CNS Infections in Children: Experience from a Tertiary Care Center.

Sir,

Bacterial meningitis is associated with high mortality and morbidity, especially in children. Most common pathogens causing bacterial meningitis in children are Haemophilus influenzae type B (Hib) and Streptococcus pneumoniae, accounting for up to 75% of cases.[1] From March 2010 to April 2011, 400 children between 0 and 15 years old with symptoms of acute central nervous system (CNS) infection were screened, of which 54 who had cerebrospinal fluid (CSF) white blood cell count ≥10 cells/µl were recruited while those with history of road traffic accidents, CNS anomalies, and postoperative meningitis were excluded.

Conventional CSF culture, BacT/ALERT for CSF, latex agglutination, and conventional polymerase chain reaction (PCR) to detect the capsular polysaccharide gene of S. pneumoniae and TaqMan real-time PCR to detect the bcs B gene of Hib were performed with the sequences of the primers and PCR protocol described by Pai et al.[2] and Mayer,[3] respectively.

Fever was observed in 90% of children, vomiting and seizures in 51% of children. In 23 of the 54 children, a cause of CNS infection could be established. Thirteen (24%) of the 54 children were confirmed to have pyogenic bacterial meningitis, with eight due to S. pneumoniae, four due to Hib, and one case of Streptococcus pyogenes meningitis was detected by BacT/ALERT culture.

Culture, PCR, and latex agglutination detected five cases of S. pneumoniae and one case of Hib, whereas six cases were detected by nonculture methods, three pneumococcal meningitis by PCR only, one Hib meningitis by PCR and LA, and one case by LA alone. Spike and dilution tests performed on this sample ruled out PCR inhibitor; this was considered a false negative PCR test. Studies have shown that non culture methods have performed better, as demonstrated by Kennedy et al.[4]

In the 41 children who did not fit in the pyogenic group, three children were diagnosed as tuberculous meningitis based on a standard case definition and response to anti-tuberculosis treatment, four as rickettsial meningitis with Weil-Felix test positive along with the presence of eschar in three of them and all four showing dramatic response to doxycycline, three children as neurocysticercosis by standard diagnostic criteria including computed tomography scans showing typical ring-enhancing lesions. Interestingly, at 6 months follow-up, sequelae were seen in children who did not have a definite diagnosis; this reiterates that identification of the agent leads to effective treatment which reduces mortality and morbidity.[5]

In conclusion, culture and nonculture methods including radiological methods are necessary for the diagnosis of meningitis. This study reiterates the need for a battery of tests for the detection of these etiological agents causing CNS infections. Further studies to identify other etiological agents, especially viral causes need to be evaluated to diagnose meningitis in children.

Financial support and sponsorship

Fluid Research Grant of Christian Medical College, Vellore.

Conflicts of interest

There are no conflicts of interest.