Background: Pertussis has been increasing in frequency and can cause protean manifestation in infants, often resulting in extensive laboratory evaluation.
Methods: We examined the prevalence of cerebrospinal fluid (CSF) anomalies in infants with pertussis and parapertussis over a 5-year period.
Results: In total, 239 of 1489 children (16.1%) had a positive PCR for pertussis or parapertussis. Eighty-three percent were infants; the mean age of the 39 years who received a lumbar puncture (LP) was 43 days. Reasons for performing LP included apnea (62%), toxic appearance (38%), fever (26%), and altered mentation (10%); several had >1 indication for LP. Twenty-four (62%) children had elevated CSF protein. No child had hypoglycorrhachia, bacterial meningitis, bacteremia, or intracranial hemorrhage; one child had a urinary tract infection and five had pneumonia. Seven children had brain imaging performed; one had a subarachnoid hemorrhage and six had normal studies. Elevated age-normalized CSF protein was a common finding in infants with pertussis, potentially due to transfer across a damaged or immature blood-brain barrier. This finding was seen in the absence of concomitant bacterial infections or detectable intracranial anomalies.
Conclusions: While the diagnostic evaluation and clinical management of a toxic-appearing infant should not be limited by a positive pertussis or parapertussis PCR, it is useful for physicians to be cognizant that elevated CSF protein can be seen in association with these infections.