SGEM#202: Lidocaine for Renal Colic?

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Date: January 9th, 2018

Reference: Soleimanpour H et al. Effectiveness of intravenous lidocaine versus intravenous morphine for patients with renal colic in the emergency department. Urology 2012

Guest Skeptics: Dr. Tony Seupaul is the Chairman of the Department of Emergency Medicine at the University of Arkansas. Dr. Rachel Littlefield is a PGY2 in Emergency Medicine at the University of Arkansas.

Knowledge Translation Window: A short note to point out that this paper was not published in the last year. However, it is less than ten years old so we are cutting the KT window down to less than ten years. It was selected because there has been a number of people on Facebook and Twitter talking about using lidocaine to treat renal colic. Of course we were skeptical and wanted to review the evidence.

Case: A 45-year-old male presents to the emergency department with sudden onset severe right-sided flank pain radiating to his groin that began one hour ago. He has also had nausea, vomiting, and difficulty urinating. He has never had anything like this before and is writhing around in pain, unable to get comfortable.

Background: Renal colic affects 1-5% of the US population [1]. The typical acute presentation is sudden onset of pain radiating from the flank to lower abdomen accompanied by microscopic hematuria, nausea, and vomiting [2].

The issue of renal colic a number of times on the SGEM. One issue that has been to use CT or ultrasound for the diagnosis.

A study from Bindman et al. in the NEJM 2014 demonstrated: Initial ultrasonography was associated with lower cumulative radiation exposure than initial computed tomography without significant differences in high-risk diagnosis with complications, serious adverse events, pain scores, return ED visits, or hospitalizations.”

SGEM#97: Hippy Hippy Shake
- Bottom Line: Bedside emergency department ultrasound is safe and has several advantages over CT for the diagnosis of kidney stones.

Passing a kidney stone is very painful. Narcotics are often used for pain relief along with intravenous NSAIDs. We learned recently about the ceiling effect of ketorolac for treating moderate to severe pain in the emergency department from Sergey Motov (@PainFreeED). He showed that 10mg IV ketorolac was just as effective as 15mg IV or 30mg IV.

SGEM#175: Dancing on the Ceiling with Ketorolac for Pain
- Bottom Line: Use 10mg IV ketorolac when treating moderate to severe pain in the emergency department.

Alpha blockers have been repeatedly tried to help with renal colic. However, there has not been high-quality evidence demonstrating efficacy.

SGEM#4: Getting Un-Stoned (Renal Colic and Alpha Blockers)
- Bottom Line: Tamsulosin 0.4 mg OD does not seem to work for renal colic beyond the placebo effect.
SGEM#71: Like a Rolling Kidney Stone (A Systematic Review of Renal Colic)
- Bottom Line: Tamsulosin is useless in most ED patients with ureteral colic unless their stone size exceeds at least 4mm.
SGEM#154: Here I Go Again, Kidney Stone
- Bottom Line: Expulsive therapy is unnecessary for ureteric stones < 5mm. There is some weak evidence that tamsulosin may help passage of larger stones (5 to 10 mm).

Lidocaine may be a useful alternative as it has been used to effectively treat visceral and neuropathic pain [3]. Finding non-narcotic alternatives to treat painful conditions is timely given the heightened attention to the opioid epidemic in the US.

Clinical Question: In emergency department patients with renal colic, is IV lidocaine as or more effective than IV narcotics for pain control?

Reference: Soleimanpour H et al. Effectiveness of intravenous lidocaine versus intravenous morphine for patients with renal colic in the emergency department. Urology 2012

Population: Patients age 18-65 presenting to the emergency department with unilateral abdominal pain radiating to the genitalia associated with a positive urine analysis for hematuria
- Excluded: Pregnant, allergy to lidocaine or morphine, or history of renal, hepatic, or cardiac disease
Intervention: IV Lidocaine 1.5mg/kg (max of 200mg)
Comparison: IV Morphine 0.1mg/kg (max of 10mg)
Outcome: Pain on VAS at 5, 10,15, and 30 minutes following the intervention

Authors’ Conclusions: “Changing the smooth muscle tone and reducing the transmission of afferent sensory pathways, lidocaine causes a significant reduction in pain.”

Quality Checklist for Randomized Clinical Trials:

The study population included or focused on those in the emergency department. Yes
The patients were adequately randomized. Yes
The randomization process was concealed. Unsure
The patients were analyzed in the groups to which they were randomized. Unsure
The study patients were recruited consecutively (i.e. no selection bias). Unsure
The patients in both groups were similar with respect to prognostic factors. Unsure
All participants (patients, clinicians, outcome assessors) were unaware of group allocation. Unsure
All groups were treated equally except for the intervention. Unsure
Follow-up was complete (i.e. at least 80% for both groups). Unsure
All patient-important outcomes were considered. Yes
The treatment effect was large enough and precise enough to be clinically significant. No

Results: 240 patients were enrolled in the study with 120 in each group. The mean age was in the mid 30’s.

Key Result: Less pain with lidocaine than morphine.

90% (108/120) patients responded to lidocaine successfully
70% (84/120) patients responded properly to morphine
Number of patients experiencing side effects were similar between groups.

Note: The trial was considered “accomplished” when either the patient had a pain score of less than 3 for 30 minutes after the last analgesic dose or the 10mL of solution in the syringe (either 200mg lidocaine or 10mg morphine) was used up.

1) Randomization Concealment: Envelopes were reportedly used for concealment but no mention is made as to whether or not the envelopes were completely opaque and unable to be seen through or if they were sealed. This method of concealment is weak at best.

2) Intention-to-Treat: There is no explicit mention of an intent to treat analysis. The authors note that: “Patients whose pain did not relieve using lidocaine or morphine were administered supplementary drugs. Then, method of drug administration, the reason for prescription and possible complications were explained to the patients and it was emphasized that using either lidocaine or morphine is safe.” There is the potential for cross-over in this trial.

3) Consecutive Patients: There was no discussion made about whether the subjects were recruited consecutively, just that they used randomization.com as their randomization tool. A lack of consecutive recruitment can lead to selection bias.

4) Similar at Baseline: We are unsure if patients were similar at baseline. More patients in the lidocaine group presented with a first stone and less with a recurrent stone.

5) Renal Colic: We are also not even sure if the study participants truly had renal colic. They were included based on history and hematuria. Follow-up studies included a kidney-ureter-bladder (KUB) X-ray and/or sonography. Neither of these diagnostic modalities are gold standard methods for diagnosing renal colic. There is the potential for substantial diagnostic bias.

6) Blinding of Patients: It is unclear whether or not all participants were unaware of group allocation. Certainly, morphine can produce side effects that could have unmasked the blinding. It would have been simple to ask the participants which group they felt they were allocated. We do not know if this potential bias would favour the morphine or the lidocaine group.

7) Blinding of Providers: The providers may have been unblinded introducing bias into the study. This is because differences in weight based dosing would result in different volume administrations of medications (ie a 100kg patient would be dosed 150mg [7.5mL of lidocaine] but would be dosed 10mg [the full 10m of morphine]). In addition, study medications were not distributed by a research pharmacist to ensure similarities between lidocaine and morphine.

8) Equal Treatment: It appears groups were treated equally aside from being administered lidocaine vs morphine. However, there is ambiguity in what additional interventions were performed when pain was not adequately controlled. Also, the authors do not address whether or not the subjects who required additional medications were excluded from data analysis in the end.

9) Follow-Up: This is not addressed in the article. It is likely that follow up was complete due to the short study interval.

10) Statistical vs. Clinical Significance: This is a key point. Although the results obtained statistically significant, the standard deviations of the means in every group at each measured time interval overlap and do not appear to have clinical significance.

Comment on Authors’ Conclusion Compared to SGEM Conclusion: The authors have a strong recommendation to use IV lidocaine for renal colic. While lidocaine MAY work, this trial certainly does not support the strength of their recommendation. This trial suffers from substantial methodologic flaws.

SGEM Bottom Line: Based on this study, lidocaine cannot be recommended for the treatment of renal colic.

Case Resolution: The patient has a bedside ultrasound performed by the emergency department physician. It demonstrates mild right hydronephrosis. He is provided with ketorolac 10mg IV and his pain is resolved. The patient is discharged home with pain control, expectant management and good instructions on when to return to the emergency department.

Clinical Application: This article did not provide convince that lidocaine works. I am not even sure that this treatment would be defensible if it was given for renal colic and someone had a bad outcome. People have reported cases of it working beautifully. There has been a smaller RCT by Firouzian et al in Am J Emerg Medicine [4]. It looked at IV morphine +/- IV lidocaine and found no statistically significant differences were observed between groups for the primary outcome of pain on the VAS. It too had some methodological issues. It would be interesting to perform a methodologically rigorous multicenter randomized control trial to tease this thing out.

What Do I Tell the Patient? You have a kidney stone that causing some mild swelling in your kidney. There does not appear to be any infection. Most kidney stones will pass on their own in about 1-2 weeks and it can be painful. We can treat your pain with some anti-inflammatories drugs. If that does not work you can also use some opioid pain pills as a back-up plan. We will also give you some anti-nausea medications. If your pain is not controlled, you are vomiting, develop a fever or are otherwise worried please come back to the emergency department. Otherwise, we will set up an outpatient appointment with a urologist for follow-up.

Keener Kontest: Last weeks’ winner was Marco Sivilotti from Queen’s University. He knew it was Sir Charles Putnam Symonds who coined the term “spontaneous subarachnoid hemorrhage” in a seminal and eponymous paper published in QJM in October, 1924.

Listen to the podcast on iTunes for this weeks’ keener question. If you think you know the answer then send an email to TheSGEM@gmail.com with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

Other FOAMed:

REBEL EM: IV Lidocaine for Renal Colic: Another Opioid Sparing Option?
WashU: IV Lidocaine for analgesia in the Emergency Department
EM Literature of Note: Lidocaine for Renal Colic

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.

O’Connor A, A’Schug S, Cardwell A: A comparison of the efficacy and safety of morphine and pethidine as analgesia for suspected renal colic in the emergency setting. Emerg Med J 2000, 17:261–264.
Leslie SW: Nephrolithiasis: Acute Renal Colic. 2005, [http://www. emedicine.com/med/topic3437. Htm] (Updated: May 3,2007).
Ferrini RA, Paice J: How to Initiate and Monitor Infusional Lidocaine for Severe and/or Neuropathic Pain. J Supportive Oncol 2004, 2:90–94.
Firouzian A et al. Does Lidocaine as an Adjuvant to Morphine Improve Pain Relief in Patients Presenting to the ED with Acute Renal Colic? A Double-Blind, Randomized Controlled Trial. Am J Emerg Med 2016