Ventriculitis pearls and a few more meningitis pearls

Ventriculitis
1.  Occurs in 30 % of adult meningitis cases, 90  % of neonatal cases.  Often thought of as a late occurrence in refractory meningitis but can occur as primary event also.

2.  Commonly occurs with EVD or VP shunt, less commonly if EVD management protocols are strictly adhered to.

3.  Hemorrhagic CSF is considered a risk factor

4.  Gram positive organisms such as Staph aureus and Staph epidermidis are most common, but gram negative organisms also occur.  (E coli, Klebsiella, Acinetobacter, pseudomonas species.

5.  Cell index is ratio of WBC: RBC in CSF:Serum.  Its used in ventriculostomy cases with IVH to consider infection.  It is one normally and in ventriculitis patients without infection.  In 7 patients with definite ventriculitis, index rose 3 days before diagnosis of ventriculitis and declined with antibiotic treatment (Pfauler et al. Acta Neurchir 2004)

CSF in meningitis
5.  Common practice is to perform CT first, then LP, then begin therapy.  These practices lead to delay in antimicrobial treatment which actually is worse for patient than risk of performing lumbar puncture.  In many cases antibiotics should be given before CT because even a delay of a few hours can be catastrophic.   Aronin et al. ANn Int Med 1998.

6.  Delay of LP is not needed if the following factors are not present:  immunosuppression, ( to R/O toxo or lymphoma), alteration in mentation, focal deficits, seizures, pappilledema, ocular palsies, bradycardia or irregular respirations, sedation or muscle paralysis.   see Mellor DH. Arch Dis Children 1992.

7.  CSF findings in bacterial meningitis WBC> 1000 (60 %) and > 100 (90%); CSF glc < 40 (50 %) but CSF : serum glc < 0.4 80 % sensitive and 98 % specific. 

8.  Blood cultures are positive in about 50 % of cases of bacterial meningitis, but touch preparation of the rash is positive in 70 % on Gram stain.

9.  CSF lactate is not helpful in community acquired meningitis but is helpful in postop neurosurgical cases.  A cutoff of 4 mmol/L lactate in CSF is superior to measuring the glucose CSF: serum ratio.  88 % sensitive, 98 % specific, ppv 96 %, npv 94 %.

10.  Latex agglutination CIE is useful only for certain organisms and in patients with pretreatment of antibiotics and negative cultures.

11.  C reactive protein is sensitive for bacterial meningitis in some pediatric population esp. with CSF profile c/w meningitis but negative gram stain. 

12.  Procalcitonin levels differentiate bacterial and virla meningitis in kids (cutoff > 5, 94 %  sensitive, 100 % specific).  Also in adults ( cutoff > .2 ng/mL , sensitivity and specificity 99 %) .  Moreover the levels decline rapidly, within 24 hours, and may be useful to monitor the effectiveness of the treatment.   (Gendrel et al, Clin Inf Dis 1997, Viallon et al, Clin Inf Dis 1999, ibid. Crit Care 2005).  PCT levels remain normal in ventriculitis and do not help in that situation.

13.  Real time PCR is emerging but disadvantage include a lack of sensitivity, lack of sensitivity to antibiotics result, false negatives and contamination issues.