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EMA Cited · Renal · Urology

Renal colic

Updated Nov 2, 2026Adults · ED management13 sources · 8 checked in PubMed2 figuresEAU 2026

Bottom line

  • An infected, obstructed kidney is a urological emergency. Start antibiotics, send cultures and decompress urgently with a stent or nephrostomy; the two work equally well.1
  • Give an NSAID first. It is the guideline's first choice. In a 1,645-patient ED trial, IM diclofenac relieved pain better than IV morphine with fewer adverse events.1,4
  • Ketorolac has a ceiling. In ED patients with acute pain, 10, 15 and 30 mg IV gave the same pain relief.6
  • Ultrasound first is safe. In 2,759 ED patients, starting with ultrasound rather than CT gave less radiation with no more missed high-risk diagnoses.2 Non-contrast CT confirms the stone.1
  • Most small stones pass. About 75% of stones under 5 mm pass on their own, at an average of about 17 days.1 Whether tamsulosin helps is disputed.1,9,10,11

First steps

  1. Treat pain now. Don't let imaging delay analgesia.1
  2. Look for infection and obstruction. Fever, sepsis or no urine output with an obstructing stone is an emergency.1
  3. Image immediately if there is fever, a single kidney, or doubt about the diagnosis.1
  4. Otherwise image by ultrasound first, with non-contrast CT to confirm the stone.1,2
  5. Decide on passage or removal by symptoms, kidney function and the stone's size and position.1
FIG 1 · Decision flowCited
  1. Suspected renal colic. Treat pain first; don't wait for imaging.1
  2. Fever or sepsis with an obstructing stone, or no urine output?
    Yes
    Antibiotics now after urine and blood cultures. Urgent decompression by stent or nephrostomy.1
    Remove the stone only after the sepsis resolves.1
  3. No
    NSAID first unless contraindicated, e.g. ketorolac IV 30 mg, or 15 mg if 65 or older, under 50 kg or renally impaired. 10 mg relieved pain as well in an ED trial.1,6,7
  4. NSAID contraindicated, or pain not controlled?
    Yes
    IV acetaminophen 1,000 mg (50 kg or more), or an opioid or ketamine as second choice.1,4,8
    Pain still refractory: urology for decompression or ureteroscopy.1
  5. Then
    Image: ultrasound first, non-contrast CT to confirm. Image at once with fever, a single kidney or an uncertain diagnosis. Pregnancy: ultrasound, then MRI, then low-dose CT.1,2
  6. Ongoing pain or obstruction, kidney failure, a single kidney, bilateral obstruction, or a stone unlikely to pass?
    Yes
    Refer to urology for stone removal.1
  7. No
    Trial of passage. About 75% of stones under 5 mm pass, at an average of about 17 days.1
  8. Tamsulosin is optional, mainly for distal stones 5–10 mm. Trials disagree on whether it helps.1,9,10,11
  9. Re-evaluate if infection, uncontrolled pain or worsening kidney function develops.1
FIG 1Renal colic in the emergency department. Drawn for this page from the EAU guideline and the trials cited below. Each box carries its own citations.1,2,6

Imaging

TestAccuracy and role
UltrasoundFirst-line. Sensitivity 45%, specificity 94% for ureteral stones; also shows dilatation. No radiation.1
Non-contrast CTConfirms the stone after ultrasound (strong recommendation). More accurate than ultrasound, and finds other causes when there is no stone.1
Low-dose CTPooled sensitivity 93.1%, specificity 96.6% in a meta-analysis cited by the guideline.1
Plain film (KUB)Sensitivity and specificity 44–77%. Helps tell radiopaque from radiolucent stones for follow-up.1
Axial non-contrast CT of the abdomen with an arrow pointing to a small bright stone next to the right renal pelvis
FIG 2Ureteric stone on non-contrast CT. A stone in the right proximal ureter (arrow) causing mild obstruction and hydronephrosis. The patient's right is on the viewer's left.James Heilman, MD · Wikimedia Commons · CC BY-SA 3.0
  • Ultrasound first doesn't miss more. In a trial of 2,759 ED patients randomized to point-of-care ultrasound, radiology ultrasound or CT, complicated high-risk diagnoses within 30 days were rare (0.4%) and the same in every arm. Radiation was lower with ultrasound first; serious adverse events, pain at 7 days, return visits and admissions did not differ.2
  • The STONE score combines sex, pain duration, race, nausea or vomiting, and microscopic hematuria. A ureteral stone was found in about 9% of low scorers, 51% of moderate and 89% of high. In the high group, other acutely important findings were seen in 0.3–1.6%.3
  • Pregnancy: ultrasound first, MRI second, low-dose CT last (all strong recommendations). Start with conservative management.1

Pain

AgentAdult doseNotes
First choice: NSAID
Ketorolac IV30 mg once; 15 mg once if ≥ 65 y, < 50 kg or renally impairedLabel dosing.7 10 mg gave the same relief in an ED trial.6 Contraindicated in advanced renal impairment, volume depletion and high bleeding risk. Total use ≤ 5 days.7
Alternatives
Acetaminophen IV1,000 mg over 15 min (≥ 50 kg); max 4,000 mg/dayLabel dosing.8 At least as effective as morphine at 30 min in one trial.4
Opioid (hydromorphone, tramadol) or ketaminePer institutional protocol and labelSecond choice (weak recommendation). Avoid pethidine (meperidine).1
Antispasmodics added to NSAIDsNot recommendedNo added pain relief.1

Unreviewed doses. Verify against the current label and your institution's protocol before giving anything.

  • The guideline position: offer an NSAID first, weighing cardiovascular risk and side effects (strong). Opioids or ketamine are second choice (weak).1
  • Diclofenac vs morphine vs acetaminophen (1,645 ED patients): at least 50% pain relief at 30 minutes in 68% with IM diclofenac 75 mg, 66% with IV acetaminophen 1 g and 61% with IV morphine 0.1 mg/kg. Diclofenac beat morphine (OR 1.35). Adverse events were 1% with each non-opioid and 3% with morphine.4
  • Meta-analysis (36 trials, 4,887 patients): NSAIDs and opioids relieved pain about equally at 30 minutes, but NSAIDs needed less rescue analgesia (NNT 11) and caused less vomiting (NNT 5). NSAIDs also needed less rescue than acetaminophen (RR 0.56).5
  • Cautions: NSAIDs can reduce kidney function when GFR is already low. Diclofenac and ibuprofen increase coronary events, so use the lowest dose for the shortest time.1
  • Refractory pain is an indication for decompression or ureteroscopic stone removal (strong).1

Infected, obstructed kidney

  • Decompress urgently with a ureteral stent or percutaneous nephrostomy (strong). They work equally well, with no difference in time to defervescence. Nephrostomy patients stay longer; stents affect quality of life more.1
  • Start antibiotics immediately, after urine and blood cultures, and involve intensive care if needed (strong).1
  • Send urine again for culture after decompression, and adjust antibiotics to the results (strong).1
  • Delay definitive stone treatment until the sepsis has resolved (strong).1

Passage, tamsulosin and referral

StonePassed on its own
By size
< 5 mm~75%
≥ 5 mm62%
By position
Upper ureter49–52%
Mid ureter58–70%
Distal ureter68–83%
By both
< 5 mm, distal89%
< 5 mm, upper71%

From the EAU guideline, which notes the data are limited. Average time to passage was about 17 days (range 6–29).1

Medical expulsive therapy

  • EAU: offer an alpha-blocker as one option for distal ureteral stones of 5–10 mm (strong; off-label). Use it only in informed patients who don't need active removal, and stop it if infection, refractory pain or worsening kidney function develops.1
  • Dose: tamsulosin 0.4 mg once daily, the labeled dose for benign prostatic hyperplasia; stone passage is not a labeled use.12,1
  • Meta-analysis (55 trials): alpha-blockers increased passage (RR 1.49), with no clear benefit for smaller stones (RR 1.19, 1.00–1.48) and a benefit for larger ones (RR 1.57).9
  • SUSPEND (1,136 UK adults): no further intervention needed at 4 weeks in 81% on tamsulosin vs 80% on placebo.10
  • STONE (512 US ED patients, stones < 9 mm, mean 3.8 mm): passage by 28 days 50% vs 47%, not significant.11 Ejaculatory problems were more common with tamsulosin (18.2% vs 7.4%).13
Sources disagree

The EAU guideline strongly recommends offering an alpha-blocker for distal stones of 5–10 mm, based on meta-analyses.1,9 The two largest placebo-controlled trials found no benefit.10,11 Stones in the US trial were mostly small (mean 3.8 mm).11 REBEL EM advises against routine tamsulosin and calls any benefit for larger stones unclear.13

When the stone needs removing

  • Refer to urology for a stone unlikely to pass, pain despite adequate analgesia, persistent obstruction, or renal insufficiency (kidney failure, bilateral obstruction or a single kidney).1
  • In pregnancy, a stent or nephrostomy is needed if the stone doesn't pass or complications develop, such as intractable symptoms, severe hydronephrosis or preterm labor.1

Pitfalls

  • Sending home a febrile patient with an obstructing stone. That kidney needs decompression and antibiotics.1
  • Reaching for morphine first. NSAIDs relieve pain at least as well, with less vomiting and less rescue analgesia.4,5
  • Giving ketorolac 30 mg when 10 mg works as well.6
  • Giving NSAIDs to a volume-depleted patient or one with advanced kidney disease.7,1
  • Holding analgesia until imaging is done.1
  • Promising that tamsulosin will help the stone pass.10,11

How strong is the evidence?

The analgesia evidence is the firmest: a large blinded trial and a meta-analysis of 36 trials favor NSAIDs, though the trials in the meta-analysis varied widely.4,5 Imaging choice rests on one large pragmatic trial.2 Drainage choice in infection rests on few, small studies of medium to very low quality.1 The evidence on alpha-blockers conflicts.1,9,10,11

On-shift teaching

Questions to ask a learner at the bedside. Tap a question to see the answer. Every answer uses facts cited above.

Q1In the 1,645-patient ED trial, which worked better for renal colic: diclofenac or morphine?
Diclofenac. 68% got at least 50% relief at 30 minutes vs 61% with morphine (OR 1.35), and adverse events were 1% vs 3%.4
Q2What IV ketorolac dose is enough?
10 mg. In ED patients with acute pain, 10, 15 and 30 mg gave the same relief at 30 minutes.6 The label single dose is 30 mg, or 15 mg if 65 or older, under 50 kg or renally impaired.7
Q3Is starting with ultrasound instead of CT safe?
Yes. In 2,759 ED patients, complicated high-risk diagnoses were 0.4% in every arm, and radiation was lower with ultrasound first.2
Q4A patient with an obstructing stone has a fever of 39 °C. What do they need?
Antibiotics now after cultures, and urgent decompression by stent or nephrostomy, which work equally well. Remove the stone only after the sepsis resolves.1
Q5What are the odds that a 4 mm distal ureteral stone passes on its own?
About 89% for stones under 5 mm in the distal ureter, at an average of about 17 days.1
Q6What did the two largest tamsulosin trials find?
No benefit. SUSPEND: 81% vs 80% needed no further intervention at 4 weeks.10 STONE: passage 50% vs 47% by 28 days.11 A meta-analysis found a benefit mainly for larger stones (RR 1.57).9

References

Evidence base

What this page is built on

13 sources, cited 95 times. Dots are sources, filled by how far each was read; stronger color means a larger share of the citations. Tap a tier to see its sources.

Read in full · 5Abstract read · 8Record only · 0Link checked · 0

Checked by the writer, not a physician. The dots show how each source was read, not that anyone has confirmed the claims.

How this page was made
  • Written from scratch. No source text was copied; facts are restated and cited.
  • Anchored on the European Association of Urology urolithiasis guideline, 2026 edition, read in full on uroweb.org. Its strength ratings are quoted as written.
  • Each PubMed citation was resolved through NCBI E-utilities, and each number was checked against the paper's abstract. The REBEL EM page was read.
  • Doses come from FDA labels on DailyMed. The diclofenac and morphine doses appear only as the doses used in a trial, not as recommendations. No opioid dose is given because the guideline names no dose.
  • Adults only. EAU imaging and treatment advice differs for children.
  • Figure 1 was drawn for this page from the cited sources. Figure 2 is an openly licensed image from Wikimedia Commons, credited under it, and keeps its own license.
  • Not for clinical use.
Not for clinical use

AI-generated draft. Not reviewed by a physician. This page is for education only and may contain errors, including in doses. Do not use it to diagnose, treat or make decisions about any patient. Rely on your own clinical judgment, your institution's protocols and current drug labeling. Reading this page does not create a physician-patient relationship. Full terms