This isn't a comprehensive article on IIH, nor is it an efficient outline of the critical information for the boards, life, or pimping. It's just a list of 5 things that took me somewhat by surprise, that I had never learned, or that I swear I had learned as the opposite.
1. "Transient visual obscurations" - The predominant visual disturbance isn't a nice, clean visual field cut. Instead, over 70% of patients have really brief episodes (< 1 minute) of loss of acuity, provoked by standing, sitting, light, Valsalva, or extra-ocular movements. Yeah, you'll get field loss on perimetry, but the TVOs are what patients will actually complain of.
2. Sparkles - They can also get flashes, or photopsias, as well as the TVOs.They are described as "white or less commonly coloured small flashes, flickering lights, stars twinkling, or flashes in the periphery of the visual field
3. Patients with IIH also report an odd kind of noise inside their heads. It's termed "pulsatile tinnitus," but it only infrequently seems to be a high-pitched tone. More often, it's described as '"a rushing river', a waterfall or a buzzing, whistling or blowing sound."
4. You get imaging to r/o something else, like a not-so-pseudo tumor or a sinus venous thrombosis. It's not used to diagnose IIH. However, one finding that would be consistent with IIH would be small ventricles or an empty sella, according to some.
5. Perhaps the imaging study that we should be using more often is our ultrasound. Up until this month, the world's literature for using ultrasound to detect papilledema was limited to this study by Michael Stone (Download). While the case provided an example of using an optic nerve sheath diameter of >5 mm to make a diagnosis of increased ICP, it also demonstrated sonographic papilledema.
|3mm posterior to the retina, check for OSD > 5 mm.|
Also note optic disc elevation.
|1880 Loring opthalmoscope. Not new.|
The authors compared EP-performed ultrasound exams of the optic disc with those of an neuro-ophthalmologist, as well as optical coherence tomography.
|Optic disc swelling as seen on OCT|
|Another example of an elevated optic disc (small arrow)|
So, the next time you have that odd headache patient, ask them about TVOs and photopsias, and put a probe on their eyes!