Infection within the central nervous system (CNS) can result in meningitis, encephalitis or the formation of abscesses and empyemas. Peripheral blood cultures, skin rash aspirates and posterior pharyngeal swabs can confirm meningococcal disease. Pneumococcal meningitis is often a complication of pulmonary infections but can also occur de novo or following skull fractures and sinus/middle-ear infections. There is evidence for the beneficial effect of corticosteroids in the treatment of bacterial meningitis by reducing this inflammation. Encephalitis occurs when there is an inflammatory reaction in the brain parenchyma, either as the primary site of infection, or secondary to subarachnoid space infection (meningoencephalitis). Many non-infectious conditions result in inflammation in the CNS; these may be post-infectious, paraneoplastic or the consequence of a chronic autoimmune disease. Sudden acute neurological dysfunction can occur, either at the time of disease onset or during relapse of the disease, resulting in focal neurological deficits or coma.