Upload
fitrie-desbassarie
View
31
Download
3
Tags:
Embed Size (px)
DESCRIPTION
radiologi. brain. abscess
Citation preview
24/7/2013 1Brain Abscess
Definition
04/17/23 Brain Abscess 2
ETIOLOGY
1.Infection :
•Infection spread by either direct or through veins
(thrombophlibitis of diploic vein)
•Characterized by solitary and located superficially
04/17/23 3Brain Abscess
PREDISPOSING CONDITION & LOCATION OF PREDISPOSING CONDITION & LOCATION OF BRAIN ABSCESSBRAIN ABSCESS
Otitis/mastoiditis Temporal lobe, Cerebellum
Frontal/ethmoid sinusitis Frontal lobe
Sphenoidal sinusitis Frontal lobe,
Sella turcica
Dental infection Frontal > temporal lobe.
Remote source Middle cerebral artery distribution (often multiple)
PATHOGENESISPATHOGENESIS
• Direct spread from contiguous foci (40-50%)
• Hematogenous (25-35%)
• Penetrating trauma/surgery (10%)
• Cryptogenic (15-20%)
Predisposing Conditions & Microbiology of Predisposing Conditions & Microbiology of Brain AbscessBrain Abscess
Predisposing Condition Usual Microbial Isolates
Otitis media or mastoiditis Streptococci (anaerobic or aerobic), Bacteroides and Prevotella spp., Enterobacteriaceae
Sinusitis (frontoethmoid or sphenoid) Streptococci, Bacteroides spp., Enterobacteriaceae, Staph. aureus, Haemophilus spp.
Dental sepsis Fusobacterium, Prevotella and Bacteroides spp., streptococci
Penetrating trauma or postneurosurgical S. aureus, streptococci, Enterobacteriaceae, Clostridium spp.
PPID,2000
PREDISPOSING CONDITION USUAL MICROBIAL ISOLATES
Lung abscess, empyema, bronchiectasis Fusobacterium, Actinomyces, Bacteroides Prevotellaspp., streptococci, Nocardia
Bacterial endocarditis S. aureus, streptococci
Congenital heart disease Streptococci, Haemophilus spp.
Neutropenia Aerobic gram-negative bacilli, Aspergillus Mucorales, Candidaspp.
Transplantation Aspergillus spp., Candida spp., Mucorales, Enterobacteriaceae, Nocardia spp., Toxoplasma gondii
HIV infection Toxoplasma gondii, Nocardia spp., Mycobacterium spp., Listeria monocytogenes, Cryptococcus
neoformans
PPID, 2000
• 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
04/17/23 Brain Abscess 8
LOCATION & CLINICAL FEATURESLOCATION & CLINICAL FEATURES • FRONTAL LOBE: H/A, drowsiness, inattention,
hemiparesis, motor speech disorder, AMS
• TEMPORAL LOBE: Ipsilateral H/A, aphasia, visual field defect
• PARIETAL LOBE: H/A, visual field defects, endocrine disturbances
• CEREBELLUM: Nystagmus, ataxia, vomiting, dysmetria
DIFFERENTIAL DIAGNOSISDIFFERENTIAL DIAGNOSIS
• Malignancy– Abscess has hypo-dense center, with surrounding smooth, thin-walled
capsule, & areas of peripheral enhancement. – Tumor has diffuse enhancement & irregular borders.– SPECT (PET scan) may differentiate. CRP too?
• CVA• Hemorrhage• Aneurysm• Subdural empyema/ICEpidural abscess
DIAGNOSISDIAGNOSIS
• High index of suspicion• Contrast CT or MRI• Drainage/biopsy, if ring enhancing
lesion(s) are seen
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) : Necrotic tissue ,local inflammatory response, marked edema This stage there is no demarcation between the lesion and surrounding brain
2.stage two (late cerebritis)(day 4-10):
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)
04/17/23 12Brain Abscess
04/17/23 Brain Abscess 13
04/17/23 Brain Abscess 14
04/17/23 Brain Abscess 15
04/17/23 Brain Abscess 16
04/17/23 Brain Abscess 17
04/17/23 18Brain Abscess
Radiological characteristic1. Brain CTS with contrast
• ring enhancement • Multi loculation • Multiplicity• Finding of gas
2. MRI : • T1 :
• necrotic center ( hypointence) • Capsule ( hyperintence)• Edema ( hypointence)
• T2 :• necrotic center ( hyperintence) • Capsule ( hypointence)• Edema ( hyperintence
04/17/23 Brain Abscess 19
04/17/23 Brain Abscess 20
Brain abscess. Axial fluid-attenuated inversion recovery (FLAIR) MRI of a left occipital-parietal brain abscess. The edema pattern (white arrows)
surrounds the central abscess (A). A secondary (daughter) abscess is
noted anterior to the primary abscess cavity.
04/17/23 Brain Abscess 21
Brain abscess. Sagittal T1-weighted spin-echo
gadolinium-enhanced MRI demonstrates an enhanced mass within the right medial cerebellum (yellow arrow).
The thick-walled cystic mass was opened. Nocardia
organisms were cultured from within the abscess.
04/17/23 Brain Abscess 22
Brain abscess. Axial T2-weighted MRI in a patient with a right
frontal abscess. Note the mass effect and surrounding edema.
The wall of the abscess is relatively thin (black
arrows).
04/17/23 Brain Abscess 23
Brain abscess. Gadolinium-enhanced coronal T1-weighted MRI in a patient who presented
with headache, fever, and diplopia. The right frontal lobe
of the brain is shifted across the midline (double arrow) by an
intracranial abscess (single black arrow) that has extended upward from the medial right orbit and medial ethmoid air cells (curved dotted arrow). Aspergillus organisms were
recovered from the sinuses and brain tissue.
04/17/23 Brain Abscess 24
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
04/17/23 Brain Abscess 25
Before Rx
After completion of Rx
Armstrong ID,Mosby inc 1999
04/17/23 Brain Abscess 27