This is a nifty little diagnosis and something that you’ll see with some regularity. In the context of sudden unexplained cardiac arrest with ROSC but no neurological response we often get a CT of the head looking for some intracranial disaster to explain what just happened.
One of the images below is a typical SAH the other is consistent with pseudo SAH, can you tell the difference? (click the radiopaedia case links to find out)
I’ve seen this a couple of times now in post arrest patients and it can cause a lot of confusion as all of a sudden you’re worried about anticoagulation if you were thinking cath lab or maybe you’re tied into doing angios and what not.
Radiopaedia has a great post on it so all kudos to them but I think it’s something we in the EM world really need to know about hence the post.
In the post arrest patient (where I first encountered it) you get lots of cerebral oedema and engorgement of the superficial venous structures.
Can also occur in:
- severe meningitis
- dural venous sinus thrombosis
- bilateral large SDH
How do you tell the difference:
- ask your radiologist
- usually a lower hounsfield unit comared to true SAH