BRAIN ABSCESS M.RASOOLINEJAD, MD DEPATMENT OF INFECTIOUS DISEASE TEHRAN UNIVERSITY OF MEDICAL SCIENCE

BRAIN ABSCESS Focal& Suppurative Process Suppurative Process in Brain Parenchyma

Anatomical Relationships of the Meninges BoneBone Dura MaterDura Mater ArachnoidArachnoid Pia MaterPia Mater BrainBrain Epidural AbscessEpidural Abscess Subdural EmpyemaSubdural Empyema MeningitisMeningitis

EPIDEMIOLOGY Uncommon intracranial infectionsUncommon intracranial infections Incidence 1:100,000/yearIncidence 1:100,000/year Predisposing conditions: Paranasal SinusitisPredisposing conditions: Paranasal Sinusitis Otitis Media Otitis Media Dental infections Dental infections Immunocompromised pts  Uncommon orgImmunocompromised pts  Uncommon org (T.gondii, Aspergillus spp, Nocardia spp, …)

ETHIOLOGY A brain abscess may develop: 1.Direct spread from a contagious cranial of infections ( Paranasal sinusitis, Otitis media, Mastoiditis,…..) 2. Following head trauma or Neurological procedure 3. Hematogenous spread from remote site of inf 4. No obivious primary source of inf ( 20-30% ) (Cryptogenic brain abscess ) (Cryptogenic brain abscess )

ETHIOLOGY Most common organisms are : Paranasal sinusitis:Microaerophilic &Paranasal sinusitis:Microaerophilic & Anaerobic strep Anaerobic strep Haemophilus spp Haemophilus spp Bacteroides spp Bacteroides spp Fusobacterium spp Fusobacterium spp Dental infections: Streptococci sppDental infections: Streptococci spp Prevetella Prevetella Prophyromanas Prophyromanas

ETHIOLOGY Most common organisms are : Otitis media & Mastoiditis: Streptococci Streptococci Bacteroides spp Bacteroides spp P. aeroginosa P. aeroginosa Enterobacteriaceae Enterobacteriaceae Hematogenous: S. Viridance S. Aureous S. Aureous Neurosergical procedure & open head trauma : (S. aureous, Enterobactericeae, P. aeroginosa)

SOURSE OF BRAIN ABSCESS Frontal lobe: Frontal & Ethmoidal & Sphenoidal sinusesFrontal lobe: Frontal & Ethmoidal & Sphenoidal sinuses Dental infections Dental infections Temporal lobe : Middle ear, Mastoid, Maxillary sinusesTemporal lobe : Middle ear, Mastoid, Maxillary sinuses Cerebellum & Brain Stem: Middle ear & MastoidCerebellum & Brain Stem: Middle ear & Mastoid Posterior Frontal or Parietal lobes:Posterior Frontal or Parietal lobes: Middle Cerebral Artery Middle Cerebral Artery Gray- White matter Gray- White matter Often multiple Often multiple

PATHGENESIS Bacterial invasion of brainBacterial invasion of brain (Parenchyma ) (Parenchyma ) Preexisting or concomitant :Preexisting or concomitant : Ischemia & Ischemia & Necrosis & Necrosis & Hypoxia of brain tissue Hypoxia of brain tissue

PATHGENESIS 4 Stages Brain Abscess formation:  Early cerebritis ( days 1 to 3 )  Prevascular infiltration of inflammatory cells  Central core of coagulative necrosis  Marked edema surrounds the lesions Stage 1

Early Cerebritis

Early cerebritis

PATHGENESIS 4 Stages Brain Abscess formation:  Late cerebritis ( days 4 to 9 )  Pus formation ( necrotic center )  Macrophages & Fibroblastrs  Thin capsule ( Fibroblast & Reticular fibers )  Marked edema around the lesions Stage 2

Late Cerebritis

PATHGENESIS 4 Stages Brain Abscess formation:  Early Capsule formation ( days 10 to13 )  Capsule formation  Ring-enhancing capsule ( Imaging ) Stage 3

Early Capsule formation

PATHGENESIS 4 Stages Brain Abscess formation: Stage 4  Late Capsule formation ( > 14 days )  Well formed necrotic center  Dense peripheral collagenous capsule  No cerebral edema  Marked gliosis & reactive astrocytes  Gliosis  Seizures

CLINICAL PRESENTATIONS Brain abscess presents as an Expanding Intracranial mass  Headache > 75% Constant, Dull, Constant, Dull, Aching sensation Aching sensation Hemicranial or General Hemicranial or General Progressive  Refractory Progressive  Refractory  Fever: 50% & Low grade  Seizure: New onset Focal or Generalized Focal or Generalized

CLINICAL PRESENTATIONS  Increased Intracranial Pressure: PapilledemaPapilledema NauseaNausea VomitingVomiting DrowsinessDrowsiness ConfusionConfusion  Meningismus: When it has ruptured intoWhen it has ruptured into Ventricle or subarachnoid space Ventricle or subarachnoid space

CLINICAL PRESENTATIONS  Focal neurologic deficit > 60% Frontal lobe  HemiparesisFrontal lobe  Hemiparesis Mental status, Drowsiness Mental status, Drowsiness Temporal lobe  DysphasiaTemporal lobe  Dysphasia Upper homonymous quadrantanopia Ipsilateral headache

CLINICAL PRESENTATIONS  Focal neurologic deficit > 60% Cerebellar  Nystagmus, AtaxiaCerebellar  Nystagmus, Ataxia Dysmetria, vomiting Dysmetria, vomiting Brain stem  Facial weakness,Brain stem  Facial weakness, Fever, Hemiparesis, Dysphagia, Vomiting, Headache, Fever

DIAGNOSIS NEUROIMAGING STUDIES Brain CT- ScanBrain CT- Scan MRI ( Early cerebritis, Posterior Fossa)MRI ( Early cerebritis, Posterior Fossa) Steriotactic Needle aspirationSteriotactic Needle aspiration Lumbar puncture  Risk of HerniationLumbar puncture  Risk of Herniation CSF  Non SpecificCSF  Non Specific Peripheral leucocytosis: 50%Peripheral leucocytosis: 50% Elevated ESR: 60%Elevated ESR: 60%

Left parietal abscess

Marked edema

Ring Enhancement

Multiple abscess in a 6 years old boy

Presumed source of polymicrobial abscess

Cerebellar Abscess

Mixed Abscess Location

T. Gondii Encephalitis

TREATMENT SURGICOMEDICAL Aspiration Or Open DrainageAspiration Or Open Drainage Empirical CombinationEmpirical Combination Antimicrobial Therapy Antimicrobial Therapy Duration: 6 to 8 wks IVDuration: 6 to 8 wks IV Prophylactic Anticonvulsant TherapyProphylactic Anticonvulsant Therapy Glucocorticoids ( Severe Edema & ICP )Glucocorticoids ( Severe Edema & ICP ) Serial CT-Scan or MRISerial CT-Scan or MRI

ANTIMICROBIAL THERAPY  Otitis media & Mastoiditis: Metronodazole & 3 rd Cephalosporin Metronodazole & 3 rd Cephalosporin  Sinusitis: Metronidazole & 3 rd Cephalosporine Metronidazole & 3 rd Cephalosporine  Dental Sepsis: Penicillin & Metronidazole Penicillin & Metronidazole

ANTIMICROBIAL THERAPY  Penetrating trauma & Neurosurgury: Vancomycin & 3 rd Cephalosporin Vancomycin & 3 rd Cephalosporin  Bacterial endocarditis: Vancomycin & Gentamycin Vancomycin & Gentamycin Nafcilline (Oxacillin) & Ampicillin Nafcilline (Oxacillin) & Ampicillin & Gentamycin & Gentamycin  Unknown: Vancomycin & Metronidazole & Vancomycin & Metronidazole & 3 rd Cephalosporin 3 rd Cephalosporin

PROGNOSIS Successfully treatment  Good prognosis Good prognosis Seizures are a common complication 70% common complication 70%

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