Controversies in Kidney Stones
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Flank pain and pain due to ureterolithiasis are common ED presentations. There exist, however, a number of controversies when you dive into the literature addressing the diagnosis and treatment of nephrology/ureterolithiasis. Is IV lidocaine effective at treating pain in these patients? Is there a way to avoid CT scans? What about tamsulosin? Is it only good for big stones/small stones? Is there a benefit at all. For our most recent Journal Club, we tackled several of these controversies. Take a listen to the podcast below or over on iTunes.
Motov S, Drapkin J, Butt M, Monfort R, Likourezos A, Marshall J. Pain management of renal colic in the emergency department with intravenous lidocaine. American Journal of Emergency Medicine 2018;36(10):1862–4.
Why we chose this article
Most recent study on the use of IV Lidocaine for renal colic
Why it’s important
Pain experienced from renal colic is severe and effective analgesia is crucial
Use of traditional pain management may be contraindicated or limited due to allergies, etc. and alternatives merit consideration
Traditional treatment may be ineffective and rescue agents should be investigated
Study details
Single center retrospective chart review (case series)
Included adult patients 18 years of age and older between 2014 and 2017
Patients must have presented to the ED with pain of renal colic origin whose final diagnosis were nephrolithiasis, renal colic or obstructive uropathy and were treated with IV Lidocaine for the purpose of pain control
Patients with any absolute or relative contraindications to Lidocaine were not included
Data obtained included age, gender, chief complaint, final diagnosis, dose, route and frequency of Lidocaine administration, pain scores, and whether IV Lidocaine was administered as a primary analgesic or as a rescue
Data analysis compared pre and post pain scores in all patients receiving IV Lidocaine; in patients receiving IV Lidocaine as a first line medication, and in patients receiving IV Lidocaine as a rescue medication
Results
44 total patients with pain of renal colic origin who received IV Lidocaine
22 patients received IV Lidocaine as a primary analgesic and 22 patients received it as a rescue
Overall average weight based dose was 1.5 mg/kg
Primary analgesia group: 45% alone, 45% in combination with Ketorolac and 10% in combination with Morphine
Rescue group: 75% who had received Ketorolac, 10% who had received Morphine and 18% who received a combination of Ketorolac and Morphine
Overall: administration of IV Lidocaine resulted in a decrease in pain score by 6.3 points
Primary analgesia group: decrease in pain score by 7.4 points
Rescue group: decrease in pain score by 5.2 points
Take-homes
Very small retrospective study but it recent and compares primary and rescue treatment which has not been compared previously
There was a significant change in pain score when IV Lidocaine was used as a primary analgesic and as a rescue but the lack of a control group severely limits the results of this study
It is difficult to determine if the results of this study are solely attributable to IV Lidocaine
Average dose was well below the minimal toxic dose of 4 mg/kg which would decrease provider hesitation to use the medication in the ED
There was a lack of reported vital sign changes and absence of symptomatic treatment for side effects, which would support the absence of side effects during treatment
Limitations
Limited by its retrospective design
Case series
Small sample size
Potential for lack of accuracy of extracted data
No control group
Daniels B, Gross C, Molinaro A, et al. STONE PLUS: Evaluation of Emergency Department Patients With Suspected Renal Colic, Using a Clinical Prediction Tool Combined With Point-of-Care Limited Ultrasonography. Annals of Emergency Medicine 2016;67(4):439–48.
Why we chose this article
Understanding how to integrate POCUS into our practice and workup of kidney stones is important
Why it's important
It is estimated 70% of patients diagnosed with kidney stones get a CT scan. Is there a way to reduce the amount of radiation with something as easy as POCUS?
Study Details
Single Center Prospective Observational Study of any adult slated to get a CT scan for concern for nephrolithiasis
Trialing if the STONE score with ultrasound increased ability to dx stone
Important to note that there is controversy in the literature about the validity of the STONE score
Primary Outcome
Symptomatic ureteral stone or acutely important alternative finding
The definition of alternative finding: cause of flank pain, required intervention in the ED (Abx, admission for pain control, hospital admission, to the OR)
Secondary Outcome: 90-day urologic intervention assessed by phone interview or chart
Hydronephrosis was designated by whoever was doing the scan (US faculty vs intern) and was grouped into mild hydro or moderate/severe
Results
Low STONE score, any hydro increased sensitivity from 3.2% to 64%, Specificity to Moderate/Severe of 98% Mod/Severe Hydro has +LR of 22
Moderate STONE score with mod/severe hydro changed from specificity of 42% to 92%,+ LR to 4.9
High STONE score did not have a change of sens/spec or LR
Moderate/Greater Hydro increased specificity of needing urologic intervention to 99% in Low and 86% in Moderate groups, still no real change or compelling data in the High group
Alternative findings were most common in the Moderate group, mostly UTI/pyelo across all groups, Diverticulitis was the second most common
Take Home Points
POCUS can help move kidney stone up on your differential if there is hydronephrosis, specifically if it is moderate to severe.
Finding Moderate/Greater hydronephrosis can indicate the need for urologic intervention in 90 days, depending on your clinical concern may need a CT for further characterization
There is a risk of alternative findings, though very low in the High risk group (<2%) even without any findings on POCUS
The author suggest getting a reduced dose CT for Low+any hydro, Moderate+no/mild
Meltzer AC, Burrows PK, Wolfson AB, et al. Effect of Tamsulosin on Passage of Symptomatic Ureteral Stones. JAMA Intern Med 2018;178(8):1051–7.
Why we chose this article
High-quality study with >500 patients
Why it’s important
Presentations for kidney stones are not infrequent in ED and practice patterns with respect to alpha-blocker therapy seem somewhat variable
For the patient, cost and side effects of alpha-blocker therapy can be non-trivial
Study details
Design: double-blind, placebo-controlled, multi-center randomized clinical trial
Primary outcome: “stone passage based on visualization or capture by the study participant by day 28”
My take: This is a reasonable primary outcome, but isn’t necessarily the most important outcome (e.g., time to resolution of symptoms or need for surgical intervention may be more relevant to patients).
Secondary outcomes:
Authors included numerous secondary variables (including one related to a subgroup of patients that got a repeat CT at day 28) but the key secondary variables were: “crossover to open-label tamsulosin, time to stone passage, return to work, use of analgesic medication, hospitalization, surgical intervention, and repeated emergency department visit for urinary stones.”
My take: A good list of secondary outcomes with a mix of patient-centered and system-oriented outcomes. Return to work is a good variable that often gets missed and while included here was not perfectly designed (operationalized as “proportion of participants who returned to work within 28 days of enrollment” rather than days missed which might have been more interesting)
Participants/Inclusion Criteria: N=512 Emergency Department patients, all adults with CT-proven stones of less than 9mm and with symptoms
My take: Straightforward inclusion and feels like a relevant population to the one in which I’m considering this clinical question in my practice
Exclusion criteria: several, but most notably prior kidney/ureter surgery, concurrent UTI, presence of a bladder stone, and admitted to hospital… oh, and 204 “other”
My take: This list is a bit longer than I’d like and a lot to remember if trying to validly generalize the findings. More importantly, the “other” category is pretty large, being >40% of the size of the study population itself and >10% of the patients screened!
Results
No difference for tamsulosin vs placebo in primary or secondary outcomes.
Take-homes
It’s not the biggest study of its kind (a Chinese study is >6x larger) but it is recent
This study is a reasonable reference to justify your practice pattern if you choose not to prescribe tamsulosin.
On the other hand, there is a Cochrane systematic review and meta-analysis that incorporates these data but finds a small benefit to tamsulosin
Ultimately, I’ll probably still offer patients the script, but I’ll be candid about the relatively small amount of benefit reported in the literature and be cautious if any risk factors for adverse effects
References
Motov S, Drapkin J, Butt M, Monfort R, Likourezos A, Marshall J. Pain management of renal colic in the emergency department with intravenous lidocaine. American Journal of Emergency Medicine 2018;36(10):1862–4.
Daniels B, Gross C, Molinaro A, et al. STONE PLUS: Evaluation of Emergency Department Patients With Suspected Renal Colic, Using a Clinical Prediction Tool Combined With Point-of-Care Limited Ultrasonography. Annals of Emergency Medicine 2016;67(4):439–48.
Meltzer AC, Burrows PK, Wolfson AB, et al. Effect of Tamsulosin on Passage of Symptomatic Ureteral Stones. JAMA Intern Med 2018;178(8):1051–7.
Authorship
Motov, et al - Diego Iparraguirre, MD, PGY-3
Daniels, et al - Jessica Koehler, MD, PGY-3
Meltzer, et al - Bennet Lane, MD, PGY-3
Editing and Posting -Jeffery Hill, MD MEd
