Children that have had whooping cough are at slightly increased risk of developing epilepsy, according to a Danish study.
Although the absolute risk was low, researchers found an increased risk of childhood-onset epilepsy among children in Denmark who were previously diagnosed with pertussis infection.
“Risk of epilepsy was increased in children with hospital-diagnosed pertussis infections compared with the general population”
During the acute phase, pertussis is associated with seizures in infants, but the likelihood of developing epilepsy has not previously been known.
Dr Morten Olsen, from the Aarhus University Hospital, and colleagues used population-based medical registries covering all Danish hospitals to identify all patients with pertussis born between 1978 and 2011, followed up until 2011.
A database was used to identify 10 individuals from the general population for each patient with pertussis, matched on sex and year of birth.
The researchers identified 4,700 patients with pertussis, of whom 53% were diagnosed before age 6 months.
In the pertussis cohort, 90 children were diagnosed with epilepsy, compared with 511 children in the comparison cohort.
The cumulative incidence of epilepsy at age 10 years was 1.7% for patients in the pertussis cohort and 0.9% for members of the comparison cohort.
Patients older than three years when diagnosed with pertussis were not at increased risk of epilepsy compared with the general population.
The study authors suggested potential mechanisms underlying the observed association might include hypoxic brain damage from coughing, perhaps via increased intrathoracic and intra-abdominal pressure and central nervous system haemorrhages.
The study was supported by grants from a research programme funded by the pharmaceutical companies Lundbeck and Novo Nordisk.
The study authors said: “Pertussis is associated with encephalopathy and seizures in infants. However, the risk of childhood epilepsy following pertussis [was previously] unknown.”
“Risk of epilepsy was increased in children with hospital-diagnosed pertussis infections compared with the general population; however, the absolute risk was low,” they added in the Journal of the American Medical Association.