Headache is the most common symptom of bacterial meningitis (87%). It is often the first symptom to appear and may be the only long-term complication of the illness. It is usually generalized (but may be predominantly frontal); it may radiate down the neck and back and into the extremities, and it is severe and unremitting. Encephalitis is characterized by headache, fever, alteration of consciousness, focal neurologic deficit, and seizures (usually focal). Because the brain parenchyma has no sensory receptors, the headache of encephalitis and brain abscess may result from the meningeal inflammation that often accompanies these processes, including a nonspecific response to fever, increased intracranial pressure, or a mass-effect producing traction on pain-sensitive intracranial structures. The most common causes of brain abscesses are otorhinogenic. Physical signs of meningeal inflammation do not help clinicians rule in or rule out meningitis accurately. Patients suspected to have meningitis should undergo a lumbar puncture regardless of the presence or absence of physical signs.