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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