Pediatric emergency medicine trisk 4024 4024

meningitis, including fever; therefore, the diagnosis may depend entirely
upon examination of CSF and careful observation. If a shunt reservoir is
present, then CSF may be obtained with a shunt tap. As mentioned in a
prior section of the chapter, a CT scan or MRI of the brain should be
performed prior to lumbar puncture. Lumbar puncture in the backdrop of
unrecognized hydrocephalus or mass lesion may risk a potentially fatal
herniation syndrome. The manifestations of postoperative meningitis are
often much more subtle than those of the typical pneumococcal or
meningococcal variety. If signs of meningeal irritation should occur in
isolation or in association with any other changes, neurologic or metabolic,
examination of the CSF is mandatory before any antibiotics are
administered. Because cell count, glucose concentration, and protein
concentration are abnormal after craniotomy, an absolute diagnosis must
await the result of CSF culture or the demonstration of bacteria on Gram
stain. Empiric treatment with broad-spectrum intravenous antibiotics should
be started immediately following LP and directed at gram-positive cocci
and gram-negative organisms, as described in the previous section. The
antibiotic regimen should then be tailored once the final culture results and
sensitivities have been obtained.
Ventriculitis. The clinical picture of ventriculitis differs little from that of
meningitis, although the presentation is usually much more subtle.
Meningeal symptoms may be minimal and fever variable, whereas
alteration in mental status and neurologic function predominate. Both
meningitis and ventriculitis tend to occur in the postoperative period more
than 3 days after violation and contamination of the subarachnoid or
ventricular space. The only diagnostic test is microscopic and bacteriologic
examination of the ventricular fluid. As with meningitis, broad-spectrum
antibiotics should be initiated pending Gram stain and culture results.
Abscess. Brain abscess, or its immediate precursor, cerebritis, is relatively
rare in the postoperative period. If an abscess does not communicate with
the ventricular or subarachnoid space, meningeal signs will usually be

absent. The development of meningeal signs or infected CSF in the face of
focal deficits must heighten the clinician’s suspicion for abscess. However,
in 95% of cases of cerebral abscess, the CSF may be completely normal and