Brain (CNS)
Brain Abscess
뇌농양
Focal pyogenic infection within brain parenchyma
- How common
- Rare (~4/million/yr)
- Typical age
- Ages 30-50
What is it?
Microorganisms from contiguous spread (sinusitis/otitis), hematogenous seeding, or trauma → cerebritis → encapsulated abscess.
Commonly affected: Frontotemporal (sinus), temporal (otitis)
How it develops
- Pathogen entrySinus, dental, endocarditis, trauma
- Early cerebritisFocal inflammation and edema
- Late cerebritis + capsuleNecrotic center + collagen capsule
- Raised ICP/herniationMass effect or rupture
Symptoms
- Headache (most common)Progressive, NSAID-resistant
- Focal deficitLocation-dependent
- SeizureIn 25-35% of patients
- Altered LOCWith raised ICP
- FeverOnly ~50% of patients, often low-grade
How it is examined
- Source searchSinus, dental, ear, cardiac exam
- Blood culturesAssess bacteremia
- HIV/immune workupConsider toxoplasmosis if immunocompromised
Imaging
Contrast-enhanced head CT.
- Ring-enhancing lesion
- Surrounding edema
- Mass effect
Contrast MRI + DWI (restricted diffusion suggests abscess).
- DWI hyperintense (restricted diffusion)
- T2 edema
- Thin uniform ring enhancement
Non-surgical care
- Empiric antibiotics (4-8 wks)Vancomycin + ceftriaxone + metronidazole
- Immunocompromised: cover toxo/nocardiaAdd TMP-SMX
- ICP controlMannitol, dexamethasone (controversial)
- AnticonvulsantsLevetiracetam
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Abscess >2.5 cm, need diagnosis/culture, neurologic deterioration
Procedures that may be discussed
- Stereotactic aspiration (first-line)
- Craniotomy with excision (multiloculated or thick capsule)
- Source control (sinus/dental surgery)
Outlook
Combined antibiotic + surgical mortality 10-15%; delayed diagnosis >60%.