Suspected renal colic in pregnancy — MRCEM SBA MCQ

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EasyProcedures, imaging and diagnosticsSuspected renal colic in pregnancyMRCEM SBA

A 28-year-old woman who is 22 weeks pregnant presents with sudden, intermittent left loin pain radiating to the groin. She has previously had a ureteric stone. She is afebrile and haemodynamically stable, with left renal angle tenderness but no abdominal guarding, uterine tenderness or vaginal bleeding. Urine dipstick shows blood but no nitrites or leucocytes; renal function is normal. Ultrasound can be performed this afternoon, while CT is available immediately. Which is the most appropriate initial imaging investigation?

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Correct answer: D — Renal tract ultrasound

The colicky loin-to-groin pain, previous stone and haematuria make renal colic the leading diagnosis. Pregnancy changes the initial imaging choice: NICE recommends ultrasound instead of CT for a pregnant woman with suspected renal colic. Her stable observations and lack of evidence of urinary infection allow the available ultrasound to be arranged promptly while she receives analgesia and is reassessed. A is the usual urgent investigation for a non-pregnant adult with suspected renal colic, but its immediate availability does not make it the first choice here. B avoids ionising radiation and may help resolve persistent diagnostic uncertainty after ultrasound; it is not the recommended initial test. C exposes the fetus to radiation and is a less useful initial investigation for suspected ureteric obstruction. E may be justified if assessment raises concern for a different serious abdominal condition requiring contrast-enhanced CT, but the presentation instead points to renal colic. Ultrasound is therefore the single best initial investigation; an inconclusive result would require further clinical assessment rather than automatic discharge.

Reference: Renal and ureteric stones: assessment and management — recommendations (8 January 2019) — https://www.nice.org.uk/guidance/ng118/chapter/recommendations Renal and ureteric stones: assessment and management — rationale and impact (2019) — https://www.nice.org.uk/guidance/ng118/chapter/rationale-and-impact Making the best use of Clinical Radiology Services — Urological, Adrenal and Genitourinary (June 2024) — https://elht.nhs.uk/application/files/8117/1887/3695/Making_the_best_use_of_Clinical_Radiology_Services_-_referall_guidelines_-_Urological_Adrenal__Genitourinary.pdf