Kidney infection; inflammation of the kidney and renal pelvis.

• A. Pyelonephritis
• B. Raynaud's disease
• C. Pericardium
• D. Duodenum

Answer: (A)

Understanding medical terms by their roots helps you identify what each term refers to. Pyelo- means the renal pelvis, nephr- means kidney, and -itis indicates inflammation. Put together, pyelonephritis denotes inflammation of the kidney and its renal pelvis, which is exactly what a kidney infection involves. The other terms point to different parts or conditions: Raynaud's disease affects blood vessels in the extremities, the pericardium is the membrane around the heart, and the duodenum is the first part of the small intestine. So the term that correctly describes a kidney infection involving the kidney and renal pelvis is pyelonephritis.