Young man with left flank pain radiating to the groin and left flank tenderness, with mild bowel hypoactivity and negative fecal occult blood. Which diagnosis is most likely?

Young man with left flank pain radiating to the groin and left flank tenderness, with mild bowel hypoactivity and negative fecal occult blood. Which diagnosis is most likely?

• A. Appendicitis
• B. Diverticulitis
• C. Ureteral calculus
• D. Pancreatitis

Answer: (C)

The main idea is that flank pain with radiation to the groin and focal left flank tenderness points toward a painful obstruction in the urinary tract, most commonly a ureteral stone. Stones cause colicky, waxing and waning pain as the stone moves down the ureter, often starting in the flank and radiating to the groin where the stone approaches the bladder. The tenderness over the flank supports renal/ureteral involvement, and the groin radiation is a classic clue. Diverticulitis would more typically present with persistent lower abdominal (usually left lower quadrant) pain, often fever and leukocytosis, and sometimes blood in stool; the patient’s age and lack of fever or LLQ localization make this less likely. Pancreatitis causes epigastric or abdominal pain radiating to the back and is not characterized by flank-to-groin radiation. Appendicitis presents with initial periumbilical pain that localizes to the right lower quadrant, not the left flank. The negative fecal occult blood test further lowers the likelihood of diverticular disease, supporting ureteral stone as the best explanation for this presentation.

The main idea is that flank pain with radiation to the groin and focal left flank tenderness points toward a painful obstruction in the urinary tract, most commonly a ureteral stone. Stones cause colicky, waxing and waning pain as the stone moves down the ureter, often starting in the flank and radiating to the groin where the stone approaches the bladder. The tenderness over the flank supports renal/ureteral involvement, and the groin radiation is a classic clue.

Diverticulitis would more typically present with persistent lower abdominal (usually left lower quadrant) pain, often fever and leukocytosis, and sometimes blood in stool; the patient’s age and lack of fever or LLQ localization make this less likely. Pancreatitis causes epigastric or abdominal pain radiating to the back and is not characterized by flank-to-groin radiation. Appendicitis presents with initial periumbilical pain that localizes to the right lower quadrant, not the left flank.

The negative fecal occult blood test further lowers the likelihood of diverticular disease, supporting ureteral stone as the best explanation for this presentation.