Pneumonia in children: how to lessen complications?

Pleural empyema was earlier a rare complication of pneumonia in children with an incidence of <1% of those hospitalized for pneumonia (1). Since the 1980s, the incidence has been on an increase, with attack rates up to 28% in children hospitalized for presumably bacterial pneumonia (2). In this issue of Acta Paediatrica, Francois et al. present the results of their retrospective study in 767 children hospitalized for pneumonia (3). The attack rate of suppurating complications was 3% in 1995–1998, increasing thereafter linearly up to 23% in 2003. Though such high rates have now been reported from both Europe and United States, the figures can not necessarily be directly generalized to most child populations. Anyway, the results are alarming. In a recent retrospective 16-year study from Finland, the incidence of empyema among children hospitalized for pneumonia increased from 0.5% between 1991 and 1998 to 3.3% between 1999 and 2006 (4). The reasons for the increase of suppurating complications in children with pneumonia are mainly unknown. In the 1990s, Byington et al. found in an 8-year retrospective study that the presence of empyema was associated with young age, recent varicella infection, pneumococcal aetiology of pneumonia, and the treatment with antibiotics and non-steroidal anti-inflammatory drugs (NSAID) prior to hospital admission (2). In the study of Francois et al. (3), the children with complicated pneumonia were older, had been longer symptomatic and had more often received antibiotics and NSAIDs, especially ibuprofen. In multivariate analysis, the use of ibuprofen before hospitalization was the only independent risk factor for suppurating complications (aOR 2.6, 95% CI 1.5–4.4). In the study of Byington et al. (2), the adjusted OR was even higher, 4.0 (95% CI 2.5–6.5). As Francois et al. discussed (3), the findings confirm an association, not a causal relationship, between the drugs and complications of pneumonia. The children with severe pneumonia probably have high fever, painful respiration and other relief demanding symptoms, leading to more use of analgesic and antipyretic drugs. An early recognition of developing empyema is challenging. In the Finnish study (4), prolonged fever, increased respiratory rate, pain on abdominal palpation and high serum C-reactive protein were significant empyema predicting factors in children hospitalized for pneumonia. However, one-third of the children with empyema were considered to have an uncomplicated pneumonia at the initial examination. In some cases, empyema developed in hospital during intravenous antibiotic therapy (4). Currently, ‘‘the 48-h rule’’ has been included in most pneumonia guidelines; if the child has not improved within 48 h after the start of antibiotics, the patient and the therapy must be re-evaluated (5). When pneumococcal conjugate vaccines are widely implemented, the epidemiology of pneumococcal infections in children will necessarily change. The empyema rates from France represent the era before large-scale vaccinations of infants and young children by pneumococcal conjugate vaccine (3). In United States, pleural effusion incidence increased until 2000, but decreased thereafter in 2001– 2002, probably due to the large-scale vaccinations of infants by the 7-valent pneumococcal conjugate vaccine (6). On the other hand, vaccinations may lead to the replacement by serotypes not included in the vaccine. For example, serotypes 1, 3, 7F and 19A have been associated with empyema Invited commentary for François et al. Prevalence and risk factors of suppurative complications in children with pneumonia. Acta Pædiatrica ISSN 0803–5253