Which symptom suggests pyelonephritis rather than cystitis?

• A. Fever and flank pain
• B. Dysuria
• C. Urinary frequency
• D. Suprapubic tenderness

Answer: (A)

Fever with flank pain points to an infection that has reached the kidney, signaling pyelonephritis. Fever shows systemic involvement, and flank pain localizes to the kidney area, indicating upper-tract infection. In contrast, cystitis is a bladder infection and typically presents with irritative voiding symptoms—dysuria, urinary frequency, urgency—and sometimes suprapubic discomfort, usually without fever or systemic signs. While the other symptoms can occur with bladder infection, they are less specific for kidney involvement. So the combination of fever and flank pain most strongly distinguishes pyelonephritis from cystitis.