Renal colic
Treat the pain, image the stone — and never miss an infected obstructed kidney or a leaking aneurysm. Give an NSAID, confirm the stone with a CT KUB, and check whether the kidney is both infected and blocked, because that needs urgent drainage. In an older patient with "first renal colic", think AAA. Built for revision, not live patient decisions.
Settle them, and check the basics
pain + danger checkRed flags — what each should make you think
A stone plus fever is an emergency. Pus behind a blocked ureter won't clear with antibiotics alone, and patients can become septic fast. They need a nephrostomy or stent, not just a drip.
First actions (NICE NG118)
- 💊NSAID first-line
- IVIV paracetamol
- OpOpioids
- 🧪Urine dip + bloods
- CTNon-contrast CT KUB
- 🌡Fever?
Understand the patient
stone size · obstruction · infectionWhat happens next depends on
- Size — under 5 mm usually pass; over 10 mm unlikely to pass alone
- Position — distal ureter more likely to pass
- Alpha-blocker (e.g. tamsulosin) — consider for distal ureteric stones under 10 mm (medical expulsive therapy)
- Surgical options — ureteroscopy, shockwave lithotripsy, PCNL for large stones
Urgent decompression (nephrostomy or stent) if
- Obstruction with infection/sepsis
- AKI, solitary kidney, transplant kidney or bilateral obstruction
- Uncontrolled pain or vomiting
Work A–E — assess and act as you go
The diagnoses you must not miss
tap to open eachWhat points toward it, what would rule it in, and how to manage it.
Fever, rigors, loin pain, raised CRP/WCC with an obstructing stone.
CT KUB (hydronephrosis + stone), urine and blood cultures.
IV antibiotics + emergency decompression (nephrostomy or stent); sepsis bundle.
Over 60, first "renal colic", hypotension, pulsatile mass, collapse.
Bedside USS aorta; CT angiogram if stable.
Vascular emergency.
Anuria, AKI, single kidney.
CT KUB, U&E.
Urgent decompression.
Loin-to-groin pain can mimic gynaecological, testicular or appendiceal pathology.
Pregnancy test, testicular exam, imaging.
Treat the actual cause.
Investigate — what to order, when, and what it tells you
test with a question in mindUrine
Bloods
Imaging
How the plan comes together
disposition · handoverhome
Pain controlled, small stone, no infection, normal renal function: analgesia, ± tamsulosin, strain urine, urology follow-up, return if fever or worse pain.
admit / urology
Infection, AKI, solitary kidney, uncontrolled pain, large stone, pregnancy.
Hand over: stone size/site, hydronephrosis, temperature, renal function, decompression plan.
NSAID for the pain, CT KUB for the stone, and two questions: is it infected, and is it really a stone? Fever with an obstructing stone means drainage, and an older patient needs their aorta checked. Nicely done getting here.
Clerking template
copy or downloadRenal colic — documentation structure
A structure and prompt list to help you document and think systematically. It is not a completeness check and cannot guarantee nothing is missed — use your trust's own proforma, your seniors, and your clinical judgement.
Test yourself
active recallCover the answer, say it out loud, then reveal. Retrieval beats re-reading.
0 / 10 knownFrequently asked questions
quick answersWhat are the red flags for renal colic?
- Fever + obstructing stone — think infected obstructed kidney — decompress
- AKI, solitary kidney, bilateral stones — think urgent decompression
- Over 60, first episode, shocked — think leaking AAA
- Pregnant — think ultrasound, not CT
- Pain not controlled — think admission / decompression
- Woman of childbearing age — think ectopic pregnancy
What is the initial management of renal colic?
- NSAID first-line — by any route (e.g. IM/PR diclofenac) unless contraindicated
- IV paracetamol — if NSAIDs are contraindicated or not enough
- Opioids — only if both of the above fail or are contraindicated
- Urine dip + bloods — blood, infection; U&E, FBC, CRP, calcium, urate
- Non-contrast CT KUB — within 24 h (USS first in pregnancy and children)
- Fever? — cultures, IV antibiotics, urgent urology for decompression
Always alongside senior support and your local guideline.
What diagnoses must you not miss in renal colic?
- Infected obstructed kidney — fever + stone
- Leaking AAA — older · first episode
- Obstructed solitary / bilateral — AKI
- Ectopic pregnancy / torsion / appendicitis (mimics) — same pain, different organ
Open each one in the must-not-miss section for what points toward it, how to rule it in, and how to manage it.
What investigations should a junior doctor order for renal colic?
- Urine — Blood (absent in some); nitrites/leucocytes → infection.
- Bloods — U&E, FBC, CRP, calcium, urate.
- Imaging — Within 24 h — size, position, hydronephrosis.
Admit or discharge: how is the plan decided for renal colic?
- Home — Pain controlled, small stone, no infection, normal renal function: analgesia, ± tamsulosin, strain urine, urology follow-up, return if fever or worse pain.
- Admit / urology — Infection, AKI, solitary kidney, uncontrolled pain, large stone, pregnancy.
Is there a clerking template for renal colic?
Yes — there is a clerking template for renal colic on this page, structured as presenting complaint, red flags asked, history, examination (A–E), investigations, differentials, plan and escalation. You can copy it or download it as a Word document. Jump to the template.
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