brain abscess explained in details, management

Brain abscess

1. BENJAMIN KIZITO BIRUNGI BRAIN ABSCESS, INTRACRANIAL SEPSIS, SUBDURAL AND EPIDURAL EMPYEMA 11/14/2018 1 Brain Abscess

2. BRAIN ABSCESS By the end of this session you will be able to: Describe the stages of development and pathogenesis of brain abscesses Identify the typical spectrum of pathogens implicated in the aetiology of brain abscess Define the nonspecific nature of the clinical features of brain abscess List the appropriate investigation of possible brain abscess and to identify the important radiological features on CT and MR scanning Develop a management plan for patients with brain abscess, including antimicrobial treatment, surgical interventions and adjunctive therapies 11/14/2018 Brain Abscess 2

3. INCIDENCE: ETIOLOGY MICROBIOLOGY PATHOGENESIS CLINICAL PRESENTATION DIAGNOSIS MANAGEMENT OUTCOME 11/14/2018 3 Brain Abscess

4. 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 . 11/14/2018 4 Brain Abscess

5. ETIOLOGY To establish intracranial infection, bacteria reach the brain via three main routes: Extension from a contiguous focus of infection , typically the middle ear or paranasal sinuses Haematogenous (metastatic) spread  from a distant extracranial source Direct inoculation following neurosurgery or penetrating trauma 11/14/2018 5 Brain Abscess

6. 11/14/2018 6 Brain Abscess Otogenic and paranasal sinus

7. Hematogenous spread 11/14/2018 Brain Abscess 7 Typically, multiple or multi- loculated abscesses are seen, occurring predominantly within the territory of the middle cerebral artery, often at the grey white matter interface where blood flow is most marginal

8. Hematogenous : other sources 11/14/2018 Brain Abscess 8

9. Penetrating trauma 11/14/2018 Brain Abscess 9

10. Whilst in immunocompetent individuals brain abscess are usually caused by pyogenic bacteria, in the immunosuppressed , a much broader array of organisms is implicated. These include: Toxoplasma gondi (shown below) Aspergillus species Candida species Nocardia Mycobacterium tuberculosis 11/14/2018 10 Brain Abscess Brain Abscesses in Immunosuppressed Patients

11. PATHOGENESIS AND HISTOPATHOLOGY OF BRAIN ABSCESS Brain abscesses occur at focal points of bacterial multiplication within the brain parenchyma; they begin as a localised area of cerebritis and later progress into a collection of pus surrounded by a vascularised capsule. By virtue of the impermeability of the blood-brain barrier, the brain parenchyma is relatively resistant to the establishment of focal bacterial infection. An area of necrosis caused by for example micro-infarction or hypoxaemia is necessary to act as a nidus for bacterial multiplication. Several stages of development  en route  to the formation of a mature encapsulated brain abscess following bacterial ingress have been defined by neuroimaging studies 11/14/2018 11 Brain Abscess

12. Early Cerebritis Days 1-3 : Perivascular inflammation, characterised by neutrophil infiltration, occurs around the site of focal infection with a surrounding area of oedema. 2. Late Cerebritis Days 4-9: A central area of necrosis develops as the surrounding oedema progresses. Peripheral accumulation of fibroblasts preludes the development of a capsule. 3. Early Capsule Days 10-14: Establishment of a ring-enhancing capsule of well-vascularised tissue with further fibroblast migration and adjacent reactive astrocytosis . 4. Late Capsule Day 14 and beyond: Collagen fibre and granulation tissue deposition leads to a thickening of the capsule effectively walling off the area of focal suppurative infection. 11/14/2018 12 Brain Abscess Stages of Development and Pathogenesis of Brain Abscesses

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14. Occur in majorities in the first 2 decades of life Males more affected ( cause is unknown ) adults depend on immune status Infants : increase in head circumference , bulging fontanel , separation of cranial sutures , vomiting , irritability , seizures 11/14/2018 14 Brain Abscess Clinical presentation :

15. 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 11/14/2018 Brain Abscess 15

16. Laboratory findings WBC : normal or mild increase ESR : increase in 90% CSF : not specific Opening pressure Protein Glucose Culture 11/14/2018 Brain Abscess 16

17. 4. radiological characteristic of brain abscess Brain CTS with contrast ring enhancement Multi loculation Multiplicity Finding of gas 11/14/2018 Brain Abscess 17

18. MRI : T1 : necrotic center ( hypointense ) Capsule ( hyperintence ) Edema ( hypointence ) T2 : necrotic center ( hyperintence ) Capsule ( hypointence ) Edema ( hyperintence 11/14/2018 Brain Abscess 18

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24. management The main treatment strategies are: Antimicrobial agents Needle aspiration  - often using stereotactic guidance Complete surgical excision In addition, adjunctive therapies such as corticosteroids and anticonvulsant agents are variably used. A combination of antimicrobial therapy and aspiration is now used for the majority of cases, with medical therapy alone and complete surgical excision reserved for particular circumstances 11/14/2018 Brain Abscess 24

25. Management 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 ) 11/14/2018 Brain Abscess 25

26. It may also be considered for… Multiple small abscesses Abscesses located in surgically unaccessible or eloquent areas It is most likely to be successful if… Abscesses are small (i.e. <1.5cm) In cerebritis stage Located in a well vascularised cortical area Frequent interval scans should be performed to assess therapeutic response and to identify complications requiring definitive surgical management. 11/14/2018 Brain Abscess 26 antibiotic therapy

27. Corticosteroids Adjuvant corticosteroids are often used to reduce vasogenic oedema associated with brain abscesses. There are important concerns regarding steroid use… Effectiveness in reducing oedema and mass effect not established in human clinical trials May retard abscess capsule development May reduce antimicrobial penetration Give false impression of a therapeutic response by reducing ring-enhancement on follow-up scans Most authors recommend that corticosteroids are reserved for situations of raised intracranial pressure resulting in a clear risk of brainstem herniation or other significant neurological deficit. 11/14/2018 Brain Abscess 27

28. Anticonvulsants Seizures are a frequent complication of brain abscess both in the acute setting and for a prolonged period after the resolution of the acute infection. Some advocate the use of seizure prophylaxis for extended periods in every case of brain abscess If commenced, anticonvulsants should probably be continued for 6-12 months and then only withdrawn if the patient is seizure-free, the EEG normal and no signs of on going inflammation on neuroimaging . 11/14/2018 Brain Abscess 28

29. Aspiration 11/14/2018 Brain Abscess 29

30. Excision of brain abscess Advantages Traumatic abscess ( contain foreign body and bone fragment ) Fungal abscess Gas containing abscess Disadvantages 11/14/2018 Brain Abscess 30

31. 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 11/14/2018 Brain Abscess 31

32. 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) 11/14/2018 Brain Abscess 32

33. Long term morbidity : ( seizure , FND, Cognitive dysfunction ) Recurrence: ( 5-10%) causes ( inadequate antibiotic therapy, incorrect choice of AB, presence of foreign body , failure to eradicate source of the abscess) 11/14/2018 Brain Abscess 33

34. SUBDURAL AND EPIDURAL EMPYEMA 11/14/2018 Brain Abscess 34

35. Subdural empyema This is an intracranial focal collection of pus between the dura mater and the arachnoid Subdural empyema is usually unilateral There is tendecy to spread rapidly in the sub dural space until limited by specific boundaries( falx cerebr , tentorium cerebelli , foramen magnum Causative bacteria same as those in prev slides of brain abscess 11/14/2018 Brain Abscess 35

36. Pathophysiology Subdural empyema has a tendecy to behave like an expanding mass This causes increased intracranial pressure and cerebral intraparenchymal penetration Cerebral edema and hydrocephalus maybe develop secondary to disruption in blood flow or CSF flow Cerebral infarction may develop due to thrombosis of the the cortical veins or the carvenous sinus or from septic venous thrombosis 11/14/2018 Brain Abscess 36

37. Pathophysisology In children, its often a complication of meningitis. Therefore its important to differentiate it from reactive subdural effusion. In older children and adults, it occurs as a complication of paranasal sinusitis, otitis media or mastoiditis 11/14/2018 Brain Abscess 37

38. Clinical presentation From history Fever above 38 Headache: initially focal and later generalised Recent hx of sinusitis, otitis media, mastoiditis , meningitis, cranial surgery, trauma, pulmonary infection, Confusion, drowsiness, stupor or coma Hemiparesis or hemiplegia Seizures: focal or generalized Nausea and vomiting Blurred vision: ambylopia Speech difficulty (dysphasia) Hx of intracranial abscess 11/14/2018 Brain Abscess 38

39. Physical examination Altered mental state Signs of meningeal irritation Focal neurologic deficits Aphasia or dysarthria Seizure Features of sinusitis Features of increased ICP Palsies of CN 3, 5, 6 11/14/2018 Brain Abscess 39

40. Investigations Labaratory studies CBC : leukocytosis Elevated ESR Blood culture Preoperative test: BUN, LFTs, electrolyts Imaging studies Cranial MRI is the choice( it outlines the extent of subdyral empyema and greater morphological details than CT scan 11/14/2018 Brain Abscess 40

41. CT scan : shows hypodense area over the hemisphere or along the falx Cranial ultrasound: important in differentiating subdural empyema from anechoic reactive subdural effusion in infants with meningitis Other tests: EEG, chest radiograph, 11/14/2018 Brain Abscess 41

42. Treatment Maintain adequate airway and ensure breathing and circulation Antibiotic therapy alone adequate in small subdural empyema <1.5cm diameter Prophylactic anticonvulsants Treatment for increased ICP 11/14/2018 Brain Abscess 42

43. Immediate surgical drainage should be considered Craniotomy: best option Stereotatic burr hole placement with drainage and irrigation Grainage and debreidement of the primary source of infection maybe necessary 11/14/2018 Brain Abscess 43

44. complications Seizures Cavernous sinus thrombosis from septic thrombosis Increased ICP Hydrocephalous Cerebral infarction Cranial osteomyelitis Focal neurological deficits 11/14/2018 Brain Abscess 44

45. Epidural empyema \abscess Rare but pontentially life threatening Occus between the dura dnthe skull There are two types Spinal epidural abscess Intracranial epidural abscess The difference is where they develop and some variationsi in risk factors 11/14/2018 Brain Abscess 45

46. Spinal epidural empyema Read more about it 11/14/2018 Brain Abscess 46

47. Intracranial epidural abscess Usually associated with subdural empyema because the pus can cross the brain dura along emissary veins Risk factirs include prior craniotomy, head injury, sinusitis, otits media and mastoiditis . Common in males in the 2 nd and 3 rd decades 11/14/2018 Brain Abscess 47

48. Clinical presentation Fever Headache Malaise Lethargy Nausea and vomiting Focal neurological deficits Altered mental state evidence of infection seizure 11/14/2018 Brain Abscess 48

49. Management Craniotomy Antibiotic therapy Anticonvulsants corticosteroids 11/14/2018 Brain Abscess 49

50. 11/14/2018 Brain Abscess 50 Thank you