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BRAIN ABSCESS M.RASOOLINEJAD, MD DEPATMENT OF INFECTIOUS DISEASE TEHRAN UNIVERSITY OF MEDICAL SCIENCE BRAIN ABSCESS Focal & Suppurative Process in Brain Parenchyma Anatomical Relationships of the Meninges •Bone •Epidural Abscess •Dura Mater •Subdural Empyema •Arachnoid •Meningitis •Pia Mater •Brain EPIDEMIOLOGY •Uncommon intracranial infections •Incidence 1:100,000/year •Predisposing conditions: Paranasal Sinusitis Otitis Media Dental infections •Immunocompromised 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 ) ETHIOLOGY Most common organisms are : • Paranasal sinusitis:Microaerophilic & Anaerobic strep Haemophilus spp Bacteroides spp Fusobacterium spp • Dental infections: Streptococci spp Prevetella Prophyromanas ETHIOLOGY Most common organisms are : Otitis media & Mastoiditis: Streptococci Bacteroides spp P. aeroginosa Enterobacteriaceae Hematogenous: S. Viridance S. Aureous Neurosergical procedure & open head trauma: (S. aureous, Enterobactericeae, P. aeroginosa) SOURSE OF BRAIN ABSCESS •Frontal lobe: Frontal & Ethmoidal & Sphenoidal sinuses Dental infections •Temporal lobe: Middle ear, Mastoid, Maxillary sinuses •Cerebellum & Brain Stem: Middle ear & Mastoid •Posterior Frontal or Parietal lobes: Middle Cerebral Artery Gray- White matter Often multiple PATHGENESIS •Bacterial invasion of brain (Parenchyma ) •Preexisting or concomitant : Ischemia & Necrosis & Hypoxia of brain tissue PATHGENESIS 4 Stages Brain Abscess formation: Stage 1 Early cerebritis ( days 1 to 3 ) Prevascular infiltration of inflammatory cells Central core of coagulative necrosis Marked edema surrounds the lesions Early Cerebritis Early cerebritis PATHGENESIS 4 Stages Brain Abscess formation: Stage 2 Late cerebritis ( days 4 to 9 ) Pus formation ( necrotic center ) Macrophages & Fibroblastrs Thin capsule ( Fibroblast & Reticular fibers Marked edema around the lesions Late Cerebritis PATHGENESIS 4 Stages Brain Abscess formation: Stage 3 Early Capsule formation ( days 10 to13 ) Capsule formation Ring-enhancing capsule ( Imaging ) 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, Aching sensation Hemicranial or General Progressive Refractory Fever: 50% & Low grade Seizure: New onset Focal or Generalized CLINICAL PRESENTATIONS Increased Intracranial Pressure: •Papilledema •Nausea •Vomiting •Drowsiness •Confusion Meningismus: •When it has ruptured into Ventricle or subarachnoid space CLINICAL PRESENTATIONS Focal neurologic deficit > 60% •Frontal lobe Hemiparesis Mental status, Drowsiness •Temporal lobe Dysphasia Upper homonymous quadrantanopia Ipsilateral headache CLINICAL PRESENTATIONS Focal neurologic deficit > 60% •Cerebellar Nystagmus, Ataxia Dysmetria, vomiting •Brain stem Facial weakness, Fever, Hemiparesis, Dysphagia, Vomiting, Headache, Fever DIAGNOSIS NEUROIMAGING STUDIES •Brain CT- Scan •MRI ( Early cerebritis, Posterior Fossa) •Steriotactic Needle aspiration •Lumbar puncture Risk of Herniation •CSF Non Specific •Peripheral leucocytosis: 50% •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 T. Gondii Encephalitis T. Gondii Encephalitis TREATMENT SURGICOMEDICAL •Aspiration Or Open Drainage •Empirical Combination Antimicrobial Therapy •Duration: 6 to 8 wks IV •Prophylactic Anticonvulsant Therapy •Glucocorticoids( Severe Edema & ICP ) •Serial CT-Scan or MRI ANTIMICROBIAL THERAPY Otitis media & Mastoiditis: rd Metronodazole & 3 Cephalosporin Sinusitis: Metronidazole & 3rd Cephalosporine Dental Sepsis: Penicillin & Metronidazole ANTIMICROBIAL THERAPY Penetrating trauma &Neurosurgury: rd Vancomycin & 3 Cephalosporin Bacterial endocarditis: Vancomycin & Gentamycin Nafcilline (Oxacillin) & Ampicillin & Gentamycin Unknown: Vancomycin & Metronidazole & 3rd Cephalosporin PROGNOSIS Successfully treatment Good prognosis Seizures are a common complication 70% THE END