Excellent point about the sensitivity of a modern CT scanner, but is this based on a neuroradiologist interpretting? Obviously in the middle of the night the scan is being read by a radiology reg who is potentially tired and it may only be his first time on call.
Certainly if it was a mechanical valve one would be very wary about reversing warfarin but in this instance it would probably be prudent.
Shame she didn't just go to the neurosurgical centre in the first instance who obviously have better access to CT radiography in the middle of the night - having worked in such a centre I was always amazed at the amount of folk who would travel past a number of EDs to arrive on my doorstep in the middle of the night with such a history!
Stuart Carr
EM Consultant
Dublin
----- Original Message -----
From: "conor deasy" <[log in to unmask]>
To: [log in to unmask]
Sent: Thursday, 8 March, 2012 10:33:43 AM
Subject: Re: loan severe headache
Adrian - Slow down Tiger!!
Do we need to be so quick as to 'Reverse warfarin irrespective of CT.' The Ottawa folks tell us that the sensitivity a modern third generation CT is 100% (97.0% to 100.0%), specificity of 100% (99.5% to 100%), negative predictive value of 100% (99.5% to 100%), and positive predictive value of 100% (96.9% to 100%) if done for suspected SAH within 6hrs of headache onset (Perry JJ, BMJ 2011 Jul 18). What if she's on warfarin for her mechanical valve??
Looking forward to catching up in Dublin at ICEM 2012 - looks like a great line up.
Conor Deasy
Emergency Physician,
Alfred Hospital, Melbourne.
Date: Thu, 8 Mar 2012 10:13:09 +0000
From: [log in to unmask]
Subject: Re: loan severe headache
To: [log in to unmask]
I think it has to be CT scan immediately with loss of radiographer the next day
By lone headache i assume you mean classical presentation with no associated features right?
Based on information given the Hunt and Hess classification is grade I
However that is based on competence of examining physician
Hunt and Hess I has a mortality of say 30%
Add in some very subtle neurology and it's Hunt and Hess II with mortality of 40%
If they are a little drowsy ("expected" and may be "accepted as normal" after midnight) then it's Hunt and Hess III and now mortality is 50%
So very subtle variations in presentation profile and more importantly assessment can have significant repercussions
Risk of rebleed is approximately 5% in the first 24 hours so reasonable risk of a rebleed while waiting for the scan alone
Irrespective of CT scan result i think one has to reverse the warfarin as if scan normal a subarachnoid haemorrhage is presumed
So vitamin K + octaplex before the CT scan as i assume the warfarin would have been a short term course and no ongoing need for same
In terms of what to do post "normal" CT scan i guess MR angiogram early to look for an aneurysmal source
If no aneurysm then risk of rebleed becomes that of the general population
Adrian Moughty
SpR in Emergency Medicine
