Last November I wrote about the severe respiratory virus season that had pediatric hospitals, and community hospitals with pediatric units like mine, overwhelmed across the country. At my hospital, with it’s 12-bed pediatric unit and no PICU, for example, we had all hands on deck providing PICU level care for many patients over several weeks because there were no higher level beds available in Boston or the surrounding area. It was scary at times, and we were beyond exhausted by the time things began to settle down in early 2023.
Unsurprising to anyone familiar with the complexities of human pathophysiology, we are now learning that this unprecedented surge in pediatric viral respiratory infections had some unexpected complications. As reported by the CDC earlier this month, there was a significant increase in the incidence of brain abscesses in children over the past several months, with a peak in December that was 200% higher than the typical pre-pandemic average. This followed a trend of increasing cases that essentially began when society decided to relax the precautions in place to reduce the risk of COVID-19, which also prevented millions of infections with the usual viral suspects.
Cases of intracranial (brain) abscesses are not typically reported to the CDC, so we don’t have good data going back decades like we do for measles and gonorrhea. I took part in the care of a child with brain abscess a few months ago, the first in my now 20 years of practice, and had no idea that the CDC would ever know about it. But in May of last year, because of an unusual cluster of cases in a California hospital, the CDC began an investigation that collected data from every state.
One of these was Nevada, where the only pediatric neurosurgeon in the state had also sounded an alarm. She reported seeing a more than 3-fold increase in brain abscesses in children, from a average yearly incidence of 4 or 5 cases to 18 in 2022. These cases seemed to coincide with increases in viral respiratory infections. Soon other doctors in other states chimed in:
After a presentation on the Nevada cases the Epidemic Intelligence Service Conference on Thursday, doctors from other parts of the country said they are seeing similar increases in brain abscesses in kids.
“We’re just impressed by the number of these that we’re seeing right now,” said Dr. Sunil Sood, a pediatric infectious disease specialist at Northwell Health, a health system in New York. He estimates they are seeing at least twice as many as usual, though they haven’t done a formal count. He urged the CDC to continue investigating and work to get the word out.
The CDC is now doing just that after reviewing data from multiple state and federal sources going back as far as January of 2016. They found that while there was certainly some month-to-month variation, the number of cases per month didn’t tend to stray too far from the historic average. Until last year, that is.
From January of 2016 through December of 2019, the largest number of brain abscess cases diagnosed in one month was 61, with an average of around 30. This actually went down from March of 2020 through May of 2021, likely because COVID-19 precautions were keeping kids from getting sick with typical respiratory viruses. I’ll never forget how odd that winter was, with hardly any admissions for RSV. It was unlike anything I had ever experienced.
Cases began to increase in June of 2021, and they continued to run at the upper limit of the historical range through September of 2022. That’s when things really took off. From November of 2022 through March of 2023, the last month with available data, between 62 and 102 cases were diagnosed each month. January, February, and March saw a downward trend that was still above pre-pandemic levels. And with the steady decline in pediatric respiratory infections that has occurred in April, May, and June so far, experts expect that there will be a coinciding decrease in brain abscess.
What do viral respiratory infections have to do with brain abscesses in kids, which are typically a bacterial infection? It makes a lot of sense once you realize that viral infections are a well known risk factor for the development of secondary bacterial infections, particularly in the upper respiratory region. That includes the ears, and more importantly in the case of brain abscess risk, the paranasal sinuses.
A brain abscess occurs when bacteria, or in some cases a fungus or parasite, invades the brain either by direct spread from a local source or via the bloodstream from a more remote source. Direct spread is by far the most common route in children, usually in the setting of an infection of the middle ear, mastoid, sinuses, or the teeth and gums. Sinus infections are the leading initiating even, and all of these, except for dental infections, are more likely to occur when a child has a viral upper respiratory infection.
Many different bacteria are known to cause brain abscesses, but several different Streptococci species are most common in children. These are common causes of sinusitis and ear infections as well as dental infections. Staph aureus is also an important potential pause, though it is more likely as a result of penetrating head trauma.
The diagnosis of a brain abscess in children is often delayed because the signs and symptoms can be vague and nonspecific. The classic triad of headache, fever, and focal neurological deficits is only seen in around 20% of patients. Headache is by far the most common presenting complaint, but fever is only seen in about half of patients. By the time focal neurological deficits or seizures occur, the infection may have been going on for weeks. Changes in mental status, and coma even more so, are extremely worrisome and predict a poor outcome.
In addition to appropriate antibiotics, the treatment of brain abscesses almost always requires surgical drainage, though this isn’t always possible depending on the location of the infection. Antibiotics are often necessary for several weeks. Though outcomes have definitely improved over the years, there is still a fatality rate of more than 10%. And only about 70% of patients can expect a full recovery without residual neurological deficits.
Conclusion: The Worst is Probably (Hopefully) Over
Pediatric brain abscesses are rare. And despite the significant increases seen during recent surges in viral respiratory infections, they remain rare. The vast majority of children with viral infections do not go on to develop a brain abscess. But it is still important for pediatric healthcare professionals to recognize their possibility and to consider neuroimaging when appropriate.
Parents definitely shouldn’t panic. Again, a child’s risk of a brain abscess is remote even if they have a rip roaring sinusitis. And appropriate treatment of these infections will reduce the risk. Overdiagnosis, unfortunately, is also a huge problem that can be inspired by fear of rare bad outcomes. It is very often safe to treat viral infections and even many suspected ear and sinus infections conservatively without antibiotics. But certainly you should talk to your child’s doctor if they have unusual persistent headaches, particularly if accompanied by fever or worrisome changes in behavior.