With idiopathic intracranial hypertension (IIH)—sometimes called pseudotumor cerebri—on the rise, optometrists are bound to find themselves frequently on the frontlines of making this tricky diagnosis.1 As it’s a diagnosis of exclusion, patients will have to undergo a series of tests to rule out other etiologies that present with similar bilateral optic disc edema of unknown cause. Researchers exploring ways to narrow diagnostic capabilities may have come upon a technique that is highly specific to IIH (without papilledema), according to a newly published report in the Journal of Neuroophthalmology.2

The Boston-based research team confirmed updated diagnostic criteria proposals suggesting that a combination of any three of four magnetic resonance imaging (MRI) features can identify IIH when present in patients with chronic headache and no papilledema.2 They looked at the brain MRIs from 80 patients with IIH with papilledema, 33 patients with chronic headache and elevated opening pressure and 70 control patients with infrequent episodic migraine. They found that:

(1) reduced pituitary gland height was moderately sensitive for IIH with papilledema (80%) but had low specificity (64%).
(2) Increased optic nerve sheath diameter was less sensitive (51%) and only moderately specific (83%).
(3) Flattening of the posterior globe was highly specific (97%) but had low sensitivity (57%).
(4) Transverse venous sinus stenosis was moderately sensitive for IIH with papilledema (78%), but of undetermined specificity.

Of patients with chronic headache and elevated opening pressure, 30% had three or more of these MRI features, suggesting IIH without papilledema in those patients. The researchers explained that a combination of any three of these four MRI features was nearly 100% specific, with a sensitivity of 64%. 

1. Wakerley B, Tan M, Ting Y. Idiopathic intracranial hypertension. Cephalalgia. 2015;35(3):248-61.

2. Mallery R, Rehmani O, Woo J, et al. Utility of magnetic resonance imaging features for improving the diagnosis of idiopathic intracranial hypertension without papilledema. J. Neuroophthalmol. February 26, 2019. [Epub ahead of print].