Introduction
Meningitis is an inflammation of the meninges (the coverings surrounding the brain)
identified by an abnormal number of white blood cells
(WBCs) in the cerebrospinal fluid (CSF). It is the most common medical emergency in children. Mortality from acute bacterial
meningitis has remained at 5 to 10 percent despite antibiotic therapy and as many as 50
percent of survivors have some sequelae from their disease. Acute meningitis is usually
caused by bacteria and viruses, but in a small number of cases may be due to TB or fungi.
Signs and symptoms
Symptoms and signs of bacterial meningitis are variable and depend on the age of
the patient, duration of illness, and the child's response to infection. Newborns and
young infants may have minimal physical signs making an early diagnosis difficult to
establish clinically. Fever (not always present) lethargy, respiratory distress, jaundice,
poor feeding, or vomiting, and diarrhea are common nonspecific manifestations of invasive
bacterial infection in newborns. In children, fever, headache, photophobia, nausea, or
excessive irritability are the usual initial complaints. These manifestations are
nonspecific and often indistinguishable from those of an acute viral illness. A change in
the child's affect or state of alertness is one of the most important signs of meningitis.
A high index of suspicion will assist in the early diagnosis of acute bacterial
meningitis.
Important points to document
When the diagnosis of meningitis is considered, the following should be
carefully documented in the medical record:
-
Temperature, vital signs, and a general statement about the condition of the child,
especially his or her state of alertness.
-
Head and neck examination: nuchal rigidity, fundi (papilledema), ears (otitis media),
throat (exudates, peritonsillar abscess), fontanelle (bulging).
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Chest (rales) and cardiac exam.
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Neurologic exam (mental status, strength, reflexes, focal neurological signs).
-
Skin rashes.
Laboratory
Diagnosis of bacterial meningitis is most dependent upon careful examination of the
spinal fluid. Laboratory studies should include a CBC with differential and a platelet
count (leukocytosis, neutropenia, thrombocytopenia) and a lumbar puncture (LP). The LP is
the only test that can rule out bacterial meningitis. Documentation of the CSF should
include the color (cloudy), WBCs with differential (total number of PMNs or lymphs), RBCs
total protein (increased), glucose (decreased), gram stain (positive or negative), and
bacterial and viral cultures. Serum sodium may be inappropriately low (SIADH). Obtain a urinalysis, electrolytes, BUN, creatinine, chest x-ray, urine culture, and blood cultures
x 2.
Differential diagnosis
A differential diagnosis of meningitis includes acute viral illness, otitis media,
sepsis, pneumonia, retropharyngeal abscess, acute tonsillitis, encephalitis, subdural
hematoma, and pyelonephritis. All patients with meningitis should be admitted to the
hospital for evaluation and treatment.
Antibiotics
The antibiotic treatment of meningitis for infants and children >3 months of age
is IV Cefotaxime (Claforan) 200 mg/kg/d divided q6h. An alternative therapy is IV
Ceftriaxone (Rocephin) 100 mg/kg/d divided q1-2h. Add Vancomycin (60mg/kg/d IV divided q6h
for a minimum of 48 hours if you suspect pneumococcal meningitis, if the gram stain
demonstrates gram positive cocci, or if frank pus is seen in the CSF. Repeat the LP in 24
to 48 hours. Infants 1-3 months of age with meningitis should be treated with a
combination of Ampicillin 200-300 mg/kg/day and Cefotaxime 200 mg/kg/day, both divided q6h
IV. If the patient does not improve within 48 to 72 hours, a repeat LP is indicated.
Carefully, monitor fluids and watch for SIADH. Restrict fluids 1/2 to 2/3 maintenance for
the first 48 to 72 hours.
Summary
Acute bacterial meningitis is a medical emergency. A physician who is familiar with
diagnosis and care of children with meningitis should be consulted immediately. Children
should never be sent home if the results of the LP are not known or are abnormal.
Reviewed by CDR Wendy Bailey, MC, USN, Pediatric Specialty Leader, Naval Medical
Center San Diego, San Diego, CA (1999).