Meningitis

The most classic symptoms of meningitis (particularly of bacterial meningitis) include fever, headache, vomiting, photophobia (sensitivity to light), irritability, lethargy (severe fatigue), and stiff neck. The disease progresses with seizures, confusion, and eventually coma.

A very young infant may not show the classic signs of meningitis. Early in infancy, a baby's immune system is not yet developed enough to mount a fever in response to infection, so fever may be absent. Some infants with meningitis have seizures as their only identifiable symptom.