During transfer of the patient from the ED, the patient developed a generalized tonic-clonic seizure and was urgently given IV lorazepam. Due to decreased level of consciousness after the seizure, the patient was intubated for airway protection and was admitted to the ICU.

This patient presented with the ‘classic triad’ for bacterial meningitis of fever, neck stiffness and altered mental status (AMS). Although the complete triad is present only 44 % of the time [1], nearly all patients with bacterial meningitis will present with one of the three findings [2]. The absence of all three of these signs in the classic triad essentially eliminates bacterial meningitis from the differential [2]. The classic physical exams for evaluation of meningeal irritation, Kernig’s and Brudzinski’s signs are not that useful as these only have 61 % sensitivity for bacterial meningitis compared to nuchal rigidity (difficulty with chin to chest or flexion of the cervical spine) which has 84 % sensitivity for bacterial meningitis [3]. While these physical exam signs may provide support in establishing the diagnosis, a lumbar puncture is still required for definitive diagnosis.

Until the specific pathogen responsible for community acquired bacterial meningitis has been identified, strong consideration should be given for initiating droplet precautions. Droplet precautions are recommended by the CDC to decrease the spread of infection caused by Neisseria meningitides and Haemophilus influenzae type b. A definitive diagnosis may be delayed for several days [4]. In addition, depending on the quality of the gram stain, differentiating between gram positive cocci and gram negative cocci may be difficult. For these reasons, a general recommendation is to keep patients with presumed community acquired bacterial meningitis in droplet precautions for at least the first 24h of therapy and until the etiology has been determined.

Although appropriate empiric antibiotics to cover the usual organisms implicated in community acquired bacterial meningitis were initiated, all adult patients with suspected or confirmed bacterial meningitis by lumbar puncture should also be treated with IV dexamethasone prior to or at the time of their first dose of antibiotics [1]. In our case, this patient should have be started on the standard dose of dexamethasone at 10 mg IV q6h, 15 min prior to initiation of his antibiotics to complete a 4 day course [1, 5]. The efficacy of steroids in bacterial meningitis is discussed further in the management section of this chapter.

It is critical to initiate empiric antibiotics promptly and without delay while awaiting CSF gram stain results or imaging of the brain. In this case, the patient did meet criteria for imaging prior to LP due to altered level of consciousness, (see below), still empiric antibiotics were given promptly. Initially, during selection of the antibiotics it is important to assume a high likelihood of antimicrobial resistance and select broad coverage. In this case, our patient’s empiric antibiotics included vancomycin and ceftriaxone to cover for the most common pathogens, Streptococcus pneumoniae and Neisseria meningitides. Because this patient was over age 50 years, ampicillin was also appropriately added to cover for Listeria monocytogenes.

Although the gram positive diplococci were seen on gram stain, suggestive of Streptococcus pneumoniae, the patient was continued on the recommended empiric antibiotics vancomycin 15 mg/kg IV q8h (15–20 ug/mL trough target) and ceftriaxone 2 g IV q12h until definitive culture results and sensitivities are available. See Fig. 36.1.