Less commonly, cystitis may occur as a reaction to certain drugs, radiation therapy or potential irritants, such as feminine hygiene spray, spermicidal jellies or long-term use of a catheter. Cystitis may also occur as a complication of another illness. The usual treatment for bacterial cystitis is antibiotics.
The maneuver is based on the fact that when a patient forcibly exhales against a closed nose and mouth while bearing down, as if having a bowel movement, specific changes occur in blood pressure and the rate and volume of blood returning to the heart.
The Shuttle uses a rocket propulsion system to get into orbit, but during re-entry the aircraft is actually an un-powered glider. Small steering rockets are used for maneuvering early in the re-entry because the low density of the air at altitudes above 50 miles makes aerodynamic surfaces ineffective.