Which symptom may indicate infection has reached the kidneys?

• A. Fever
• B. Cough
• C. Itchy eyes
• D. Dizziness

Answer: (A)

Fever signals a systemic response to infection, which can occur when bacteria reach the kidneys and cause pyelonephritis. When the kidneys are involved, the body often responds with fever as part of the inflammatory process, and it is commonly accompanied by flank pain and urinary symptoms, though fever itself is a key red flag that something is affecting internal organs rather than just a localized issue. The other symptoms point to unrelated systems: cough suggests a respiratory process, itchy eyes to irritation or allergy, and dizziness is nonspecific to kidney involvement. Thus, fever is the best indicator among these options that infection has reached the kidneys and needs medical attention.