Prevalence of alternative diagnoses in patients with suspected uncomplicated renal colic undergoing computed tomography: a prospective study

Impact of a delayed presentation to the emergency department for acute renal colic on biochemical and clinical outcomes

INTRODUCTION AND OBJECTIVE

To verify the impact of delay on biochemical and clinical outcomes for patients presenting to the emergency department (ED) with acute renal colic.

MATERIALS AND METHODS

Data were retrospectively collected from three institutions of two European countries between 01 January and 30 April 2020. Patients who presented to the ED with unilateral or bilateral renal colic caused by urolithiasis confirmed by imaging tests during the study period were included. A presentation after 24 h since the onset of symptoms was considered a delay. Patients presenting before 24 h from the symptom onset were included in Group A, while the patients presenting after 24 h in Group B. Clinical and biochemical parameters and management were compared.

RESULTS

A total of 397 patients who presented to ED with confirmed urolithiasis were analyzed (Group A, n = 199; Group B, n = 198. The median (IQR) delay in presentation was 2 days (1,5-4). At presentation, no statistically significant differences were found amongst the two groups of patients regarding presenting symptoms such as fever and flank pain, and the median serum levels of creatinine, C reactive protein and white blood cells. No differences were found in terms of conservative or operative management.

CONCLUSION

Delay in consultation >24 h is not associated with worsening biochemical parameters and clinical outcomes. Most patients with acute loin pain do not necessarily need urgent attendance to the ED and may be managed in the outpatients.

What are the clinical effects of the different emergency department imaging options for suspected renal colic? A scoping review

OBJECTIVES

Clinicians have minimal guidance regarding the clinical consequences of each radiologic imaging option for suspected renal colic in the emergency department (ED), particularly in relation to patient-centered outcomes. In this scoping review, we sought to identify studies addressing the impact of imaging options on patient-centered aspects of ED renal colic care to help clinicians engage in informed shared decision making. Specifically, we sought to answer questions regarding the effect of obtaining computed tomography (CT; compared with an ultrasound or delayed imaging) on safety outcomes, accuracy, prognosis, and cost (financial and length of stay [LOS]).

METHODS

We conducted a comprehensive search using Pubmed, EMBASE, Web of Science conference proceedings index, and Google Scholar, identifying studies pertaining to renal colic, urolithiasis, and ureterolithiasis. In a prior qualitative study, stakeholders identified 14 key questions regarding renal colic care in the domains of safety, accuracy, prognosis, and cost. We systematically screened studies and reviewed the full text of articles based on their ability to address the 14 key questions.

RESULTS

Our search yielded 2570 titles, and 68 met the inclusion criteria. Substantial evidence informed questions regarding test accuracy and radiation exposure, but less evidence was available regarding the effect of imaging modality on patient-oriented outcomes such as cost and prognosis (admissions, ED revisits, and procedures). Reviewed studies demonstrated that both standard renal protocol CT and low-dose CT are highly accurate, with ultrasound having lower accuracy. Several studies found that ureterolithiasis diagnosed by ultrasound was associated with overall reduced radiation exposure. Existing studies did not suggest choice of imaging influences prognosis. Several studies found no substantial differences in monetary cost, but LOS was found to be shorter if a diagnosis was made with point-of-care ultrasound.

CONCLUSION

There is a plethora of data related to imaging accuracy. However, there is minimal data regarding the effect of CT on many patient-centered outcomes. Further research could improve the patient-centeredness of ED care.

The diagnostic yield of computed tomography in the management of acute flank pain and the emergency intervention rate for a proven acute ureteric stone

INTRODUCTION

The diagnostic and management pathways for patients presenting with acute flank pain are complex. Although computed tomography (CT) of the kidneys, ureters and bladder (KUB) is the gold standard investigation for urolithiasis, the multitude of differential diagnoses must also be considered in the context of long-term risk from ionising radiation. This study investigated the integrated role and diagnostic yield of non-contrast CT in cases of acute flank pain.

METHODS

A retrospective cohort study was undertaken of 1,442 consecutive patients investigated with CT KUB between March 2013 and February 2015. The primary outcome was diagnostic yield of CT with secondary outcomes being predictors of need for urological intervention.

RESULTS

A cause for acute flank pain was identified in 717 patients (50%), there was an incidental finding in 389 patients (27%) and normal imaging was reported in 336 patients (23%). A diagnosis was more commonly made in male than in female patients (70% vs 40%) and with increasing age (46% in patients aged <30 years, 56% in those aged 30-49 years and 63% in those aged ≥50 years). The overall rate for an ipsilateral urinary tract stone was 41%. Factors strongly associated with emergency intervention included stone size >10mm (odds ratio [OR]: 11.7, 95% confidence interval [CI]: 3.3-42.7), stones located at the pelviureteric junction (OR: 7.8, 95% CI: 2.6-22.9), C-reactive protein >50mg/l and ≤100mg/l (OR: 15.2, 95% CI: 5.1-45.3), and estimated glomerular filtration rate ≤30ml/min (OR: 5.8, 95% CI: 1.5-21.8).

CONCLUSIONS

This contemporary study identifies age and sex as independent variables affecting the diagnostic yield of CT KUB in cases of acute flank pain, and highlights factors associated with a need for emergency intervention in proven ureteric stones.

A comparative, epidemiological study of acute renal colic presentations to emergency departments in Doha, Qatar, and Melbourne, Australia

Background

This study aimed to compare the epidemiology, clinical presentations, management, and outcomes of renal colic presentations in two major academic centers from geographically diverse populations: Qatar (a country in the Afro-Asian stone belt) and South-Eastern Australia (not within a stone belt).

Methods

We undertook a retrospective cohort study of patients with renal colic who presented to the Hamad General Hospital Emergency Department (HGH-ED), Qatar, and The Alfred ED, Melbourne, Australia, during a period of 1 year from August 1, 2012, to July 31, 2013. Cases were identified using ICD-9-CM codes, and an electronic template was used to record the data on predefined clinical variables.

Results

A total of 12,223 from the HGH-ED and 384 from The Alfred ED were identified as renal colic presentations during the study period. The rate of renal colic presentations at the HGH-ED was 27.9 per 1000 ED visits compared to 6.7 per 1000 ED visits at The Alfred ED. Patients presenting to the HGH-ED were significantly younger [34.9 years (29.0–43.4) than The Alfred ED [48 years (37–60); P < 0.001].

The median stone size was larger in the HGH-ED group [6 (4–8) mm] versus The Alfred ED group [4 (3–6) mm, P < 0.001]. The intervention rate in the stone-positive population was significantly higher in the HGH-ED group as opposed to The Alfred ED group (38.7 versus 11.9%, P < 0.001). At the time of discharge, The Alfred ED group received fewer analgesic prescriptions (55.8 versus 83.5%, P < 0.001) and more tamsulosin prescriptions (25.3 versus 11.7%, P < 0.001).

Conclusions

Renal colic presentations to the HGH-ED, Qatar, were younger, with larger stone size mostly located in the lower ureter, compared to The Alfred ED, Melbourne, Australia. The findings suggest that the benefits of treatment including medical expulsion therapy will vary between the two populations. Differences in epidemiology and patient mix should be considered while tailoring strategies for effective management of patients with renal colic in a given setting.

Ultrasound vs. Computed Tomography for Severity of Hydronephrosis and Its Importance in Renal Colic

Introduction

Supporting an “ultrasound-first” approach to evaluating renal colic in the emergency department (ED) remains important for improving patient care and decreasing healthcare costs. Our primary objective was to compare emergency physician (EP) ultrasound to computed tomography (CT) detection of hydronephrosis severity in patients with suspected renal colic. We calculated test characteristics of hydronephrosis on EP-performed ultrasound for detecting ureteral stones or ureteral stone size >5mm. We then analyzed the association of hydronephrosis on EP-performed ultrasound, stone size >5mm, and proximal stone location with 30-day events.

Methods

This was a prospective observational study of ED patients with suspected renal colic undergoing CT. Subjects had an EP-performed ultrasound evaluating for the severity of hydronephrosis. A chart review and follow-up phone call was performed.

Results

We enrolled 302 subjects who had an EP-performed ultrasound. CT and EP ultrasound results were comparable in detecting severity of hydronephrosis (x²=51.7, p<0.001). Hydronephrosis on EP-performed ultrasound was predictive of a ureteral stone on CT (PPV 88%; LR+ 2.91), but lack of hydronephrosis did not rule it out (NPV 65%). Lack of hydronephrosis on EP-performed ultrasound makes larger stone size >5mm less likely (NPV 89%; LR− 0.39). Larger stone size > 5mm was associated with 30-day events (OR 2.30, p=0.03).

Conclusion

Using an ultrasound-first approach to detect hydronephrosis may help physicians identify patients with renal colic. The lack of hydronephrosis on ultrasound makes the presence of a larger ureteral stone less likely. Stone size >5mm may be a useful predictor of 30-day events.

Low-Dose (10%) Computed Tomography May Be Inferior to Standard-Dose CT in the Evaluation of Acute Renal Colic in the Emergency Room Setting

Introduction: Noncontrast CT is the standard of care to evaluate nephrolithiasis. We evaluated the performance of low-dose CT (LDCT) scan for evaluation of renal colic in the emergency room (ER).

Materials and Methods: Patients visiting the ER with suspected nephrolithiasis received a standard-dose CT (SDCT) and an LDCT. Two urologists read the LDCTs and later they read SDCTs. Stone information was recorded on a diagram of the renal system. Findings on SDCTs and LDCTs were correlated through side-by-side comparison of the diagrams. Later, the two urologists adjudicated all nonconcordance between SDCTs and LDCTs in an unblinded manner.

Results: Twenty-seven patients were included. SDCTs revealed 27 stones in 18 patients. Mean stone size was 3.81 mm. LDCTs revealed 27 stones in 18 patients with a mean stone size of 4.7 mm (p = 0.23). Overall sensitivity and specificity of LDCTs were 70% and 39%, respectively. There were eight false-positive and eight false-negative stones. All the false-positive stones on LDCTs were placed in the ureter, in which all of the corresponding SDCTs were visible calcifications outside the ureter. Of the eight false-negative stones on LDCTs, seven were visible calcifications on the SDCTs and the eighth stone was 1 mm and was not visible.

Conclusion: LDCT may not perform well in the evaluation of suspected nephrolithiasis in the acute setting. LDCT scan accurately demonstrates calcifications; however, accurate placement of calcifications in or out of the urinary tract may be diminished due to impaired resolution of soft tissue structures.

Imaging patients with renal colic-consider ultrasound first

Renal colic is a common disease in Europe and a common cause of visit to the Emergency Department. Clinical diagnosis is usually confirmed by imaging modalities. Unenhanced computed tomography (CT) is considered the best diagnostic test due to its excellent accuracy detecting ureteral stones. However, ultrasound (US) should be considered as the primary imaging technique. It is a reproducible, non-invasive and non-expensive imaging technique, achieving accurate diagnosis in most cases without the need for radiation. Diagnosis is based on the presence of ureteral stones, but indirect findings such as the asymmetry or absence of ureteric jet, an increase of the resistive index or a colour Doppler twinkling artefact may help to suggest the diagnosis when the stone is not identified.

MAIN MESSAGES

• Renal colic diagnosis is usually confirmed by imaging modalities. • Imaging diagnosis of renal colic is based on the detection of ureteral stones. • CT is the most accurate imaging technique to identify ureteral stones. • US allows correct diagnosis in most cases without using radiation. • US should be used as the first imaging modality in patients with renal colic.