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.

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.

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).

• Chest (rales) and cardiac exam.

• Neurologic exam (mental status, strength, reflexes, focal neurological signs).

• Skin rashes.

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.

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.

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.

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.