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Emergent Treatment of Obstructive Pyelonephritis
Ishaan Sangwan • Oct 3, 2021 • 52 hits
Obstructive pyelonephritis can be an emergency, and a physician must be able to determine if the patient needs to have their kidney drained. This diagnosis can be made based on a patient’s vitals, labs, and imaging, and the kidney can be drained with a nephrostomy or stent placement. A trial of passage may also be attempted in non-emergent cases, and must be managed with appropriate pain medication.
Dr. Jodi Antonelli discusses her approach to managing obstructive pyelonephritis on the BackTable Urology Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Urology Brief
• An obstructive pyelonephritis patient usually presents to the ER with renal colin, fever, tachycardia, hypotension, elevated creatinine, and elevated WBCs.
• Nephrostomy and stent placement are found to have similar outcomes in treating obstructive pyelonephritis.
• A large stone or narrow ureter may require a nephrostomy, whereas a stent may be more appropriate for a hemodynamically unstable patient, as it can be placed under sedation instead of general anesthesia.
• If obstructive pyelonephritis is not emergent, a trial of passage may be attempted. NSAIDs may be used for pain management, along with alpha blockers to help pass the stone.
Table of Contents
(1) Work-Up of Renal Colic to Diagnose Obstructive Pyelonephritis
(2) Nephrostomy vs. Stent for Obstructive Pyelonephritis
(3) Trial of Passage in Obstructive Nephrolithiasis
Work-Up of Renal Colic to Diagnose Obstructive Pyelonephritis
A patient presenting with renal colic pain can be evaluated for obstructive pyelonephritis by checking their vitals, labs, and past medical history. Obstructive pyelonephritis may present with a high temperature, tachycardia, hypotension, elevated creatinine, and elevated WBCs. Of these, immediate drainage would be indicated in a febrile patient with hypotension coupled with tachycardia. A urinalysis may show certain elevated parameters in a simple infection, but the presence of nitrate would cause concern for potential pyelonephritis.
[Dr. Jodi Antonelli]
I'd like to know about the patient's vital signs. Do they have a temperature, tachycardia, hypotension? Did they do any preliminary blood work, specifically with an interest in knowing their creatinine, their serum white blood cell count, and then a urinalysis, and then, obviously, have they obtained imaging at that point? I'd go and see the patient myself, but getting a little bit more history as well from the provider who has seen them, presenting symptoms, duration of the pain, if they have a history of stones previously, and do they appear toxic, non-toxic, is their pain controlled now, are they tolerating PO.
[Dr. Aditya Bagrodia]
Okay. Yeah. Clearly, a comprehensive history, physical, review of information. What are going to be your dead ringers, "This is a sick patient. Time to do something, urgent decompression"?
[Dr. Jodi Antonelli]
The immediate triggers to want to intervene and do something to drain the kidney would be if the patient is febrile, if they're at all hemodynamically unstable, and sometimes pain can give you tachycardia, but tachycardia coupled with hypotension certainly is worrisome. Then from the standpoint of the objective lab work that you get, putting that in the context of the patient's presentation and elevated white blood cell count in isolation sometimes could be just due to inflammation, but that coupled with a patient who may have some of those other signs, again, certainly heightens my concern.
Then the urinalysis. So, the urinalysis is tricky. Some of the parameters could be elevated in the setting of inflammation. Additionally, sometimes surprisingly, the urinalysis is not that impressive if a stone is truly obstructing. Sometimes it doesn't look as bad as you would expect, but if you have a urinalysis with positive nitrate, that really heightens my concern. Very severe gross hematuria or Pyridium, things that change the color of the urine can sometimes falsely elevate a nitrite that isn't actually a sign of infection, but a positive nitrate is worrisome. Then Leukocyte esterase I think more often can be elevated with just pure inflammation, and then elevated white cells or presence of bacteria on a UA can also be worrisome.
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Nephrostomy vs. Stent for Obstructive Pyelonephritis
Once an obstructive pyelonephritis has been diagnosed, the kidney must be drained through either a stent or a nephrostomy. While some physicians recommend a nephrostomy in a septic presentation, research shows that outcomes are similar between the two procedures. The decision to perform one or the other should be based on the stone and anatomy of the patient. If a stone is too big, or if the patient has an enlarged prostate, a nephrostomy would be preferred. However, a stent can be placed under sedation instead of general anesthesia, and may be indicated in a hemodynamically unstable patient.
[Dr. Jodi Antonelli]
Yeah. Dr. Pearle actually did a nice study in the late 1990s and was essentially a randomized trial where she assigned folks to either a stent or a nephrostomy tube. They actually found that there wasn't any significant difference in terms of outcomes, having a normal temperature, normalization of white count between those two groups. So, I think there is this thought that if a patient comes in more on the curve of sepsis that a nephrostomy tube is really what's warranted, her data would suggest otherwise.
My points that I use in deciding whether to go with a nephrostomy tube or a stent have a lot to do with the stone and the anatomy. If it's an extremely large ureteral stone, I mean, I'd say over a 1-1.5 cm and I'm concerned that I'm not going to be able to get a wire and a stent passed it, certainly those patients I'd prefer have a nephrostomy tube. Anybody with any difficult anatomy in the pelvis, bladder, a very large prostate, if I'm going to consider an older gentleman just maybe difficult to find the ureteral orifice. So, those patients, for sure, I think do much better with a nephrostomy tube.
The difference is in what you have to have a patient undergo to get either tube. So, general anesthesia versus some sort of sedation. I mean, if a patient is really hemodynamically unstable, theoretically, you can have a nephrostomy tube without a general. Again, it's really a conversation that has to happen with IR and whoever anesthetist at your facility as to how comfortable they are with doing that. That's also I think just the patient stability and a discussion with those groups is definitely something to undertake when you're deciding between which tube is better.
[Dr. Aditya Bagrodia]
Yeah. I remember one time being on call and there's a lady that came in with a pretty dramatic presentation, and we just did it without general anesthesia, which had to be done, and it worked out. Once upon a time, we used to do some stenting in clinic and it's full spectrum in terms of patient tolerability, but I suppose it's an option.
Trial of Passage in Obstructive Nephrolithiasis
In certain cases, a stone may just pass on its own, or with help from certain medications. While attempting a trial of passage, NSAIDs can be used for pain management, as long as a patient has normal renal function. Narcotics may be used as a breakthrough medication in severe cases, but should be second line treatment to NSAIDs. While the data to support the use of alpha blockers to help pass a stone remains inconclusive, the AUA still recommends them as long as they are not contraindicated in the patient.
[Dr. Jodi Antonelli]
Yeah. So, I think it's important to get an idea from the patient how long had they been having symptoms when they are presenting to the ER because that's where your clock starts in terms of how long you want to attempt a trial of passage. So, I mean, the limited data that's out there, obviously, there's not a real ethical way to test this in humans, it's basically animal data, is we try not to leave a stone in a location that could potentially be obstructing or partially obstructing for more than six weeks.
So, typically, I'll make sure a patient has pain medication. There's a lot of emerging data now that NSAIDs actually may be better in terms of pain control than narcotics. So, if a patient has a normal renal function, no contraindications to NSAIDs, I actually prefer a ketorolac or diclofenac over narcotics. Sometimes I'll give the patient a breakthrough narcotic prescription as well like Tylenol 3 or tramadol or occasionally hydrocodone, but recommend that the patient uses the NSAIDs as our first line.
Then there's a lot of mixed data, and I think a lot of differing opinions around the globe about medical expulsive therapy, so the use of alpha blockers for promoting stone passage. The US versus Europe, and specifically the UK, I think, have very different thoughts on what should be done. So, there's a large trial, probably 2015, that was conducted in the UK and they had a very different outcome measure than many of the other studies that were done that was basically not a radiographic outcome in terms of stone passage, but lack of needed intervention.
Based on that trial, I think, the UK and most Europe are less inclined to prescribe alpha blockers for medical expulsive therapy. I think in the US it's still recommended in our AUA guidelines specifically for larger distal stones. The data is greatest there. So, I think prescribing a patient an alpha blocker is something that even if it's a proximal stone I tend to do.
My thought is that potentially some of these studies may not actually be powered to really show a difference that maybe matters clinically. I mean, if taking a pretty well-tolerated medication even has a 1% chance of preventing me from needing a surgery and a stent. I think it's worth it. So, certainly for larger distal stones over 5 mm distally I would definitely recommend an alpha blocker, but I'm usually inclined to prescribe it for any ureteral stone, and then plus/minus on anti-emetics depending on how the patient is feeling.
Dr. Jodi Antonelli
Dr. Jodi Antonelli is a practicing Endourologist and Associate Professor in the Department of Urology at UT Southwestern Medical Center.
Dr. Aditya Bagrodia
Dr. Aditya Bagrodia is an associate professor of urology and genitourinary oncology team leader at UC San Diego Health in California and adjunct professor of urology at UT Southwestern.
Cite This Podcast
BackTable, LLC (Producer). (2021, August 12). Ep. 13 – Tips & Tricks for Difficult Ureteroscopy [Audio podcast]. Retrieved from https://www.backtable.com
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