Youmans Neurological Surgery

1. Brain Abscess
YOUMANS Chapter 43

2. Outline
• Epidemiology
• Etiology
• Initiation of infection
• Stage of infection
• Clinical finding
• Diagnosis
• Management

3. Epidemiology
• 0.3 -1.3 cases per 100,000 person
• Male : Female 2:1
• Median age 30-40 years
– Otitic focus : < 20 Yrs , >40 Yrs
– Paranasal sinus : 30 – 40 Yrs
• After cranial operation : 0.2 % of 1587 , 10 of 16540
• Commonly in Immunocompromised : infected with
HIV, receiving chemotherapy for cancer, receiving
immunosuppressive therapy after organ
transplantation, or after prolonged use of
corticosteroids.

4. Risk factor
• Pulmonary abnormality
– Infection
– AV fistula
• Congenital cyanotic heart disease
• Bacterial endocarditis
• Penetrating trauma
• Chronic sinusitis or otitis media
• AIDS

5. Pathogenesis
• Organism transmit
– contiguous source of infection, 25-30 % of case
– hematogenous dissemination 20-35% of cases
– trauma

6. Pathogenesis
• Contiguous source : middle ear, mastoid cells,
paranasal sinuses
• From purulent sinusitis : spread by osteomyelitis or
by phlebitis of emissary vein
• Rare in infant because they lack aerated paranasal
and mastoid air cells
• Localize of Contiguous source
– Otitis media : temporal lobe or cerebellum
– Paranasal sinusitis : frontal lobe
– Sphenoid sinusitis(less common for sinusitis ) : temporal
lobe, sella turcica

7. Pathogenesis
• Hematogenous dissemination : multiple,
multiloculated abscesses, higher mortality rate
• Most common source in adult
– Most common : pyogenic lung diseases (especially lung
abscess)
– bronchiectasis
– Empyema
– cystic fibrosis
– Skin infection, osteomyelitis, pelvic infections, and intra-
abdominal infections

8. Pathogenesis
• In children
• Cyanotic congenital heart disease (tetralogy of Fallot)
because increase Hct and low PO2 provide and hypoxic
environment suitable for abscess proliferation
• Right to left shunt
• Streptococcal oral flora from oral dental procedure

9. Pathogenesis
• Trauma : open cranial fracture with dural breach or
foreign body injury or as a sequela of neurosurgery
• Nosocomial brain abscess : halo pin insertion,after
electrode insertion to localize seizure foci,and in
malignant glioma patients treated by placement
of Gliadel wafers in the tumor bed to release
carmustine

10. Etiology
• Bacterial : most common, streptococci (aerobic,
anaerobic, and microaerophilic), 70%
• Streptococcus anginosus (milleri) : oral cavity,
appendix, and female genital tract
• Staphylococcus aureus : cranial trauma or infective
endocarditis
• Enteric gram-negative bacilli ,25-30% (e.g., Proteus
spp., Escherichia coli, Klebsiellaspp., Pseudomonas
aeruginosa, and Enterobacterspp.) : otitis media,
bacteremia, neurosurgical procedures, and the
immunocompromised state

11. • Negative culture : 0-43% (previous use ATB)
• Listeria monocytogenesis uncommon (<1% of cases),
considered in patient who are immunocompromised
(e.g., leukemia, lymphoma, HIV infection, and
conditions requiring corticosteroids or other agents
that cause immunosuppression)
• Salmonella, Nocardia, Streptococcus pneumoniae,
Haemophilus influenzae, Burkholderia pseudomallei,
and Actinomyces species
Etiology

12. Etiology
• the incidence of fungal brain abscess has been
rising as a result of the increased use of
corticosteroid therapy, broad-spectrum
antimicrobial therapy, and immunosuppressive
agents
• Candida : microabscesses, macroabscesses,
noncaseating granulomas, and diffuse glial nodule

13. Etiology
• Risk factors for candidal brain abscess include the
use of broad-spectrum antimicrobial agents,
corticosteroids, and hyperalimentation; premature
birth; malignancy; neutropenia; chronic
granulomatous disease; diabetes mellitus; thermal
injury; and the presence of a central venous catheter
• Aspergillosis : neutropenia, hepatic disease, diabetes
mellitus, chronic granulomatous disease, Cushing’s
syndrome, HIV infection, injection drug use, organ
transplantation, and bone marrow transplantation

14. Etiology
• Mucorales group : Diabetes mellitus, patients with
acidemia from profound systemic illness (e.g., sepsis,
severe dehydration, severe diarrhea, chronic
kidney disease)
• Scedosporium : immunocompetent and
immunocompromised hosts
• Cryptococcus neoformans, the endemic mycoses
(Coccidioides spp., Histoplasma spp., and
Blastomyces dermatitidis)

15. Etiology

16. Initiation of infection
• The brain appears to be significantly more sensitive
to infection than many other tissues.
• The brain may also be more susceptible to
infection by different organisms

17. Stages of infection

18. Stages of infection

19. Host defence mechanism
• Although the brain is generally protected from
infection by an intact blood-brain barrier, once
infection is established, immune defenses are
usually inadequate to control the infection
• Encapsulate bacteria : E.coli, B.fragilis

20. Clinical finding

21. Clinical finding
• Newborn
– Patent suture
– Seizure
– Meningitis
– Irritabilitiy
– Increasing OFC(occipital-frontal circumference)
– Failure to thrive
– May afebrile

22. Clinical finding

23. Clinical finding
• Intraventricular rupture of brain abscess : severe
headaches and signs of meningeal irritation were
prominent findings before rupture
• Intraventricular rupture appears to be more likely
if the abscess is deep-seated, multiloculated, and in
close proximity to the ventricular wall

24. Clinical finding
• Related to pathogen
– Nocardia : concomitant pulmonary, skin, or muscle
lesions
– Aspergillus brain abscess : commonly manifest signs of a
stroke syndrome as a result of ischemia or intracerebral
hemorrhage, or both
– rhinocerebral mucormycosis : symptoms referable to
the eyes or sinuses and complaints of headache, facial
pain, diplopia, lacrimation, and nasal stuffiness or epistaxis
 cranial nerve involvement  blindness

25. Clinical finding
• Related to pathogen
– Scedosporium apiospermum brain abscess :
• occur in immunocompromised patients or in
individuals 15 to 30 days after an episode of near-
drowning
• cerebrum, cerebellum, or brainstem
• Clinical finding : seizures, altered consciousness,
headache, meningeal irritation, focal neurological
deficits, abnormal behavior, and aphasi

26. Diagnosis
• WBC : mildly elevate (>10,000)
• Blood C/S : should be obtain (usually negative)
• ESR : may be normal
• CRP : may arise
• LP : dubious, OP increase, WBC count, Protein
elevate, risk for tantentorial herniation

27. Diagnosis
• MRI is more sensitivity than CT, early detection of
cerebritis, more conspicuous spread of inflammation
into the ventricles and subarachnoid space, and
earlier detection of satellite lesions
• T1 : the abscess capsule often appears as a discrete
rim that is isointense to mildly hyperintense
• T1 c Gad : rim enhancement, cerebral edema
• T2 : zone of edema : hyperintensity, capsule : ill-
defined hypointensity
• DWI : restricted diffusion (bright signal) may be seen
• ADC : Dark

28. Diagnosis

29. Diagnosis
• Aspergillosis : finding of a cerebral infarct, which
typically develops into either single or multiple
abscesses, in immunocompromised patients, there
may be little or no contrast enhancement on MRI
• Rhinocerebral mucormycosis : sinus opacification,
erosion of bone, and obliteration of deep fascial
planes; cavernous sinus thrombosis

30. Diagnosis
• stereotactic MRI- or CT-guided aspiration
• Specimens sent for : Gram stain, routine aerobic
and anaerobic culture, modified acid-fast smears,
acidfast smears and culture, and fungal smears and
culture
• Aspergillus brain abscess : septate hyphae with
acute-angle, dichotomous branching
• Mucormycosis : irregular hyphae with right-angle
branching.

31. Diagnosis

32. Diagnosis
• Scedosporiumspecies are indistinguishable from
those caused by Aspergillus species. The hyphae of
dematiaceous fungi may be brownish on
hematoxylin-eosin staining but are not
distinguishable from those of other molds.

34. Management
• Multidisciplinary, neuroradiologist, neurosurgeon,
and infectious disease specialist
• Larger than 2.5 cm : excision
• Smaller than 2.5 cm : aspiration for definite diagnosis
• Empirical ATB : metronidazole + third-generation
cephalosporin
• S.aureus consider : add vancomycin
• gram-negative bacilli such as P. aeruginosa :
ceftazidime, cefepime, or meropenem

35. Management
• no clear predisposing factors : combination of
vancomycin, metronidazole, and a third- or fourth-
generation cephalosporin
• Once the infecting pathogen is isolated, antimicrobial
therapy can be modified for optimal treatment

36. Medical management alone
• Treatment began in cerebritis
• Small lesion 0.8-2.5 cm
• Duration of symptom < 2 Wk
• Patient show clinical improvement in 1 wk

37. Surgical treatment
• Significant mass effect exerted by lesion
• Difficult in diagnosis
• Proximity to ventricle
• Evedence of significane increase intracranial
pressure
• Poor neurological condition
• Traumatic abscees associated with foreign
material
• Fungal abscess

38. Management

39. Bacterial brain abscess
• The principles of antimicrobial therapy for bacterial
brain abscess
– penetrate the abscess cavity
– in vitro activity against the isolated pathogen
• Metronidazole
– excellent in vitro activity against strict anaerobes
– an excellent pharmacokinetic profile
– good oral absorption
– penetration into brain abscess cavities
– must always be used in combination with an agent
effective against streptococci

40. Bacterial brain abscess
• Vancomycin, The third generation cephalosporins
are common used
• Imipenem : pyogenic and nocardial brain abscess,
beware seizure
• Meropenem : Enterobacter cloacae

41. Bacterial brain abscess
• Surgical therapy : aspiration after bur-hole
placement or complete excision after craniotomy
• Stereotactic aspiration : eloquent or inaccessible
regions
• Complete excision by craniotomy
– patients with multiloculated abscesses in whom
aspiration techniques have failed
– for abscesses containing gas
– for abscesses that fail to resolve
– posttraumatic abscesses that contain foreign bodies or
retained bone fragments to prevent recurrence

42. Bacterial brain abscess
• In patients with intraventricular rupture of a
purulent brain abscess :
– rapid evacuation and débridement of the abscess cavity
via urgent craniotomy and ventricular drainage
– intravenous or intrathecal ATB
• groups of patients may be treated with medical
therapy alone
– medical conditions that increase the risk associated with
surgery
– multiple abscesses

43. Bacterial brain abscess
• groups of patients may be treated with medical
therapy alone
– abscesses in a deep or dominant location
– the presence of coexisting meningitis or ependymitis
– early reduction of the abscess with clinical improvement
after antimicrobial therapy
– abscess size less than 3 cm

44. Bacterial brain abscess
• ATB optimal duration : 6-8 Wk IV then follow by oral
ATB for 2-3 Mo
• Repeat neuroimaging studies performed biweekly for
up to 3 months after completion of therapy has been
suggested to monitor for reexpansion of the abscess
or failure of resolution

45. Nocardial brain abscess
• Sulfonamide with or without trimethoprim is
recommend
• Alternative agent : minocycline, imipenem, amikacin,
third-generation cephalosporins, and linezolid
• In immunocompromised patients or those in whom
therapy fails : combination treatment with
regimens + a third-generation cephalosporin or
imipenem + a sulfonamide or amikacin

46. Nocardial brain abscess
• Craniotomy with total excision is difficult in
patients with Nocardia brain abscess because
these abscesses are often multiloculated
• ATB duration : 3-12 Mo but in immunocompromised
should be up to 1 Yr

47. Fungal brain abscess
• Candidal brain abscess : amphotericin B preparation
plus 5-flucytosine
• Aspergillusbrain abscess : voricazole
• CNS mucormycosis : amphotericin B deoxycholate
or a lipid formulation of amphotericin B with
aggressive surgical debridment
• Scedosporiumspecies : surgery

48. Management

50. Adjunctive Therapy
• Steroid effect
– Reduced edema
– Decrese likehood of fibrous encapsulation
– May be reduced penetration of antibiotic into abscess
• Corticosteroid use
– edema and mass effect
– progressive neurological deterioration
– impending cerebral herniation
• High dose : dexamethasone 10 mg q 6 hr and
then tapered

51. Cranial Subdural empyema and
Epidural abscess
YOUMANS Chapter 43

52. Epidemiology and Etiology
• Cranial subdural empyema : collection of pus
between the space of the dura and arachnoid, 15-20
% intracranial lesion
• Less common than brain abscess
• SDE may be complicated by cerebral brain abcess,
cortical vein thrombosis, localized cerebritis
• Location : 70-80 % convexity, 10-20% parafalcine

53. Epidemiology and Etiology
• most common predisposing conditions :
otorhinologic infections, especially of the
paranasal sinuses
• Other predisposing conditions : skull trauma,
neurosurgical procedures, and infection of a
preexisting subdural hematoma

54. Epidemiology and Etiology
• Organisms
– aerobic streptococci (25% to 45%)
– staphylococci (10% to 15%)
– aerobic gram-negative bacilli (3% to 10%)
– anaerobic streptococci
– other anaerobes
• If the predisposing condition is postoperative or
posttraumatics : staphylococci and aerobic gram-
negative bacilli

55. Clinical finding
• Clinical manisfestation of subdural empyema
– rapidly progressive, with symptoms and signs related to
increased intracranial pressure (headache, vomiting)
– meningeal irritation
– focal cortical inflammation (hemiparesis and hemiplegia,
ocular palsies, dysphasia, homonymous hemianopia,
dilated pupils, and cerebellar signs
– Altered mental status
– Seizure
– Fever

56. Clinical finding
• Clinical manisfestation of cranial epidural abscess
– Insidious onset
– Abscess enlarge too slowly to produce a sudden onset of
major neurological deficits, as is seen in patients with
cranial subdural empyema
– Most common : fever, headache
– If the location of the epidural abscess is near the petrous
bone, Gradenigo’s syndrome may develop (involvement
of cranial nerves V and VI and manifested clinically as
unilateral facial pain and weakness of the lateral
rectus muscle)

57. Diagnosis
• Cranial subdural empyema should be suspected in
any patient with meningeal signs and a focal
neurological deficit
• CT brain : iv contrast : hypodense crescentric
• LP : potential hazardous for herniation

58. Diagnosis
• MRI in Cranial subdural empyema : crescentic or
elliptical area of hypointensity (on T1 images) below
the cranial vault or adjacent to the falx cerebri, high
signal on T2
• MRI in cranial epidural abscess : superficial,
circumscribed area of diminished intensity with
pachymeningeal enhancement.

59. Management of
Cranial subdural empyema
• Cranial subdural empyema is a surgical emergency
because antimicrobial therapy alone does not
reliably sterilize the empyema
• The goals of surgical therapy are to achieve adequate
decompression of the brain and to evacuate the
empyema completely.
• The optimal surgical approach is controversial.

60. Management of
Cranial subdural empyema
• Patients who underwent drainage via bur holes or
craniectomy required more frequent operations to
drain recurrent or remaining pus and exhibited
higher mortality rates and worse outcomes
• Drainage via bur holes or craniectomy is therefore
recommended only for
– patients in septic shock, those with localized parafalcine
collections
– children with subdural empyema secondary to
meningitis because there is usually no brain swelling and
the pus is thin

61. Management of
Cranial subdural empyema
• S. aureusis suspected : vancomycin
• suspected anaerobes : metronidazole
• aerobic gram-negative bacilli are suspected,
empirical : ceftazidime, cefepime, or meropenem
• ATB continued for 3-4 wk after drainage

62. Management of
Cranial subdural empyema
• ATB alone in
– patients with cranial subdural empyema who have
minimal or no impairment of consciousness
– no major neurological deficit
– limited extension of the empyema with no
midline shift
– early improvement with antimicrobial therapy

63. Management of
Cranial epidural abscess
• combined medical and surgical approach
• Empirical antimicrobial therapy is similar to that for
cranial subdural empyema
• For surgical drainage, craniotomy or craniectomy
is generally preferred over bur-hole placement or
aspiration of purulent material through the scalp
• ATN length 3-6 wk or longer in osteomyelitis

64. Thank you