IIH is a disorder characterized by elevation of the ICP without evidences of CSF cytochemical alterations, dilated ventricles or mass lesions ◘ The annual incidence of IIH is increasing in association with higher obesity rates, whereas recent scientific studies indicate a possible role for androgen sex hormones and adipose tissue in the pathogenesis of the disease

4. ◘ NMS is a 31-years old female with history of IIH 4-years ago.
◘ She is presented recently by subacute holocranial headache,
mild tinnitus and progressive visual deterioration after
gaining weight rapidly in the previous few months.
◘ She sought ophthalmological advice and her fundus has
Grade-I papilledema.
◘ CSF manometry, visual field, ON head OCT and ONSD were
ordered.
◘ CSF pressure was 480 mm H2O, ONSDs were 8.59 and 8.44,
mean deviation of visual fields were – 8.34 and – 8.79 dL
OS and OD respectively.
◘ ON head OCT showed within normal RNFL thickness.

5. ◘ IIH is a disorder characterized by elevation of the ICP
without evidences of CSF cytochemical alterations,
dilated ventricles or mass lesions.
◘ The annual incidence of IIH is increasing in association
with higher obesity rates, whereas recent scientific
studies indicate a possible role for androgen sex
hormones and adipose tissue in the pathogenesis of
the disease.

6. ◘ As a consequence of increasing obesity, the IIH incidence
has been doubled between 1988 and 2017 epidemiological
studies.
◘ IIH incidence is 2.4 per 100,000 general population, with
female / male ration 10: 1 (0.3 versus 3.3 per 100 000).
◘ The incidence reach up to 22 per 100 000 in obese women
during the childbearing period in (especially with rapid
weight gain).
◘ IIH incidence is 0.7 per 100 000 in pediatric population < 16
years, increasing to 4.2 and 10.7 per 10 000 in obese male
and female respectively between 12 – 15 years.

7. (1) IIH is a diagnosis of exclusion, the etiology is unknown
and the raised ICP is a consequence rather the entire
pathology.
(2) The course varies from accidently discovered to
fulminant cases with severe visual impairment within
few days.
(3) The prognosis span from complete resolution to total
blindness.
(4) How many cases had followed regularly > 1-year after
resolution of papilledema.

8. ◘ IIH, open-angle glaucoma and Meniere’s disease are
collectively considered fluid tension disorders where
symptoms develop due to fluid hypertension within
relatively closed chambers.
◘ The fluid is secreted by a vascular structure and drained
passively to the venous system.
◘ So, these diseases are not simply number measure but
pathogenesis is more complex where leaky aquaporins
induced by autoimmune processes or microbial
infection may be implicated

9. ◘ The concept of skull trephining to treat headache is
present since Ancient Egyptian.
◘ In 1806 Tenon described the continuity of the dura with
the ON sheath.
◘ In 1853, Türck and Coccius had independently described
ON in cases of raised ICP secondary to intracranial SOL
◘ Heinrich Quincke was the first to report IIH in 1893 and
termed it meningitis serosa.
◘ The disorder was termed pseudotumor cerebri and benign
intracranial hypertension.

10. ◘ NocturnalrhythmicpulsatileCSFwavesflowoverthebrainswhilesnoozingclearingout anytoxinsorwasteproduct.
◘ DisturbedCSFflowmaybe incriminatedin abnormalbraindepositsas β-amyloidinAD.

11. ◘ Blockage of CSF absorption at the level of the
arachnoid villi, perhaps as a consequence of or
exacerbated by cerebral venous hypertension
secondary to transverse venous sinus stenosis.
◘ Given the increased incidence in women and
strong association with obesity, sex hormones
(e.g., androgens) and adipose tissue may play a
role
◘ Abdominal obesity and consecutive increased
intraabdominal pressure may be transmitted to
the veins.

13. ◘ IIH may be asymptomatic and discovered accidently during routine
ophthalmological examination.
◘ Headache is the presenting symptom in > 85% of cases.
Usually bifrontal and may show morning exacerbation
and in Valsalva Maneuver.
◘ Pulsatile tinnitus due to disturbed flow within the cerebral
venous system
◘ Diplopia due to abducent nerve paresis in 40% of cases.
◘ Progressive constriction of the visual field.

14. ◘ Episodes of unilateral or bilateral visual loss, from few
seconds up to minutes, precipitated by change of head
posture, eye rolling or Valsalva Maneuver, and followed by
full recovery to the baseline.
◘ It is the second most frequent symptom of IIH affecting >
70% of cases due to transient ischemia or distortion of
myelin at the nodes of Ranvier in the swollen ON fibers.
◘ Theclinical significanceof TVOis a matter of debate:
(1) In the IIHTT, TVO was found to be a predictor of
progressive visual deterioration.
(2) Many studies declared that, TVO is mainly subjective with
un-estimated sensitivity / specificity and unknown
prognostic value.

15. A. New headache, or a significant worsening of a pre-
existing headache, fulfilling criterion C.
B. Both of the following:
1. IIH has been diagnosed.
2. CSF pressure exceeds 250 mm CSF (280 mm in obese children).
C. Either or both of the following:
1. headache has developed or significantly worsened in temporal
relation to the IIH, or led to its discovery
2. headache is accompanied by pulsatile tinnitus and/or
papilledema.
D. Not better accounted for by another ICHD-3
diagnosis.
◘ Reliefof theheadacheafterCSFremovalis supportivebut not diagnosticofIIH(sensitivity72%andspecificity77%).

17. ◘ The total CSF volume is 160 mL; 25% in the ventricles
and 75% in the subarachnoid space (cranial & spinal).
◘ The CSF is secreted by the choroid plexus and ventricular
ependyma in a rate of 0.3 – 0.6 ml/min (500 – 600
ml/day) which means that the CSF is exchanged 3 times
/ day.
◘ The CSF is absorbed by the choroid plexus of the superior
sagittal sinus.
◘ The opening CSF pressure is 80 – 180 mm H2O in lateral
recumbent position.
◘ The CSF pressure is non-significantly different between
sitting and lateral decubitus position (Magnaes,1976).

18. ◘ Intracranial mass e.g., tumor, hemorrhage
◘ Blockage of ventricular system (obstructive
hydrocephalus)
◘ Blockage of CSF absorption (communicating
hydrocephalus) e.g., SAH
◘ Obstruction of venous outflow e.g., cerebral venous
sinus thrombosis
◘ Diffuse cerebral edema e.g., following head injury
◘ Increased CSF secretion e.g., choroid plexus tumor
◘ Idiopathic intracranial hypertension

20. ◘ NormalON length:
(1) The optic head (in the globe) 1 mm.
(2) The orbital part 24 – 30 mm.
(3) The intra-canicular part (optic canal) 9 mm.
(4) The intracranial part 16 mm.
◘ NormalON sheathdiameter:
(1) 4.5±1.3 mm at 3 mm from the globe.
(2) 4.4±0.7 mm at 8 mm from the globe.
(3) 3.6±0.7 mm at 3 mm from the optic canal.
◘ Distance from posterior pole of the globe to optic foramen is 18
mm.

21. ◘ Empty sella turcica.
◘ Flattening of the posterior aspect of the
globe.
◘ Distention of the peri-optic subarachnoid
space.
◘ Vertical tortuosity of the ON.
◘ Intraocular protrusion of the ON head.
◘ Transverse venous sinus stenosis.

22. Decreased ONSD in SIH vs. increased ONSD with increased CSF rim in IIH

23. Magnetization Prepared Rapid Acquisition Gradient Echo image along the plane of the
ON
(C) Increased ON tortuosity in IIH.
(A) Straightened ON in SIH.
- Due to its traction by downward vertical
brain sagging.
(B) ON angle in a normal subject.

25. ◘ Typical criteria of IIH except papilledema.
◘ Idiopathic unilateral or bilateral sixth nerve palsy.
◘ Three of the following imaging criteria:
(1) Empty sella turcica.
(2) Flattening of the posterior aspect of the globe.
(3) Distention of the peri-optic subarachnoid space with
or without a tortuous ON.
(4) Transverse venous sinus stenosis.
◘ Elevated lumbar puncture pressure > 250 mm CSF.
◘ May result from anatomic compartmentalization of the peri-optic subarachnoid
spacewhichstopsthe highCSF pressurefromreachingtheretrolaminarportion.
◘ Intracanalicular ON swelling exerting
ball and valve effect in a case of
IIH without papilledema.

26. ◘ Recurrent IIH is relatively uncommon but not rare,
occurring in up to 10% of cases who reported rapid
increase in body weight or during pregnancy.
◘ Fundoscopic examination may be misleading as the
degree of papilledema is always disproportionate
with the rise in CSF pressure.
◘ Visual field and OCT may be beneficial if compared
with the last patient’s chart.
◘ CSF manometry and ONSD are good ancillary tools.
◘ The classic definition of recurrent IIH is recurrence or increased severity of papilledema in one or both eyes after at least 3 months of
ophthalmoscopicevidenceof itsresolutionorstabilizationrespectively.

27. Papilledemaas wellas visualfieldimpairmentmaybe definitely asymmetricalin 5%ofIIHcases,butbe carefulaboutpossibleFoster
KennedySyndrome
Follow-up visual field of a case of
IIH
Asymmetrical Papilledema in IIHFoster Kennedy Syndrome

28. ◘ The possible etiology is obvious (not idiopathic) and its management
alleviatethe disorder.
◘ Transverse sinus stenosis; whether a cause or a
consequence of IIH still a matter of debate although
most findings supports the former evidenced by
improvement following stenting of the sinus.
◘ Obstructive sleep apnea, anemia, hyperthyroidism, renal diseases,
sarcoidosis, SLE, sickle cell disease, Behcet, and thrombocytopenic
purpura are associated with secondary intracranial
hypertension and should be suspected in males and
no-obese female with raised ICP.
Secondary Pseudo-tumor Cerebri

30. Resolutionofpapilledemaaftermedicaltreatment
◘ Thediseaseis usuallyself-limitedandgoodvisualoutcomeis the rolein> 90%ofcasesif appropriatemanagementhasfollowed.
◘ Chronicpapilledemacanleadto progressiveandpermanentlossofnervefibersdueto retinalinfarcts.

31. ◘ Diagnostic delay or improper management put 10–20% of IIH
cases at risks of severe irreversible visual impairment.
◘ CSF diversion modalities are exposed to risks of post-operative
infections, shunt over-drainage, obstruction, migration, and
subsequent failure.
◘ Unfortunately, RCTs are little while most current treatment
modalities are based on clinical experience and off-label
drugs.
◘ Debatedissuesinclude:
(1) The best medical treatment.
(2) When to do surgery.
(3) The best CSF shunting modalities.
(4) The role of transverse sinus stenting.

32. ◘ Theprimarygoalsarepreservationof visionandalleviationofsymptoms.
◘ Ifa secondarycauseis identified,it shouldbe treatedappropriately.
◘ Weight reduction is the key for disease modifying long-term remission. The targeted amount of weight loss is debated but must not be less than
10%ofbaseline.

33. ◘ Acetazolamide:-
- Carbonic anhydrase inhibitors, decrease production of
CSF, by reducing sodium ion transport across the
choroidal epithelium. The appropriate dose is 1 – 2
gm /day (up to 4 gm in IIHTT).
◘ Methazolamide (Neptazane) is well tolerated than
acetazolamide and had used as an alternative.
◘ Topiramate:-
- Could be also used with weak carbonic anhydrase
inhibiting effect and helps in weight reduction.
◘ Diuretics and steroids has no role in IIH management and
when combined with acetazolamide, put the
patient in the risk of hypokalemia.

34. ◘ The rationale behind the procedure is uncertain, but
some authors assume that, rapid lowering of the ICP
may reopen the collapsed transverse sinus. It may be
beneficial in selected individuals with intermittent
symptom exacerbations or IIH worsening during
pregnancy.
◘ The amount of aspirated CSF is also debated, some
clinicians favor a “high-volume” lumbar puncture,
removing > 20 mL of CSF, another approach is to
lower the pressure into the normal range (180 mm
H2O).

35. ◘ CSFDiversionProcedures:.
(1) Lumbo-peritoneal shunt.
(2) Stereotactic ventriculoperitoneal shunt.
(3) Stereotactic Ventriculo-atrial shunt.
◘ OpticNerve SheathFenestration:.
- Helps in preservation of vision but its role in
alleviating headache and lowering the ICP is
inferior than CSF diversion.
ResolutionofpapilledemaafterCSFDiversion

36. ◘ Transverse sinus stenosis (TSS) may be intrinsic (short
segment) or extrinsic (long segment).
◘ Stenting is indicated in patients with focal short segment
TSS (intrinsic granulation tissue) with post- and pre-
stenotic pressure gradient > 8 cm H2O (> 4 cm H2O in
some studies) in catheter venography.
◘ Unilateral stenting is usually sufficient even in the
presence of bilateral stenosis.
◘ Patients with long segment TSS (external compression)
have little response to sinus stenting.

37. (1)Case1: distalsuperiorsagittalsinusstenting. (2)Case2 : righttransversesinusstenting

40. ◘ Good neurologist, ophthalmologist and neurosurgeon communication is the
basesof successfuloutcome.
◘ Follow-up schedule should be individualized, objective and be vigilant and assess
newlydiagnosedcasesin shortinterval visits for possiblefulminant IIH.
◘ ON head OCT is suitable for objective follow-up of newly diagnosed IIH cases
whileONSDis useful for diagnosis of recurrent ones.
◘ Registration of the patients’ follow-up data is highly beneficial for diagnosis of
recurrent IIH.

41. (1) Rapidrateof progression(fulminant IIH)
(2) Severepapilledema(gradeIV, V).
(3) Very frequent TVO(subjective manifestation).
(4) Hemorrhagein the peripapillary RNFL.
(5) IncreasedRNFLthicknessin OCTdespitetreatment.

42. ◘ Thevalueof earlyshuntingon longtermON functions.
◘ The best shunting procedure; lumbo-peritoneal or lumbo-pleural
shunts.
◘ The relation of IIH without papilledema to chronic tension
headache.
◘ Therelationof IIHwith migraine.
◘ The biomarkers toolkit guiding for the best time of intervention in
progressivecases.

43. ◘ SIGHT study is a recently begun RCT of surgical interventions is going on to provide insight into the indications for surgical intervention,
optimal timingandchoiceof intervention,andlong-termoutcomes.

44. [1] Bahnasy, et al. EJNPN. 2019. doi: 10.1186/s41983-019-0081-z
[2] Moodley, et al. Medical Hyposthesis. 2019. doi:
10.1016/j.mehy.2019.109361
[3] Libien J, et al. J. Neurol Sciences. 2017. doi: 10.1016/j.jns.2016.11.014
[4] Agarwal, et al. Clinical Neurology. 2017. doi:
10.1016/j.clineuro.2017.05.009
[5] Miller. Youmans & Winn. 2017. doi: https://lccn.loc.gov/2016035901
[6] Smith, et al. Headache. 2017. doi: 10.1111/head.13144
[7] Eidsvaag, et al. Brain R. 2018. doi: 10.1016/j.brainres.2018.02.017
[8] Wall, et al. Am J Ophthalmol 2017. doi: 10.1016/j.ajo.2017.01.004
[9] Olesen, et al. Doc Ophthalmol. 2016. doi: 10.1007/s10633-016-9553-y
[10] Kishk, et al. Neuroradiology. 2018. doi: 10.1177/1971400918789385
[11] Bassi, et al. Indian J. Ophthal. 2014. doi: 10.4103/0301-4738.149136
[12] Odom, et al. Doc Ophthalmol. 2016. doi: 10.1007/s10633-016-9553-y
[13] Wall, et al. JAMA Neurol. 2014. doi: 10.1001/jamaneurol.2014.133
[14] Hoffmann, et al. J. Headache Pain. 2018. doi: 10.1186/s10194-018-
0919-2
[15] Mulroy, et al. Journal of Clinical Neuroscience. 2018; 50:108–10.
[16] Berezovsky, et al. J. Neuro. Sciences. 2017. doi:
10.1016/j.jns.2017.08.3264
[17] Margeta, et al. J AAPOS 2015. doi: 10.1016/j.jaapos.2015.01.006
[18] Fahmy, et al. J. Neurol. Sciences. 2016. doi: 10.1016/j.jns.2015.11.034
[19] Biousse. Revue Neurologique. 2012. doi: 10.1016/j.neurol.2012.07.018
[20] Bekerman, et al. Am. J. Emergency Medi. 2016. doi:
10.1016/j.ajem.2016.08.045
[21] Liu, et al. BMC Neurol. 2017. doi: 10.1186/s12883-017-0964-5
[22] Ang, et al. Arch Clin Exp Ophthalmol. 2018. doi: 10.1007/s00417-017-3896-2
[23] Bolay, et al. Cephalalgia. 2018. doi: 10.1177/0333102417738202
[24] Echegaray, et al. IOVS. 2011. doi: 10.1167/iovs.11-7484
[25] Wall, et al. Br J Ophthalmol 2017. doi: 10.1136/bjophthalmol-2016-309852
[26] Leishangthem et al. J Neuroradiology. 2019. doi:
10.1016/j.neurad.2018.09.001
[27] Shields et al., World Neurosurgery. 2018. doi: 10.1016/j.wneu.2018.09.070
[28] Kimberly et al., Academic Emergency Medicine. 2008. doi: 10.1111/j.1553-
2712.2007.00031.x
[29] Chagot et al., Journal of Obesity. 2017. doi: 10.1155/2017/5348928
[30] Sheils et al., Am J Ophthalmol. 2018. doi: 10.1016/j.ajo.2018.07.032
[31] Scott et al., Arch Ophthalmol. 2010; 128(6): 705-711.
[32] Radojicic et al., J. Neuro. Sciences. 2019. doi: 10.1016/j.jns.2019.02.006
[33] Berezovsky et al., J. Neuro. Sciences. 2017. doi: 10.1016/j.jns.2017.08.3264
[34] Kwee et al., European Journal of Radiology. 2019. doi:
10.1016/j.ejrad.2019.04.023
[35] Kupersmith et al., Am J Ophthalmol. 2016. doi: 10.1016/j.ajo.2016.12.017
[36] Sengupta et al., JAMA Neurol. 2019. doi: :10.1001/jamaneurol.2019.1696
[37] D’Antona et al., JAMA Neurol. 2019. doi: :10.1001/jamaneurol.2019.2935
[38] Adderley et al., JAMA Neurol. 2019. doi: :10.1001/jamaneurol.2019.1812
[39] Aldossary. eNeurologicalSc. 2018. doi: 10.1016/j.ensci.2018.01.006
[40] Arcidiacono et al., Interdisciplinary Neurosurgery. 2019. doi:
10.1016/j.inat.2019.100484
[41] Chen rt al., World Neurosurg. 2019. doi: 10.1016/j.wneu.2018.12.052