E. R. Flotte
MD, 2009
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Cerebral abscess
·
Most common organisms: anerobic/ microaerophilic Strep.
o
Immunocompromised:
Nocardia (disseminated with skin lesions), Toxo.
o
Neonates: GNR, Proteus, Citrobacter.
·
Predisposing factors: Sinus/dental
infection, pulmonary abscess/empyema, cyanotic
cardiac disease (Tetralogy, etc), pulmonary AVF
(Osler-Weber-Rendu, hereditary hemorrhagic telangectasia), endocarditis
(rare), AIDS
·
Symptoms: 50% have low-grade fever.
·
Lab: CXR, ESR/CRP, CBC (WBC >10K), BCx (10% positive), HIV, Toxo
testing.
o
LP contraindicated.
o
Check echocardiogram (SBE).
·
Imaging
o
Cerebritis
vs encapsulated abscess: On delayed CT capsule
enhancement decays, cerebritis doesn’t. Cerebritis usually thicker
o
MR-Spect: ↑ lactate, acetate, pyruvate.
May use to follow response to treatment. Also WBC-tagged
scans.
o
MRI: restricted diffusion on DWI/ADC
map
·
Treatment
o Medical:
antibiotics ± steroids
o
Indications: Cerebritis,
<3cm abscess, multiple, deep, eloquent cortex, <2 weeks of symptoms.
o
Steroids controversial: may delay
encapsulation, but most evidence argues against routine
use. Usually used only if significant edema present.
o
Antibiotics: 6 weeks IV then 6 weeks
oral. Vanc/Rocephin/Flagyl (empiric). Nocardia = Bactrim. Toxo = Pyrimethamine +
Sulfadiazine. Anaerobic GNR (Bacteroidies) = Flagyl. Strep = PCN. Staph epi = Vanc ± Rifampin. Staphj aureus = nafcillin. Fungal
= Ampho B.
o
Surgical:
o
Indications: Encapsulated, periventricular (>80% mortality w/rupture), >3cm,
mass effect, diagnosis unclear, difficult follow-up, medical failure (increased
after 2wks or no change after 4wks)
o
Aspiration:
o
Excision: Aspirate first then corticectomy & capsule excision (in noneloquent
areas). Preferred for penetrating trauma, fungal, multiloculated,
failure of repeated aspirations, posterior fossa, gas-containing.
o
Follow-up:
Continue antibiotics for 6-8wks (12wks if empiric) then may d/c even if CT
abnormalities persist (may take 3-6mos to resolve). CT q2-4 wks until CT
resolution, then q2-4mos for 1yr.
·
Audio: Goel A NF6/08
Subdural
empyema
·
Usually secondary to sinusitis/otitis in young people. Strep & Staph aureus are most
common organisms. Causes cortical vein thrombosis.
·
Treatment: emergent craniotomy (craniectomy?) – even if small. Do
not remove membrane adherent to cortex.
Skull
Osteomyelitis
·
Give 3 months of antibiotics, replace
bone in 6 months
·
Focal lesions: most common are
o
Toxoplasmosis:
most common (75%). MRI: Hypodense area with edema and
ring-enhancement. Common in basal ganglia. Treatment: pyrimethamine
and sulfadiazine.
o
Progressive Multifocal Leukoencephalopathy (PML)
o
Primary CNS Lymphoma.
May rim enhance or are “target lesions” in AIDS lymphoma (enhance strongly in
other PCNSL). Treatment: WBRT.
o
Also: cyrptococcal
abscess (more commonly meningitis)
·
Management:
o
PML can be differentiated by lack of
enhancement.
o
SPECT
may differentiate lymphoma (hot) from toxo (cold)
o Obtain
CSF for cytology (lymphoma), PCR for EBV and serum toxo
titers.
o AAN
guidelines for AIDS: only an isolated
ring-enhancing lesion in the setting of negative toxoplasmosis serology
requires early biopsy. Otherwise, a trial of pyrimethamine
and sulfadiazine is appropriate for presumptive toxoplasmosis.
o
Single lesions are more likely
lymphoma than toxo.
o
Biopsy role in non-enhancing lesions
are unclear – most are PML or non-specific.
·
Meningitis: bacterial, Cryptococcus
·
Infection of larvae of pork tapeworm Taenia solium. Most
common CNS parasitic infection.
·
Tapeworm (intestinal) infection
results from eating undercooked pork. Cystercercosis
results from eating tapeworm eggs (ie through fecal
contamination of food or autoinoculation).
·
Endemic in
·
Incubation: months to >10years.
·
Seizures common
·
May be meningeal,
parenchymal, ventricular. Usually ring-enhancing
lesions with minimal edema. May have subcutaneous nodules.
·
Diagnosis: MRI – cyst, scolex may appear as mural nodule.
o
Serum (25% sensitive) and CSF (50%
sensitive) antibody titers can be checked. CSF may show eosinophilia.
·
Treatment: Albendazole
x 1 wk (more effective than Praziquantel) and
steroids (up to 30mg/d decadron and 10mg qod chronically).
o
Biopsy may not be required when
imaging and clinical are suggestive according to some
o
Ventricular cysts: surgical resection vs antihelminthics and shunting
(higher rate of malfunction). Consider endoscopic resection+- 3rd
ventriculostomy
o
Contacts: Single dose of praziquantel
·
Rare parasities
o
Echinococcus
(hydatid cyst): Dog tapeworm. May grow to be large.
Excision: be careful not to rupture cyst. More common in Australia and New
Zealand
o
Amebiasis
Bacterial
meningitis:
·
Steroids decrease mortality and poor
outcome
Fungal
meningitis/abscess: Cryptococcus, candidiasis,
mucorycosis (diabetics), aspergillosis (transplants)
·
Occur in immunocompromised
patients: Candida, Aspergillus, Mucor
·
Occur in immunocompotent
or immunocompromised: Cryptococcus, Coccidiodes, Histoplasma
·
Cryptococcus associated with dilated
Virchow-Robin spaces and basal ganglia (or brain-stem or cerebral) pseudocysts
Gradenigos Syndrome:
osteomyelitis of petrous apex. CN6 palsy & retroorbital pain, from otitis
Whipple disease: Caused
by bacteria Tropheryma whippelii.
Symptoms: gastrointestinal symptoms and migratory arthralgias.
Path: perivascular macrophages with
diastase-resistant PAS (+) granules. Involves CNS in 25%: dementia, multifocal
grey-matter lesions, especially temporal cortex, thalamus, etc.
Herpes
Encephalitis
·
See Neurology: Herpes Encephalitis
·
Preferentially affects temporal lobes.
Diagnosis: PCR on CSF.
·
Biopsy rarely needed unless diagnosis
is unclear. Open anterior temporal cortical/subcortical
biopsy with viral isolation.
·
Treatment: acyclovir (begin immediately
empirically).
Osteomyelitis/ Discitis
·
Osteomyelitis often involves
the disc space (discitis), spinal mets
usually do not (Cancer = C-shape around the disc)
·
Discitis may occur without
osteomyelitis
·
Discitis can be postoperative or occur
spontaneously in adults (with same risk factors as spinal epidural abscess)
·
Children: average 2-3 years-old – due
to persistence of nutrient feeding arteries. In children presents as refusal to
walk.
·
Staph aureus
most common organism.
·
CT-guided needle biopsy: perform
before antibiotics or stop antibiotics for 3 days before biopsy. Consider open
biopsy after 2 negative needle biopsies
·
Send Gram, fungal, and AFB stains,
cultures for aerobic, anaerobic, fungal and TB (grow for weeks)
·
Treatment:
Generally manage with antibiotics and bracing if neurologically and
mechanically stable
·
Indications for reconstruction and
stabilization controversial but include: instability, neurologic deficit, or
significant canal compromise
·
Titanium expandable cages with
allograft or autograft (rib, iliac crest) have been
used to reconstruct corpectomies (Lu
DC N1/09)
·
Surgical debridement options:
laminectomy; anterior decompression with or without
anterior and/or posterior instrumentation (staged or simultaneous)
·
Cage with autograft preferred over
allograft strut by some
·
It is generally felt that
instrumentation can be placed in the setting of infection (during primary
debridement)
·
See Neurosurg Focus 12/04
·
Can use ESR, CRP to follow treatment.
Spinal
epidural abscess
·
Symptoms: Similar to osteo: back pain, fever, tenderness (with neurologic
deficit).
·
Risk factors: immunocompromise, IV
drug use, diabetes, alcoholism.
·
Most common organisms: Staph aureus.
·
Treatment:
o
Neurologic Deficits or canal
compromise (most cases): emergent evacuation.
·
Significant recovery can occur in
patients with deficits of <36 hours duration
·
Non-operative management considered
for complete deficits with >72 hours duration
o
Extensive length (panspinal)
or complete deficits for >3 days: immobilization (TLSO) and antibiotics
(4wks IV then 4wks oral). (If no deficits & minimal compromise require close monitoring and is controversial)
Pott’s Disease
·
Pott’s
disease: Tuberculosis vertebral osteomyelitis.
·
Pain usually mild, slowly progressive
·
ESR normal
(or mildly elevated). CBC may be normal
·
PPD may be nonreactive in immunocompromised patients
·
Imaging: Spares disc space (pathognomonic). Vertebral destruction out of proportion to
pain (usually mild)
·
Psoas
abscess (often calcified) and subligamentous
spread common,
·
Treatment usually anttituberculosis
drugs – 12 months +.
·
Nontuberculous
granulomatous osteomyelitis:
often fungal (coccidiomycosis), sarcoid.
·
Superficial: skin and subcutaneous
tissue
·
Deep: below lumbbodorsal
fascia (lumbar) or platysma (cervical). Includes diskitis or osteomyelitis.
·
Symptoms: return of pain, fever, wound
drainage
·
Check ESR (80% sensitive), CRP (more
rapid and sensitive). WBC unreliable.
·
Imaging (deep): contrasted MRI (93%
sensitive, 97% specific)
·
CT guided biopsy/aspiration for
cultures if deep
·
Explore for: wound
drainage/dehiscence, sepsis,
neurologic deficits, epidural abscess, instability from bone destruction or
hardware failure, and failure of medical management
o
Explore/ I&D necessary for
purulent drainage after postop day 4-5 (do not discharge patients with wound
drainage)
·
Wound Drain left in place for as long
as wound is draining.
·
MRSA: Vancomycin
and rifampin 6-8 weeks
·
Generally instrumentation is left in
place.
Revised 6/1/09
Text Copyright 2009