Hi, my name is Alex Niven. I am a consultant in the division of pulmonary and critical care medicine at Mayo Clinic in Rochester, Minnesota, and it is a true pleasure to have the opportunity to talk through with you today one of the questions that I wrote for CHESS Critical Care Seek. This is based on a real patient case, so let's go through it and talk through the responses here. So this is a 73-year-old patient who was admitted two days ago for abdominal septic shock. The patient has a history of end-stage renal disease and is receiving peritoneal dialysis and clearly meets clinical criteria for peritonitis on initial presentation. So the patient was treated with crystalloid resuscitation, broad-spectrum antibiotics, norepinephrine, and hemodialysis while the infection is being treated and initially responds very nicely. But when you see the patient on the second morning, they're becoming more somnolent and blood pressure is a little bit more labile on hemodialysis requiring reinstitution of norepinephrine. And although the white counts come down, it's bumped up a little bit this morning compared to the day prior. Now, a key element in the stem is the cultures that have returned from the peritoneal fluid that was drawn off on presentation, essentially growing four organisms, Staph aureus, strep mitis, which is a very unusual bug for typical primary peritonitis from peritoneal dialysis, E. coli in Canada. And so really the question is, while we're pulling off more fluid samples to look at how the cell count is trended and if there's changes in the gram stain, is what's the most appropriate next step? And the correct answer in this case is to perform an exploratory laparotomy. And let's talk about why. So the learning objective for this case is really to help differentiate between primary peritonitis, which is an infection of the lining of the abdomen, commonly seen, or at least frequently seen in patients with peritoneal dialysis, largely because of technique and contamination related to that procedure. So primary peritonitis is simply abdominal pain, cloudy effluent from the dialysate associated with an elevated white count of that effluent and positive cultures. And really the biggest challenge that we face in this situation, because many people on peritoneal dialysis have multiple comorbidities and also have had multiple abdominal procedures related to catheter placement and the like, is whether or not there's any evidence of secondary peritonitis, which is really some underlying intra-abdominal pathology driving the infection, which is often surgical in nature. So the key elements for this case is, first of all, the initial improvements followed by some now evolving clinical decline. It's very unusual for primary peritonitis associated with a peritoneal dialysis infection. Most patients actually respond very promptly to therapy and improve very rapidly. And the second is the polymicrobial nature of the cultures that you have back that includes a couple of organisms that we typically associate with, you know, bowel flora. And so really the concern at this point is that there's an occult perforation or leakage that's really driving this infection. So what we did in this situation was consult general surgery who agreed that the appropriate next step will be to perform exploratory laparotomy to exclude an occult source of infection. Now there was a number of comments from individuals that took this question that the correct answer should be to perform a CT scan first before we go to exploratory laparotomy. I completely agree with that bias. We actually performed a CT scan as part of the preoperative planning that actually demonstrated new free air. And so on exploratory laparotomy, there was actually a small leak at the gastrointestinal anastomosis site that needed to be repaired. That being said, even without the free air on the CT scan, we were planning to proceed forward with exploratory laparotomy, again, because of those two big things. The patient initially responds and now is clinically deteriorating after appropriate initial therapy where they should be getting better. And then again, those polymicrobial cultures, it's just very unusual, especially with some of those organisms for a primary peritonitis from a peritoneal catheter infection. And so just to run through the other options and sort of explain why they're not the best choices in this situation. So certainly starting an antifungal is very appropriate at this point, given the candida and the peritoneal fluid, but the IDSA recommendations in the setting for somebody who's critically ill would be to start with an echinocandin, not for connoisseur. Stopping vancomycin in this situation would be very appropriate because we've identified methicillin-sensitive staph aureus, and so there's no real reason to continue that drug. However, it's not really going to address the underlying problem that's driving this clinical picture. So it's a less than ideal choice. And removing the peritoneal dialysis catheter, I think is also appropriate in this setting. In the setting of relapsed peritonitis or fungal peritonitis, those are the primary indications to remove that catheter, but it's still not going to address that question of whether or not there's underlying intra-abdominal surgical pathology. And so removing that catheter needs to be done as part of an exploratory laparotomy to really answer that question. So I hope this discussion was helpful for you, and thank you very much for spending a little bit of time with me to talk through it.

abdominal septic shock

end-stage renal disease

peritoneal dialysis

secondary peritonitis

exploratory laparotomy