What to do if i have fever of 104 degrees. should we be scared of the possibility of mediastinitis?

Temp of 104: It is time to seek medical care.

Unlikely Unless: Unlikely unless you have had recent chest surgery or fairly severe pneumonia. The other source of mediastinal infections would be dental type infections or severe pharyngeal infections that can track into the chest. Usually you would have some upper chest discomfort and or redness above the sternal notch. If present that is an emergency, but otherwise most likely some other source of fever.