Mycoplasma pneumoniae infections in children presenting with central nervous system manifestations

Objectives To study the incidence of Mycoplasma pneumoniae infection among children presenting with central nervous system (CNS) manifestations. Design Prospective study. Setting University Paediatric Unit, Teaching Hospital, Karapitiya. Method Children above 1 year of age, presenting with features of CNS infection, from January to December 2001, were included. Serum samples were tested for Mycoplasma pneumoniae infection by using particle agglutination test in addition to the usual laboratory tests. The conventional management protocols for CNS infections were carried out. Anti mycoplasma therapy was started once the dignosis of Mycoplasma pneumoniae infection was established. Results Mycoplasma pneumoniae infection was established in 8 of 35 children presenting with CNS manifestations. Their age range was 2-12 years. Five had meningoencephalitis and 3 had encephalitis. Mycoplasma antibody titres ranged from 160 to 5,120. Conclusions Mycoplasma pneumoniae is an important association in children with meningoencephalitis or encephalitis.


Introduction
Mycoplasma pneumoniae characteristically causes respiratory tract infections in both children and adults 1,,2 .It is a well known agent for atypical pneumonia.However, infections in central nervous system (CNS), hepatobiliary system and _________________________________________ 1 Senior Lecturer in Paediatrics, Faculty of Medicine, Galle.

Method
A prospective study was carried out in the university paediatric unit, Teaching Hospital, Karapitiya from January to December 2001, on children above 1 year of age, presenting with features of CNS infection, to find out the incidence of Mycoplasma pneumoniae among these patients.
Blood for mycoplasma antibody titre was taken along with blood culture, white cell count, erythrocyte sedimentation rate (ESR) and serum for virology (including Japanese encephalitis).Lumbar punctures were not done during the acute stage and cerebrospinal fluid (CSF) analysis was done around 3 rd to 5 th day.Particle agglutination test for Mycoplasma pneumoniae was done at the Department of Microbiology, Faculty of Medicine, Galle.With this test a titre of 80 or more was considered as diagnostic of mycoplasma infection.Mycoplasma antibody titre of the CSF was not done as facilities were not available.Conventional management protocols for CNS infections were carried out until mycoplasma infection was established when anti mycoplasma therapy was started.
Informed consent was obtained from the parents.Ethical approval was obtained from the Ethics Committee, Faculty of Medicine, Galle.

Results
Fever, signs of meningeal irritation and alteration of level of consciousness were found in 35 patients (23 boys, 12 girls).19 of these patients had features of meningoencephalitis, 10 of meningitis and 6 of encephalitis without meningitis.Headache was found in 24 patients, vomiting in 20 and in 14 patients.Diagnosis of Mycoplasma pneumoniae infection was established in 8 patients (5 boys, 3 girls).Five of the eight patients had meningoencephalitis and the other three had encephalitis.Mycoplama antibody titres ranged from 160 to 5120.Mycoplasma antibody test results were available by 4 th day after admission in most instances.Then the CNS treatment protocol was stopped and only the anti mycoplasma therapy was continued except in 3 cases who were very ill on admission in whom both conventional therapy and anti mycoplasmal therapy were continued for the full length of time.Seven patients were seen between November to April which is the period where the incidence of Mycoplasma pneumoniae infection is high according to my experience (Table 1).This could be due to administration of antimeningitic therapy before doing a lumbar puncture.Viral studies, including Japanese encephalitis serology, were negative in 6 of the Mycoplasma pneumoniae positive patients.Results could not be traced in the other 2 patients.

CNS manifestations appear in 1 per 1000 patients with
Mycoplasma pneumoniae infections 11 .Encephalitis is the most frequent manifestation but meningitis, myelitis, polyradiculitis, acute cerebellitis and Guillain-Barré Syndrome have also been reported.Very rarely it can cause brain stem encephalitis 12 .Onset of these manifestations is usually acute with lowered consciousness, convulsions, pareses and other neurological signs.Severe and even fatal cases have been reported.
In our study 8 out of 35 patients with CNS manifestations had an established Mycoplasma pneumoniae infection.Majority of them had meningoencephalitis.The pathophysiology of CNS manifestations of Mycoplasma pneumoniae is unknown.Mycoplasma pneumoniae has never been isolated from the brain tissue, but it has been recoverd from CSF specimens in some cases.Biochemical and CSF findings are similar to that of meningoencephalitis.
The author has observed that Mycoplasma pneumoniae pneumonia has an increased incidence during the period from November to April.A similar pattern was observed with Mycoplasma pneumoniae associated CNS infections too.It is important to suspect the possibility of Mycoplasma pneumoniae infection in any child with symptoms of CNS infection, especially in those who are above 4 years of age.

Conclusions and recommendations
• Mycoplasma pneumoniae is an important association and possible causative agent of CNS infections such as meningoencephalitis and encephalitis. • . Early diagnosis of some of these infections would prevent serious consequences 9 .

Table 1
Description of Mycoplasma pneumoniae positive patients.