Idiopathic Intracranial Hypertension

KEY FACTS

Empty or partially empty sella
Posterior globe flattening
Intraocular protrusion of optic nerve head
Optic nerve sheath enlargement: Widened ring of cerebrospinal fluid around optic nerve
Optic nerve tortuosity
Slit-like ventricles, rare: Poor neuroimaging sign of IIH
MRV: Often shows transverse sinus stenosis and “flow gaps”
- Whether this is cause or consequence of raised ICP is controversial
Best imaging tool: MR brain + T2 coronal fat-sat orbit + MRV

Secondary pseudotumor syndromes
- Cerebral venous thrombosis, dural sinus stenosis
Idiopathic or postinflammatory (i.e., multiple sclerosis) optic nerve atrophy
Idiopathic empty sella (normal variant)

Obese woman age 20-44 years most common
- Headache in 90-95%
- Papilledema (bilateral optic nerve head swelling) virtually universal
Progressive visual loss ± CN6 paresis, diplopia
Chief hazard: Vision loss from chronic papilledema
Treatment: Medical or surgical (lLP and VP shunt, optic nerve sheath fenestration)

Funduscopy in a patient with IIH, severe papilledema shows swelling/blurred margins of the optic disc

, striking venous engorgement

, and focal hemorrhages

adjacent to the disc.

Axial T2WI MR shows dilated CSF spaces around the optic nerves

and protrusion of the optic nerve papilla into the posterior globes

. Opening CSF pressure in this 32-year-old woman was 45 cm of H₂O. Prominent CSF space in the suprasellar cistern represents an empty sella

. Note the tortuosity of the left optic nerve

Axial T1WI C+ MR in the same patient demonstrates enhancement, as well as protrusion of prelaminar optic nerves bilaterally

. Mild diffuse optic nerve sheath enhancement

is also present.

↑ intracranial pressure (ICP) without identifiable cause
Association of any medication or condition with IIH better termed “secondary pseudotumor syndrome”

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