Brain abscesses are collections of infected material within the brain parenchyma that can develop from local or distant infections. They are more common in males under 40 years old in developing countries. Common causes include infections from the sinuses, ears, or lungs. Staphylococcus aureus and streptococci are frequent pathogens, while fungi are rising due to immunosuppression. Patients present with headaches, mental status changes, neurological deficits, and seizures. Diagnosis involves imaging like CT or MRI along with blood and abscess cultures. Treatment is typically antibiotics along with surgical drainage or excision of larger abscesses. Complications include rupture and recurrence, while prognosis has improved but morbidity remains from neurological sequelae.

1. BRAIN ABSCESS
OLUWATAYO SAMUEL
OLUWAKEYE VICTOR TAYO

2. INTRODUCTION
• A brain abscess (or cerebral abscess) is a focal collection within the
brain parenchyma which can arise as a complication of a variety of
infections, trauma, or surgery.
• It results from inflammation and collection of infected material,
coming from local (ear infection, dental abscess, infection of
paranasal sinuses, infection of the mastoid air cells of the temporal
bone, epidural abscess) or remote (lung, heart, kidney etc.) infectious
sources, within the brain tissue.

3. RELEVANT ANATOMY

4. EPIDEMIOLOGY
• Brain abscesses are rare in developed countries but are a significant
problem in developing countries.
• Brain abscesses are more common in males than in females.
• Brain abscesses occur more frequently in the first 4 decades of life.

5. ETIOLOGY
The microbial etiology of brain abscess depends on the
• patient's age,
• site of primary infection, and
• the patient's immune status.

6. ETIOLOGY cont’d
• A significant number of brain abscesses are polymicrobic but the
most common agents are bacterial.
• The predominant organisms include the following:
• Staphylococcus aureus, including methicillin-resistant
• Streptococcus viridans
• Anerobic bacteria
• Etc

7. ETIOLOGY cont’d
• The incidence of fungal brain abscess has been rising as a result of
increased use of corticosteroid therapy, broad-spectrum antimicrobial
therapy, and immunosuppressive agents. Common agents include
• Aspergillus, Candida, Cryptococcus
• Other agents are
• Protozoa e.g. Toxoplasma gondii
• Helminths e.g. Taenia solium
• Co-infection with bacterial, viral, and fungal organisms can occur.

8. PATHOPHYSIOLOGY
• Brain abscess is caused by intracranial inflammation secondary to
infection with subsequent abscess formation.
• Infection may enter the intracranial compartment directly or
indirectly via 3 routes
• Contiguous suppurative focus
• Hematogenous spread from a distant focus
• Trauma

9. PATHOPHYSIOLOGY cont’d
The process of abscess formation occurs in four stages-
• Early cerebritis (days 1–3)
• Late cerebritis (days 4–9)
• Early capsule formation (days 10–13)
• Late capsule formation (>14 days)

10. CLINICAL FEATURES- History
• Most symptoms are a result of the size and location of the space-
occupying lesion or lesions.
• The frequency of common symptoms and signs is as follows:
• Headache - 70%
• Mental status changes (may indicate cerebral edema) - 65%
• Focal neurologic deficits - 65%
• Fever - 50%
• Seizures - 25-35%
• Nausea and vomiting - 40%
• Nuchal rigidity - 25%
• Papilledema - 25%

11. CLINICAL FEATURES- Examination
• On examination, the following signs might be present-
• Low-grade or high-grade fever
• Confusion
• Stupor
• Focal motor or sensory impairments
• General or focal seizures
• Papilledema
• Ataxia
• Hemiparesis
• Neck stiffness

12. INVESTIGATIONS
• FBC count with differential
• Erythrocyte sedimentation rate (ESR)
• Serum C-reactive protein (CRP)
• Serological tests for some pathogens
• Blood cultures for aerobic and anerobic bacteria (at least 2; preferably
before antibiotic usage)
• Abscess aspirate
• Culture
• Histopathological examination
• Lumbar puncture is rarely warranted

13. INVESTIGATIONS cont’d
• CT Scan
• MRI
• Biopsy of cerebral lesion
• Immunochemical tests

14. Brain CT Brain MRI

15. TREATMENTS
• Medical
• Abscesses in a deep or dominant location
• The presence of coexisting meningitis or ependymitis
• Early reduction of abscess with clinical improvement after antimicrobial
therapy
• Abscess size less than 2.5 cm
• Surgical
• Significant mass effect exerted by lesion
• Proximity to ventricles
• Evidence of significant increased intracranial pressure
• Traumatic abscess associated with foreign material

16. TREATMENTS
• Larger than 2.5 cm – excision
• Smaller than 2.5 cm – aspiration for definitive diagnosis
• Empirical ATB – metronidazole + third-generation cephalosporin
• Once the infecting pathogen is isolated, antimicrobial therapy can be
modified for optimal treatment
• Antibiotics optimal duration is about 6 to 8 wks IV followed by oral
antibiotics for 2 to 3 months.

17. TREATMENTS
Surgical therapy –
• Aspiration after bur-hole placement
• Stereotactic aspiration
• Complete excision by craniotomy

18. COMPLICATIONS
• Rupture of abscess into ventricles or subarachnoid space.
• Recurrence of abscess
• Uncal or tonsillar herniation due to increased intracranial pressure
• Long-term neurologic sequelae in 50 percent of patients e.g.
hemiparesis, seizures, etc.

19. PROGNOSIS
• The mortality rate from brain abscess is currently approximately 10%
• However, if the abscess ruptures into the ventricular system, the
mortality rate may be 80%.
• Morbidity in survivors is generally due to residual neurologic defects,
increased incidence of seizures due to scar tissue foci, or
neuropsychiatric changes.

20. THANK YOU