symptoms of pyelonephritis in adults
1 Urethritis: Burning urination is often the result of urethritis, the infection of the urethra. 2  In men, urethritis can also cause penile discharge. 3  Pyelonephritis: Pyelonephritis occurs when a bladder infection spreads to the kidneys. 4  It can cause upper back and flank pain, shaking, chills, nausea and vomiting.