Correct!
4. Microbiological confirmation of S. pneumoniae as the pathogen is recommended before dexamethasone is administered.
Dexamethasone should be started before, or at the same time, as initial antibiotics in all adults with suspected community-acquired bacterial meningitis. The etiology of bacterial meningitis is not usually known at the time of treatment initiation, and S. pneumoniae is the most common cause of bacterial meningitis in adults in resource-rich settings. Use in pediatrics is generally limited to patients with suspected H influenza type B meningitis. Dexamethasone given prior to, or at the same time as antibiotics has been associated with a reduction in the rate of hearing loss, other neurologic complications, and mortality in adult patients. However, in some cases (such as our patient initially given ceftriaxone for a UTI) antibiotics are administered before dexamethasone is considered. The data in such cases are of lower quality and provide conflicting conclusions. Some experts have recommended that dexamethasone might be reasonably given within an hour, to as long as 12 hours, after antibiotics – this despite observational data suggesting that giving dexamethasone after antibiotics might potentially worsen outcomes. Dexamethasone can be continued for four days, even if an alternative (non-pneumococcal) microbiological diagnosis is made.
On the second hospital day, dexamethasone 14mg Q6 hourly was administered. An EEG showed diffuse slowing and no seizure activity. Detailed neurological examinations were not recorded on days two and three, but a neurologist noted GCS 3t, no pupillary or cough reflexes on fourth hospital day.
A non-contrasted MRI of the brain showed diffuse increased cortical FLAIR/T2 hyperintensity throughout the cerebral and cerebellar hemispheres, basal ganglia, and thalamus consistent with meningoencephalitis and loss of FLAIR CSF suppression in the ventricles was consistent with purulent ventriculitis (see figure 1). Diffusion restriction of the thalami and temporal lobes consistent with evolving ischemia was noted on DWI images. Loss of normal dural venous sinus flow voids and diffuse susceptibility hypointensities on GRE (see figure 2) were consistent with dural venous sinus thrombosis and extensive petechial hemorrhages throughout the brain. Intracranial mass effect resulting in right uncal herniation and tonsillar herniation were described. Ethmoid and sphenoid sinuses air-fluid levels and bilateral mastoid effusions were noted. (Of note: infectious CNS complications of sinusitis include meningitis, subdural empyema, brain abscess and temporal or frontal osteomyelitis, possibly suggesting sinusitis as the origin of S pneumoniae in our patient).
Figure 1. A FLAIR MRI image from our patient with a (smaller) normal FLAIR image on the right for comparison.
Figure 2. A gradient echo (GRE) MRI image from our patient with a (smaller) normal GRE image on the right for comparison.
Which of the following are false regarding the neurological complications of pneumococcal meningitis? (Click on the correct answer to be directed to the fifth and final page)