Infections of the Nervous System

Acute Bacterial Meningitis

Clinical manifestations (NEJM 2006;354:44; Lancet 2012;380:1684)

  • Fever (77%), headache (87%), stiff neck (31%), photosensitivity, Δ MS (69%) (defined as GCS <14), seizures (5%); 2 of 4 (fever, HA, stiff neck, Δ MS) present in 95%
  • Presentation may be atypical (eg, lethargy w/o fever) in elderly and immunosupp.

Physical exam

  • Nuchal rigidity (Se 31%), Kernig’s sign (Pt supine, hip flexed at 90°, knee flexed at 90°; ⊕ if passive extension of knee → resistance), Brudzinski’s sign (Pt supine and limbs supine; ⊕ if passive neck flexion → ion)