It has been a steady day in the pediatric ED. The volume is beginning to pick up a little. The resident has just presented the sickest kid of the day to you. He’s a four-year-old with fever, headache, vomiting and neck pain. He has nuchal rigidity. He has no rash or focal neurologic signs. He has been healthy up until this point. He has received all the routine childhood immunizations expected of a four year old. He has had no known sick contacts.
Clearly, this child has a high likelihood of meningitis. He needs a lumbar puncture and antibiotics promptly. You and the resident outline the plan and then the resident asks you “What about steroids?”
So, what about steroids? You review the major pathophysiologic events of bacterial meningitis. The seminal event is a breakdown of the blood brain barrier. From there, the bacteria do two things: they cause direct tissue damage and they elicit an inflammatory response, which causes further tissue damage. Research has shown that steroids have the potential to mitigate the damage done by the inflammatory response. So why not give steroids? Is there a downside to giving steroids?
First, let’s discuss the downside. Theoretically, steroids suppress the immune response. Maybe not such a good idea in someone with a potentially devastating infection. However, evidence does not support the idea that mortality is increased with steroid administration.
Are there other potential problems with steroids? A few. For instance, a small percentage of patients who receive steroids can experience GI bleeding. Steroids also can produce a re-emergence of fever after they are discontinued. This can complicate management decisions for the ward team. Vancomycin has emerged as a front line drug in the treatment of bacterial meningitis in infants beyond the neonatal period as well as children and adolescents. Theoretically, the anti-inflammatory effects of steroids can reduce the concentration of vancomycin in the cerebrospinal fluid by reducing its ability to cross the blood brain barrier.
And the benefit of steroids? The main benefit of giving dexamethasone, the main steroid studied, to pediatric patients with meningitis appears to be a reduction in the incidence of sensorineural hearing loss. Sensorineural hearing loss is a bad thing, so that means we should treat with dexamethasone, right?
It turns out that not everyone reliably gets this benefit from treatment with dexamethasone. The only group that has been shown consistently to derive this particular benefit is children with meningitis from Haemophilus influenzae type b (Hib). Data about children with meningitis from Streptococcus pneumoniae have been inconclusive. There is no other bacterial cause of meningitis in which a reduction in hearing loss has been clearly demonstrated.
Not every bacteria is equally likely to produce meningitis. For reasons not clearly understood, there are a small number of usual suspects. In the US, the big three in children have been Hib, S. pneumoniae, and Neisseria meningitidis.
Because Hib was once the dominant member of the evil trio, the recommendation used to be that every child with suspected bacterial meningitis received dexamethasone. To work optimally, the experts further advised that the dexamethasone be given either before or concurrently with the first dose of antibiotics or at least within the first hour.
However, since the research about the benefits of dexamethasone came out, there have been two major developments in the war against pediatric meningitis. First came the introduction of universal vaccination against Hib. According to the latest report of the American Academy of Pediatrics Committee on Infectious Diseases, this vaccine reduced the incidence of invasive Hib disease by 99%. Second, the introduction of universal vaccination against S. pneumoniae caused a dramatic decrease in invasive disease from that organism. That left N. meningitidis as the most common cause of bacterial meningitis in the pediatric population.
So, looking at the odds, it is very unlikely that the next child you see in the United States with meningitis is going to have the disease due to Hib. And unless you know the child has Hib, the administration of dexamethasone is not recommended.
Where does this leave our four-year-old patient? He is extremely unlikely to have Hib meningitis, since he is fully vaccinated. And we have to make the decision to give dexamethasone right now to get the potential benefit. Logically, he should not receive steroids since the benefit does not outweigh the risks unless it is Hib. And that is going to be true in almost any other child you see with meningitis unless you know that the child is highly likely to have Hib disease. When would you know this? Maybe if the child is unvaccinated and has had close contact with a patient with known Hib disease. Other than that, there is probably no way you could suspect Hib disease in time to dose with steroids.