Idiopathic Intracranial Hypertension

Question 1

what is another name for idiopathic intracranial HTN

Answer 1

pseudotumor cerebri

Question 2

what is IIH

Answer 2

defined by clinical criteria that include signs/symptoms isolated to those produced by increased ICP, elevated ICP with normal CSF composition, and no other causes of ICH evident on neuroimaging

Question 3

is IIH benign

Answer 3

No - many people suffer from intractable, disabling headaches and have a risk of severe permanent visual loss

Question 4

what is the epidemiology of IIH

Answer 4

higher in obese women of childbearing years

Question 5

what medications is IIH associated with

Answer 5

growth hormone, tetracyclines, hypervitaminosis A

Question 6

what illnesses are associated with IIH

Answer 6

Addison’s, hyperparathyroidism, severe anemia, sleep apnea, SLE, Behcet’s syndrome, PCOS, coagulation disorders, uremia, hypervitaminosis A

Question 7

what is the pathogenesis of IIH

Answer 7

proposed etiologies:

• cerebral venous outflow abnormalities [venous stenosis, venous HTN]
• increased CSF outflow resistance at either the level of arachnoid granulations or CSF lymphatic drainage sites
• obesity-related increased abdominal and intracranial venous pressure
• altered sodium and water retention mechanisms
• abnormalities of vitamin A metabolism

Question 8

what is the clinical presentation of IIH

Answer 8

typically an obese woman of childbearing years who complains of headaches and is found to have papilledema on exam

Question 9

what are the symptoms of IIH

Answer 9

headache
bilateral or unilateral visual symptoms, photopsias
intracranial noise (pulsatile tinnitus)
- hearing of rushing water/wind, vascular pulsations transmitted by CSF under high pressure to the venous sinuses
diplopia
- intermittent or continuous horizontal diplopia
- unilateral or bilateral with abducens palsy or divergence insufficiency

Question 10

what is seen on examination in IIH

Answer 10

papilledema [hallmark]
- typically bilateral and symmetric
- more severe = higher risk of permanent vision loss
HAs and elevated opening pressure
gradual visual loss (visual field before acuity; abnormal confrontation)
abducens palsy (nonlocalizing effect of IIH)

Question 11

what are the neurologic signs of IIH

Answer 11

do not usually have overt cognitive deficits

Question 12

what is included in evaluation of IIH

Answer 12

suspected in a patient with papilledema and HA

• urgent neuroimaging to rule out secondary causes of ICH
• increased opening pressure on LP (>250)
• measure systemic BP to rule out optic neuropathy related to malignant HTN

Question 13

how is IIH diagnosed

Answer 13

Dandy Criteria

• symptoms and signs of increased ICP
• no other neurologic abnormalities or impaired level of consciousness
• elevated ICP with normal CSF composition
• neuroimaging study with no etiology for ICH
• no other acute cause of ICH apparent

Question 14

what is on the differential for IIH

Answer 14

secondary intracranial hypertension = any entity that increases ICP may lead to papilledema
- intracranial mass lesion (tumor, abscess)
- obstruction of venous outflow
- obstructive hydrocephalus
- decreased CSF granulations
- increased CSF production
- malignant systemic hypertension
optic disc abnormalities
- elevated optic nerve head

Question 15

what are the goals in treatment of IIH

Answer 15

alleviation of symptoms and preservation of vision

Question 16

what are the treatments for IIH

Answer 16

weight loss (low sodium weight reduction program)
medications
- carbonic anhydrase inhibitors = reduce rate of CSF production [acetazolamide; topiramate]
- loop diuretics [furosemide]
- avoid corticosteroids [weight gain, withdrawal, side effects]
- indomethacin [secondary ICH]
- iron [for iron-def anemia]
- HA prophylaxis
serial LPs not recommended
- CSF reforms within 6hrs unless leak, uncomfortable, complications, technically difficult in obese patients

Question 17

what are the surgical treatments for IIH

Answer 17

optic nerve sheath fenestrations
- stabilize or improve visual loss due to papilledema in IIH
- primary goal = preservation of vision
- complications = temporary diplopia, pupillary dysfunction, vision loss
shunting
venous sinus stenting

Question 18

what are the indications for surgical treatment in IIH

Answer 18

worsening visual field defect despite medical therapy
presence of visual acuity loss attributed to papilledema
intractable headache
anticipated hypotension (BP treatment, hemodialysis)
patients unable to participate in follow-up examinations (noncompliance, impaired cognition, itinerant lifestyle)