Symptoms:

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

Signs and tests:

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

Other signs and tests include:

• Bulging of the fontanelles (the soft spots on an infant's head)
• Opisthotonos (lying with the back arched, head, back, and chin up)
• Seizures
• Poor circulation(blood flow through the body)
• Mental status changes (such as irritability, reduced consciousness, coma)
• High white blood cell count in blood
• Spinal fluid showing increased number of white blood cells
• Spinal fluid culture showing bacteria
• Serology (antibodies in blood) showing recent exposure to H. influenzae
• Blood culture growing H. influenzae