Only around half of babies under three months of age who have bacterial meningitis present with fever, which has for decades been the trigger for further medical investigation, warn UK researchers.
The team from St George’s, University of London also found other features often associated with meningitis in infants, like a bulging fontanelle, coma, seizures and neck stiffness, were uncommon.
“The classic features of meningitis were uncommon in many cases”
The researchers said their new study showed classic symptoms associated with bacterial meningitis were uncommon in young infants less than three months old – the age group at highest risk.
For example, they noted that babies under three months of age were 70 times more likely to get bacterial meningitis than adults in the UK, with newborn babies at the highest risk of all.
Previous research by the team suggested there were around 350 cases a year in infants aged under three months in the UK and Ireland, with group B streptococci and Escherichia coli the main causes.
But, based on their new findings, the study authors noted that meningitis in young babies was often non-specific and hard to distinguish from mild illnesses, with common features like poor feeding.
The study involved 263 infants across the UK and Ireland and found that fever was reported in only 54% of cases, seizures in 28%, bulging fontanelle in 22%, coma in 6% and neck stiffness in only 3%.
The study found that infants who did present with fever tended to be older than infants without fever. The median age for this symptom was around 21 days old.
“We hope that this can ultimately improve outcomes for this vulnerable age group”
In contrast, common features were found to be poor feeding, lethargy and irritability, all of which can be difficult to distinguish from mild illness, noted the researchers.
They said the study suggested that there should be a low threshold for performing investigations on young infants when they arrive at hospital.
Of note, 52% of the infants without fever did have other features suggestive of bacterial meningitis, such as apnoea (33%), seizures (32%), bulging fontanelle (16%), coma (7%) and neck stiffness (3%).
Study author Professor Paul Heath said: “The classic features of meningitis were uncommon in many cases. The symptoms displayed by young infants when they are seen by doctors at first in hospital are often non-specific and only half of cases showed signs of a fever.
Professor Heath noted that guidelines focusing on serious infections in children, including meningitis, had been introduced in the UK and the US, but all of them specified fever as a key feature of infection.
“Unfortunately, neither the rates of bacterial meningitis in babies, nor the numbers of deaths, has changed since the 1980s,” he said. “Clinicians must, therefore, still consider bacterial meningitis in the diagnosis of an unwell infant that doesn’t present with fever.”
The study, published in the journal Paediatric Infectious Diseases, was funded by the charity the Meningitis Research Foundation.
Charity chief executive Vinny Smith said that, based on the study, it had collaborated with the authors to create a teaching package for health professionals to aid rapid diagnosis and treatment.
It includes an eTool to help recognise bacterial meningitis in young infants, a lumbar puncture information sheet for explaining the procedure to parents, and an algorithm to aid management of bacterial meningitis.
“We hope that this can ultimately improve outcomes for this vulnerable age group,” said Mr Smith.
- Meningitis 1: meningococcal disease in children and teenagers
- Meningitis 2: prevention and treatment of meningococcal disease