Idiopathic Intracranial Hypertension (AKA Pseudotumor Cerebri)

Define: Increased intracranial pressure without an identifiable structural pathology

Epidemiology: 90% – female, obese, child-bearing age

Risk Factors: Vitamin A toxicity, tetracycline antibiotics, isotretinoin, pregnancy, steroid use/withdrawal

Symptoms:   Headache (worse with Valsalva, bending over)
Nausea (30%)
Visual Loss (30-60%); Diplopia (30%)
Neck stiffness, tinnitus, ataxia, dizziness

Signs:  Papilledema (~100%) – can be subtle
6th Nerve Palsy (~10-20%) – “false localizing sign”

Diagnosis:
CSF opening pressure > 20 cm H20
Normal CSF composition (possible exception of low protein)
Signs / Symptoms of elevated ICP

Empty Sella (25-80%): can be seen in IIH – increased pressure causes the pituitary to compress and give the appearance of an empty sella.

Intracranial Imaging:
CT adequate for mass lesions  in acute setting
MRI/MRV preferred due to superior ability to rule out thrombosis

Lumbar Puncture:
ONLY AFTER RULING OUT INTRACRANIAL MASS    Measure opening pressure (lay patient on side), send normal studies

Treatment:

Goals with treatment:
1) Alleviation of symptoms
2) Preservation of vision

Weight Loss – recommended for all obese patients with IIH

Medications:
Carbonic Anhydrase Inhibitors – reduce the rate of CSF production (acetazolamide first line)
Loop diuretics – may be useful adjunctive therapy to acetazolamide

Serial Lumbar Punctures – not generally recommended given short term benefit and complication risk

Surgical Options: indicated only after patient’s fail medical therapy (<10% of patients)
CSF Shunt (VPS or LPS)
Optic Nerve Sheath Fenestration – incision in meninges surrounding optic nerve to relieve pressure