Idiopathic Intracranial Hypertension - Dr James Beatty

1. Idiopathic Intracranial
Hypertension
By J Beatty

2. Introduction
 Common cause of disc swelling.
 Most common cause of papillodema.
 NB because papilloedema can = mass lesion.
 NB because IIH can lead to significant visual
loss.

3. Modified Dandy Criteria
 Signs and symptoms of raised intracranial
pressure
 Normal neuro exam, except 6th
nerve palsy
 Elevated CSF pressure with normal
constituents
 Normal neuroimaging

4. Demographics and General Info
 Typical = early adult, women, overweight or
recent weight gain.
 Cause and mechanism unclear (? decreased
CSF absorption from dysfunctional arachnoid
villi). Numerous other postulations.

5. Clinical Presentation
 Headache.
– 90% of patients (most common).
– 60% pulsatile intracranial noise.
 Visual symptoms.
– Transient visual obscurations (TVOs), 72%.
– Blurred vision.
– Enlarged blind spot or other visual field loss.
– Diplopia.

6. Associated Conditions
 Before examination, think!?
 Very long list of conditions to consider in the
differential diagnosis.
 Need to exclude cranial venous conditions,
mass lesions and specific known causes of
elevated intracranial pressure.

7.  Venous thrombosis or obstruction.
– Pseudotumor like appearance, difficult to exclude.
– Cerebral dural venous sinus thrombosis > increased
venous pressure >decreased CSF absorbtion.
– Seriously effected patients develop cortical vein
thrombosis and cerebral infarction.
– Also thrombosis of transverse and sigmoid sinus.
– Cause of clot formation:

8.  Dural Arteriovenous malformations
 Apnea

9. Neuro-ophthalmic Examination
– Insidious visual or field loss.
– Sever loss (chronic papilloedema, RD, Hx, macular
exudate).
– Peripheral field defects, enlarged blind spot.
– Colour and pupil normal.
– 50% abnormal contrast sensitivity.
– 6th
nerve palsy.

10.  Papilloedema
– Usually bilatereal
– Pantons lines
– Vascular changes (2nd
to compression)
– Loss of spontaneous venous pulsation
– Acute vs chronic

11.  Pseudopapilloedema
– Congenital, harmatoma, mylinated nerve fibers,
drusen
– Serial examinations
– Optic disc drusen
 Defect in axonal metabolism
 1-2% of population, often bilat, inherited
 Examination, u/s, CT
– Other causes

12. Diagnostic Evaluation
 MRI better than CT
– Empty sella, dilation optic nerve sheath, flat post
globe, elevation of optic disc, slit like ventricles
 LP
– >25mm H20

13. Management
 No visual loss
– Weight reduction
– Acetazolamide (500-2000 mg/day)
 Mild to moderate visual loss
– Acetazolamide (up to 2-3 gms/day)
– Or furosemide (40-80mg daily)
– Weight reduction

14.  Sever or progressive visual loss.
– Optic nerve sheath fenestration.
– High-dose IV steroids and acetazolamide.
– Lumboperitoneal shunt for failed ONSF or
intractable headache.

15. Outcome
 Mild and moderate do well
 Sever can have decreased vision and field
defects. Devestating 5%