogenous spread can result in the following [2]
    • Early cerebritis
    • Late cerebritis
      • Occurs after 2–3 weeks
      • Necrosis, liquefaction, and infiltration of macrophages
      • Eventually results in the formation of a fibrotic capsule around the lesion
    • Spread patterns
      • Hematogenous spread of pathogens is associated with multiple brain abscesses.
      • Single abscess is associated with contiguous spread (e.g., otits media/mastoiditis).
  • Common sites of contiguous spread [3]

Clinical features

Clinical features depend on the size and location of the lesion. [4]


Differential diagnoses

Other intracranial lesions with ring enhancement:

The differential diagnoses listed here are not exhaustive.



  • If treated early
    • High survival rates
    • Low rates of residual neurological sequelae
  • Multiple, deep, ruptured, or inadequately treated abscesses have a poor prognosis.
  • 1. Patel K, Clifford DB. Bacterial Brain Abscess. Neurohospitalist. 2014; 4(4): pp. 196–204. doi: 10.1177/1941874414540684.
  • 2. Gaillard F et al. Brain abscess. https://radiopaedia.org/articles/brain-abscess-1. Updated January 1, 2017. Accessed February 20, 2017.
  • 3. Williams NS, Bulstrode C, O'Connell PR. Bailey & Love's Short Practice of Surgery. Boca Raton, FL : CRC Press; 2013.
  • 4. Muzumdar D, Jhawar S, Goel A. Brain abscess: An overview. Int J Surg. 2010. doi: 10.1016/j.ijsu.2010.11.005.
last updated 09/08/2020
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