Meningitis is a pathological condition resulting from any of a wide population of viruses, parasites or bacteria (pathogens).
Pathogens in the space between the arachnoid and pia layers of the meninges (the sheathing that coats nerves) cause the breaking of subarachnoid blood vessels, therefore swelling the subarachnoid space and applying pressure on the underlying cortical brain tissue, resulting in lack of oxygen to and compression of neurons. This leads to the loss of function of the pressured neurons. Continual pressure can lead to permanent loss of function.
In Kids, House is helping the hospital dealing with an outbreak of meningitis when he finds a patient with similar symptoms that are not meningitis.
In Airborne, the patient appears to have symptoms that suggest bacterial meningitis. Cuddy wants to land the plane so they can all get treatment, but House does not believe the disease is meningitis. However, several other passengers, including Cuddy, develop the same symptoms after the plane has passed its point of no return. Luckily, it merely turns out to be mass hysteria and the symptoms of everyone except the original patient disappear when they are reassured by House that there is nothing wrong with them.