Lumbar Puncture in Children With Influenza or Other Viruses
Lumbar Puncture in Children With Influenza or Other Viruses
The study was approved by the CHW Human Research Ethics Committee. Subjects for this study were identified by searching the database of the department of virology at the CHW for positive test results with influenza A, influenza B, parainfluenza viruses 1, 2, 3 and adenoviruses from nasopharyngeal aspirates and/or nose/throat swabs collected between 1 January and 31 December 2007. This year was chosen as it was a peak influenza year. Respiratory syncytial virus infections were excluded from the study as it is already established that the rate of RSV and concomitant bacteraemia and meningitis is very low in children.
Medical records for all children thus identified were reviewed to confirm that they had respiratory illness; additional data on clinical presentation, investigations performed and the course of illness were collected for analysis.
Baseline data on the influenza burden at our hospital for the same year have been published elsewhere. Our primary outcome measures for this study were the 'need for' (performance of) invasive diagnostic procedures, primarily LP but also blood culture, in children with influenza and ORVIs and whether bacterial meningitis or bacteraemia were concomitantly present.
Bacterial meningitis and bacteraemia were defined as the growth of a single known bacterial pathogen in the respective specimen cultures from normally sterile sites, cerebrospinal fluid or blood. Urinary tract infection (UTI) was defined as the growth of a single pathogenic organism with 10 colony-forming units/l of urine collected either by supra-pubic aspiration, in-and-out catheter or a clean catch. UTI was considered as coincidental infection (bacterial infection with a definite non-pulmonary focus). A culture was considered contaminated if there was a growth of bacteria that are usually considered contaminants (e.g. coagulase-negative staphylococcus) or if >1 bacterial organism was isolated.
Children presenting to CHW with respiratory symptoms underwent the collection of a nasopharyngeal aspirate or a nose/throat swab according to the clinical judgement of the treating paediatrician; it was transported to the virology laboratory in viral transport medium at 4°C. Specimens were then batched and tested for respiratory viruses using Simulfluor Respiratory Screen (Chemicon International, Temecula, CA, USA). Positive samples had influenza A confirmed with antibodies (Imagen; DakoCytomation, Ely, UK) using direct fluorescent microscopy. Samples that were negative for influenza A by direct immunofluorescence were cultured on R-Mix cells (Diagnostic Hybrids, Athens, OH, USA) at 37°C for 3 days and then labelled with antibodies to influenza A and influenza B (Imagen; DakoCytomation) using direct fluorescent microscopy. A laboratory diagnosis was defined by identification of a virus either by direct fluorescent antibody (DFA) or by culture fluorescence.
Data analysis was carried out using the Statistical Package for the Social Sciences (IBM SPSS Statistics 19 Inc, Somers, NY, USA). Comparisons were made between groups on several variables (e.g. type of respiratory viral infection, clinical presentation and presence of any SBI) using the chi-square test (with Yeats correction) or Fisher's exact test and multinominal logistic regression analysis where appropriate. Tests for normality were performed (Kolmogorov–Smirnov test), and when data were normally distributed, the differences in means between groups were compared by the independent samples t-test. The relative risk and corresponding 95% confidence interval (CI) were also calculated. A P-value of ≤0·05 was considered as significant.
Methods
Study Population and Setting
The study was approved by the CHW Human Research Ethics Committee. Subjects for this study were identified by searching the database of the department of virology at the CHW for positive test results with influenza A, influenza B, parainfluenza viruses 1, 2, 3 and adenoviruses from nasopharyngeal aspirates and/or nose/throat swabs collected between 1 January and 31 December 2007. This year was chosen as it was a peak influenza year. Respiratory syncytial virus infections were excluded from the study as it is already established that the rate of RSV and concomitant bacteraemia and meningitis is very low in children.
Medical records for all children thus identified were reviewed to confirm that they had respiratory illness; additional data on clinical presentation, investigations performed and the course of illness were collected for analysis.
Baseline data on the influenza burden at our hospital for the same year have been published elsewhere. Our primary outcome measures for this study were the 'need for' (performance of) invasive diagnostic procedures, primarily LP but also blood culture, in children with influenza and ORVIs and whether bacterial meningitis or bacteraemia were concomitantly present.
Bacterial meningitis and bacteraemia were defined as the growth of a single known bacterial pathogen in the respective specimen cultures from normally sterile sites, cerebrospinal fluid or blood. Urinary tract infection (UTI) was defined as the growth of a single pathogenic organism with 10 colony-forming units/l of urine collected either by supra-pubic aspiration, in-and-out catheter or a clean catch. UTI was considered as coincidental infection (bacterial infection with a definite non-pulmonary focus). A culture was considered contaminated if there was a growth of bacteria that are usually considered contaminants (e.g. coagulase-negative staphylococcus) or if >1 bacterial organism was isolated.
Laboratory Methods
Children presenting to CHW with respiratory symptoms underwent the collection of a nasopharyngeal aspirate or a nose/throat swab according to the clinical judgement of the treating paediatrician; it was transported to the virology laboratory in viral transport medium at 4°C. Specimens were then batched and tested for respiratory viruses using Simulfluor Respiratory Screen (Chemicon International, Temecula, CA, USA). Positive samples had influenza A confirmed with antibodies (Imagen; DakoCytomation, Ely, UK) using direct fluorescent microscopy. Samples that were negative for influenza A by direct immunofluorescence were cultured on R-Mix cells (Diagnostic Hybrids, Athens, OH, USA) at 37°C for 3 days and then labelled with antibodies to influenza A and influenza B (Imagen; DakoCytomation) using direct fluorescent microscopy. A laboratory diagnosis was defined by identification of a virus either by direct fluorescent antibody (DFA) or by culture fluorescence.
Statistical Analysis
Data analysis was carried out using the Statistical Package for the Social Sciences (IBM SPSS Statistics 19 Inc, Somers, NY, USA). Comparisons were made between groups on several variables (e.g. type of respiratory viral infection, clinical presentation and presence of any SBI) using the chi-square test (with Yeats correction) or Fisher's exact test and multinominal logistic regression analysis where appropriate. Tests for normality were performed (Kolmogorov–Smirnov test), and when data were normally distributed, the differences in means between groups were compared by the independent samples t-test. The relative risk and corresponding 95% confidence interval (CI) were also calculated. A P-value of ≤0·05 was considered as significant.