Meningitis can be difficult to diagnose.

It usually comes on suddenly and can be confused with flu because many of the symptoms are the same.

Seek immediate medical help if you notice any of the signs and symptoms of meningitis, particularly in a young child.

This may mean going to your local accident and emergency (A&E) department in the middle of the night. Don't wait for the purple rash to appear, because not everyone gets a rash.

A suspected case of meningitis should always be treated seriously. If you're not sure whether it's meningitis, you can get more advice by calling:

• your GP, practice nurse or health visitor
• NHS 111
• the Meningitis Research Foundation on 080 8800 3344
• Meningitis Now on 0808 80 10 388

Both of the above charities run a 24-hour freephone helpline. The Meningitis Trust also have a free meningitis signs and symptoms iPhone app that you can download.

Confirming the diagnosis

If meningitis is suspected, treatment will usually begin before the diagnosis has been confirmed. This is because some of the tests can take several hours to complete, and it could be dangerous to delay treatment.

The doctors will carry out a physical examination to look for signs of meningitis or septicaemia (blood poisoning), such as a rash. They will also carry out tests to confirm the diagnosis.

Diagnostic tests for meningitis may include:

• a blood test – to check for the presence of bacteria or viruses that can cause meningitis
• a lumbar puncture – where a sample of cerebrospinal fluid (CSF) is taken from the base of the spine under local anaesthetic and checked for the presence of bacteria or viruses
• a computerised tomography (CT) scan – if there are any other suspected problems, such as brain damage
• a chest X-ray – to look for signs of infection