What are the typical clinical features of acute pyelonephritis?

• A. Nocturia only.
• B. Fever, flank pain, CVA tenderness, dysuria, frequency, and pyuria.
• C. Weight gain and edema.
• D. Hypertension, edema, proteinuria.

Answer: (B)

Acute pyelonephritis is an infection of the kidney that brings both systemic and upper-tract urinary features. The fever reflects the body's response to the infection, while flank pain or costovertebral angle tenderness points to renal parenchymal involvement. Added urinary symptoms like dysuria and increased frequency arise from irritation of the urinary tract by the infection. Pyuria, or pus in the urine, is a direct sign of the inflammatory process happening in the urinary tract, often with bacteria present. This combination—fever, kidney-localized pain, voiding symptoms, and pyuria—best characterizes acute pyelonephritis and helps distinguish it from conditions that cause edema or hypertension without a fever or CVA tenderness, such as certain glomerular diseases.