Right flank pain for 2 days most likely indicates which diagnosis?

• A. Nephrolithiasis.
• B. Pyelonephritis.
• C. Cholelithiasis.
• D. Gastritis.

Answer: (A)

Unilateral flank pain that is severe and comes in waves (colicky) is classic for kidney stones. A stone moving through the urinary tract causes sudden, intense pain that can wax and wane as it irritates the lining, often staying on one side and sometimes radiating to the groin. Blood in the urine can accompany this as well, though it’s not always present.

In comparison, a kidney infection (pyelonephritis) usually brings fever, chills, and a more constant, dull ache rather than sudden, intermittent colicky pain. Gallbladder-related pain from cholelithiasis tends to show up as right upper quadrant or epigastric pain, often after meals, and may radiate to the right shoulder blade rather than the flank. Gastritis produces epigastric discomfort with nausea rather than focal flank pain.

So the pattern described aligns most closely with nephrolithiasis.