Ventriculitis

OVERVIEW

Bacterial ventriculitis (BV) is inflammation of the ventricular drainage system, usually due to bacterial infection of the cerebrospinal fluid (CSF)

• Ventriculitis can occur as a primary process, or as a complication of:
  • meningitis (30% of adult cases and up to 90% of neonatal cases)
  • cerebral abscess
  • intraventricular haemorrhage, or
  • iatrogenesis
• Frequently associated with the presence of a CSF shunt, external ventricular drainage (EVD), or other intracranial device
• most CSF shunt-related infections occur in the first month after insertion

EVD-RELATED VENTRICULITIS

Bacteria can access through skin site and connections between tubes

• EVD-related infections rates range from <1% to 40% (9% in the UK according to Jamjoon et al, 2017)
• mortality rates vary from 10% to 75%

Risk factors

• length of time the EVD is in place (e.g >7 days)
• management (e.g. frequency of manipulation of EVD, especially repeated sampling)
• type of EVD
• insertion technique
• multiple catheter insertions or exchanges
• underlying disease
• neurosurgery
• CSF leakage
• previous infections

CAUSE

Usual organisms in EVD and CSF shunt infections:

• Staphylococcus aureus
• Coagulase negative Staphylococci (S. epidermidis)
• GNBs (up to 25%; more common if VP shunt due to peritoneal contamination): Escherichia coli, Klebsiella species, Acinetobacter, and Pseudomonas species
• consider fungi if immunosuppressed

CLINICAL FEATURES

Clinical features may be subtle in EVD-associated infections

• headache
• nausea and vomiting
• fever
• altered mental state
• focal neurological deficits
• secondary hydrocephalus/ raised ICP

INVESTIGATIONS

Blood tests

• WBC, CRP and procalcitonin are not very helpful

CSF analysis

• high WCC in the CSF (Normal RCC:WCC Ratio = 500:1 but this alone is of questionable reliability)
• CSF protein may be normal or high
• Reduction in CSF glucose may be a more sensitive indicator of infection
• Elevated CSF lactate has not been proven of utility
• Cell index (ratio of leukocytes to erythrocytes in CSF divided by leukocytes to erythrocytes in peripheral blood) may prove to be useful
  • usually about 1
  • tends to increase in ventriculitis, and fall with response to antibiotics
  • Beer et al (2009) used a 5-fold increase in Cell Index as indicative of ventriculitis (should be considered experimental)

CT/ MRI

• Ventriculitis is detected best by T2 fluid-attenuated inversion recovery (FLAIR) images showing periventricular hyperintensity on ependymal enhancement and irregular intraventricular debris
• CT may be non-specific

DIAGNOSTIC PITFALLS

In post-neurosurgical patients or patients with a ventriculostomy:

• systemic inflammatory response and clinical signs may be absent or subtle
• the CSF cell count may be elevated as a result of surgical manipulation and inflammation
• no single parameter can reliably predict or exclude EVD-related infection
• imaging should not delay treatment

MANAGEMENT

Treatment

• Clinical suspicion of nosocomial ventriculitis mandates prompt initiation of empiric antibiotic therapy
• Intravenous antibiotics (may vary according to local guidelines):
  • vancomycin 1.5 g (<12y: 30 mg/kg up to 1.5 g) Q12H (adjust for renal function)
  • PLUS EITHER:
    • ceftazidime 2 g (child: 50 mg/kg up to 2 g) IV Q8H, OR
    • meropenem 2 g (child: 40 mg/kg up to 2 g) Q8H
• Intraventricular antibiotics
  • not used routinely
  • use preservative-free formulations
  • options (may vary according to local guidelines):
    • vancomycin 10 to 20 mg daily
    • gentamicin 4 to 8 mg daily, or
    • amikacin 30 mg daily
• Removal +/- replacement of infected EVD if present
  • this may not be necessary unless there is inadequate response to antimicrobial therapy or the CSF is purulent
• rationalise antibiotics according to sensitivity
• antibiotic duration is usually 14 days after the last positive culture

Prevention in ICU

• antibiotic- and silver-impregnated EVD catheters appear to reduce rates of BV but are not in universal use
• remove EVD as early as possible (review indication daily)
• access EVD in a protocolised meticulous sterile fashion
• minimise the frequency of EVD manipulations
• routine CSF cultures are not necessary but should be performed if fever (e.g. >38.5 C), peripheral leukocytosis, neurological deterioration, or a change in CSF appearance is noted

References and Links

Journal articles

• Beer R, Pfausler B, Schmutzhard E, et al. Management of nosocomial external ventricular drain-related ventriculomeningitis. Neurocrit Care. 2009;10(3):363-7 [PMID 18982457]
• Flint AC, Rao VA, Renda NC, et al. A simple protocol to prevent external ventricular drain infections. Neurosurgery. 2013 Jun;72(6):993-9; discussion 999 [PMID 23467249]
• Jamjoom AAB, Joannides AJ, Poon MT, et al. Prospective, multicentre study of external ventricular drainage-related infections in the UK and Ireland. Journal of neurology, neurosurgery, and psychiatry. 2017 [PMID 29070645]

FOAM and web resources

• Radiopaedia — Ventriculitis