Symptoms:

• Fever (in young infants the temperature may actually be below normal)
• Irritability, poor feeding in infants
• Nausea and vomiting
• Pain in back when neck is bent forward and chin is brought toward chest (older children)
• Sensitivity to light (photophobia)
• Severe headache (older children)
• Stiff neck or pain in neck
• Unusual body positions

Signs and tests:

Signs include:

• Bulging of the fontanelles in an infant
• Lying with the back arched, head, back, and chin up (opisthotonos)
• Mental status changes (such as irritability, reduced consciousness, coma)
• Poor blood flow (circulation)
• Seizures

For any patient with meningitis, it is important to perform a lumbar puncture ("spinal tap"), in which spinal fluid (known as cerebrospinal fluid, or CSF) is collected for testing.

Other tests include:

• Antibodies in blood (serology)
• Blood culture
• Spinal fluid culture
• White blood cell count