OF SEIZURES THAT REQUIRE ANTIEPILEPTIC DRUGS
presence of bacterial meningitis is suspected on clinical grounds. Bacterial
meningitis is tentatively diagnosed by an abnormal cerebrospinal fluid
cell count, sugar level, and protein concentration, and the detection
of antigen in the cerebrospinal fluid. Bacterial meningitis is conclusively
diagnosed by cerebrospinal fluid Gram-stained smear and culture.
Meningitis usually occurs with late-onset (after
7 days) sepsis. Seizures may be the first sign of meningitis. Neonates
with bacterial meningitis are usually lethargic after the seizures. The
anterior fontanel may be bulging. Neck rigidity may be present.
Seizures in neonates with meningitis are usually due to microscopic or
macroscopic ischemic vascular parenchymal lesions but the possibility
of hypocalcemia, hypoglycemia, hyponatremia, abscess, and subdural empyema
should be considered. The organisms usually associated with bacterial
meningitis are group B streptococcus, Escherichia coli, Listeria monocytogenes,
Staphylococcus aureus, and Pseudomonas aeruginosa.
The tentative diagnosis of bacterial
meningitis should be made in neonates with seizures if the cerebrospinal
fluid shows less than 100 red blood cells per cubic millimeter and more
than 11 white blood cells per cubic millimeter (90% of neonates without
meningitis have 11 white blood cells per cubic millimeter or less)
or if organisms are present in the Gram-stained smear. Neonates with seizures
having any of these parameters should be treated with antibiotics while
awaiting the results of the CSF culture. These patients should undergo
a careful physical examination searching for a primary source of infection
such as otitis media, arthritis, or skin infection.
For practical purposes, a negative
cerebrospinal fluid culture eliminates the possibility of bacterial meningitis
if the Gram-stained smear is also negative and the patient did not receive
antibiotics before the lumbar puncture. If a cerebrospinal fluid culture
is negative but the Gram-stained smear is positive, or the patient received
antibiotic treatment before the lumbar puncture was done, a full course
of antibiotics should be administered.
An MRI of the brain should be
performed when the patient is stable or if deterioration occurs after
initiation of treatment or fever persists after several days of the appropriate
antibiotic treatment. Deterioration raises the possibility of localized
intracranial infection. Localized intracranial infections include brain
abcesses, subdural empyema, and ventriculitis.
The choice of antibiotics depends
on the type of organism isolated and its sensitivity. Prior to isolation
of the organism, treatment should be initiated with ampicillin and gentamicin.