Clinical spectrum of meningococcal infection in infants younger than six months of age.

BACKGROUND

Neisseria meningitidis is one of the most significant bacterial infections in children and adolescents. As transplacental antibodies in the circulation gradually decline, the prevalence of meningococcal disease among young infants is high, and often presents an invasive clinical manifestation. The purpose of the study was to investigate the clinical spectrum of meningococcal infection in young infants.

METHODS

We retrospectively reviewed of the medical charts and analyzed the clinical characteristics and outcomes of 10 infants younger than 6 months old with meningococcal disease at the Chang Gung Children's Hospital from 1994 through 2004.

RESULTS

A total of 10 male infants with a mean onset age of 2.9 +/- 1.79 months old were enrolled. All patients presented initial symptoms of fever and decreased activity. Seizure attack was noted in six cases, and only three patients had purpuric or petechial rash. Laboratory findings reflected pyogenic infection including elevated C-reactive protein (159.1 +/- 108.8 mg/L), pleocytosis (791.11 +/- 660.83/microL), high protein levels (190.43 +/- 157.91 g/dl) and hypoglycorrhachia (28 +/- 20.89 mg/dl) in the cerebrospinal fluid. Seven cases presented meningitis; among those, N. meningitidis was isolated from blood in two cases. Three of the remaining patients had meningococcemia. Penicillin was the most common drug of choice; cephalosporin was the alternative. Prolonged antimicrobial therapy (range, 14 to 42 days) was prescribed in six patients complicated with subdural empyema. No deaths were documented. During long-term follow up, two patients developed mental retardation, and one of those two also had epilepsy. Both of them had lower birth body weight, altered initial conscious level, leukocytopenia and subdural empyema with encephalomalacia on brain images. One had insufficient therapy and another one was infected by a penicillin resistant strain.

CONCLUSIONS

Clinicians should be aware of meningococcal infection in young infants because the initial presentations may be difficult to distinguish from viral syndrome, and may rapidly progress to clinical deterioration. Patients with subdural empyema required prolonged courses of antimicrobial therapy. Brain images confirmed the presence of encephalomalacia which increased the risk of permanent neurologic deficit.