Brain abscess Flashcards
1
Q
What is brain abscess?
A
A suppurative collection of microbes (often bacterial, fungal or parasitic) within a gliotic capsule occurring within the brain parenchyma.
2
Q
What causes brain abscess?
A
Spread of an infection (otitis media, sinusitis, dental infection, meningitis, endocarditis etc.), trauma or surgery to the scalp, penetrating head injuries.
Most common pathogens → viridans streptococci(secondary to sinusitis), staphylococcus aureus
3
Q
What are some risk factors for developing brain abscess?
A
- Right-to-left cardiac shunts
- Bronchiectasis
- Immunosuppression
4
Q
What are the presenting symptoms/ signs of a brain abscess?
A
- Features of raised ICP → nausea, vomiting, papilledema, seizures
- Dull persistent headache (ruptured abscess is associated with sudden worsening of headache and meningism)
- Focal Neurology → 3rd or 6th Cranial Nerve Palsy (secondary to raised ICP)
- CN6 (abducens) is most likely to be compressed due to raised ICP as it has the longest course
- Palsy has affect on ipsilateral side.
Adduction = towards nose. Abduction = towards ear - Positive Kernig or Brudzinski sign
- Classic triad:
Headache + fever + focal neurology = brain abscess
5
Q
What investigations are used to diagnose/ monitor a brain abscess?
A
- MRI with contrast → best initial test. ring-enhancing lesions (IV contrast material cannot pass through capsule; accumulates around lesion= bright ring with dark center
- CT Head (With or Without contrast)
- Elevated ESR & CRP
- Biopsy → best confirmatory test
6
Q
How is a brain abscess managed?
A
- Surgery → craniotomy is performed and the abscess cavity is debrided
- IV Antibiotics → IV 3rd generation cephalosporin (ceftriaxone) + metronidazole
- ICP Management → dexamethasone
- Seizure Prophylaxis → anticonvulsants
7
Q
What complications may arise from brain abscess?
A
- Ishchemia/ necrosis of pituitary= pituitary insufficiency= addisonian crisis
