Morning, some good neuro critical care action at the VA this week, thought we’d cover something today not yet covered on the blog: non-invasive estimations of elevated ICP, namely fundoscopy and ocular ultrasound
Dan Reiss correctly pointed out the acute finding in elevated ICP on an ocular ultrasound is the optic nerve sheath diameter, a handful of smaller studies (n in each about 40-60) have evaluated the correlation between nerve sheath diameter and MRI/CT findings of elevated CT, Sensitivity and Specificy depends on the cutoff chosen, in adults typically a ONSD of >4.5mm is considered too high, which yields a sens and spec of around 70-80% for the detection of elevated ICP. The challenge here, as with fundoscopy, is inter-observer variability presumably due to operator characteristics. Here is a review paper on non-invasive determination of ICP.
Other quick pearls
#generally opt for beta blockers and ccb in the acute treatment of hypertensive emergency due to the theoretical concern for cerebral vasodilation with nitro/hydral, nicardipine and esmolol are good options
#PRES, covered elswhere, stands for posterior reversible encephalopathy syndrome, though not always posterior or reversible. Remember, MRI is the diagnostic test for PRES.