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Do all patients presenting to the emergency department with renal colic require hospital admission?

Three Part Question

In [adults presenting to the Emergency Department (ED) with renal colic] does [discharge with follow-up or admission to hospita] lead to [a lower rate of obstructive or infective complications]?

Clinical Scenario

A 45 year old man presents with acute renal colic, with no signs of infection or renal failure. You consider discharging the patient with analgesia and an out-patient urology appointment but remain concerned about the safety of this approach.

Search Strategy

Ovid MEDLINE 1946 to September week 3 2012

Ovid Embase 1980 to 2012 week 39

Cochrane Database of Systematic Reviews 2005 to September 2012
(exp Renal Calculi\\ OR OR exp Urolithiasis\\OR exp Kidney Calculi\\OR exp Ureteral Calculi\\ OR exp Calculi\\ OR ((renal or ureteric or ureteral) adj colic).mp.) AND (exp Patient Admission\\ or admission$.mp. or exp Patient Discharge\\ or discharge$.mp. or admit$.mp.) AND (exp Emergency Service, Hospital\\ OR emergency OR exp Emergency Medical Services\\ OR (A&E or (Accident adj2 Emergency)).mp.) limit to human and English language.

Search Outcome

In total, 68 papers were identified in MEDLINE, 203 in Embase and two in the Cochrane Database of Systematic Reviews. Five papers were relevant to the three-part question.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Kartal et al,
227 Consecutive patients presenting to the ED with unilateral loin pain who were discharged if urinalysis and ultrasound were consistent with uncomplicated renal stones. 176 Patients were finally diagnosed with renal stones on either IVU, CT or passage of stones Prospective observational studyProportion of patients discharged 122 (54%)Limited details on General morbidity and complications of discharged patients not reported. No data on how many phone interviews had to be performed.
Proportion of patients with life-threatening complications0 (0%)
Morris et al,
58 Patients presenting with ureteric colic, who had confirmed stones on an immediate IVU undertaken in the ED. The study aimed to validate a protocol for outpatient management. Patients with infection, inadequate pain relief, atypical presentation, delayed contrast excretion (suggesting obstruction) or delayed IVU were admitted Prospective observational studyProportion of patients discharged29 (50%) dischargedSmall sample size. For 12 (21%), reason for admission was delay in IVU, possibly leading to a higher admission rate than if investigations were readily accessible Unclear protocol for follow-up; short duration of follow-up
Incidence of complications within 1 week among discharged patients19 (66%) required no additional treatment. Five (17%) returned for intravenous analgesia after 48 h. Three (10%) retruned within 48 h for analgesia. Two patients lost to follow-up. Overall, 19\\58 (33%) patients (worst case scenario) safely and appropriately discharged, and no complications were reported.
Yan et al,
359 Patients who presented to the ED with suspected renal colic and were discharged from the ED. Telephone follow-up after 10–14 days. Prospective observational cohort studyPatients reporting passage of stone at follow-up95 (27.4%) reported passage within 72 h; 31 additional patients (36.3%) reported passing a stone within 14 daysConference presentation therefore only abstract available for review Not clear which patients were eligible for discharge from the ED and whether imaging was undertaken in the ED
Patients requiring analgesia after discharge270 (77.8%) Patients required analgesia for a median of 4 days
Patients needing further medical attention after discharge24 (14.5%) Re-attended the ED; 71 (42.8%) saw their general practitioner; five (3.0%) went to a walk in centre and 61 (36.7%) saw a urologist
Patients requiring urological intervention after discharge57 (16.4%) Patients required urological intervention within 90 days
Mancini et al,
(a) 1402 Patients seen in the ED with renal stones over 3 years (76 were admitted and excluded). (b) In a case–control study, 24 patients admitted with urosepsis after ED discharge over a 10 year period were compared with two age, sex and race-matched controls (a) Retrospective chart review (b) Matched case–control study Incidence of urosepsis after ED discharge (retrospective review)0.68% Patients returned to the ED with urosepsis after a median of 2 daysConference presentation therefore only abstract available for review ED protocol not available for review. Unclear whether patients underwent imaging in the ED Retrospective
Predictors of urosepsis after dischargeTemperature >37.5°C (OR 7.64, 95% CI 1.79 to 32.63). White cell count, subjective report of fever and urinalysis positive for leucocyte esterase or nitrites were not significant predictors of urosepsis
Kastner et al,
Following an initial audit, a novel algorithm was implemented and audited. 19 patients presenting with symptoms of renal colic managed according to the algorithm, by which patients with a diagnosis of renal stones could be discharged if only oral analgesia was required, if the IVU demonstrated no more than partial obstruction, the blood results were normal and the patient generally fit Prospective auditReduction in admissionsWaiting time for IVU fell by 75%. Admissions reduced from 50% to 21%. Unnecessary admissions fell from 71% to 25%Small sample size Unclear protocol for follow-up
Complications during treatment and follow-upNone reported


White cell count and stone size have been shown to be significant predictors of spontaneous stone passage.

A predictive model derived to predict the need for intervention in patients presenting with confirmed urolithiasis after discharge from the ED contains: visual analogue score at discharge of 2 cm or greater; size of calculus 6 mm or greater; calculus above mid-ureter.

Renal colic is a frequent reason for ED attendance and its course is often benign. A protocol that could be used to allow a subgroup of patients to be safely discharged would potentially save inpatient beds and cost, while reducing inconvenience to patients. There is weak evidence in the literature suggesting that a proportion of patients with renal stones can be safely discharged from the ED. However, the existing studies supporting the safety of this approach generally mandated imaging (intravenous urography, CT or ultrasound) before discharge.

In addition to the studies that directly address the three-part question, two studies have defined predictors of complications in patients presenting to the ED with suspected renal colic. Sfoungaristos et al demonstrated that white cell count and stone size were predictors of complications. Papa et al derived a multivariate model for the prediction of the need for urological intervention. The prediction model included the following variables: visual analogue pain score at discharge 2 cm or greater; size of calculus 6 mm or greater and calculus located above the mid-ureter. Further large-scale prospective studies are required to assess accurately the associated risks and cost benefits, and stratify the importance of factors for admission. Patients satisfying all three conditions had a 90% probability of requiring intervention, compared to 4% of the patients meeting no criteria. This algorithm has the potential to facilitate early discharge in this patient group, although imaging would still be required in the ED

Editor Comment

ED, emergency department; IVU, intravenous urography.

Clinical Bottom Line

The current evidence base does not support the safe discharge of ED patients with suspected renal colic, in the absence of imaging. Patients with smaller stones, more distal locations of the stones, who have pain controlled by oral analgesia and have no clinical signs of infection are at very low risk of complications.


  1. Kartal M, Eray O, Erdogru T, et al. Prospective validation of a current algorithm including bedside US performed by emergency physicians for patients with acute flank pain suspected for renal colic. Emerg Med J 2006; 23:341-4
  2. Morris SB, Shearer RJ, Hampson SJ, et al. Should all patients with ureteric colic be admitted? Ann R Coll Surg Engl 1995; 77:450-2
  3. Sfoungaristos S, Kavouras A, Perimenis P. Predictors for spontaneous stone passage in patients with renal colic secondary to ureteral calculi. Int Urol Nephrol 2012;44:February. 2012;Feb;44(1):71-9
  4. Papa L, Stiell IG, Wells GA, et al Predicting intervention in renal colic patients after emergency department evaluation. Can J Emerg Med 2005;7(2):78-86.
  5. Yan J, Edmonds M, McLeod S, et al. Delayed outcomes for patients with suspected renal colic after discharge from the emergency department. Acad Emerg Med 2012;Conference(var.pagings):April.
  6. Mancini J, Raymundo E, Yong D, et al. What factors can better predict the incidence of urosepsis following an acute stone episode? J Urol 2010 Conference(var.pagings):April.
  7. Kastner C and Tagg A. Emerg Med J 2003;20:449-450 doi:10.1136/emj.20.5.449 Short report Improving the effectiveness of the emergency management of renal colic in a district general hospital: a completed audit cycle. Emerg Med J 2003;20:449-450.