High fever in neonates may indicate serious bacterial infection

By Nicole MacKee
High fever in very young infants should raise the suspicion of a serious bacterial infection, according to research published in The Journal of Emergency Medicine.

In a secondary analysis of the Pediatric Emergency Care Applied Research Network study on febrile infants, researchers evaluated 4821 infants aged up to 8 weeks old. All children had a documented temperature – either taken in the enrolling emergency department, at another health care facility or at home – of 38°C or higher.

The researchers found that the height of fever was associated with an increased risk of bacteraemia, urinary infection or bacterial meningitis (odds ratio, 1.5). Where the temperature was taken was less strongly associated with an increased risk of serious bacterial infection (odds ratio, 1.3), and no association was found with the duration of the fever.

The researchers did note, however, that the height of fever alone was not sufficiently sensitive to rule out a serious bacterial infection. ‘Even children with a temperature [less than] 39°C still had a 9.1% risk of [serious bacterial infection],’ they wrote. ‘Among children with fever [greater than] 39°C, though, the risk of [serious bacterial infection] doubled to 20.4%.’

Commenting on the findings, Professor David Isaacs, Clinical Professor of Paediatrics and Child Health at the University of Sydney, said: ‘Given the fact that serious bacterial infection is rare and fever is extremely common – and almost always due to viral infections – then, just knowing that the height of the fever is important, is relevant, but doesn’t help hugely.’

It was more important, he said, to consider how the child presented clinically.

‘GPs and paediatricians are generally very good at assessing whether a child with high fever is toxic or not,’ he told Medicine Today, pointing to the ‘ABCD of toxicity’.

‘What does the child look like – are they alert? Can they be aroused easily? Is their breathing laboured in any way? What is their colour like? Are they pale? What is their circulation like? Are they dehydrated?

‘Nevertheless, it is useful to know that if the child has a high fever, you had better be pretty sure that that child is okay, and you may have a lower threshold for giving antibiotics.’
J Emerg Med 2019; 57: 306-313.