Prevalence and clinical features of mycoplasma pneumoniae in Thai children.

OBJECTIVE: To determine the prevalence and clinical features of mycoplasma pneumoniae in Thai children with community acquired pneumonia (CAP). MATERIAL AND METHOD: Diagnosis of current infection was based on > or = 4 fold rise in antibody sera or persistently high antibody titers together with the presence of mycoplasma DNA in respiratory secretion. The clinical features were compared between children who tested positive for M pneumoniae, and those whose results were negative. RESULTS: Current infection due to M. pneumoniae was diagnosed in 36 (15%) of 245 children with paired sera. The sensitivity and specificity of polymerase chain reaction (PCR) in diagnosing current infection in the present study were 78% and 98% respectively. The mean age of children with mycoplasma pneumoniae was higher than CAP with unspecified etiology. The presenting manifestations and initial laboratory finding were insufficient to predict mycoplasma pneumoniae precisely, the presence of chest pain and lobar consolidation on chest X-ray, however, were significant findings in children with mycoplasma pneumoniae. CONCLUSION: The present study confirms that M. pneumoniae plays a significant role in CAP in children of all ages. Children with this infection should be identified in order to administer the appropriate antibiotic treatment.

Prevalence and clinical presentations of atypical pathogens infection in community acquired pneumonia in Thailand.

OBJECTIVES: To determine the prevalence of atypical pneumonia and clinical presentations in patients with community acquired pneumonia (CAP). MATERIAL AND METHOD: A prospective multi-centered study was performed in patients aged > or = 2 years with the diagnosis of CAP who were treated at seven governmental hospitals in Bangkok from December 2001 to November 2002. The diagnosis of current infection was based on > or = 4 fold rise in antibody sera or persistently high antibody titers together with the presence of DNA of M. pneumoniae or C. pneumoniae in respiratory secretion or antigen of L. pneumophila in the urine. Clinical presentations were compared between patients with atypical pneumonia and unspecified pneumonia. RESULTS: Of 292 patients, 18.8% had current infection with atypical respiratory pathogens (M. pneumoniae 14.0%, C. pneumoniae 3.4%, L. pneumophila 0.4% and mixed infection 1.0%). Only age at presentation was significantly associated with atypical pneumonia in adults, while absence of dyspnea, lobar consolidation, and age > or = 5 years were significant findings for atypical pneumonia in children. CONCLUSION: The present study confirms the significance of atypical pathogens in adults and children. Moreover lobar consolidation is likely to predict atypical pneumonia in childhood CAP.

A prospective, randomized double-blind study in children comparing two doses of nebulized L-epinephrine in postintubation croup.

OBJECTIVE: To compare the effectiveness and side effects of nebulized l-epinephrine (NLE) at a dose of 0.05 mL/kg versus 0.5 mL/kg in the treatment of postintubation croup in children. MATERIAL AND METHOD: Thirty-nine children, who developed signs and symptoms of upper airway obstruction (UAO) after extubation, were randomized to receive either 0.05 mL/kg or 0.5 mL/kg of NLE. UAO scores, vital signs (VS) and possible side effects were recorded before and at 20 and 40 minutes after the treatment. RESULTS: Twenty-one and 18 patients were allocated to the 0.05 and 0.5 mL/kg groups, respectively. Both groups showed improvements in UAO scores over time. There were no significant differences in UAO scores and VS between the groups at all time points. Side effects of epinephrine were not observed. CONCLUSION: In children with postintubation croup, the administration of NLE at the dose of 0.05 mL/kg results in similar improvements in the UAO scores, compared with the dose of 0.5 mL/kg. No complications were seen in either dose.

Dead space ventilation in volume controlled versus pressure controlled mode of mechanical ventilation.

Dead space ventilation (VD) is one of the important measurements that indicates the ventilatory efficiency of a patient who requires mechanical ventilation. However, VD is not constant and can change according to the pathology in the lungs, ventilatory patterns, perfusion and ventilation-perfusion matching. The objective of this study was to measure and compare the dead space in pediatric patients who were using pressure controlled and volume controlled modes of mechanical ventilatory by measuring the difference between arterial PCO2 and end-tidal PCO2 [P(a-ET)CO2]. From November 1996 to March 1997, 12 patients who were admitted to the pediatric intensive care unit and needed ventilator support for various reasons, were enrolled in the study. Their ages ranged from 2 to 15 years. The mechanical ventilator (Benett 7200 or Servo 900C) setting during VD measurement i.e. tidal volume, inspiratory time and positive end expiratory pressure were kept constant between changing from pressure controlled to volume controlled mode or vice versa for twenty minutes in order to allow adequate time for equilibration. The P(a-ET)CO2 between volume controlled and pressure controlled mode were 3.1 and 2.6 torr (p = 0.5) and peak inspiratory pressure were 20.0 and 17.3 torr (p = 0.01), respectively; whereas mean airway pressure, PaO2, O2 saturation and heart rate revealed no significant difference between these two modes. The authors concluded that VD in pressure controlled mode from the present study was not significantly different from VD when using volume controlled mode of mechanical ventilation in the same patient. However, VD will change according to the pathophysiologic change in respiratory system and can be used for monitoring of ventilatory pattern of patients in the pediatric intensive care unit.

Respiratory syncytial virus-associated lower respiratory tract infection in under-5-year-old children in a rural community of central Thailand, a population-based study.

The population-based cohort study on the epidemiology of respiratory syncytial virus (RSV)-associated lower respiratory tract infection (LRI) (RSV-LRI) was conducted in Takhli district from November 1998 to February 2001. The incidence of RSV-LRI was 12.6/1,000 child-year and 5.8/ 1,000 child-year during the first and second year, respectively. RSV accounted for 35.8 per cent of all LRI cases during the first year and significantly decreased to 17.5 per cent during the second year. Three-quarters of RSV-LRI occurred among children under 2 years old (76.6% during the first year and 62.2% during the second year). Most of RSV-LRI in both years occurred from July to October. Risk factor for morbidity of RSV infections were age less than or equal to 2 years (OR = 2.38, 95% CI = 1.22-4.67 p = 0.009) and sleeping with more than 3 persons in the patient's bedroom (OR = 2.92,95% CI = 1.42-6.00, p = 0.002). Most RSV-LRI (63.9%) were clinically diagnosed as having pneumonia. No RSV-LRI deaths were detected. During the first year, RSV subtype B was predominate, in contrast to the second year when subtype A was more predominate. Further research to determine the annual change in subtype of RSV-LRI and correlation of severity of disease with specific subtypes needs to conducted in order to prepare for the future introduction of a vaccine.

Acute viral lower respiratory infections in children in a rural community in Thailand.

The present study was conducted as a population based cohort in a rural community of Amphoe Takhli, Nakhon Sawan province for the determination of the prevalence of acute viral lower respiratory infection (ALRI) in pediatric cases under 5 years of age from November 1998 to February 2001. There were 472 ALRI episodes during the study period; and there were 5 cases who contracted ALRI twice. The etiologic agents were determined by indirect immunofluorescence (IIF) test using specific monoclonal antibodies for the staining of exfoliated cells in nasopharyngeal aspirate (NPA) samples. The slides of fixed cells were prepared by Takhli Hospital and posted in ambient temperature to the Virology Laboratory, Siriraj Hospital where they were stained and examined. Among 472 episodes of ALRI, 170 (36.0%) viral agents were found. Viral agents were associated with 41.4 per cent of all pneumonic cases. Respiratory syncytial virus (RSV) was the most common virus observed in the present study; and it was also the most common virus associated with pneumonia and bronchitis. RSV subgrouping was performed directly in NPA samples by IIF test using a panel of subgroup specific monoclonal antibodies. RSV subgroup B predominated over subgroup A in the first study year, and it was vice versa in the second year. Overall, more cases of subgroup B were found which was in contrast to what the authors had reported in the previous study. Prevalence of RSV was seasonal dependent, the epidemic was seen during the rainy season with peaks in August or September of each year. As the method of viral identification was limited to IIF only, therefore, fewer viruses were detected. Parainfluenza viruses were detected as the second most common viral agent, the viruses spread during early summer with peaks in February or March of each year. However, its association with croup could not be demonstrated which may be due to the insensitivity of IIF in the diagnosis of non-RSV infection. Nevertheless, in terms of feasibility to investigate the disease in a rural area, IIF is economic, convenient and rapid; and gives enough information for the nationwide plan of a health care development system.