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A 38-year-old man presents to the emergency department with sudden onset of severe right-sided flank pain radiating to his right testicle and groin. He is pacing the room and unable to sit still, and he has vomited twice. Temperature 37.1C, pulse 100, blood pressure 140/90. Urinalysis: blood 3+, leucocytes negative, nitrites negative, pH 5.0.
Questions
a) What is the most likely diagnosis and which bedside feature is the key discriminator from an acute surgical abdomen? (2 marks)
Diagnosis: Ureteric (renal) colic from a urinary stone.
The patient is writhing, pacing and unable to find a comfortable position — the hallmark of visceral pain from ureteric spasm. In contrast, a patient with peritonitis (e.g. appendicitis) lies perfectly still because movement worsens pain. This single bedside observation is the highest-yield discriminator.
b) What is the gold-standard investigation in this adult, and what alternative is used in pregnancy and children? State its key performance characteristics. (2 marks)
Non-contrast CT KUB is the gold standard — 95 to 98 percent sensitive and 96 to 98 percent specific; it detects all stone types (including radiolucent uric acid), defines size, location and the degree of obstruction (hydronephrosis), and excludes competing diagnoses (appendicitis, AAA, diverticulitis). Ultrasound is the first-line imaging in pregnancy and children to avoid ionising radiation.
c) Outline the initial (acute) management. (3 marks)
- NSAID first-line — diclofenac 75 mg IM/IV (or ketorolac 30 mg IV); non-inferior to opioids and reduces ureteric spasm via prostaglandin inhibition.
- Anti-emetic — ondansetron 4 mg IV.
- Hydration — oral if tolerated, IV isotonic saline if vomiting (euvolaemia, NOT forced diuresis; IV fluids do not accelerate passage).
- Strain all urine to capture any passed stone for analysis.
- Assess for the complicated stone (sepsis, AKI, solitary kidney, bilateral obstruction) — if present, convert to emergency management.
d) CT shows an 8 mm stone in the distal ureter with grade 1 hydronephrosis and no complication. What are the options and the recommended next step? (3 marks)
For an 8 mm distal-ureteric stone (spontaneous passage ~50%):
- Medical expulsive therapy (MET): tamsulosin 0.4 mg nocte for up to 4 weeks with analgesia and hydration; the benefit is modest and concentrated in larger (5 to 10 mm) distal stones (SUSPEND, MUSIC). Strain urine, review in 2 to 4 weeks.
- Ureteroscopy with Holmium:YAG laser lithotripsy if MET fails, pain is uncontrolled, the patient prefers definitive treatment, or renal function deteriorates — stone-free >90% for distal stones; optional JJ stent.
- ESWL is an alternative for proximal ureteric stones but less suitable for distal stones (bony pelvis impeding focusing).
If MET is chosen the patient must be given written advice to return immediately with fever, uncontrollable pain, vomiting or anuria.