Definition - raised intracranial pressure and papilledema without evidence of any mass lesion, hydrocephalus, infection, or hypertensive encephalopathy (Dx of exclusion)
Etiology
unknown (majority), but associated with:
lateral venous sinus thrombosis
habitus/diet: obesity, hyper/hypovitaminosis A
endocrine: reproductive age, menstrual irregularities, Addison's/Cushing's disease, thyroid irregularities
hematological: iron deficiency anemia, polycythemia vera
drugs: steroid administration or withdrawal, tetracycline, nalidixic acid, etc.
risk factors overlap with those of venous sinus thrombosis; similar to those for gallstones ("fat, ♀, fertile, forties")
Epidemiology
incidence ~0.5/100,000 per year
usually in 3rd and 4th decade (♀>♂)
Clinical Features
symptoms and signs of raised ICP (H/A in >90%, pulsatile intracranial noise), but no LOC or diplopia
decreased visual acuity, papilledema, visual field defect, optic atrophy (key morbidity)
usually self-limited, recurrence is common, chronic in some patients
risk of blindness is not reliably correlated to symptoms or clinical course
Investigations
CT, CSF studies: normal
MRI: ✓for venous sinus thrombosis
Treatment
rule out conditions that cause intracranial hypertension (especially sinus thrombosis)
discontinue offending medications, encourage weight loss, fluid/salt restriction
pharmacotherapy: acetazolamide (decreases CSF production), thiazide diuretic or furosemide
if above fail: serial LPs, shunt
optic nerve sheath decompression (if progressive impairment of visual acuity)
2-yr follow-up with imaging to rule out occult tumour, ophthalmology follow-up