84 yo female with HA

[pbruss]

84 yo female with h/o htn, hld, copd, cad, presents with acute onset of worst HA of her life with. family reports confusion which is not normal for her. pt reports nausea, one episode of vomiting and feeling off balance. was doing fine before onset of HA. does not usually get headaches.

HR- 65, BP - 205/95, R- 20, T- 37, O2-95% on RA
AAOx3 complaining of mild HA, not toxic in apearance
ENT - normal, eyes normal, non tender supple neck
CV - normal
Lungs - normal
ABD - normal
Neuro - no focal deficits, ataxia in all 4 limbs (mild) and positive rhomberg.

Attahced is a non contrast CT of her head. HA started at 2 pm CT done at 7 pm.

Base on H/P and your interp of CT what is your next step in treatment?

A. CTA head and neck
B. LP
C. MRI head
D. STAT EEG

Attachments:

[Bjs04f]

MRI. Based on bp and posterior symptoms could be press.

[tyson]

basilar artery almost looks hyperdense. would fit with the symptoms of N/V/HA + ataxia & confusion. cta head and neck.

[pbruss]

try again.

stransky - visual disturbance, which she didi not have, would make me think more pf PRES ( posterior reversible encephalopathy syndrome) and the MRI findings with PRE do not usually show up for 48 hours. (see attached)

tyson - im glad your not a radiologist. the cross section of the CT is at the level of the midbrain based on the presence of the cerebral peduncles ( circled in ct attachment). this the basilar artery has already terminated.

Attachments:

PRES.pdf (780.22 KB)

[tyson]

gave it the old college try

can't put a price tag on being retarded.

thanks for red circles.

can you also circle what i should be seeing in that head CT?

thanks

[tyson]

so at this point, based on HX alone (radiology skills non withstanding), I would go ahead and LP, r/o SAH, would at least be reasonable next step.

[pbruss]

Bravo young lad. Ct is normal. History and physical very concerning for SAH but if you look at the time from onset to time of ct the sensitivity drops as there may nor of been enough time to show on ct.

I did the lp twice, first time looked bloody and figured traumatic tap so got new lp needle andv went one level higher but still looked jest as bloody. Elevated protein, elevated RBC and wbc, and showin
xanthomic color with no o micro biology

Which abnormality on lp is most concernenc?

[Bjs04f]

Interesting. I've been reading a few things about us going from ct/lp to ct/CTA as it is more sensitive and painless.

[pbruss]

once again, attach paper. I have read some of that as well and am interested to see the sensitivity and specificity in relation to time since onset of HA.

TEACHING POINTS:

1. for this case the issue was SAH not seen on CT. if you look at the history again the CT was done 5 hours after onset of headache. I can not find a clear cut time when SAH will show up on CT but have seen that less then 6-8 hours can miss some things which was the case here.

2. the MOST CONCERNING thing on her LP was NOT the blood but the XANTHOCROMIA. xanthocromia means that there has been blood sitting in the CSF for a while that has begun to be broken down and is the hallmark for SAH on LP. same as for CT the xanthochromia does not show up for at least 6-8 hours. for this case I read the H/P and the dictating doc painted a picture that I was an idiot and the blood was from traumatic tap. he would not listen when I told him I did not care about the blood but the xanthochromia. turns out she had angiography that showed small ruptured aneurysm.

3. ALWAYS keep in mind how long the CT was done after the onset of HA and that less the 6-8 hours may be falsely neg for SAH.

[kemple]

So even if the RBC don't drop from tubes 1-->4 they don't care? I get why xanthochromia is so sensative but I would think that much blood not dropping off combined with CSF would warrant admission and further workup.

[Bjs04f]

www.bmj.com/content/343/bmj.d4277
CT
scanners, it has been reported that the negative likelihood
ratio of a negative CT scan at < 12 h from onset of symptoms
is 0.02 (25). This means that with a pretest probability
of 5%, one would have to perform 1000 LPs to pick up
one SAH that was missed on CT. Based on estimated complication
rates from LP, this would lead to hundreds of
post-LP headaches, increasing morbidity and health care
costs.
So what I keep seeing is the opposite, CT in less than 12, and definitely less than 6 hrs are more sensitive and lose sensitivity after 12 hrs.

[pbruss]

well played. nice article there is just a few things.

1. in the methods they say "a local neuro-radiologist, or radiologist" was the one who read the CT scans. i would like to know how many scans were read by neuro-radiologists and how many by regular radiologists, which they don't say. how many of the CT's that you order are read by neuro-radiologists? every hospital I have ever worked at the CTs I order are read by a regular radiologist.

2. if you look figure 1 the number of patients enrolled was 3132. if you take away the 240 who were positive for SAH, you have 2883 patients who had Ct's that were negative for SAH in the ER in the setting of acute headache.  they completed follow up at 6 months with 1506 of those patients, that's only 52%.

this article does make me re-think my idea on possibility of false negative of CT for SAH with an acute HA. but i dont think there is enough for me to change my practice just yet.

thanks for the article stransky, i enjoyed it