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brain abscess

Etiology: 1) spread from a contiguous focus of infection a) otitis media, mastoiditis: - Streptococci, Bacteroides, Enterobacteriaceae, Prevotella b) sinusitis: - Streptococci, Bacteroides, Enterobacteriaceae, Staphylococcus aureus, Haemophilus c) dental sepsis: - Streptococci, Bacteroides, Fusobacterium, Prevotella 2) hematogenous spread from distant focus of infection a) lung abscess, empyema, bronchiectasis - Streptococci, Bacteroides, Fusobacterium, Prevotella, Actinomyces, Nocardia b) endcarditis - Streptococci, Staphylococcus aureus c) abdominal infection, pelvic infection, gynecologic infection - enteric gram-negative bacteria, anaerobes 3) penetrating trauma, neurosurgery - Streptococci, Staphylococcus aureus, Enterobacteriaceae, Clostridium 4) idiopathic (10-35%) 5) risk factors - immunocompromised patients, HIV1 infection - Listeriosis, nocardiosis - mycoses - cryptococcosis, coccidioidomycosis, aspergillosis - parasitic infections (toxoplasmosis) Clinical manifestations: - < 50% of patients present with classic triad - headache, fever*, focal neurologic deficit - neck stiffness [1] - symptoms evolve over several hours to days * fever in 25% Special laboratory: - avoid lumbar puncture due to risk of herniation - aspiration of brain abscess for culture (see Management:) Radiology: - brain CT initial diagnostic test (fast) [5] - ring-enhancing lesions include brain abscess [1] - brain magnetic resonance imaging (MRI) a) more sensitive than computed tomography (CT) b) early detection of cerebritis & satellite lesions c) visualizing spread of inflammation into cerebral ventricles & subarachnoid space Differential diagnosis: - meningitis does not present with focal neurologic defects - encephalopathy does not present with focal neurologic defects - stroke evolves over seconds or minutes & does not present with fever Management: 1) neurosurgery - stereotactic aspiration or surgical excision of all lesions > 2.5 cm in diameter 2) empiric antibiotics ASAP a) unknown source: - vancomycin* + metronidazole + 3rd generation cephalosporin# b) spread from a contiguous focus of infection 1] otitis media, mastoiditis: - metronidazole + 3rd generation cephalosporin# 2] sinusitis: - vancomycin* + metronidazole + 3rd generation cephalosporin# 3] dental sepsis: - penicillin + metronidazole c) hematogenous spread from distant focus of infection 1] lung abscess, empyema, bronchiectasis - penicillin + metronidazole + sulfonamide 2] endcarditis - vancomycin + gentamicin 3] abdominal/pelvic/gynecologic infection - metronidazole + 3rd generation cephalosporin# d) penetrating trauma, neurosurgery - vancomycin + 3rd generation cephalosporin# e) immunocompromised patients, HIV1 infection - metronidazole + 3rd generation cephalosporin#, antifungal agent or antiparasitic agent f IV antibiotics continued for 6-8 weeks, followed by prolonged oral therapy if appropriate agent is available [1] 3) successful treatment generally combines surgical drainage with antimicrobial therapy [1] * vancomycin if MRSA suspected # cefotaxime or ceftriazone; cefepime may also be used

Related

triad of brain abscess

General

intracranial abscess

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018, 2021. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Lu CH, Chang WN, Lui CC Strategies for the management of bacterial brain abscess. J Clin Neurosci. 2006 Dec;13(10):979-85. PMID: 17056261
  3. Carpenter J, Stapleton S, Holliman R. Retrospective analysis of 49 cases of brain abscess and review of the literature. Eur J Clin Microbiol Infect Dis. 2007 Jan;26(1):1-11. PMID: 17180609
  4. Helweg-Larsen J, Astradsson A, Richhall H et al Pyogenic brain abscess, a 15 year survey. BMC Infect Dis. 2012 Nov 30;12:332. PMID: 23193986 Free PMC Article
  5. NEJM Knowledge+ Question of the Week. Dec 22, 2020 https://knowledgeplus.nejm.org/question-of-week/5036/ - Brouwer MC et al. Brain abscess. N Engl J Med 2014 Jul 31; 371:447 PMID: 25075836 https://www.nejm.org/doi/full/10.1056/NEJMra1301635