Fact-sheet: Idiopathic intracranial hypertension
Updated on 04/18/2018 at 3:50 PM
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Definition
Syndrome combining:
- isolated intracranial hypertension without intracranial lesion.
- elevated cerebrospinal fluid pressure with normal composition.
- indirect neuroradiological signs.
Typical context:
- young woman (20-40 years)
- overweight
Clinical features
Signs of isolated intracranial hypertension (headache, nausea/vomiting, etc.) or papilledema.
No focal neurological deficit other than sixth nerve palsy (in the setting of intracranial hypertension).
Documented elevated CSF opening pressure, measured during lumbar puncture in the lateral decubitus position:
- > 25 cm H2O in an adult
- > 28 cm in a child
- normal CSF composition.
No other cause of intracranial hypertension identified (metabolic, toxic, or hormonal).
The most common sign of idiopathic intracranial hypertension is bilateral papilledema, sometimes asymmetric or unilateral.
Visual disturbances (diplopia, transient visual obscurations or decreased visual acuity, visual field defects).
Occasionally: tinnitus, dizziness.
CT
The same abnormalities can be observed as on MRI:
- empty sella appearance
- tortuous optic nerves
- enlargement of the perioptic subarachnoid spaces
- small ventricles
- mild cerebellar tonsillar descent
- no intracranial mass lesion
MRI
No hydrocephalus, mass, or structural or vascular lesion to account for the intracranial hypertension.
Friedman criteria:
- brain MRI (or brain CT with CT venography if MRI unavailable) for all patients
- venous MRA in addition for atypical cases: men, normal-weight women, prepubertal children, or age over 44 years.
Protocol:
Diffusion, axial T2 FLAIR, T2*, T1, 2 mm axial or coronal T2 TSE slices centered on the orbits.
After injection: cerebral venous MR angiography, axial or coronal T1 fat-sat slices centered on the orbits, and axial (or 3D) T1 sequences.
Semiology:
- empty or partially empty sella appearance.
- tortuous optic nerves with enlargement of the perioptic subarachnoid spaces.
- bulging of the optic discs associated with flattening of the posterior globe (papilledema).
- Occasionally: T2 hyperintensity of the optic nerves, small ventricles, mild cerebellar tonsillar descent.
Search for dural venous sinus stenosis on venous MRA.
Management
- weight loss
- therapeutic lumbar puncture
- carbonic anhydrase inhibitors
- venous stent placement (controversial)