C C34965 Pyelonephritis Pyelonephritis An inflammatory process affecting the kidney. The cause is most often bacterial, but may also be fungal in nature. Signs and symptoms may include fever, chills, flank pain, painful and frequent urination, cloudy or bloody urine, and confusion. C2890 Bacterial Disease C90259 NICHD Pediatric Terminology C C34965 Pyelonephritis Pyelonephritis An inflammatory process affecting the kidney. The cause is most often bacterial, but may also be fungal in nature. Signs and symptoms may include fever, chills, flank pain, painful and frequent urination, cloudy or bloody urine, and confusion. C2890 Bacterial Disease C92712 NICHD Pregnancy & Childbirth Terminology