2. • Idiopathic intracranial hypertension (IIH) is a disorder
characterized by increased intracranial pressure (ICP)
of unknown cause, predominantly seen in women of
childbearing age and associated with a history of
recent weight gain .
3. terminology
• The first report of IIH was by the German physician Heinrich Quincke, who
described it in 1893 under the name serous meningitis.
• The concept of raised intracranial pressure in the absence of a space
occupying lesion was first introduced by Max Nonne as ‘pseudotumour
cerebri’ (PTC) in 1904. ,
• the term otitic hydrocephalus reported by London neurologist Sir Charles
Symonds(1931) may have resulted from venous sinus thrombosis caused
by otitis media .
• Later the term ‘benign intracranial hypertension’ became popular and was
often used interchangeably with PTC.
• The condition was considered ‘benign’ in comparison with cases of
tumour but it has been argued that loss of visual function in up to 25% of
cases and progression to blindness if untreated means that it should not
be considered ‘benign’. Hence the term IIH is now generally used.
5. Incidence
• Annual incidence figures for the Mayo Clinic (Rochester, MN) between
1976 and 1990 were as follows:
• 0.9 case per 100,000 population
• 1.6 cases per 100,000 women
• 3.3 cases per 100,000 females aged 15-44 years
• 7.9 cases per 100,000 obese women aged 15-44 years
6. Etiology
• Most cases of IIH occur in young women who are obese; a considerably
smaller percentage occur in men who are otherwise healthy.
Patients with higher body mass indexes (BMIs) and recent weight gain are
at increased risk.
• If IIH presents in an individual who is not overweight, it is necessary to
rule out associated risk factors, such as the following :
• Exposure to or withdrawal from certain exogenous substances (eg, drugs)
• Systemic diseases (including Lyme disease)
• Disruption of cerebral venous flow
• Certain endocrine or metabolic disorders
8. Systemic diseases
A myriad of illnesses are associated with IIH. Some of these disorders are known to
result in increased viscosity of the CSF. In most however, the causal link with is not
clear :
• Anemia
• Chronic respiratory insufficiency/OSA
• Familial Mediterranean fever
• Hypertension
• Multiple sclerosis
• Psittacosis
• Chronic renal disease
• Reye syndrome
• Sarcoidosis
• Systemic lupus erythematosus
• Thrombocytopenic purpura
9. Endocrine risk factors
Endocrine risk factors that have been confirmed in epidemiologic studies include
the following:
• Female sex
• Reproductive age group
• Menstrual irregularity
• Obesity
• Recent weight gain
Endocrine risk factors that meet minimal criteria but have not been confirmed in
case-controlled studies include the following:
• Adrenal insufficiency
• Cushing disease
• Hypoparathyroidism
• Hypothyroidism
• Excessive thyroxine replacement in children
• Pregnancy is occasionally associated with IIH. The disorder can present at any
stage of pregnancy.
10. Criteria for including a drug or a disease as
a cause of IIH:
• Radhakrishnan et al..
– At least 2 cases should have been described
– The reported cases should have met all the criteria for the
diagnosis of IIH.
– Intracranial dural sinus thrombosis should have been ruled
out with reasonable certainty
Radhakrishnan K, Ahlskog JE, Garrity JA, Kurland LT. Idiopathic intracranial
hypertension. Mayo Clin Proc. Feb 1994;69(2):169-80
11. Pathophysiology
• The pathophysiology of IIH is unclear. Various theories have been proposed.
• Dural venous sinus stenosis and compression
A ‘self-sustained venous collapse’ is proposed as a crucial causative mechanism in
predisposed patients, leading to intracranial hypertension in the presence of a
wide range of triggering factors. The proposed mechanisms predict the long-term
remission of IIH syndromes frequently observed after a single or few serial CSF
subtractions by lumbar puncture .
Controversy remains as to whether venous sinus stenosis is consequent upon or is
causative of the raised ICP.
12. • Sinus venous stenoses have been
found at magnetic resonance
venography (MRV) in the large
majority of IIH patients in some
studies.
• .Jugular valve insufficiency was found
to be significantly more frequent in
patients with IIH (70% as opposed to
30% in a control group) and may
facilitate pressure transmission from
increased intra-abdominal pressure
in obesity into the intracranial venous
system.
13. • Increased arterial inflow: Bateman showed that
some IIH patients with normal dural venous
drainage have increased arterial inflow, which
suggests that collateral venous drainage occurs
in addition to the drainage provided by the
superior sagittal sinus and transverse sinuses.
• Bateman also used MR venography and MR flow
quantification in cerebral arteries and veins in 40
IIH patients, 21 of whom had venous stenosis;
arterial inflow was 21% higher than normal, and
superior sagittal sinus outflow was normal,
resulting in a reduced percentage of venous
outflow as compared with inflow.
Bateman GA. Association between arterial inflow and venous outflow in idiopathic and
secondary intracranial hypertension. J Clin Neurosci. Jun 2006;13(5):550-6; discussion 557.
14. IIH and Obesity
• IIH commonly occurs in women who are overweight; however, the role
obesity plays in this disorder is unclear. In some instances, obesity and IIH
may be familial.
• It has been proposed that obesity increases intra-abdominal pressure and
thereby raises cardiac filling pressures. These rises in pressure lead to
impeded venous return from the brain (due to the valveless venous
system that exists from the brain to the heart) with a subsequent
elevation in intracranial venous pressure.
• Waist-to-hip ratio (WHR) is a descriptive measure of body fat distribution
approximately reflecting upper to lower body fat ratio. In a study of IIH
patients compared with two obese control groups, WHR was 0.79 in IIH
versus 0.84 and 0.91 in the controls. The authors concluded that in IIH, fat
tends to preferentially accumulate in the lower body .
15. Signs and symptoms
• Symptoms of elevated intracranial pressure (ICP)
• Headaches are recorded in almost all IIH patients. They are typically
nonspecific and vary in type, location, and frequency. The pain is generally
described as being diffuse, worsening in the morning and being
exacerbated by the Valsalva maneuver.
• Patients who present with double vision most frequently complain of
horizontal displacement of the images. Horizontal diplopia is a symptom
of a false-localizing CN VI palsy. Vertical diplopia is rare, but it has been
reported.
• Pulsatile tinnitus may be reported. This is a rhythmic sound, heard in one
or both ears, with a pulsing synchronous rhythm that may be exacerbated
by the supine or bending position.
• Radicular pain (usually in the arms) is an uncommon symptom.
16. Symptoms of papilledema
• Transient visual obscurations occur in most patients. The disturbance can last up
to 30 seconds and is described as a dimming or blackout of vision in one or both of
the eyes. These obscurations may be predominantly or uniformly orthostatic (ie,
developing with standing up or bending over).
• Progressive loss of peripheral vision in one or both of the eyes may be noted.
Typically, the vision loss starts in the nasal inferior quadrant and is followed by loss
of peripheral & later central visual field (possibly affecting visual acuity) and,
finally, loss of color vision.
• Blurring and distortion (ie, metamorphopsia) of central vision is caused by macular
wrinkling and subretinal fluid spreading from the swollen optic disc.
• Sudden visual loss is due to intraocular hemorrhage secondary to peripapillary
subretinal neovascularization related to chronic papilledema.
• In a study among 353 patients studied, the prevalence of those without
papilloedema was 5.7% .
17. Physical Examination
• The most significant physical finding in patients with IIH is bilateral disc edema
secondary to the increased ICP.
• This papilledema varies from patient to patient and is indistinguishable from optic
nerve swelling caused by intracranial space-occupying lesions.
• If left untreated, chronic disc swelling eventually leads to clinically significant visual
loss.
• Peripapillary flame hemorrhages, venous engorgement, and hard exudates are
features consistent with acute papilledema.
• Telangiectatic vessels on the disc surface and optic disc pallor are associated with
chronic papilledema.
18. Pathophysiology of papilledema
• The disc swelling in papilledema is the result of axoplasmic flow stasis with intra-axonal
edema in the area of the optic disc. The subarachnoid space of the brain is
continuous with the optic nerve sheath.
Hence, as the cerebrospinal fluid (CSF) pressure increases, the pressure is
transmitted to the optic nerve, and the optic nerve sheath acts as a tourniquet to
impede axoplasmic transport. This leads to a buildup of material at the level of the
lamina cribrosa, resulting in the characteristic swelling of the nerve head.
25. Grade V Papilledema
Criteria of Grade IV +
partial or total
obscuration of all
vessels on the disc
26. Duration & papilledema
• Early manifestations
– Disc hyperemia
– obscured fine peripapillary vessels.
– Small hemorrhages
– Spontaneous venous pulsations lost.
• Late manifestations
– obscured normal disc margins & disc becomes grossly elevated.
– Venous congestion develops, and peripapillary hemorrhages become more
obvious, along with exudates and cotton-wool spots.
– The peripapillary sensory retina may develop concentric or radial folds known
as Paton lines.
• Chronic manifestations
– If the papilledema persists for months, the disc hyperemia slowly subsides,
giving way to a gray or pale disc that loses its central cup.
– With time, the disc may develop small glistening crystalline deposits (disc
pseudodrusen).
27. Evaluation of vision
• The most common visual finding in IIH is enlargement of blind spot.
• The first sign of incipient post papilledema optic atrophy is
constriction of the inferior nasal quadrant of the visual field with a
border reflecting the nasal horizontal midline (nasal step).
• colour testing is not sensitive in picking up early postpapilledema
optic atrophy, because color perception is concentrated in the
central visual field.
• Diplopia testing may be used to detect even a low-grade CN VI
paresis.
28.
29.
30. Visual field defects in idiopathic intracranial hypertension. (a) Enlarged
blind spot. (b) Nasal step. (c) Biarcuate scotoma. (d) Severe visual field
constriction [Humphrey gray scale]
31. complications
• The only severe and permanent complication of IIH is progressive
blindness from postpapilledema optic atrophy. As optic nerve axons die,
the apparent degree of papilledema may diminish, giving a false sense of
improvement. For this reason the patients must be monitored with
frequent visual field examinations.
34. Work up
• Recommended blood tests include the following:
• Complete blood count
• Erythrocyte sedimentation rate
• Serum iron and iron-binding capacity
• Antinuclear antigen (ANA) profile (eg, anti-dsDNA and anti-ssDNA)
• Full procoagulant profile (in patients with a previous history of thrombosis or MRI
evidence of dural venous sinus occlusion on MRI)
• Lyme screening test in patients who have a history of exposure to Lyme in areas of
endemic disease
35. • Cerebrospinal fluid studies include the following:
• Opening pressure
• White blood cell and differential counts
• Red blood cell count
• Total protein
• Quantitative protein electrophoresis
• Glucose
• Aerobic bacterial culture and sensitivity
• Acid-fast bacilli culture
• xanthochromia
• Syphilis markers (eg, rapid plasma reagin [RPR])
• Tumor markers and cytology (in patients with a history of cancer or with
clinical features suggesting occult malignancy)
36. Imaging
• MRI of the brain with gadolinium enhancement is probably the study of
choice for all patients with IIH.
• MR venography is now increasingly accepted as a routine study for all
patients with IIH.
• In a retrospective study of imaging features that have been suggested as
typical for patients with IIH, only flattening of the posterior globe was
found to be a reliable indicator of IIH, with a specificity of 100% and a
sensitivity of 43.5%.
41. Treatment Approach
• The treatment goal for patients with idiopathic intracranial hypertension (IIH) is to
preserve optic nerve function while managing increased intracranial pressure
(ICP).
• Optic nerve function should be carefully monitored with an assessment of visual
acuity, color vision, optic nerve head appearance, and perimetry.
• Weight control is recommended for obese patients.
• Exogenous agents related to increased ICP should be discontinued.
• Patients without visual loss most often are treated with a carbonic anhydrase
inhibitor (eg, acetazolamide) to lower the ICP.
• In patients with severe symptoms, early visual field loss, or poor response to
standard medical therapy, some clinicians utilize a short course of high-dose
corticosteroids .
• When new visual field loss is documented, medical management should be
coupled with plans for emergency surgical intervention if the visual function
continues to deteriorate .
42. Pharmacological
• Acetazolamide appears to be the most effective agent for lowering ICP.
Most patients experience adequate relief of symptoms (typically,
headache) with this first-line agent.
Most patients respond to a dosage of 1-2 g/day. In the event of
intolerance to acetazolamide, furosemide may be used.
• In a new study of 165 patients with IIH and mild vision loss, researchers
found that acetazolamide treatment for six months in conjunction with a
low-sodium weight-reduction diet modestly improved vision, reduced
intracranial pressure, improved quality of life, and reduced papilledema.
Data show that the effect of the drug was independent of weight loss.
• {Wall M, McDermott MP, Kieburtz KD, Corbett JJ, Feldon SE, Friedman DI, et al. Effect of
acetazolamide on visual function in patients with idiopathic intracranial hypertension and
mild visual loss: the idiopathic intracranial hypertension treatment trial. JAMA. Apr 23-30
2014;311(16):1641-51.}
43. • Headache prophylaxis
For patients with stable visual function but inadequate headache relief
with first-line pressure-lowering drugs, primary headache prophylaxis
should be considered.
amitriptyline, propranolol, or other commonly prescribed migraine
prophylaxis agents are used.
• Corticosteroids are effective in lowering ICP in patients whose IIH has an
inflammatory etiology. In addition, they may be used as a supplement to
acetazolamide to hasten recovery in patients who present with severe
papilledema. Patients experiencing a progressive loss of visual field in one
or both of the eyes should immediately be placed on high-dose (60-100
mg/day) oral prednisone or an equivalent
44. • Topiramate is also an excellent choice, in that one of its side effects is
weight loss , which can help put the disease in remission.
• A study of 44 pts assessed the efficacy of topiramate in the treatment of idiopathic
intracranial hypertension (IIH) and to compare it with acetazolamide.
When the follow-up visual field grades were compared with the visual field grades
at the beginning of the study in each group a statistically significant improvement
was detected with both drugs. When the results of the two treatment groups were
compared with each other no statistically significant difference was present.
Prominent weight loss was recorded in the topiramate group.
Acta Neurol Scand. 2007 Nov;116(5):322-7.
Treatment of idiopathic intracranial hypertension: topiramate vs acetazolamide, an open-label
study.
45. Surgical management of IIH
IInnddiiccaattiioonnss ffoorr SSuurrggeerryy
• New worsening visual field defect
• Reduction in visual acuity
• Presence of severe visual loss
(6/36 or worse) in one/ both eyes
• Headache unresponsive to
medication
SSuurrggiiccaall OOppttiioonnss
• Optic nerve sheath fenestration
• Lumboperitoneal shunt
• Ventriculoperitoneal shunt
• Dural venous sinus stenting
• Bariatric surgery
46. • Optic nerve sheath fenestration
• The ophthalmic surgical approach to managing patients with progressive vision
loss and papilledema involves cutting slits or rectangular patches in the dura
surrounding the optic nerve immediately behind the globe. This allows direct
egress of CSF into the orbital fat, where it is absorbed into the venous circulation.
47. • CSF diversion procedures
• CSF diversion procedures are highly effective in lowering ICP. In some facilities,
they remain the procedures of choice for treating IIH patients. Lumboperitoneal
shunting is the traditional method . However, this procedure has a high 1-year
failure rate. Some neurosurgeons currently prefer ventriculoperitoneal or
ventriculoatrial shunting to lumboperitoneal shunting.
• Intracranial venous sinus stenting
• In patients with IIH with focal venous sinus stenosis, endovascular stent
placement across the stenotic sinus region represents an effective treatment
strategy with a high technical success rate and decreased rate of complications
compared with other treatment modalities .
48. Bariatric surgery
• A review of the literature examining the use of bariatri surgery in IIH was
published, reporting on a total of 62 patients. The Roux-en-Y gastric bypass was
the most common bariatric procedure performed. Over 90% had resolution of
their IIH symptoms, and 97% of those with papilloedema were found to have
resolution. The average postoperative ICP decrease was 25 cmH2O. Prospective,
controlled studies are necessary .
[Fridley J, Foroozan R, Sherman V, Brandt ML, Yoshor D. Bariatric surgery for the
treatment of idiopathic intracranial hypertension. J Neurosurg. Jan 2011;114(1)]
49. • A meta-analysis comparing visual outcomes after these interventions
reported the following findings[5] :
• 252 optic nerve sheath decompressions: Visual defects improved or
resolved in 80%
• 31 VP shunt placements: Visual defects improved or resolved in 38.7%
• 44 LP shunt placements: Visual defects improved or resolved in 44.6%
• 17 intracranial venous sinus stent placements: Visual defects improved or
resolved in 47%
Feldon SE. Visual outcomes comparing surgical techniques for management of
severe idiopathic intracranial hypertension. Neurosurg Focus. 2007
51. COURSE & Monitoring
• The appearance of papilledema can be deceptive. The swelling may
decrease among patients with papilledema due to progressive optic
atrophy. Therefore, it is difficult to interpret the appearance of the optic
disc in cases of chronic papilledema; optic nerve function is most
important.
• Testing of the visual fields with finger confrontation is notoriously
insensitive. The best method is automated perimetry(Humphrey
perimetry),
• All patients with a suspected diagnosis of IIH should undergo regular
testing of the visual fields with quantitative perimetry.