Bacteria and other infectious organisms can reach the brain and meninges in several ways: Hematogenous spread Penetrating head wounds (including neurosurgical procedures) Direct extension of cranial infections (eg, sinusitis, osteomyelitis) Many symptoms and signs of brain infections (eg, acute or subacute obtundation, seizures, focal neurologic deficits, signs of increased intracranial pressure) can develop in various brain infections (eg, brain abscess, intracranial epidural abscess, subdural empyema); thus neuroimaging is frequently necessary to differentiate among the infections.