I am both an emergency physician and a neurointensivist, and this is one way that my fellowship has changed my EM practice. I scan a lot more now.
I fairly often see patients with chronic subdurals that were almost certainly due that fall a couple of months ago that was missed. Sometimes the delay is an issue and they need a bigger surgery than they otherwise would have. Sometimes it's an issue because they were continued on anticoagulation and subsequently re-bled.
I think people are falsely reassured by not having seen bounce backs. Even if you are the only hospital with a neurosurgeon in house, patients can still present to another hospital and be transferred to your ICU without passing through the ER. Unless you are involved in reviewing all transfers for your institution, you would not know about these. And also, people cross county lines (and even state lines I hear) and are perhaps more likely to do so if they have a suspicion something was missed the first time.
I have a fairly low threshold to get a CTH in anyone over 65 or so. Would get for most but the mildest of head trauma in that age group. Would scan anyone on anticoagulation almost regardless of mechanism or actual head strike. Anyone who has a headache/nausea/confusion after injury even if they did not hit their head.
Also surgery for subdural is not necessarily a big crazy thing. A lot of times it's some combination of a single burr hole and/or middle meningeal artery embolization. Both are very well tolerated, including in the elderly. For chronic subdurals there are even bedside techniques like SEPS. For Even craniotomies (taking off a section of the skull and then putting it back) is pretty well tolerated. I think most people are imaging craniectomies (when a section of the skull comes off and stays off) but that's mostly done for more severe head injuries, ones in which you are not on the fence about getting a CT scan of the head in the first place.
How would you interpret the following scenario. Patient comes to ED with blunt head trauma (from a very mild mechanism) on forehead with no symptoms beside mild HA right at the site of the impact (note not 2 inches around it either), no lac, normal neuro exam, no other concerning symptoms and signs. On DOAC. 1) ED doc images, there is a very small 2 mm subdural. Reversal to DOAC given. Admitted. Repeat CTH 6-12 hours from now unchanged. NSG consults and says d/c. 2) ED doc does not image. Pt sent home. Fast forward 4 months from now...in both cases pt gets repeat CTH from some doctor which now shows a much larger SDH/hygroma with acute on chronic blood products, mild shift, and pt has mostly HA with some mild contralateral weakness. NSG consulted again, says stops DOAC, and pt receives surgery 48 hours later with uneventful course. What would have Dr. Wyer said? Image or no image?
Would it have mattered if a tennis ball hit the pt in the head? What if said tennis ball was tossed and not hit with a racket? What if a piece of luggage slipped coming out from the overhead airplane bin and hit the pt on the head? I can think of innumerable number of other mechanisms.
Is there even a point in asking someone questions about what happened during the trauma? Based on some of the comments listed above, I suspect that many would say no and there is no reason to even ask about mechanism. Pt should go right to CT.
What is magical about age 65 and DOAC? Would medical decision making change if pt was 64.5 years old and on a DOAC? What about 62? What about even younger? Do skulls stop providing any protection once we hit 65?
With the above example, this pt had a non clinically important TBI and unfortunately it got worse over the next 4 months. That's low risk.
The only thing I can think of, in an ideal world, is that in the above example the NSG doctor will have made an appointment to see that patient in 3-4 weeks and gotten a repeat CTH regardless of symptomology. I'm not a NSG so I don't know if that is good medicine. I don't know if it's important to get a repeat CTH in the above example if the pt remains asymptomatic in perpetuity. I suspect not, but I don't know. Even if the repeat CTH in 4 weeks the SDH grew from 2mm to 5mm and otherwise normal, I don't know if that's an indication for surgery.
I just wonder with all the comments above why people even talk to and examine patients with mild blunt head trauma on DOAC. Probably just for show. The paper I quoted above says that physical gestalt doesn't miss clinically relevant TBI, at least in that study over 6 community sites and 6 academic sites, imaging about 4000 patients over a year.
Is there harm in imaging every single person with suspected mild TBI?
The thing is I'm confident that none of us here image 100%, so we do use gestalt. We just don't want to admit it.