040 postoperative infection of the head and brain
TRANSCRIPT
Postoperative Infections of the Head and Brain
Youmans Neurology surgeryChapter 40
Outline
• Epidemiology and etiology• Risk factor for infection and preventive
strategies• Principles of treatment• Superficial infections and bone flap osteomyelitis• Subdural empyema• Brain abscess• Bacterial meningitis
Epidemiology and etiology
• Anatomic site– Superficial : skin and subcutaneous– Deep : subgaleal space and bone flap
• subdural emyema, brain abscess and meningitis(most common)
• McClelland and Hall– Elective cranial craniotomy,over 15 yrs,low rate 0.8%– S.aureus : most common
Epidemiology and etiology
• NNIS : s.aureus, coagulase-negative, staphylococci
• Other bacteria : enterococci, Streptococcus spp., Pseudomonas aeruginosa, Acinetobacter spp., Citrobacter spp., Enterobacter spp., Klebsiella pneumoniae, Escherichia coli, miscellaneous other gram-negative bacilli, and yeast
Risk factor for infection and preventive strategies
• Contamination of the wound with bacteria from the patient’s skin
• Host defence mechanism : low level of antibody, underlying pathology, corticosteroids, chemo receptor, radiation, trauma
• Prevention of craniotomy infection : – minimization corticosterois use, – nutritional support– glucose support
Risk factor for infection and preventive strategies
• Korinek, predictor of infection– surgery lasting longer than 4 hours, – emergency surgery – clean-contaminated and contaminated surgery– neurosurgical intervention in the preceding month
• Synthetic dural substitutes, potential risk factor for infection
Risk factor for infection and preventive strategies
• Preoperative ATB reducing the incidence of SSI after craniotomy
• Adhesive tape barrier, Bathing, Showing not approved to reduce infection
Risk factor for infection and preventive strategies
• The Surgical Infection Prevention (SIP)– selection of an appropriate antibiotic, – administration within 1 hour before incision (2
hours is allowed for the administration of vancomycin and fluoroquinolones)
– discontinuation of the antibiotic within 24 hours after surgery is completed
Risk factor for infection and preventive strategies
• Surgical site control and environment control– Remove hair(clipper,close to time surgery)– Antiseptic skin prep(chlorhexidine, iodophor)
• Operating room– Number of health care– Traffic in the room– Adequate ventilation– Used of high-efficiency particulate air (HEPA)
filters
Principles of treatment
• keystone of successful treatment – Effective source control (i.e., drainage of abscesses
and infected fluid collections and débridement of necrotic )
– Antibiotic Therapy• ATB
– Passive diffusion down concentration gradient– Molecular weight– Lipophilicity– Protein binding
Principles of treatment
• Empirical treatment of postoperative infections– vancomycin + a second drug such as a third- or
fourth-generation cephalosporin having antipseudomonal activity (e.g., ceftazidime, cefepime)
– carbapenem (e.g., meropenem)• Vancomycin : weaker activity against
staphylococcal infections relative to β-lactamsand decreased penetration into the CNS
Principles of treatment
• Cefazolin : poor CNS penetration• Third-generation cephalosporins (specifically
cefotaxime, ceftriaxone, and ceftazidime) : low toxicity, good CNS penetration, and excellent in vitro activity
• Carbapenems such as imipenem (with cilastatin) and meropenem : broad antimicrobial spectrum, brain abscess (imipinem increase seizure)
Principles of treatment
• Fluoroquinolones : high rate of bacterial resistance, increased seizure potential
• Linezolid– bacteriostatic : MRSA, vancomycin-resistant
enterococci – bactericidal : streptococci– IV or Oral– SE : reversible myelosuppression and
irreversible peripheral neuropathy
Principles of treatment
• Rifampin – Infection associated with foreign body implantation,
bone flap osteomyelitis– effectively penetrate biofilms and kill organisms in the
sessile phase of growth– Combination with a second active agent
• Daptomycin– vitro microbicidal activity against MRSA
Principles of treatment
• Polymyxins– gram-negative bacilli – nephrotoxicity.
• Aminoglycoside– aerobic gram-negative bacilli (P.aeruginosa)– Toxic, narrow therapeutic window,poor CNS
penetrate
Superficial infections and bone flap osteomyelitis
• Clinical manifestation– Local erythema, swelling, tenderness, wound
breakdown, suppurative drainage– Systemic sign : malaise, fever, chill– Neurological symptom : meningismus, altered
mental status, or new focal deficits– Pathogen : gram-positive cocci, including S.
aureus, coagulase-negative staphylococci, P. acnes
Superficial infections and bone flap osteomyelitis
• Diagnostic imaging and laboratory data– CT or MRI : fluid collections in the subgaleal or
epidural spaces– bone flap destruction suggestive of osteomyelitis– ESR, CRP : detecting infection, monitor
Superficial infections and bone flap osteomyelitis
• Treatment– Superficial infection
• Oral : first-generation cephalosporins (e.g., cefazolin) or β-lactamase–resistant penicillins (e.g., dicloxacillin)
• IV : rapidly spreading infection, prominent systemic symptoms, or significant comorbidity
Superficial infections and bone flap osteomyelitis
• Treatment– Bone flap osteomyelitis
• ATB • débridement with replacement of the bone flap• surgical débridement with removal of the bone
flap
Superficial infections and bone flap osteomyelitis
• Hyperbric oxygen(HBO) therapy• Complicated superficial infection• increases oxygen tension in infected tissues• improving oxidative killing of aerobic bacteria by
phagocytic cells and providing a direct bactericidal effect on anaerobic organisms such as P. acnes
• Useful in radiation injury : promote neoangiogenesis and reverse the vascular compromise
• Limitation : cost, multiple session, increase tumour growth
Subdural empyema
• Clinical manifestation– fever and headache, followed by the rapid
development of focal neurological deficits, altered mental status, and seizures
– most common findings were evidence of superficial wound infection and the presence of diffuse encephalopathy
– subdural empyema occurred more than 1 month after the craniotomy
Subdural empyema
• Diagnostic imaging and laboratory data– CT NC : crescent-shaped fluid collection, more
dense than CSF, located beneath the craniotomy flap or adjacent to the falx
– MRI : • T1, FLARE : increase intensity• Gd : peripheral enhancement
– Laboratory finding• Nonspecific : ESR normal, CSF normal• LP contrain contraindicated herniation
Subdural empyema
• Treatment– Surgical drainage– Craniotomy advocate (maximal drainage,
inspection of adjacent area, removal bone flap)– Empirical ATB : skin flora, gram-negative bacilli– Vancomycin + 3rd cephalosporin (ceftazidime) :
P.aeruginosa– Duration 4-6 wks
Brain abscess
• Clinical manifestation– Direct seeding, extension of superficial– classic triad of headache, fever, and focal
neurological deficit is rarely present– Symptom : irritative mass lesion and include
altered level of consciousness, nausea, vomiting, and seizures
Brain abscess
• Clinical manifestation– Intraventricular rupture of a brain abscess
(IVROBA) : • preexisting headache with new onset of
meningismus, coma• severe widespread meningoencephalitis and
alterations in CSF flow causing an increase in intracranial pressure, hydrocephalus(50%)
• Risk factor : multiloculates, near ventricular
Brain abscess
• Diagnostic imaging and laboratory data– CT
• cerebritis stage : poorly defined area of low attenuation with a mass effect and significant edema
– MRI• T1-weighted images as a ring of gadolinium
enhancement surrounding a necrotic cavity of low signal intensity
Brain abscess
• Diagnostic imaging and laboratory data– Corticosteroids : reduce thickness of the abscess
capsule and the extent of contrast enhancement on both CT and MRI
– DWI MRI • most sentivity,specifitivy for Ddx ring-
enhancing lesion (residual or recurrent tumor, treatment effect, infarction, or resolving hematoma)
• T2 shine-through effect : bright
Brain abscess
• Diagnostic imaging and laboratory data– Peripheral leukocytosis is frequently absent– ESR and CRP level are usually elevated,
normal values may occur in patients with proven infection
– Blood cultures– CSF analysis is rarely helpful and typically reveals
only a nonspecific elevation in protein level and cell count
– -LP contraindicated
Brain abscess
• Treatment– Goal : mass effect, improve clinical symptoms,
and fully resolve the infection– Surgical : open drainage or excision of the lesion
and stereotactic aspiration(higer recurrence)– Specimens for GS and CS– Empirical ATB : vancomycin and a third- or
fourth-generation cephalosporin with antipseudomonal activity (e.g., ceftazidime, cefepime)
Brain abscess
• Treatment– High dose for 6-8 Wks– Progressive enlargement of the abscess or failure
of the abscess to become smaller despite treatment of a susceptible organism with an appropriate antibiotic : repeat surgical drainage and microbiologic reassessment
– Corticosteroid : Pt c significant cerebral edema– Antiseizure prophylaxis
Bacterial meningitis
• Clinical manifestation– < 1%, mortality > 20%– fever, headache, and neck stiffness– sterile postoperative meningitis
• most frequently in children and after posterior fossa surgery
Bacterial meningitis
• Clinical manifestation– sterile postoperative meningitis
• presumed to be caused by irritation from blood breakdown products or from factors released by surgical materials such as dural substitute
• Dx : negative CSF GS and CS• Pt fully recovery without administration of ATB• Corticosteriod provide symptomatic relief
Bacterial meningitis
• Diagnostic imaging and laboratory data– No diagnostic test for chemical and bacterial
meningitis– Neuroimaging studies rarely assist in the
diagnosis of postoperative meningitis– CSF culture is gold standard for diagnostic
postoperative bacterial meningitis– CSF Gram staining is highly insensitive for
infection
Bacterial meningitis
• Diagnostic imaging and laboratory data– CSF hypoglycorrhachia and pleocytosis with
neutrophilic predominance are common findings in both aseptic and bacterial meningitis
– CSF lactate : > 4 mmol/L, IL-1b > 90 ng/L presence of bacterial meningitis with good sensitivity and specificity in postsurgical patients
Bacterial meningitis
• Treatment– vancomycin + third-generation cephalosporin
with antipseudomonal activity (e.g., ceftazidime)– patient is not deteriorating clinically, CSF culture
results remain sterile, and the treating clinician believes the original clinical syndrome to have been consistent with aseptic chemical meningitis, antibiotics may be discontinued after several day
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