Table 2.

Predisposing factors and signs of severity

Aetiologic agent		Predisposing factors
Streptococcus pneumoniae		Previous history of head injury, surgery at the base of the skull, meningitis, rhinorrhea, sudden onset, neurological signs, otitis, sinusitis or associated pneumopathy, asplenia, human immunodeficiency virus infection
Neisseria meningitidis		Possible epidemic, purpura
Listeria monocytogenes		Immunodepression, signs of rhomboencephalitis, cloudy cerebrospinal fluid with mixed composition
Haemophilus influenzae		Age <5 years, absence of vaccination.
Principal signs of severity		Purpura fulminans, deep coma (Glasgow coma score <8), cardiorespiratory failure