Most commonly, meningitis develops over 1-4 days. 

However, in severe cases, a child who looks healthy can rapidly become seriously ill within 1 day. In these cases, death is possible.

In children, the signs and symptoms of meningitis depend on the child's age and are not always obvious because the child cannot communicate symptoms in the same way as an adult. Therefore, caregivers must pay very close attention to the child's condition.

Classic symptoms in infants younger than 3 months are as follows:

• Decreased liquid intake
• Vomiting
• Increased irritability
• Increased lethargy
• Fever
• Bulging fontanelle (soft spot on the top of the head)
• Seizure activity

Classic symptoms in children older than 1 year are as follows:

• Nausea and vomiting
• Headache
• Increased sensitivity to light
• Fever
• Altered mental status (seems confused or odd)
• Lethargy
• Seizure activity
• Neck stiffness or pain
• Knees automatically brought up toward the body when the neck is bent forward or pain in the legs when bent (called Brudzinski sign)
• Inability to straighten the lower legs after the hips have already been flexed 90° (called Kernig sign)