Which of the following conditions is associated with flank pain?

• A. Pneumonia
• B. Pyelonephritis
• C. Small bowel obstruction
• D. Appendicitis

Answer: (B)

Flank pain is typically associated with conditions affecting the kidneys or the structures surrounding the kidneys. Pyelonephritis, which is a bacterial infection of the kidney, commonly leads to flank pain due to inflammation and irritation of the renal capsule. Patients often experience this pain on the affected side, and it may be accompanied by other symptoms such as fever, dysuria, and increased urinary frequency.

In contrast, conditions such as pneumonia generally present with respiratory symptoms and chest pain rather than flank pain. Small bowel obstruction can cause diffuse abdominal pain and distension but is not localized in the flank. Appendicitis causes pain that starts around the umbilicus and typically moves to the right lower quadrant rather than the flank area. Therefore, pyelonephritis is the condition most directly linked to the presentation of flank pain.