CAUSATIVE AGENTS OF SEVERE COMMUNITY ACQUIRED VIRAL PNEUMONIA AMONG CHILDREN IN EASTERN THAILAND

Pneumonia is a leading cause of morbidity and mortality among infants and young children. The most common causes of pneumonia in children are respiratory viruses. In Thailand, the epidemiology of the viruses causing community-acquired pneumonia (CAP) among children is poorly defined. In this cross sectional study we used nasopharyngeal samples collected from hospitalized children diagnosed with severe CAP in accordance with WHO criteria between June 2013 and May 2014 to determine the causes of infection. The samples were analyzed for respiratory syncytial virus (RSV), parainfluenza viruses (PIV) types 1,2 and 3, adenovirus, rhinovirus, influenza viruses types A and B and coronavirus by polymerase chain reaction (PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). Of 102 cases of severe CAP, samples were obtained in 91 cases and 48 (52.7%) were positive for respiratory viruses. The most common viruses were RSV (n = 22; 45.8%), rhinovirus (n = 11; 22.9%) and adenovirus (n = 9; 18.7%). Patients were aged 1 month to 4 years 5 months, with a median age of 1 year 1 month. Thirty-seven (77.1%) were male. Asthma was the most common co-morbidity affecting 5 (10.4%) of the 48 cases with an identified virus. The peak prevalence occurred during October (n = 17). All patients required oxygen therapy and 17 (35.4%) required mechanical ventilation. The median length of hospitalization was 11 days. Preterm infants had a significantly higher rate of RSV infection than other respiratory viruses (8 of 21; 38% vs 3 of 27; 11.1%) (p = 0.02). Viruses were most commonly associated with severe CAP among children aged less than 1 year. The peak prevalence occurred during the rainy season. Our findings suggest that young and preterm infants with CAP should be monitored closely due to their high risk for developing serious complications.

Human parainfluenza virus infection in Thai children with lower respiratory tract infection from 2010 to 2013

Human parainfluenza virus (HPIV) is a common cause of upper and lower respiratory illness in infants and young children. In order to classify the HPIV isolates circulating in the central part of Thailand, 650 samples obtained from the lower respiratory tract of patients from two hospital pediatric wards during 2010 to 2013, were analyzed for the presence and types of HPIVs by multiplex semi-nested PCR of hemagglutinin-neuraminidase (HN) gene. The results showed that 4.8% of the samples were positive for HPIV, among which 0.5%, 2.5% and 1.5% were positive for HPIV-1, HPIV-3, and HPIV-4, respectively, and none were positive for HPIV-2. A phylogenetic tree constructed from 31 HPIV HN gene sequences compared to those in GenBank showed greater than 80% identity to other reference strains. Prevalence of HPIV infection and phylogenetic characteristics of the circulating HPIVs may help explain the impact of HPIVs infection in Thai children.

Clinical outcomes after utilizing surviving sepsis campaign in children with septic shock and prognostic value of initial plasma NT-proBNP

BACKGROUND AND OBJECTIVE

The surviving sepsis campaign treatment guideline (SSC) implementation is associated with improved outcome in adults with severe sepsis. The effect on outcome of pediatric sepsis is less clear.

PURPOSE

To determine the clinical outcomes of SSC implementation and to investigate the prognostic value of initial plasma NT-proBNP and procalcitonin in children.

MATERIALS AND METHODS

Infants and children (aged 1month/0-15 years with severe sepsis or septic shock) were prospectively enrolled and treated according to the guidelines. Initial blood drawn was saved for NT-pro-BNP, procalcitonin measurements and clinical data were also recorded.

RESULTS

A total of 47 subjects were recruited. Since the application of the SSC, our mortality rate had significantly decreased from 42-19% (P = 0.003) as compared to the data in the previous 3 years. Clinical factors that significantly increased the mortality rate were: Initial central venous oxygen saturation < 7 0% after fluid resuscitation [odds ratio (OR) = 23.3; 95% confidence interval (CI) 3.7-143; P = 0.001], and initial albumin level (≤ 3 g/dl, OR = 6.7; 95% CI 1.2-37.5, P = 0.03). There was asignificant difference between the initial NT-proBNP levels between survivors and non survivors, (6280.3 ± 9597 ng/L, P < 0.001), but not for procalcitonin (12.7 ± 24.8, 29.3 ± 46 μg/L, P = 0.1), respectively. An initial NT-proBNP level of more than 11,200 pg/ml predicted Pediatric Intensive Care Unit (PICU) mortality with a sensitivity of 85.7% and a specificity of 90%.

CONCLUSIONS

A modified SSC for severe sepsis and septic shock significantly reduced the mortality rate in our PICU. High initial NT-ProBNP level was associated with mortality.

Incidence of recurrent wheezing in under 5-year-old human bocavirus infection during one year follow-up

BACKGROUND

Human bocavirus (HBoV) is a newly identified virus that can cause acute wheezing in young children. The present study aimed to evaluate the incidence and factors associated with recurrent wheezing during 1 year after HBoV lower respiratory tract infection (LRI).

MATERIAL AND METHOD

Children younger than 5 years old who were admitted to King Chulalongkorn Memorial Hospital between February 1, 2006 and September 30, 2008 due to LRI were recruited. Their nasopharyngeal aspirates were evaluated for respiratory virus by polymerase chain reaction (PCR) assays. Those who had positive PCR for HBoV and had no underlying diseases were studied. Their clinical presentations were evaluated and their clinical data about recurrent wheezing as well as pulmonary function tests were followed-up for 1 year.

RESULTS

Fifteen patients with HBoV-LRI were regularly followed-up. Seven patients (47%) had co-infection with other respiratory viruses. Generalized wheezing was the most common lung sign detected in 73% of cases (11 cases) and 36% (4 cases) of them responded well to bronchodilators. During one year follow-up, serial pulmonary function tests were normal in all cases and most patients were doing well. However 27% of HBoV infected patients (4 cases) developed recurrent wheezing associated with respiratory tract infections. Two of them had to be re-hospitalized. Compared to patients without recurrent wheezing, eosinophil count tended to be higher in those with recurrent wheezing and isolated HBoV infected patients tended to develop recurrent wheezing more than those with co-infection.

CONCLUSION

Acute wheezing is a common presenting lung sign in HBo V-LRI. Although the pulmonary function tests of all patients were normal, more than a quarter of patients suffered from recurrent wheezing during one-year follow-up.

Potent inflammatory cytokine response following lung volume recruitment maneuvers with HFOV in pediatric acute respiratory distress syndrome

OBJECTIVE

Lung volume recruitment maneuver (LVRM) may improve gas exchange but inflating the lungs to nearly vital capacity may cause further lung injuries. Our aim was to determine the potent inflammatory cytokine response following lung volume recruitment (LVRM) with high frequency oscillator ventilation (HFOV) in pediatric acute respiratory distress syndrome (ARDS).

METHODS

We prospectively recruited pediatric patients (age >1 month - <15 year old) with a diagnosis of ARDS within 72 hrs of PICU admission. They underwent the LVRM protocol combined with HFOV. Any enrolled subject who had a 20% improvement in PaO2/FiO2 (PF ratio) 1 hr after the LVRM we classified as a responder. Baseline clinical data were recorded. Blood was also drawn at baseline, 1 & 24 hrs after LVRM and kept for further sICAM-1, IL-6 & IL-8 analysis.

RESULTS

Eighteen children with ARDS were enrolled. Their mean age was at 6.8 +/- 6.1 years (mean +/- SD). The initial oxygen index (iOI) was at 26.8 +/- 17.8 (11.5-84.9). There was no significant differences in sICAM-1, IL-6 and IL-8 levels at baseline; (34 +/- 17.5, 121.7 +/- 115.15, 601.5 +/- 675 pg/ml); 1 hr (39.6 +/- 28.7, 99.8 +/- 75.5, 617.4 +/- 692.5 pg/ml) and at 24 hrs (44.23 +/- 34.4, 109.4 +/- 63.9, 737.6 +/- 922.3 pg/ml) following LVRMs, respectively. However, there was significant difference in the elevation of sICAM-1 levels (%change) from baseline in responders (-1.8 +/- 12.2%) vs. non-responders (47.65 +/- 43.5%) at 1 hr. Additionally, sICAM-1 levels were also significantly higher at baseline, 1 hr and 24 hrs in non-survivors as compared with survivors.

CONCLUSION

There was no significant elevation of potent inflammatory cytokines that may indicate further lung injuries in the majority of our patients. However, there was significant elevation of sICAM-1 levels in non-responders and in those who did not survive that may indicate more lung injuries in these individuals.

The long duration of extracorporeal membrane oxygenation in a child with acute severe hypoxic respiratory failure treated in a resource-limited center

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) has been indicated in patients with severe refractory respiratory failure from various causes for more than 30 years, even for the small infant.(1) Improved outcome from using ECMO for respiratory failure has been reported worldwide, ranging from 15% to over 50% in recent reviews.(1,2) The rationale of this therapy is to allow time for the lungs to heal, minimizing further lung injury from positive pressure ventilation.(3,4) We describe a case of severe acute respiratory distress syndrome (ARDS) with extensive barotrauma supported by VV-ECMO for 96 days in a resource-limited center. This is likely the longest ECMO support ever reported in a child.

Gas exchange abnormality during sleep in non-snoring severe thalassemia children

OBJECTIVE

To study the prevalence and associated factors of gas exchange abnormality during sleep in non-snoring severe thalassemia children.

MATERIAL AND METHOD

Non-snoring severe thalassemia children aged 6 to 15 years who had been followed up at King Chulalongkorn Memorial Hospital between June 2009 and March 2010 were studied. Overnight pulse oximetry and end-tidal carbon dioxide tension (P(ET)CO2) monitoring as well as pulmonary function tests were evaluated.

RESULTS

Fifty-eight non-snoring severe thalassemia children (aged 10.5 +/- 2.6 years, 43% male) were studied. 67.2% showed abnormal gas exchange during sleep. All of them had nocturnal desaturation (nadir SpO2 87 +/- 6.9%; range 65 to 94%). 33.3% of those who had nocturnal desaturation had associated lung function abnormality. Abnormal lung function was found in 32.8% of the present study patients. Of these, 68.4% had associated nocturnal desaturation. Age, gender nutritional status, size of liver and spleen, history of splenectomy, hemoglobin and serum ferritin level, and lung function were not associated with abnormal gas exchange during sleep.

CONCLUSION

Nocturnal desaturation was demonstrated in more than a half of non-snoring severe thalassemia children. Normal lung function did not guarantee normal gas exchange during sleep. However, more than a half of those who had lung function abnormality had associated nocturnal desaturation. Evaluation of gas exchange during sleep would be merited in this group of patients.

High prevalence of human rhinovirus C infection in Thai children with acute lower respiratory tract disease

Objective

To determine the prevalence of human rhinoviruses (HRV) infections in children with lower respiratory disease in Thailand and monitor the association between species of HRV and clinical presentation in hospitalized paediatric patients.

Method

Two hundred and eighty-nine nasopharyngeal (NP) suction specimens were collected from hospitalized paediatric patients admitted to King Chulalongkorn Memorial Hospital, Thailand during February 2006–2007. Nucleic acids were extracted from each sample with subsequent amplification of VP4/2 by semi-nested RT-PCR for HRV detection. Other viral respiratory pathogens were also detected by PCR, RT-PCR or real time PCR. Nucleotide sequences of the VP4 region were used for genotyping and phylogenetic tree construction.

Result

In total, 87 of 289 specimens were positive for HRV indicating an annual prevalence of 30%. Wheezing or asthma exacerbation was the most common clinical presentation observed in infected patients. Sequence analysis and phylogenetic tree showed that 29 (33%) and 8 (9%) specimens belonged to HRV-A and HRV-B, respectively. Most of the HRV positive samples were HRV-C (58%). Moreover, species C was predominantly found in the paediatric population of Thailand in raining season (p < 0.05). The frequency of co-infection of HRV-C with other respiratory viral pathogens was approximately 40%.

Conclusion

HRV-C represents the predominant species and is one of the etiologic agents in acute lower respiratory tract infection, causes of wheezing and asthma exacerbation in infants and young children in Thailand.

Multidrug-resistant hospital-associated infections in a pediatric intensive care unit: a cross-sectional survey in a Thai university hospital

OBJECTIVE

To determine the incidence and associated factors of multidrug-resistant hospital-associated infections (MDR-HAI) in a pediatric intensive care unit (PICU) of a university hospital in Thailand.

METHOD

A prospective study was performed in the PICU of King Chulalongkorn Memorial Hospital during the period May-December 2005. Children aged < or = 15 years who developed a PICU-related HAI were studied.

RESULTS

Forty-four patients (median age 6 months; male:female = 1.4:1) developed 58 episodes of PICU-related HAI. The HAI rate was 28.3 per 1000 patient-days. Thirty episodes (52%) were MDR-HAI. The following were found more frequently in MDR-HAI when compared to non-MDR-HAI: Acinetobacter baumannii (50% vs. 23%, p = 0.04), female sex (60% vs. 29%, p = 0.02), admission to the PICU with a medical condition (90% vs. 64%, p = 0.03), PICU stay longer than 7 days prior to the development of HAI (67% vs. 36%, p = 0.03), and previous use of broad-spectrum antibiotics (83% vs. 43%, p = 0.002). Independent risk factors for MDR-HAI included female sex (OR = 5.5, p = 0.03) and previous use of a broad-spectrum antibiotic (OR = 9.7, p = 0.01).

CONCLUSION

The incidence of MDR-HAI was high in the PICU. Female sex and previous use of a broad-spectrum antibiotic were independent risk factors for MDR-HAI.

Prevalence, clinical presentations and complications among hospitalized children with influenza pneumonia

Viral respiratory tract infections are a major cause of hospitalization in children. Influenza is common but often not laboratory proven. We report a prospective study of children admitted with a clinical diagnosis of pneumonia. Infants and children (ages 1 month-15 years) who were hospitalized with community-acquired pneumonia were enrolled in the study. Their nasopharyngeal aspirated samples were analyzed for common respiratory viruses, including influenza virus, by reverse transcription-polymerase chain reaction (RT-PCR) or PCR. Out of 257 patients, we identified 127 (49.4%) cases with respiratory viruses, and influenza was found in 32 of these cases (12.5%). Other common respiratory viruses included respiratory syncytial virus in 42 (16.3%), human metapneumovirus in 24 (9.3%), adenovirus in 17 (6.6%) and parainfluenza virus in 12 (4.7%). The median age of the influenza group was 2 years and 3 months, and 27 (84%) of children in this group were under the age of 5. Asthma was the most common co-morbidity (4/32, 12.5%). Common clinical presentations were fever and cough (100%) with crepitations (90%). The median length of hospitalization was 6 days. Three patients developed respiratory failure, with one mortality (3.1%). One child developed infection-associated hemophagocytic syndrome. Our study demonstrated that young children had a high risk of hospitalization due to influenza pneumonia, which contributed to a significant morbidity.

Optimal level of physical activity in children with chronic lung diseases

AIM

To determine the optimal level of physical activity and its relationship with disease severity in children with chronic lung diseases (CLD).

METHODS

Pulmonary function and exercise tests were compared between 18 CLD children (aged 13.5 +/- 2.4 years, 33% male) and 18 healthy controls without any history of lung diseases (age and sex matched).

RESULTS

CLD children had lower forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV)(1), forced expiratory flow rate between 25% and 75% of vital capacity (FEF)(25-75%) and total lung capacity (TLC) and higher residual volume (RV)/TLC ratio than controls (77.3 +/- 22.6 vs. 97.9 +/- 12.5%pred; p = 0.002, 74.3 +/- 17.6 vs. 104.0 +/- 12.6%pred; p < 0.001, 49.9 +/- 23.1 vs. 75.6 +/- 18.6%pred; p < 0.001, 82.8 +/- 18.6 vs. 95.6 +/- 9.8%pred; p = 0.04, 30.8 +/- 10.2 vs. 24.4 +/- 5.9%; p = 0.04, respectively). Oxygen consumption at anaerobic threshold (AT) and optimal level of physical activity (metabolic equivalents [METs] at AT) were not different between the two groups and between mild and moderate to severe CLD. However, when the exercise was continued beyond the AT, CLD children demonstrated poorer exercise performance than normal controls.

CONCLUSION

Children with CLD demonstrated the same level of optimal physical activity as normal children despite their lower lung function. The optimal level of physical activity was not related to disease severity. The exercise test and exercise should not be performed beyond the AT by the CLD children. Proper exercise test should be done to determine their optimal exercise activity.

Detection of influenza virus types A and B and type A subtypes (H1, H3, and H5) by multiplex polymerase chain reaction

Infections with influenza virus type A and B present serious public health problems on a global scale. However, only influenza A virus has been reported to cause fatal pandemic in many species. To provide suitable clinical management and prevent further virus transmission, efficient and effective clinical diagnosis is essential. Therefore, we developed multiplex PCR assays for detecting influenza types A and B and the subtypes of influenza A virus (H1, H3 and H5). Upon performing multiplex PCR assays with type-specific primer sets, the clearly distinguishable products representing influenza A and B virus were separated by agarose gel electrophoresis. In addition, the subtypes of influenza A virus (H1, H3 and H5), which are most common in humans, can be readily distinguished by PCR with subtype-specific primer sets, yielding PCR products of different sizes depending on which subtype has been amplified. This method was tested on 46 influenza virus positive specimens of avian and mammalian (dog and human) origins collected between 2006 and 2008. The sensitivity of this method, tested against known concentrations of each type and subtype specific plasmid, was established to detect 10(3) copies/microl. The method's specificity was determined by testing against other subtypes of influenza A virus (H2, H4 and H6-H15) and respiratory pathogens commonly found in humans. None of them could be amplified, thus excluding cross reactivity. In conclusion, the multiplex PCR assays developed are advantageous as to rapidity, specificity, and cost effectiveness.

Detection and discrimination of WU/KI polyomaviruses by real-time PCR with melting curve analysis

WU and KI polyomaviruses are novel viruses of the Polyomaviridae family, which have been identified recently in respiratory secretions from patients with acute respiratory tract infection. Their potential role in respiratory disease is still unclear and requires additional investigation. To facilitate further studies and diagnosis, a real-time PCR with melting curve analysis was optimized and evaluated to detect WU and KI polyomaviruses. Primers specific for the VP1 gene were designed from regions conserved among WU and KI polyomaviruses which provided amplification products of 198 and 231bp corresponding to WU and KI, respectively and thus yielded a difference in melting temperature (Tm) between WU and KI polyomaviruses. The assay proved highly specific for WU and KI polyomaviruses as no cross amplification was detected with other respiratory viruses or human genomic DNA. The assay was also highly sensitive with a detection limit as low as 10copies/microL for both WU and KI polyomaviruses. The performance of the real-time PCR assay was evaluated in terms of amplification efficiency (92%). Finally, the assay was validated using DNA extracted from clinical respiratory specimens for WU and KI polyomaviruses and the results were confirmed by direct nucleotide sequencing. The results obtained by melting curve analysis were in perfect agreement with nucleotide sequencing. In conclusion, this method is advantageous because it is rapid, specific, sensitive, reproducible, accurate, cost-effective and thus, would be feasible and attractive for large-scale analysis aimed at investigating the clinical role of WU and KI polyomaviruses.

Typing (A/B) and subtyping (H1/H3/H5) of influenza A viruses by multiplex real-time RT-PCR assays

In this study, a specific and sensitive one-step multiplex real-time RT-PCR was developed in two assays by using primers and a number of specific locked nucleic acid (LNA)-mediated TaqMan probes which increase the thermal stability of oligonucleotides. The first assay consisted of primers and probes specific to the matrix (M1) gene of influenza A virus, matrix (M1) gene of influenza B virus and GAPDH gene of host cells for typing of influenza virus and verification by an internal control, respectively. The other assay employed primers and probes specific to the hemagglutinin gene of H1, H3 and H5 subtypes in order to identify the three most prominent subtypes of influenza A capable of infecting humans. The specificity results did not produce any cross reactivity with other respiratory viruses or other subtypes of influenza A viruses (H2, H4 and H6-H15), indicating the high specificity of the primers and probes used. The sensitivity of the assays which depend on the type or subtype being detected was approximately 10 to 10(3)copies/microl that depended on the types or subtypes being detected. Furthermore, the assays demonstrated 100% concordance with 35 specimens infected with influenza A viruses and 34 specimens infected with other respiratory viruses, which were identified by direct nucleotide sequencing. In conclusion, the multiplex real-time RT-PCR assays have proven advantageous in terms of rapidity, specificity and sensitivity for human specimens and thus present a feasible and attractive method for large-scale detection aimed at controlling influenza outbreaks.

Prevalence and molecular characterization of WU/KI polyomaviruses isolated from pediatric patients with respiratory disease in Thailand

WU and KI polyomaviruses represent novel viruses discovered in respiratory secretions from human patients with acute respiratory tract infection. However, the association between WU/KI polyomaviruses and human disease has remained unclear. In this study, the prevalence of these two novel viruses and occurrence of co-infection with other respiratory viruses were determined in Thai pediatric patients with respiratory disease. Previously described PCR assays were applied to detect WU/KI polyomaviruses as well as other respiratory viruses in 302 nasopharyngeal suction specimens collected from February 2006 through February 2007. The results revealed the anneal prevalence of WU and KI polyomaviruses in the Thai population was 6.29% and 1.99%, respectively. The frequency of co-detection of WU and KI polyomaviruses with other respiratory viral pathogens was 42.11% and 33.33%, respectively. Moreover, each of the two complete genome sequences of WU (CU_295 and CU_302) and KI (CU_255 and CU_258) polyomaviruses were genetically and phylogenetically characterized. Sequence analysis showed that they contained features common to those found in previous studies. However, there were several nucleotide variations within the non-coding regulatory regions and various non-synonymous mutations within the coding regions which may influence virulence and pathogenesis of these viruses. Nevertheless, it is still possible that these viruses are not the causative agents of clinical respiratory disease. Therefore, judging the association of WU/KI polyomavirus infections with a particular disease will be challenging and require more comprehensive case control investigations.

Prevalence of Mycoplasma and Chlamydia pneumonia in severe community-acquired pneumonia among hospitalized children in Thailand

Pneumonia is the leading cause of pediatric morbidity and mortality worldwide, and Mycoplasma pneumoniae and Chlamydia pneumoniae are the two most common atypical pathogens. This study was designed to determine the prevalence and clinical impact of mycoplasma and chlamydia pneumonia in children hospitalized with severe pneumonia. Children 1 month-15 years old with a diagnosis of severe pneumonia (WHO criteria) were recruited between March 2005 and March 2006. Serologic studies were performed for anti-M. pneumoniae and anti-C. pneumoniae IgG/M on admission and 2-4 weeks afterward using ELISA. Of 52 patients, 13 (25%) were positive for Mycoplasma, 8 (15%) were positive for Chlamydia, 4 (7.6%) were positive for a mixed infection and 27 (52%) were negative. The subjects' mean age was 23.8+/-4.1 months. The mean of initial oxygen saturation on admission was 87.5+/-1.2%. Fever and prolonged cough were the leading symptoms. The mean of hospitalization was 18.8+/-2.6 days, chlamydia pneumonia had the longest duration, 30+/-10.2 days and 13/52 (25%) study subjects developed respiratory failure. Only 10% were treated with adequate antibiotic prior to serologic results. There was one mortality (1/52, 2%). Our study suggests that mycoplasma and chlamydia infections are commonly found among children hospitalized with severe pneumonia. Coverage with an appropriate antibiotic should be considered to hasten recovery.

Human bocavirus (HBoV) in Thailand: clinical manifestations in a hospitalized pediatric patient and molecular virus characterization

Objective

Human bocavirus (HBoV), a novel virus, which based on molecular analysis has been associated with respiratory tract diseases in infants and children have recently been studied worldwide. To determine prevalence, clinical features and perform phylogenetic analysis in HBoV infected Thai pediatric patients.

Methods

HBoV was detected from 302 nasopharyngeal (NP) suctions of pediatric patients with acute lower respiratory tract illness and sequenced applying molecular techniques.

Results

The incidence of HBoV infection in pediatric patients amounted to 6.62% with 40% co-infected with other respiratory viruses. There were no clinical specific manifestations for HBoV; however, fever and productive cough were commonly found. Generalized rales and wheezing were detected in most of the patients as well as perihilar infiltrates. The alignment and phylogenetic analysis of partial VP1 genes showed minor variations.

Conclusion

Our results indicated that HBoV can be detected in nasopharyngeal aspirate specimens from infants and children with acute lower respiratory tract illness.

Levels of protein C activity and clinical factors in early phase of pediatric septic shock may be associated with the risk of death

Severe sepsis and septic shock are major causes of morbidity and mortality among children in pediatric intensive care units (PICUs) worldwide. Activated protein C (PC) is a critical endogenous regulator of coagulation and inflammation in patients with sepsis. However, the role of PC in pediatric sepsis is still obscure. We prospectively recruited infants and children aged between 1 month and 15 years old who were admitted to PICU with a clinical diagnosis of systemic inflammatory response syndrome, sepsis, or septic shock. Clinical data were recorded and blood samples kept for further analysis. We then measured the levels of PC activity. Of the approximately 1,100 pediatric patients admitted to PICU from January 1, 2004 to December 31, 2005, 75 were diagnosed with septic shock (6.8%), and 67 samples were available for analysis. Out of these, 41 (61%) were survivors, and 26 (39%) were nonsurvivors. The average plasma PC activity (%) was at 37.8 +/- 4.4. Plasma PC activity (%) was significantly lower in the nonsurvivors compared with the survivors at 23.6 +/- 4.3 and 46.8 +/- 6.3 (P = 0.002), respectively. D-Dimer levels were not significantly different between the survivors (1,461 +/- 266 ng/mL) and the nonsurvivors (1,989 +/- 489 ng/mL) (P = 0.68). Also, there was no correlation between plasma PC activity and D-dimer levels (r = -0.07; P = 0.6). Importantly, the odds of dying were significantly higher in patients whose level of PC activity was less than 25% (odds ratio = 5.6; P = 0.02). Pediatric patients with septic shock demonstrate very low levels of PC activity, and this may be associated with an increased risk of death.

Molecular characterization and phylogenetic analysis of H1N1 and H3N2 human influenza A viruses among infants and children in Thailand

The annual influenza outbreaks can cause a high mortality rate among infants and children. In the tropics, influenza shows no clear dependence on seasons. In the present study, we performed molecular and phylogenetic analysis of H1N1 and H3N2 influenza virus isolated from infants and children diagnosed with respiratory tract illness between February 2006 and February 2007. A total of 33 samples (10.92%) were found positive for human influenza virus infection. Characterization of the hemagglutinin gene revealed conserved sequences at the receptor-binding site as well as variations due to amino acid substitutions at the antigenic site, potentially resulting in an N-linked glycosylation site. As for the neuraminidase gene, amino acid substitutions were found in N1 and N2 but not directly at the catalytic or framework sites of this enzyme. Based on the phylogenetic tree, the hemagglutinin 1 (HA1) region and the neuraminidase (NA) gene of both H1N1 and H3N2 isolated subtypes clustered with the current vaccine strain for the Northern Hemisphere 2007-2008. This finding contributes to understanding the evolution of influenza A viruses in humans and is useful for surveillance and vaccine strain selection.

Adrenal insufficiency in early phase of pediatric acute lung injury/acute respiratory distress syndrome

INTRODUCTION

Adequate adrenal function is essential to survive critical illness. Several recent articles have reported the significant effect of adrenal insufficiency (AI) in patients with sepsis. However, the prevalence of AI in pediatric acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is so far still scanty. Thus, we elected to study its prevalence and its clinical outcome.

METHODS

This is a cross-sectional observational study. We enrolled eligible infants and children aged between 1 month and 15 years who were admitted to our tertiary pediatric intensive care unit from February 1, 2005, to December 31, 2005, with ALI or ARDS diagnosed by the American-European Consensus criteria. A short corticotropin stimulation test (250 microg) was done within 24 hours of enrollment, and all clinical data were also recorded. Cortisol levels were measured at baseline, 30 minutes, and 60 minutes posttest. Adrenal insufficiency was defined as a baseline cortisol level of less than 15.1 microg/dL or an increment of cortisol level of less than 9 microg/dL after the adrenocorticotropic hormone stimulation test.

RESULTS

Of 507 patients admitted to the pediatric intensive care unit, there were 20 diagnosed with ALI/ARDS. Of 20 children, 16 met the inclusion criteria and had none of the exclusion criteria. Of 16, there were 9 (56%) with ARDS, and 7 (44%) of 12 had ALI. The prevalence of AI was observed in 37.5% (6/16), diagnosed by baseline level criteria in 25% (4/16) and by incremental criteria in 12.5% (2/16). The Baseline level of the adrenocorticotropic hormone was 7.8 +/- 5 (nmol/L). The median age in the AI group was 2 months. Of 6 children, 5 (83.3%) were in the ARDS group. Pediatric Risk of Mortality III score was significantly higher in the AI group compared with that in the non-AI (P < .05). Initial Pao(2)/fraction of inspired oxygen ratio tended to be lower in the AI group (123.2 +/- 62.2) compared with that in the non-AI group (183.8 +/- 79.1), although not statistically significant (P = .1). The mortality was also not statistically different between the AI (1/6, 16.7%) and the non-AI groups (1/10, 10%).

CONCLUSIONS

Our study demonstrated that the prevalence of AI was common in pediatric ALI/ARDS. These results would be an initial step to further study the impact of AI on clinical outcomes of these children in a larger scale.