Tag Archives: spleen

Complications

Prevnar 13 And Spleen Trauma

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Recently, I’ve noticed television commercials for Prevnar-13, a 13-valent pneumococcal vaccine for immunocompromised or asplenic adults. And interestingly, I noticed that the CDC has now added a recommendation such that these patients receive this vaccination, and then the good old 23-valent vaccine (Pneumovax) 8 weeks later.

WTF? Patients with splenectomy (or significant angio-embolization) for trauma are considered functionally asplenic. And although the data for immunization in this group is weak, giving triple vaccinations with pneumcoccal, H. flu, and meningococcal vaccines has become a standard of care.

This was difficult enough already because there was debate around the best time to administer: during the hospital stay or several weeks later after the immune system depression from trauma had resolved. The unfortunate truth is that many trauma patients never come back for followup, and so don’t get any vaccines if they are not given during the hospital stay.

And then came the recommendation a few years ago to give a 5-year booster for the pneumococcal vaccine. I have a hard time remembering when my last tetanus vaccine was to schedule my own booster. How can I expect my trauma patients to remember and come back for their pneumococcal vaccine booster?

So what do we do with the CDC Prevnar-13 recommendation? If we add it, it means that we give Prevnar while the patient is in the hospital, and then hope they come back 8 weeks later for their Pneumovax. And then 5 years later for the booster dose. Huh?

Looking at the package insert, I read that Pneumovax protects against 23 serotypes of S. Pneumo, which represent 85% of most commonly encountered strains out there. So it’s not perfect. Prevnar-13 protects against 13 serotypes, and there is no indication as to what percent of strains encountered are protected against.

So I decided to dig deeper and look at the serotypes included in each vaccine. Here they are:

  • Pneumovax: 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F, and 33F
  • Prevnar: 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F

I bolded the serotypes in Prevnar-13 not found in the Pneumovax vaccine. There was only one, serotype 6A. Unfortunately, it’s nearly impossible to find the prevalence by serotype, and it varies geographically and over time.

Bottom line: I’m not an epidemiologist. But making a set of vaccination rules more complicated for a complex population, and for indications that are a bit weak in the first place, seems unwise. Especially since the added vaccine offers protection for only one more serotype of Pneumococcus.

So please help me out here. Show me something I’m missing. Otherwise, I’ll stick to the original three vaccines, and try to remind my patients to get that booster five years down the road.

Related posts:

Reference: Use of 13-Valent Pneumococcal Conjugate Vaccine and 23-Valent Pneumococcal Polysaccharide Vaccine for Adults with Immunocompromising Conditions: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 61(40):816-819, October 12, 2012.

Abdomen

Post-Embolization Syndrome In Trauma

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A reader requested that I write about post-embolization syndrome. Not being an oncologist or oncologic surgeon, I honestly had never heard about this before, let alone in trauma care. So I figured I would read up and share. And fortunately it was easy; there’s all of one paper about it in the trauma literature.

Post-embolization syndrome is a constellation of symptoms including pain, fever, nausea, and ileus that occurs after angio-embolization of the liver or spleen. There are reports that it is a common occurrence (60-80%) in patients being treated for cancer, and there are a few papers describing it in patients with splenic aneurysm. But only one for trauma.

Children’s Hospital of Boston / Harvard Medical School retrospectively reviewed 12 years of their pediatric  trauma registry data. For every child with a spleen injury who underwent angio-embolization, they matched four others with the same grade of injury who did not. A total of 448 children with blunt splenic injury were identified, and (thankfully) only 11 underwent angio-embolization. Nine had ongoing bleeding despite resuscitation, and two had developed splenic pseudoaneursyms.

Here are the factoids:

  • More of the children who underwent embolization had extravasation seen initially and required more blood products.  They also had longer ICU (3 vs 1 day) and hospital stays (8 vs 5 days). Not surprising, as that is why they had the procedure.
  • 90% of embolized kids had an ileus vs 2% of those not embolized, and they took longer to resume regular diet (5 vs 2 days)
  • Respiratory rate and blood pressure were higher on days 3 and 4 in the embolized group, as was the temperature on day 5 (? see below)
  • Pain was higher on day 5 in the embolized group (? see below again)

Bottom line: Sorry, but I’m not convinced. Yes, I have observed increased pain and temperature elevations in patients who have been embolized. Some have also had an ileus, but it’s difficult to say if that’s from the procedure or other injuries. And this very small series just doesn’t have enough power to convince me of any clinically significant differences in injured children.

Look at the results above. “Significant” differences were only identified on a few select days, but not on the same days across charts. And although the authors may have demonstrated statistical differences, are they clinically relevant? Is a respiratory rate of 22 different from 18? A temp of 37.8 vs 37.2? I don’t think so. And length of stay does not reveal anything because the time in the ICU or hospital is completely dependent on the whims of the surgeon.

I agree that post-embolization syndrome exists in cancer patients. But the findings in trauma patients are too nondescript. They just don’t stand out well enough on their own for me to consider them a real syndrome. As a trauma professional, be aware that your patient probably will experience more pain over the affected organ for a few days, and they will be slow to resume their diet. But other than supportive care and patience, nothing special need be done.

Related posts:

Reference: Transarterial embolization in children with blunt splenic injury
results in postembolization syndrome: A matched
case-control study. J Trauma 73(6):1558-1563, 2012.

Abdomen, Complications

Incidental Finding: Gas In The Spleen After Embolization

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Most solid organ injury practice guidelines include angioembolization in part of the pathway. But very few require re-imaging at any point to see how the liver or spleen are coming along.

But every once in a while another condition arises, or symptoms worsen unexpectedly, causing us to get another CT scan that includes the abdomen and pelvis. And sometimes we see things that we wouldn’t normally see, like air bubbles in the organ that was embolized.

So what is okay, and what requires some kind of intervention? Our friends at ShockTrauma in Baltimore looked at this in 2001 and can provide some pretty good guidance. They reviewed patients who underwent CT scan both before and after embolization over about 2.5 years. They performed the post-embolization scans for specific indications like fevers, elevated WBC count (!), increasing abdominal pain, or an episode of hypotension. A total of 53 patients were studied.

Here are the factoids:

  • 24 patients underwent embolization of the main splenic artery, 22 had selective embolization of part of the spleen, and 7 had both
  • Splenic infarcts occurred in 63% of patients with main artery embolization, but were large (> 50% of the parenchyma) in only 20% of those
  • Infarcts occurred in 100% of selective embolizations, but were small (< 50%) in 93% of cases
  • Infarcts occurred in 71% of patients with both main and selective embolization, and most were small (80%)
  • Seven (13%) patients developed gas bubbles in the spleen, and was usually present for 1-7 days before disappearing
  • One patient developed increasing gas with pneumoperitoneum and underwent splenectomy for a splenectomy for abscess

This picture that shows tiny bubbles in the spleen parenchyma that represent “normal” gas after embolization:

And the following one shows an air/fluid collection in the spleen that indicates an abscess:

Bottom line: Tiny bubbles in the spleen (and probably the liver) occur normally after angioembolization. They usually develop within an area of infarction, and most are benign. It is possible for them to evolve into a splenic abscess, but unlikely. Many embolization patients develop fevers at some point, and most have an elevated WBC count. So in most cases, you can ignore this incidental finding, as long as your patient has mild symptoms.

However, if the patient develops high fevers, very elevated WBC (> 25K), increasing abdominal or flank pain, and the spleen develops an air/fluid level, an abscess is forming. Despite what your radiologist might suggest, catheter drainage is not a good idea. The tubes are too small to remove the slurry that is generally found within the abscess. A trip to the OR is the only effective treatment, and splenectomy is generally the only option.

Related posts:

Reference: CT Findings after Embolization for Blunt Splenic Trauma. J Vasc Intervent Radiol 12(2):209-214, 2001.

Complications, Solid organ

EAST 2017 #12: Revaccination Compliance After Splenectomy

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The incidence of overwhelming post-splenectomy sepsis, and the need and effectiveness for vaccination after splenectomy is still subject to debate. However, the administration of three vaccines to protect against encapsulated bacteria is a standard of care. For decades, this was a one time thing and the vaccines were usually given before the spelenctomized trauma patient was discharged from the hospital.

Then several years ago, the CDC updated their recommendations to include a booster dose of 23-valent penumococcal vaccine. Trauma professionals have inconsistently advised their patients about this dose, and patients have not reliably sought their booster.

Researchers at Christiana Care in Delaware looked at this potential problem by identifying all of their trauma splenectomy patients over a 10 year period. They were interviewed by phone to determine their understanding of the asplenic state and the need for booster vaccination.

Here are the factoids:

  • During the 10 year period, 267 trauma splenectomies were performed
  • 196 survived, but only 52 agreed to participate (? – see below)
  • Although all patients received vaccines before discharge (!), only 23% were aware that they had
  • Only about half of patients were aware that they may be at risk for infectious complications
  • Only 19% understood they would require a booster dose, and 22% had actually received one (?? – see below)

Bottom line: Although we still aren’t sure how important these vaccines are, vaccination is the standard of care. This study, although a little confusing, shows that we are falling down in educating our patients about the impact of their splenectomy (surgical or via embolization). And it’s difficult for anyone to remember to get a booster shot. Are you up to date on your tetanus vaccination?

This abstract shows us that we need to counsel these patients prior to discharge regarding their at-risk condition. We also need to make sure they (and their primary care provider) are aware that they need to get a pneumococcal booster five years down the road.

News flash! Take a look at page 3 of the CDC recommendations (download here) to see the official recommendations regarding pneumococcal vaccination. It is recommended that PCV-13 vaccine (Prevnar 13) be given first, then the 23-valent vaccine (Pneumovax) 8 weeks later! This complicates things a bit, since both pneumococcal vaccines cannot be given while the patient is still in the hospital. This will reduce the likelihood that patients will get their second pneumococcal vaccine.

Questions and comments for the authors/presenters:

  1. The number of patients is off by one. There were 267 splenectomy patients, 49 died in the hospital and 23 after discharge. 267-49-23=195, not 196.
  2. Only 52 of this 195 agreed to participate. You were able to find all 195? It seems that some of these 143 patients just could not be located.
  3. Please clarify the numbers in my last bullet point. Of the 52 patients, only 9 were aware of the revaccination requirement, and only 1 got it?
  4. This is important work. What have you done to improve these numbers at your hospital?

Click here to go the the EAST 2017 page to see comments on other abstracts.

Related posts:

Reference: Revaccination compliance after trauma splenectomy: a call for improvement. Poster #31, EAST 2017.