Incidence, aetiology and outcome of pleural empyema and parapneumonic effusion from 1998 to 2012 in a population of New Zealand children.

AIM: To document rising incidence rates of childhood empyema and parapneumonic effusion (PPE) in South Auckland, New Zealand between 1998 and 2012; to compare epidemiology, pathogens and outcomes of children with empyema and PPE; and to ascertain whether primary care antibiotic prescribing, delayed presentation, or bacterial epidemiology might account for the rising incident rates.

METHODS: Children aged 0 to14 years hospitalised with pleural empyema or PPE were retrospectively identified. Empyema was defined by ultrasound and pleural tap criteria. PPE was defined as the presence of pleural fluid on chest xray not fulfilling empyema criteria. Epidemiology, clinical features, microbiology and outcomes of empyema and PPE were compared and incidence rates analysed.

RESULTS: Of 184 cases identified, 104 met the criteria for empyema. Empyema incidence increased from 1 per 100 000 children aged 0 to 14 years in 1998 to 10 per 100 000 in 2012, with a peak incidence of 13 per 100 000 in 2009. Staphylococcus aureus was most frequently detected (n=38), followed by Streptococcus pneumoniae (n=31). Cases of S. aureus empyema increased 4 fold over the 15 years. Dominant S. pneumoniae serotypes were 1 and 14. Thirty-five percent of empyema and 53% of PPE cases received pre-hospital antibiotics. Children who received pre-hospital antibiotics were more than 40% less likely to require surgical intervention than those not pre-treated.

CONCLUSIONS: Childhood empyema incidence has increased markedly in South Auckland. Paediatric S. aureus empyema is becoming increasingly common in South Auckland. Pre-hospital antibiotic prescribing may mitigate the need for surgical intervention in our population.