the Balloon is RUINED!!!

Causes of pericarditis
RUINED

Radiation/Rheumatic fever
Uremia
Infection/Injury/Infarct
Neoplasm
End Stage Renal Disease
Dressler's syndrome

Ok, so this mnemonic is a little bit over the top, but so is the cure if you destabilize.

Pericarditis is inflammation of the pericardium, a "plastic" bag that surrounds your heart. If too much fluid flows in, be it blood or pus or anything like that, then you get a cardiac tamponade and your heart stops pumping blood. It needs to be dealt with swiftly and sometimes, punching a needle through the chest wall to draw the fluid out of the pericardium is necessary. That's pretty scary, because you don't want to hit the lungs or the heart... just the pericardium.