No Relief for the ?SAH=CT/LP Routine

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docB

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Interesting study in Annals this month:

Sensitivity of Noncontrast Cranial CT for the ED Diagnosis of SAH

Anyone hoping that imaging will save us from the annoying CT/LP paradigm for working up “suspected SAH” is out of luck. This study shows that CT alone is just as insensitive for SAH (missing ~7%) as we always thought.

The real problem is that the CT/LP mantra translates to having to do a lot of LPs, an invasive, painful procedure that is sometimes technically difficult, often time consuming and have several significant complications. The reason is that anyone who describes their headache as the worst they’ve ever had or as sudden onset is under “suspicion of SAH” even though that’s a huge population of those who come to the ED for headache.

There’s an interesting editorial attached to the article by Clifton Callaway (that you can only get if you’re an Annals subscriber.

He brings up a few really interesting points:
- Future imaging technology my help but not anytime real soon.
- It may not be necessary to rule out tiny amounts of blood from “non-treatable” lesions. This is analogous to the “If you can’t see the PE with the CT chest it’s too small to worry about” argument.
- We need a better definition of the “low risk” patient for SAH.

This last point is the most interesting to me. Is there a way we can identify patients who are low risk enough to skip the LP? We need a NEXUS style tool for this clinical entity. I smell research project!

Lastly, some good news. Perry, et. al. studied the CT/LP regimen and found that it is sensitive enough to effectively rule out SAH. Thank goodness for that.

Is the Combination of Neg CT and Neg LP Sufficient to RO SAH?

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...- We need a better definition of the “low risk” patient for SAH.

This last point is the most interesting to me. Is there a way we can identify patients who are low risk enough to skip the LP? We need a NEXUS style tool for this clinical entity. I smell research project!
I'm always up for crunching numbers. PM me if you're serious :D
 
Interesting study in Annals this month:

Sensitivity of Noncontrast Cranial CT for the ED Diagnosis of SAH

Anyone hoping that imaging will save us from the annoying CT/LP paradigm for working up “suspected SAH” is out of luck. This study shows that CT alone is just as insensitive for SAH (missing ~7%) as we always thought.

The real problem is that the CT/LP mantra translates to having to do a lot of LPs, an invasive, painful procedure that is sometimes technically difficult, often time consuming and have several significant complications. The reason is that anyone who describes their headache as the worst they’ve ever had or as sudden onset is under “suspicion of SAH” even though that’s a huge population of those who come to the ED for headache.

There’s an interesting editorial attached to the article by Clifton Callaway (that you can only get if you’re an Annals subscriber.

He brings up a few really interesting points:
- Future imaging technology my help but not anytime real soon.
- It may not be necessary to rule out tiny amounts of blood from “non-treatable” lesions. This is analogous to the “If you can’t see the PE with the CT chest it’s too small to worry about” argument.
- We need a better definition of the “low risk” patient for SAH.

This last point is the most interesting to me. Is there a way we can identify patients who are low risk enough to skip the LP? We need a NEXUS style tool for this clinical entity. I smell research project!

Lastly, some good news. Perry, et. al. studied the CT/LP regimen and found that it is sensitive enough to effectively rule out SAH. Thank goodness for that.

Is the Combination of Neg CT and Neg LP Sufficient to RO SAH?

I like the approach that they use in Rosen's under the "Cardinal Cases" for defining low risk HAs or the "all clear" vs "warning signal" groups as they put it. Unfortunately I don't think that helps reduce the number of CTs that are done, as they have the same warning signs of "worst HA" or "sudden onset".
 
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