In The Temporo Occipital Region Of The Brain That Controls Language, An Abcess Causing Epileptic Seizures And Several Hours Of Aphasia Is Visible. Gadolinium Enhanced Mri T1. (Photo By BSIP/UIG Via Getty Images)
CNN  — 

The United States saw a 200% increase in brain abscesses in children in December 2022 following a surge in respiratory infections over the winter.

Even with the increase, abscesses continue to be extremely rare, according to the US Centers for Disease Control and Prevention.

Brain abscesses are pockets of pus that form in brain tissues. They typically arise when an ordinary sinus infection or ear infection travels to the brain.

The CDC began collecting information on brain abscesses in children in May 2022 after doctors in Clark County, Nevada, and California reported seeing unusual clusters of cases.

After a first analysis of the data, which considered cases through May 2022, the CDC said the fluctuations in case numbers were within normal ranges, but said it would continue to monitor the situation.

An update on Thursday analyzed cases through March 2023, an additional 10 months of data. The update supports what pediatric infectious disease experts have reported seeing across the US this winter and spring: Cases had, in fact, risen.

Working with a large database run by the Children’s Hospital Association, which collects information from 37 children’s hospitals in 19 states and Washington, D.C., CDC investigators combed through medical records to count brain abscess cases in children ages 18 and younger since 2016.

The new investigation published in the CDC’s Morbidity and Mortality Weekly Report on Thursday.

Investigators determined that between 2016 and 2019, the average monthly number of brain abscesses in children reported to the database was about 34, with 61 as the highest number of cases reported in a month. During the pandemic, when people were social distancing and school was virtual – from May 2020 to May 2021 – the number of brain abscesses in children fell below those levels as other respiratory infections like RSV and influenza also dipped.

The number of brain abscesses rebounded in the summer of 2021 as people resumed their normal activities, according to the study.

In December 2022, following unusually large surges of several respiratory illnesses in kids, the number of brain abscesses hit a high of 102 cases, which represents a 200% increase over the pre-pandemic midpoint. In January, February, and March 2023, the numbers came down off that peak, but remain above the pre-pandemic monthly maximum.

“That would be consistent with seeing secondary bacterial infections a few weeks or months after the viral spread,” said Dr. Sunil Sood, a pediatric infectious disease expert at Northwell Health’s Cohen Children’s Medical Center.

The reason for the increase isn’t fully understood, but experts say that because brain abscesses often follow more routine types of infections, it stands to reason we would see an increase in secondary bacterial infections following such a heavy season for viral illnesses in kids.

Sood says he noticed an increase in brain abscesses at his children’s hospital in New York that corresponded to the national trends. He expects that cases will slow down since viral illnesses have fallen, too.

“We’re seeing fewer viral respiratory infections,” Sood said. “We’re still seeing some and so, it is something that is good to be aware of.”

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He says most parents don’t know the signs that a child might have a sinus infection that needs treatment. These include an eye that’s swollen or swollen shut following a stuffy nose, or if the child has a headache in one spot in their forehead that they can point to. Those symptoms may be worth a trip to the doctor for further evaluation.

Dr. Taryn Bragg, a pediatric neurosurgeon with the University of Utah who first sounded the alarm about the Nevada cluster, says many of her patients are still recovering from their brain abscesses. Some needed multiple surgeries.

“They were really severe infections,” Bragg said Thursday.

Study author Emma Accorsi of the CDC’s National Center for Immunization and Respiratory Diseases added that because brain abscesses may follow viral infections, it’s important for kids to stay up to date on immunizations, including for Covid-19 and the flu.