Dr. Amanj Burhan specialist Neurosurgeon

04/18/23 1Brain Abscess

• INCIDENCE:• ETIOLOGY• MICROBIOLOGY• PATHOGENESIS• CLINICAL PRESENTATION• DIAGNOSIS• MANAGEMENT• OUTCOME

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INCIDENCE

• Is 1-2% of SOL in brain (USA)• Is 8% (INDIA)• Decreased incidence (because of antibiotic

and improved life)• Lastly increased incidence because of

opportunistic infection in immune compromised patient .

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ETIOLOGY

1.Infection :

From PNS ,middle ear and mastoid

Characterized by solitary and located superficially

Infection spread by either direct or through veins(thrombophlibitis of

diploic vein)

PNS (frontal and temporal lobe )

Middle ear (temporal lobe)

mastoid (temporal lobe and cerebellum)

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2. Heamatogenous

•hematogenous dissemination microorganism from remote site of infection •The abscess are multiple and deeply located •Mostly located in the frontal and parietal lobe?•Primary foci include (skin pustule ,pulmonary infection , diverticulitis …etc.•In Cyanotic cong. Heart dis. Brain abscess is leading cause of mortality and morbidity •Most common type of CHD. Is TOF 50%•Brain abscess in CHD are generally solitary

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3. Penetrating trauma :

A. Penetrating trauma are seen occur soon or

after years from trauma.

Contaminated bone fragments and debris

provide anidus for infection

Bullet cause brain abscess or not ?

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B. Basal skull fracture with CSF leak and

meningitis cause post traumatic abscess

•Brain abscess from penetrating trauma is

preventable or not?

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4.Previous craniotomyBecause of :

A. Introduce of M.O.at time of surgeryB. Spread of M.O. intracranialy through the woundC. Bone flap infection

5. Immune compromised person

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MICROBIOLOGY•Otogenic and dental infection caused by anaerobic organism •Sinusitis caused by staph aureus, aerobic streptococci • CHD caused by strep. SPP.•In immune deficiency caused by fungus •In AIDS by toxoplasma gondi •Incidence of –ve culture is 25-30%

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PATHOGENESIS AND HISTOPATHOLOGY OF BRAIN ABSCESS

• Preceding antibody formation there is an area of necrosis which is seeded by bacteria

• Brain abscess formation are 4 stages 1.stage I:early cerebritis (day 1 to day 3)

characterized by necrotic tissue ,local inflammatory response, marked edema This stage there is no demarcation between the lesion and surrounding brain

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2.stage two (late cerebritis)(day 4-10):

characterized by : pus , maximum edema

3.stage three (early encapsulation)(day10—13)

Capsule limits spread of infection

Capsule develops slowly in medial wall of abscess?

4.Stage four: late capsule stage ( day 14 and on )

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• Symptoms : 1. Head ache ( 90 %) 2. Change in conscious level ( 60 %) 3. FND ( 60 %)

Parietal lobe : hemiparesis Temporal lobe : dysphasia Cerebellar : ataxia and nystagmus

4.Fever (more than 50 %) 5. Nausea and vomiting ( 50 %) 6. Seizure ( 50 %) 7.Papilledema and meningismus

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Laboratory findings

1. WBC : normal or mild increase 2. ESR : increase in 90%3. CSF : not specific

1. Opening pressure 2. Protein 3. Glucose 4. Culture

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4. radiological characteristic of brain abscess1.Brain CTS with contrast

• ring enhancement • Multi loculation • Multiplicity• Finding of gas

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• MRI : • T1 :

• necrotic center ( hypointence) • Capsule ( hyperintence)• Edema ( hypointence)

• T2 :• necrotic center ( hyperintence) • Capsule ( hypointence)• Edema ( hyperintence

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Management

1. Antibiotic therapy : • Antibiotic is mandatory and should given • Antibiotics depends on C/S• Imperial treatment depend on the etiology

– Sinusitis : ( penicillin + metronidazole )– Otitis : ( penicillin + metronidazole + 3rd generation cephalosporin)– Metastatic abscess :(metronidazole + 3rd generation cephalosporin)– Post traumatic abscess ( vancomycin)

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• Advantage of antibiotic therapy • Small size • Deep seated •Multiple

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2. Aspiration : •Advantages : 1.Confirm diagnosis 2.Remove of purulent material 3.Provide environment for antibiotics to work4.Provide immediate relief of IICP•Stereotactic guided aspiration

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3.Excision of brain abscess •Advantages

1.Traumatic abscess ( contain foreign body and bone fragment )2.Fungal abscess 3.Gas containing abscess

•Disadvantages

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Follow up •CT weekly during antibiotic therapy•And then monthly CT •2-3 week decrease size of abscess •3-4 months complete resolution of abscess• 6-9 months no residual contrast enhancement

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Outcome of abscess :

Mortality influenced by ( herniation , rupture of

abscess to the ventricle , clinical course of

the patient, type of abscess, neurological

state of patient at time of diagnosis)

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1. Long term morbidity : ( seizure , FND, Cognitive dysfunction)

2. Recurrence: ( 5-10%) causes ( inadequate antibiotic therapy, incorrect choice of AB, presence of foreign body , failure to eradicate source of the abscess)

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