48. Differential diagnosis of brain abscess
•Epidural and subdural empyema
•Septic dural sinus thrombosis
•Mycotic cerebral aneurysms
•Septic cerebral emboli with associated infarction
•Acute focal necrotizing encephalitis (most commonly due to
herpes simplex virus)
•Metastatic or primary brain tumors
•Pyogenic meningitis

50. Dental infection
Frontal or ethmoid
sinuses
Brain Direct
abscess spread
otitis media and
mastoiditis
Post neurosurgery
Bullet wounds

52. Chronic pulmonary
infections
Skin infections
Pelvic infection
Brain Hematogenous Intraabdominal
abscess spread infection
Esophageal dilation and
endoscopic sclerosis of
esophageal varices
Bacterial
Cyanotic endocarditis
congenital
heart diseases

54. Microbiologic pathogens in brain abscesses, according to major primary
source of infection
Source of infection Pathogens
Streptococcus (especially Streptococcus
Paranasal sinuses milleri), haemophilus, bacteroides,
fusobacterium
Streptococcus, bacteroides, prevotella,
Odontogenic sources
fusobacterium, haemophilus
Enterobacteriaceae, streptococcus,
Otogenic sources
pseudomonas, bacteroides
Streptococcus, fusobacterium,
Lungs
actinomyces
Urinary tract Pseudomonas, enterobacter
Staphylococcus aureus, enterobacter,
Penetrating head trauma
clostridium
Staphylococcus, streptococcus,
Neurosurgical procedure
pseudomonas, enterobacter
Endocarditis Viridans streptococcus, S. aureus
Congenital cardiac malformations
Streptococcus
(especially right-to-left shunts)

55. Viridans streptococci
Streptococcus milleri
Streptococcus pneumoniae
Gram-positive
cocci Staphylococcus aureus
Aerobic
Gram-negative Escherichia coli,
rods
Pseudomonas spp,
Klebsiella pneumoniae,
Proteus spp

56. The most frequent anaerobes cultured from a brain
abscess
•anaerobic streptococci.
• Bacteroides spp (including B. fragilis).
•Prevotella melaninogenica.
• Propionibacterium.
•Fusobacterium.
• Eubacterium.
• Veillonella.
•Actinomyces

57. Immunocompromised hosts
•Toxoplasma gondii
•Listeria
•Nocardia asteroides
•Aspergillums'
•Cryptococcus neoformans.
•Coccidioides immitis.
• Mucormycosis

58. CT-Scan
Early cerebritis appears as an irregular area of low
density that does not enhance following contrast
injection.
the lesion enlarges with thick and diffuse ring
enhancement following contrast injection
thin ring which may not be uniform in thickness

59. MRI
•more sensitive for early cerebritis
•more sensitive for detecting satellite lesions
•More accurately
•estimates the extent of central necrosis
•ring enhancement,
•cerebral edema
•Better visualizes the brainstem

60. LP
a lumbar puncture (LP) is contraindicated
Decompression of the cerebrospinal fluid (CSF)
pressure associated with brain stem herniation
in 1.5 to 30 percent of cases

61. Culture and biopsy
•Gram's stain
• aerobic
• anaerobic
• mycobacterial
•fungal culture

62. Antibiotics
•Penicillin G covers most mouth flora including both aerobic and anaerobic
streptococci.
•Metronidazole readily penetrates brain abscesses, Given the excellent
intralesional concentrations and the high probability of anaerobes.
•Ceftriaxone covers most aerobic and microaerophilic streptococci also covers
many Enterobacteriaceae
•Ceftazidime should be used when brain abscess complicates a neurosurgical
procedure or in cases where the abscess culture grows P. aeruginosa.
•Vancomycin should be included when brain abscess follows penetrating head
trauma or craniotomy or when S. aureus bacteremia is documented

63. Aspiration
•preferred for speech areas and regions of the
sensory or motor cortex and in comatose
patients.
•Not preferred for:
•Early cerebritis without evidence of cerebral
necrosis.
•Abscesses located in vital regions of the brain or
those inaccessible to aspiration

64. Surgery
•indications for excision after initial aspiration
and drainage:
•Traumatic brain abscesses (to remove bone chips
and foreign material)
•Encapsulated fungal brain abscesses
•Multiloculated abscesses