Etiology of community-acquired pneumonia in hospitalized school-age children: evidence for high prevalence of viral infections.

BACKGROUND: Community-acquired pneumonia (CAP) in young children is most commonly associated with viral infections; however, the role of viruses in CAP of school-age children is still inconclusive. METHODS: Seventy-five school-age children hospitalized with CAP were prospectively evaluated for the presence of viral and bacterial pathogens. Nasopharyngeal washes were examined by polymerase chain reaction for viruses and atypical bacteria. Antibody assays to detect bacterial pathogens in acute-phase and convalescent-phase serum samples were also performed. RESULTS: A viral infection was identified in 65% of cases. Rhinovirus RNA was detected in 45% of patients; infection with another virus occurred in 31%. The most common bacterial pathogen was Mycoplasma pneumoniae, which was diagnosed in 35% of cases. Chlamydia pneumoniae DNA was not detected in any patient; results of serological tests were positive in only 2 patients (3%). Mixed infections were documented in 35% of patients, and the majority were a viral-bacterial combination. CONCLUSIONS: The high prevalence of viral and mixed viral-bacterial infections supports the notion that the presence of a virus, acting either as a direct or an indirect pathogen, may be the rule rather than the exception in the development of CAP in school-age children requiring hospitalization.

Otitis and respiratory distress episodes following a respiratory syncytial virus infection.

OBJECTIVE: To document, over two consecutive respiratory syncytial virus (RSV) seasons, the occurrence of acute otitis media (AOM) and recurrence of respiratory distress in children < 2 years of age hospitalized for respiratory distress. METHODS: Patients were examined during hospitalization and at 6 weeks and 6 months after discharge. RSV testing was performed on all patients, and hospitalized patients were evaluated daily for the occurrence of AOM. RESULTS: In total, 347 children were enrolled; 54.8% were RSV positive, and 45.2% were RSV negative. Children were most frequently diagnosed as having bronchiolitis (71.9%) or asthmatic bronchitis (17.9%); other diagnoses included pneumonia, laryngitis, and rhinitis. During hospitalization, AOM was diagnosed in 16.8% of RSV-positive versus 8.3% of RSV-negative children (P < 0.05). Six weeks after discharge, AOM was reported in 10.4% of RSV-positive as compared with 5.8% of RSV-negative patients. Six months later, AOM was reported in 2.9% of the RSV-positive and 7.6% of the RSV-negative patients. A second episode of acute respiratory distress, which either required (9) or did not require (35) hospitalization, occurred in 18.4% of the total population, with similar proportions of RSV-positive and RSV-negative children (17% versus 18.6%). CONCLUSION: We conclude that RSV appears to be an important contributing factor for the occurrence of AOM in young children hospitalized with respiratory distress. The occurrence of a second episode of acute respiratory distress did not appear to correlate with the previous RSV infection, but longer-term follow-up is required.

Epidemiology of respiratory syncytial virus bronchiolitis in hospitalized infants in Greece.

New therapies have been introduced for the prophylaxis and treatment of respiratory syncytial virus (RSV) infection in recent years. The aim of the study was to determine the epidemiological and clinical characteristics of infants hospitalized with bronchiolitis in our area. All patients under 1 year of age admitted with acute bronchiolitis during four consecutive RSV seasons from February 1, 1997 to June 30, 2000 were enrolled in the study. The records of patients admitted during the first season were reviewed retrospectively while the rest were followed prospectively. A total of 636 infants with bronchiolitis were admitted and RSV infection was documented in 61% of those tested. Admission to intensive care unit (ICU) was required for 6.2% of them and was more common in premature infants (26%) (p < 0.001). Case fatality rate was 0.7% (overall 0.3%). RSV bronchiolitis accounted for about 12% of all infant admissions during the 5 months of the yearly outbreak. Patients with documented RSV infection had a more severe illness with a higher ICU admission rate (6 vs. 1%, p = 0.008) and longer duration of hospitalization (mean 6.3 vs. 5.3 days, p < 0.001) compared to those who tested negative. Although none of the patients had a positive blood culture on admission a considerable number of them (210/636, 33%) were treated with antibiotics. RSV infection has a significant impact on infant morbidity in our settings which is more serious among those born prematurely. Documentation of RSV infection may be a marker of more severe illness in infants hospitalized with bronchiolitis. Antibiotic use has to be restricted since the occurrence of a serious bacteraemic illness on admission is a very rare event.

Intrinsic positive end-expiratory pressure in mechanically ventilated patients with and without tidal expiratory flow limitation.

OBJECTIVE: To assess static intrinsic positive end-expiratory pressure (PEEPi,st) and expiratory flow limitation (FL) in 32 consecutive mechanically ventilated patients with acute respiratory failure (ARF), using a commercial ventilator with an incorporated device that allows the application of a negative expiratory pressure (NEP). DESIGN: Prospective clinical study. SETTING: Multidisciplinary intensive care unit of a university hospital. PATIENTS: Thirty-two consecutive ventilated patients with ARF of various etiologies. INTERVENTIONS: Evaluation of respiratory mechanics, PEEPi,st, and FL from pressure, flow, and volume traces provided by the ventilator. MEASUREMENTS: Peak airway pressure, PEEPi,st, dynamic elastance, and interrupter resistance were measured in relaxed patients in a supine position. Comparison of tidal flow-volume curves before and during the application of an NEP of 5 cm H2O was used to assess tidal expiratory FL. RESULTS: Twelve of 32 patients studied exhibited tidal expiratory FL, which was detected by the absence of increase in expiratory flow despite application of an NEP over the entire or part of the baseline expiratory flow-volume curve. All patients exhibited PEEPi,st, which amounted to 1.2 +/- 0.9 cm H2O (mean +/- SD) in the 20 non-FL patients and 7.1 +/- 2.8 cm H2O in the 12 FL patients (p < 0.00001). The majority of patients with ARF resulting from underlying lung disease (11 of 13) had FL and a PEEPi,st > 4 cm H2O, whereas in patients with ARF of extrapulmonary origin, PEEPi,st was always < 4 cm H2O and only one grossly obese patient exhibited FL. Based on multiple regression analysis, in non-FL patients, PEEPi,st correlated significantly only with minute ventilation, whereas in FL patients PEEPi,st correlated significantly with peak airway pressure. CONCLUSIONS: Because all the patients exhibited PEEPi,st and 12 of 32 patients (38%) also had FL, the authors conclude that the assessment of these variables at the bedside could provide useful information concerning respiratory mechanics in mechanically ventilated patients.