Category Archives: General

Incidental Pulmonary Embolus

In my last post, I described a case where a fresh trauma patient was found to have an incidental finding of small, distal pulmonary embolus (PE) on her initial trauma evaluation. What should you do when you see this? Reflexively anticoagulate for months?

There are only a few papers dealing with this topic. One is from the MGH, which looked at their experience in screening for deep venous thrombosis (DVT) with duplex ultrasound and diagnosing PE with chest CT. They found that quite a few PEs were found that had no associated DVT in the legs or with clot in the pelvic veins. They also noted an interesting distribution: PEs with no DVT tended to be more distally located, and vice versa for those with DVT. This suggested that some PEs may not be emboli at all, but clot that forms spontaneously in the distal lung circulation.

Scripps Hospital in San Diego did some similar work. Only 31 of some 12,000 patients developed PE, and 19 of these had no identifiable DVT as a source. They also noted that these “de novo” PEs tended to be single and peripherally located. PE associated with DVT tended to be multiple and more central. They also noted an association with chest trauma (pulmonary contusion, rib fractures), blood transfusion, and pneumonia.

Bottom line: As usual, the literature is of little help in this relatively recently identified phenomenon. So what’s the trauma professional to do? Here’s my take. If a PE is found incidentally on the initial trauma evaluation, take a good history to see if there are any family members with clotting problems. Failing that, search for DVT using duplex ultrasound. If the PE is central or multiple, or there is a positive history or duplex screen, anticoagulate as you would any other patient with this problem. If not, carry out the usual prophylaxis and screening as laid out in your usual protocol (you have one, don’t you?), but don’t consider it a “real” PE. At least until we know more about this phenomenon.

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What Would You Do? Incidental Pulmonary Embolus

You recently received a trauma activation patient after a high speed car crash. She was restrained with belts and airbags, and really has minimal trauma. There is clinical evidence of a few right-sided rib fractures, and nothing else. She has no significant past medical history, but is overweight to obese. You estimate the BMI as about 31.

Following your blunt trauma imaging protocol, one of the scans you obtain is a chest CT. It confirms that the aorta has not been injured and shows two rib fractures. After review, the radiologist calls you with a puzzling result. The patient has a small pulmonary embolus seen in a distal (third order) branch of the pulmonary artery in the left lung.

Here’s a coronal view of the scan that you looked at. The arrows show some peripheral branches, but you didn’t see anything on your average resolution monitor.

image

Here’s a sagittal view in high-rez that the radiologist looked at.

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Yup, looks like a pulmonary embolus. Here are my questions:

  • Where did it come from?
  • What do you do next?
  • What type of treatment is needed?

Think this over this weekend. Discussion and answers on Monday.

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CT Angiography Of The Head In TBI?

Trauma professionals rely heavily on diagnostic tests these days, particularly CT after blunt trauma. Apparently, the neurosurgeons at the Massachusetts General Hospital are asking for CT angiography of the brain on occasion in patients with TBI. Ostensibly, this is to rule out cases when a brain aneurysm causes a car crash or other blunt trauma.

WTF? Now, I know that we occasionally agonize over older victims of blunt trauma who come in pre-terminal or in arrest. Did they have an MI which caused the event, or did the trauma stop their heart? I had no idea that a ruptured/rupturing aneurysm was such a problem in blunt trauma.

So the surgeons at the MGH decided to critically look at this issue to see if the extra head scan was warranted. 

Here are the factoids:

  • 600 patients with blunt TBI over a one year study period were reviewed
  • 22% underwent CT angio in addition to the normal head CT
  • 66% had the CT angio immediately, 27% within 24 hours, and 7% beyond 24 hours after arrival
  • Specialists who requested the study were neurosurgeons (23), radiologists (15!), neurologists (7!!)
  • Reasons for getting the study: look for cause of subarachnoid hemorrhage (aneurysm) in 43, look for vascular injuries near a skull fracture in 14, rule out stroke in 4, and no particular reason in 71
  • Head CTA changed management in only 1 patient, prompting a formal angiogram which was negative
  • 33 patients (25%) had incidental findings on CTA, but none required any intervention in the hospital or on later followup

Bottom line: There is no value to adding CT angio of the head to the usual scan protocols. Having said that, if the patient was witnessed to lose consciousness prior to the event, and the CT shows subarachnoid hemorrhage in a more typical middle cerebral artery distribution, you might consider it to look for an aneurysm. That’s a lot of if’s. Just move the zebra off the CT scanner first. And as you can see from the last factoid above, if we scan it, we will find stuff. Fortunately, most of that stuff doesn’t need further workup or treatment.

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Reference: Is CT angiography of the head useful in management of traumatic brain injury? J Am Col Surg 220(6):1027-1031, 2015.

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Hypertension After Pediatric Renal Trauma

Renal injuries are not very common, and the number of pediatric kidney injuries is even smaller. One potential complication after this injury is hypertension. As usual, there are many theories as to why this occurs. There are undoubtedly areas of the injured kidney that are under-perfused. The most popular theory is that this results in release of renin, upregulating the renin-angiotensin system. 

But how much do we need to worry about this problem? Retrospective adult studies put the incidence at about 5%, and the onset generally occurs 2 to 8 weeks after injury. 

And what about children? Are they just small adults when it comes to this problem? Primary Children’s Hospital in Salt Lake City designed a retrospective study to try to answer this question. They examined 11 years of their own registry data on children, defined as <18 years old. They focused on high grade injuries (grade III-V), as these should have the highest incidence of complications.

Here are the factoids:

  • Hypertension was defined as elevated BP anytime after admission that required control with medication, but only after pain was controlled
  • 62 children sustained high grade injury, with an average age of 10
  • Most were grade III (21) and grade IV (40)
  • Four (6.5%) developed hypertension while hospitalized
  • Only two requiring ongoing medication months after discharge
  • None of the non-hypertensive children became hypertensive later

Bottom line: Obviously, these numbers are small. The fact that it took over 10 years

at a pediatric hospital to accumulate this data demonstrates the difficulty in getting good, actionable information. It looks like that the incidence is similar to adults (about 5%). It does seem that some patients recover and don’t need long-term medication. I recommend that everyone (adult and child) with a significant renal injury (grade 3+) be monitored for hypertension while in the hospital, and for 2-3 months after discharge by their primary practitioner.

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Reference: The incidence of long-term hypertension in children after high-grade renal trauma. J Ped Surg, in press June 2015.

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