Clues Pointing TO This Diagnosis

Sudden, severe, colicky flank pain coming in waves — the classic presentation of a ureteral stone with intermittent rises in pyelocalyceal pressure
Pain radiating from flank down toward the groin — the descending stone produces pain that migrates toward the gonad/lower quadrant
Patient writhing, unable to find a comfortable position — characteristic of renal colic and distinguishes it from peritonitis (patients with peritonitis lie still)
Gross hematuria (visible blood in urine) — occurs in about 90% of stone patients
Nausea, vomiting, and sweating — shared splanchnic innervation of the renal capsule and gut produces GI symptoms in renal colic
Absence of fever or signs of infection — supports uncomplicated stone rather than infected obstruction
Male sex, middle age (41) — men are affected more than women and incidence rises with age
CT confirming a 4 mm ureteral stone — noncontrast CT is the reference-standard confirmatory study
Spontaneous passage on day 2 — a 4 mm stone has a very high spontaneous passage rate
Calcium oxalate composition on stone analysis — the most common stone type

Why It's NOT the Similar Diseases

NOT pyelonephritis — pyelonephritis produces fever, chills, and CVA tenderness with pyuria; Leroy is afebrile with colicky pain and a stone on CT
NOT ruptured abdominal aortic aneurysm — AAA causes tearing pain with hypotension/pulsatile mass; Leroy is hemodynamically stable with a confirmed ureteral stone
NOT acute appendicitis or another peritoneal process — peritonitis makes patients lie still with rebound/guarding, whereas Leroy is writhing without peritoneal signs
NOT bladder infection/cystitis — although a distal stone can mimic dysuria/frequency, cystitis does not cause severe colicky flank-to-groin pain with a stone on CT
NOT musculoskeletal back strain — flank strain does not produce hematuria, nausea/vomiting, or a stone visualized on imaging

Differential Diagnosis List

Pyelonephritis — ruled out by absence of fever and infection with a stone confirmed on CT
Ruptured abdominal aortic aneurysm — ruled out by hemodynamic stability and a ureteral stone on CT
Acute appendicitis/peritoneal process — ruled out by absence of peritoneal signs and a writhing (not still) patient
Cystitis — ruled out by severe colicky flank-to-groin pain and stone on imaging rather than isolated lower urinary tract symptoms
Musculoskeletal back pain — ruled out by hematuria, GI symptoms, and CT findings

Key Distinguishing Test

Noncontrast (low-dose) CT of the abdomen and pelvis is the reference-standard test; it detects virtually all stones, localizes and sizes them, and identifies secondary signs such as hydronephrosis and perinephric stranding (pooled sensitivity ~97%).
Ultrasound is a reasonable safe first-line alternative (especially in pregnancy or children), and gross/microscopic hematuria plus classic colic supports the diagnosis but does not confirm it.

Board Note

Confirm with noncontrast CT; use ultrasound first in pregnant patients and children to limit radiation
Acute pain control is the priority: NSAIDs (e.g., ketorolac) and/or opioids are effective, and combination therapy outperforms single agents; add IV fluids and antiemetics as needed
Stone size drives disposition: stones <5 mm usually pass, 5–10 mm are variable, and stones >10 mm generally will not pass; distal stones pass more readily than proximal ones
Offer medical expulsive therapy with an alpha-blocker (tamsulosin) for uncomplicated distal ureteral stones—an off-label but guideline-supported use
An obstructing stone with fever/infection or a solitary kidney, acute kidney injury, or intractable pain is a urologic emergency requiring urgent decompression (stent or nephrostomy)—refer immediately
Prevent recurrence (risk ~50% over 5 years): increased fluid to achieve at least 2 L urine/day, reduced sodium and animal protein, normal-to-high dietary calcium, and citrate (e.g., citrate therapy/lemonade); thiazides, alkali/citrate, and allopurinol reduce recurrence in calcium stone formers
For stones that fail to pass or need removal, shock wave lithotripsy or ureteroscopy are first-line, with percutaneous nephrolithotomy reserved for large (>2 cm) or complex renal stones
The following figure is a practical algorithm for choosing initial imaging in acute renal colic, matching the CT-versus-ultrasound decisions central to Leroy's workup:
Figure 1. Suggested algorithm for diagnostic imaging for acute renal colic. Adapted from Miller and Stoller
Acute Kidney Stone Management. A Clinical Guide to Urologic Emergencies. December 31, 2020.
Used under license from Wiley.

“Leroy’s Story”