Adults with a history of immunocompromise or central nervous system (CNS) disease (mass lesion, stroke, focal infection), new onset seizure, papilledema, abnormal level of consciousness, or focal neurologic deficit should undergo head CT prior to LP.

This question was addressed in a single-center prospective observational study at an urban academic ED of adults (>16 years) with clinically suspected meningitis.¹ Patients who had undergone CT scanning prior to enrollment or for alternate indications were excluded. The decision to undergo CT was at the discretion of the treating physician. Among patients who underwent CT, scans were categorized as normal (including isolated atrophy) or as having a focal (such as stroke or mass) or nonfocal (such as hemorrhage or hydrocephalus) abnormality. The presence and degree of mass effect was also noted in abnormal scans.

Of 301 eligible patients, 235 (78%) underwent CT scan prior to LP, of whom 179 (76%) had normal CT scans and 56 (24%) had abnormal scans. Risk factors associated with abnormal CT include age >60 years (P < .001), immunocompromised state (P = .01), history of CNS disease (P < .001), seizure within 1 week prior to presentation (P < .001), reduced level of consciousness (P < .001), and abnormal focal neurologic signs on examination (such as gaze palsy [P = .003], visual field abnormality [P < .001], facial palsy [P < .001], arm/leg drift [P < .001], or abnormal language [P < .001]).

The above features were absent in 96 (41%) of the patients who underwent CT, with scans being normal in all but 3 of these 96 patients (NPV 97%). All three underwent LP without herniation. Four patients had mass effect on CT that led clinicians to defer LP, each of whom had at least one of the risk factors identified above.

Patients undergoing CT scan prior to LP had a delay in time from presentation to LP when compared to those who did not undergo CT (mean 5.3 vs. 3.0 hours; P = .01). Caveats include the study’s single-centered setting and that head CTs were ordered at the discretion of the treating physician rather than routinely. Infectious Diseases Society of America (IDSA) guidelines recommend CT imaging prior to LP in patients with immunocompromised state, CNS disease, new onset seizure, papilledema, abnormal level of consciousness, or focal neurologic deficit (B-II).²

Adults with suspected pneumococcal meningitis should receive early glucocorticoids before or at the time of antibiotic administration to reduce the risk of unfavorable outcomes including mortality.

This question was evaluated in a prospective, double-blinded, multicenter randomized control trial comparing early administration
of adjunctive dexamethasone to placebo in 301 adults with suspected acute bacterial meningitis presenting to participating centers in the Netherlands, Germany, Austria, and Denmark.³ Patients received either dexamethasone 10 mg (n = 157) or placebo (n = 144) 15 to 20 minutes prior to the first dose of antibiotics, which was continued every 6 hours for 4 days. This study included adults (age ≥17 years) with clinically suspected meningitis in combination with either cloudy cerebrospinal fluid (CSF), bacteria on CSF gram stain, or a CSF leukocyte count >1000/mm³. Patients with a CSF shunt or peptic ulcer disease were excluded. The primary outcome was the score on the Glasgow Outcome Scale (GOS), separated into “favorable” (mild or no disability) or “unfavorable” (ranging from moderate disability to death) categories. Secondary outcomes included mortality, focal neurologic abnormalities (defined as aphasia, cranial nerve palsy, monoparesis, hemiparesis, or severe ataxia), hearing loss, and clinically significant gastrointestinal bleeding. Prospective subgroup analyses were performed based on pathogenic organisms grouped as follows: Neisseria meningitidis, Streptococcus pneumoniae, other bacteria, or unidentified cause (negative CSF culture).