Streptococcus pneumoniae is the most common cause of bacterial meningitis in adults.

Enterovirus is the most common viral cause of meningitis.

Cryptococcus neoformans is the most common fungal cause of meningitis.

Herpes simplex virus is the most common cause of encephalitis.

Streptococcus pneumoniae is the most common cause of brain abscess.

Streptococcus pneumoniae is the most common cause of subdural empyema.

Staphylococcus aureus is the most common cause of epidural abscess.

Headache is the most common clinical manifestation of meningitis.

Altered mental status is the most common clinical manifestation of encephalitis.

Headache is the most common clinical manifestation of brain abscess.

Headache is the most common clinical manifestation of subdural empyema.

Headache is the most common clinical manifestation of epidural abscess.

Hydrocephalus is the most common complication of meningitis.

Seizures are the most common complication of encephalitis.

Focal neurological deficits are the most common complication of brain abscess.