Bacterial Meningitis in the ICU

Abstract

Bacterial meningitis is a condition which carries a high mortality and morbidity rate and involves inflammation of the tissues surrounding the brain and spinal cord. Bacterial meningitis is a neurologic emergency that presents with at least one of the symptoms forming the classic triad: nuchal rigidity, fever and altered mental status (Attia et al. JAMA 281(2):175–181, 1999). The classic triad is only present in 44 % of patients at presentation, so physicians must maintain high clinical suspicion (van de Beek et al. N Engl J Med 351(18):1849–1859, 2004). Management is aimed at early recognition and rapid administration of antibiotics with adjunctive dexamethasone therapy (de Gans and van de Beek N Engl J Med 347(20):1549–1556, 2002). The two most common community acquired pathogens include Streptococcus pneumoniae and Neisseria meningitidis. In immunocompromised patients or patients above the age of 50, Listeria monocytogenes must also be considered. Diagnosis is typically made through a lumbar puncture (LP) demonstrating elevated white blood cells (WBC) with a neutrophil predominance. Cerebral spinal fluid (CSF) microbial analysis and blood cultures yield a definitive diagnosis. Empiric therapy includes broad spectrum antibiotics with vancomycin and a third generation cephalosporin. Dexamethasone prior to or at the time of initial antibiotics is recommended to reduce the neurologic sequelae and complications of pneumococcal meningitis. Although some patients require imaging prior to LP, antibiotics should not be delayed as this is associated with poor outcomes including chronic neurological deficits and death. Healthcare associated bacterial meningitis is less common and usually occurs after a neurosurgical procedure or trauma and differs in the microbial pathogens.