"Febrile" generally indicates an instance of a high temperature. If a patient is febrile, that means they have a temperature. If you've ever heard of a 'febrile convulsion' it would relate to a 'convulsion' or 'fit' brought on by a high temperature, as opposed to a fit associated with Epilepsy. It's like a 'one off' episode of a convulsion, or there could be several episodes depending on how long the temperature is raised. These convulsions generally relate to children, who may have episodes of high temperatures, and can occur up to the age of 5 or 6.