Pertussis-associated encephalitis/encephalopathy with marked demyelination in an unimmunized child.

Encephalitis/encephalopathy is a rare, but severe, complication of pertussis. Here, we report a case of an unimmunized 7-year-old boy with confirmed pertussis complicated by acute encephalitis/encephalopathy. Eighteen days after the onset of pertussis, generalized seizures began. Magnetic resonance imaging (MRI) indicated that marked demyelination without cytotoxic edema may have occurred to the patient. Notably, this is the first report to show precise MRI findings of pertussis-associated encephalitis/encephalopathy. Markedly increased myelin basic protein levels in the cerebrospinal fluid were consistent with the MRI findings. There was no evidence of direct invasion of the causative bacterium or its products into the central nervous system. The levels of interleukin-6 and -10 in the cerebrospinal fluid were higher than those in serum. Taken together, we conclude that indirect immune-mediated mechanisms may have contributed to the pathogenesis of the encephalitis/encephalopathy.

Cerebrospinal fluid findings in infants with pertussis or parapertussis(1)).

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.