Researchers have uncovered a recent, perplexing increase in brain infections and abscesses in kids and teens. These rare and life-threatening conditions can be complications of severe sinus infections and ear infections, but the reason for the rise isn't clear yet.
For the study, presented at the Centers for Disease Control and Prevention's Epidemic Intelligence Service (EIS) annual conference in April, researchers tracked cases of brain infections and abscesses in Nevada's Clark County. Specifically, they looked for patients who'd been diagnosed with an abscess or empyema (another type of pocket of pus) in brain tissue or in the tissues that surround the brain inside the skull.
From 2015 to 2021, there were an average of four cases of these intracranial issues among kids per year in Clark County, the study shows. That number nearly doubled between 2020 and 2021 — the early years of the COVID-19 pandemic — to an average of seven cases per year.
While still very rare overall, that number spiked in 2022: The researchers counted 18 cases of intracranial abscesses among kids ages 4 to 15 that year. And, so far, experts aren't sure why.
"We did see more cases in 2022 than we had seen previously but without a clear underlying explanation for what we found," Dr. Jessica Penney, an EIS officer assigned to the Southern Nevada Health District, said on a call with reporters on May 1.
It's also not clear how widespread the trend is yet, but Penney explained that "one of the primary reasons we wanted to share our findings with the public health community is to raise awareness of the issue" and encourage others to monitor the situation in their areas.
An August 2022 CDC report based on data from eight children’s hospitals around the country found the rate of these cases doubled between March 2020 and March 2022, and they were particularly common alongside sinus infections but not ear infections.
The trends "were alarming to us because the increase was quite marked compared to prior years," Dr. Rosemary Olivero, pediatric infectious disease specialist at Helen DeVos Children's Hospital and one of the authors on the August 2022 CDC report, tells TODAY.com via email. Because these were life-threatening infections, Olivero and her colleagues wanted to make sure others "were on alert and looking for a national trend."
Other CDC research published in September 2022 showed there were more of these complications in kids during the summer of 2021 and that they peaked in March 2022. However, Olivero notes that it's not clear whether the trends she and her colleagues observed in the past are related to the new findings.
What's more, the data for 2023 "has really been reassuring," and "the numbers have started to decline," said Dr. Taryn Bragg, associate professor at the University of Utah and a pediatric neurosurgeon with Intermountain Healthcare and Sunrise Children’s Hospital, on the May 1 call.
How does an abscess develop?
The researchers looked for any risk factors the patients might have had in common that could have been related to the complications they developed.
"We focused on things like travel, pets, secondhand smoke exposure and things regarding COVID-19 and mask-wearing as well," Penney said, but those did not seem to be related. None of the children in the study had been diagnosed with COVID-19.
The risk factors that did seem related were already well-known to increase the likelihood of these complications, she said. In particular, many of the children who developed abscesses (13 of the 18 Nevada patients) had been diagnosed with severe ear infections or sinus infections right before or had developed cold-like symptoms before hospitalization.
That's not totally surprising because intracranial abscesses and infections can be complications of severe sinus infections or ear infections, Bragg said.
"They had sinus infections (or) they had ear infections that then traveled through the bone locally, that then infected the brain," said Bragg, who also treated the patients in Nevada and first noticed the pattern there.
Those ear and sinus infections are typically caused by a buildup of bacteria that can't drain properly, which can itself be a complication of an initial respiratory infection, Dr. Aaron Milstone, a pediatric infectious disease specialist at Johns Hopkins Children’s Center, tells TODAY.com.
The sinuses sit within the bones of the face and above the eyes, Milstone explains, adding, "If those infections in the sinuses get really bad, they can erode and go through the bone and go back into the space in front of the brain." That can lead to the brain infection and abscesses that Bragg described.
These complications are more likely to develop in kids and teens because of the way the sinuses develop as children get older. But these issues can occur in adults as well, and Bragg noted that, anecdotally, other doctors are seeing a rise in that population. "But not nearly to the level that we've seen in 2022 in our pediatric population," she said.
Ear infections, on the other hand, can lead to brain complications because the inflammation from a viral infection (like RSV, adenovirus, rhinovirus or influenza) causes swelling that prevents the eustachian tube from properly draining the middle ear, TODAY.com explained previously.
When that happens, bacteria that live there normally in small numbers are allowed to collect and multiply. In more serious cases, the infection can spread to the mastoid bone behind the ear and possibly to the brain.
However, keep in mind that these brain complications are "extremely rare," Olivero says. "We don’t have perfect estimates, but it’s probably rarer than 1 in 1,000,000 people who get a common cold."
Could this be a result of the "tripledemic" ?
While it's not clear what's at the root of this rise in brain abscesses, one persuasive theory is that it's a result of the surges in children's respiratory illnesses seen this past winter, as well as the emergence of an invasive strain of strep A, Olivero says.
“We definitely have noticed, as a team, more kids with complications of respiratory viral infections,” Milstone says. In particular, they have been seeing an increase in Pott’s puffy tumors — another rare sinusitis complication that causes swelling in the forehead due to an abscess in a nearby sinus and inflammation in the surrounding bone tissues.
“These bacteria are really just opportunists,” Milstone says. “And all these colds are giving them an opportunity to create a little more havoc.”
So it’s not necessarily that the viral infections have become more serious than they were previously; it could be that more kids are getting sick and getting sick repeatedly. "My speculation is that, yes, we’re seeing these rare bacterial complications more often. But we’re seeing a lot more respiratory viral infections in kids,” Milstone explains. “So it’s a numbers game.”
Alongside the rise in these severe complications, pediatricians noted an increase in ear infections and a temporary shortage of kids' cold and flu medication during the winter of 2022, as TODAY.com reported previously.
“There are lots of kids that are sick with lots of viruses,” Milstone continues. “And these viruses break down some of our barriers of defense and make people more susceptible to these rare bacterial complications.”
Still, the researchers emphasize they don't know the actual cause of the increase in brain complications yet. And while the thinking is that the rise in brain abscesses is likely related to the surges in COVID-19 and other viral illnesses, that isn’t clear yet, Olivero adds.
Ultimately, "this is complex to sort out," Olivero says, due to the resurgence of many viral and bacterial pathogens that were quiet during some phases of COVID, as well as delays in routine vaccination and the emergence of invasive strep A.
Signs of severe infections
"We really just need our community and our parents to understand that if you have persistent symptoms, (bringing it) to the attention of your primary care providers is the biggest thing," Bragg said.
The experts listed these possible signs of severe infection or brain abscess:
- Persistent cold- or flu-like symptoms that don't respond to standard treatment
- Persistent headaches (especially if your child doesn't usually have headaches)
- Persistent sleepiness
- Persistent vomiting without explanation
- High fever that spikes multiple times in a day
- Discolored drainage from the nose
- Swelling of the forehead
- Swelling around one or both eyes
- Seizures
- Weakness
- Speech or language difficulties
Treatment for brain abscesses and infections typically requires antibiotics and surgery, Milstone explains. If left untreated, these complications can be life-threatening, Bragg said, adding that all children in the new study survived following treatment.
While you may not be able to prevent complications like these entirely, there are measures you can take to prevent the initial respiratory illness. "At this point, prevention is really vaccination," Milstone explains. Kids can get vaccinated against the flu, COVID-19 and pneumococcal bacteria (one of the most common causes of these severe complications, he says).
"Most kids that get viruses don't get these bacterial infections and don't need antibiotics," Milstone says. "So the good thing is these are uncommon." But it's always a good idea to be aware that these rare complications can happen and "never hesitate to call your child’s doctor if you have concerns," Olivero adds.
