Meningitis and encephalitis may start with flu-like symptoms and intensify over a few hours to a few days. Characteristic signs and symptoms of these two conditions may overlap and can include:

• Fever
• Severe persistent headache
• A stiff neck
• Sensitivity to light
• Mental changes
• Lethargy

Other symptoms may include confusion, nausea, vomiting, a red or purple rash, and seizures. Elderly patients may be lethargic and show few other signs. Patients with compromised immune systems may have atypical symptoms. Infants may be irritable and cry when they are held, vomit, have body stiffness, have seizures, refuse food, and have bulging fontanels (the soft spots on the top of the head).

Encephalitis symptoms may also include neurological problems – difficulty with hearing or speech, loss of sensation, partial paralysis, seizures, hallucinations, muscle weakness, changes in personality, and coma.

Complications and Prognosis

The outcome of those with meningitis and encephalitis depends on the specific cause of the condition, the severity, the patient’s health and immune status, and how quickly the condition is identified and treated. Patients with mild cases may recover fully within a few weeks or may have persistent or permanent complications.

As many as 15-25% of newborns and 15% of other patients with bacterial meningitis die, even when treated appropriately and rapidly. Up to 15-25% of those who survive may have neurological sequelae including hydrocephalus, deafness, blindness, periodic seizures, and/or some degree of impaired thinking processes. These complications may occur at any age, but newborns are at the highest risk.