Page 8 - AN-2-2

Advanced Neurology Venous stenting, intracranial hypertension

is around 1/100,000 and is most common in obese women Dandy criteria were penned and proposed by Friedman
of childbearing age. One study has compared the incidence et al. in 2013 [13,14] . The modified Dandy criteria, which have
of IIH in 2017 with that in 1990 and showed a correlation been widely used, include signs and symptoms of elevated
between the rise in IIH and that in obesity. The same ICP, no signs of neurological deficits, with an exception
study has shown that the incidence of IIH was higher in for abducens nerve palsy, normal CSF with elevated ICP,
women (3.3/100,000) compared to men (0.3/100,000) and a computed tomography (CT) scan that does not show
the incidence of IIH in all women between the ages of 15 etiology for elevated ICP, and no other known causes for
[12]
and 44 was 6.8/100,000; in comparison, the incidence was intracranial hypertension .
higher at 22.0/100,000 in obese women within the same CSF: Cerebrospinal fluid; CVSS: Cerebral venous sinus
[5]
age group . The prevalence of IIH in pediatric patients stent; DSV: Digital subtraction venography; IIH: Idiopathic
has increased, but it is not associated with obesity or the intracranial hypertension; MRI: Magnetic resonance
female sex, like in older patients [6,7] . Other potential risk imaging; MRV: Magnetic resonance venography; PTCS:
factors associated with IIH include anemia, sleep apnea, Pseudotumor cerebri syndrome.
amiodarone, hypovitaminosis A, hypothyroidism, systemic
lupus erythematosus, and polycystic ovary syndrome. Magnetic resonance imaging and MRV are two
Further research is required to understand the underlying diagnostic imaging modalities that can aid in the diagnosis
mechanisms of these associations . of IIH. Some common findings include an empty sella
[7]
turcica, distension of the optic nerve sheath, and slit-
The etiology of IIH is not fully understood. However, like ventricles. These findings may aid in the diagnosis
there is evidence showing a correlation between IIH and of IIH. However, their absence does not rule out IIH .
[15]
elevated ICP. Theories explaining this increase in ICP Digital subtraction angiography (DSA) is another imaging
include increased CSF secretion, CSF outflow obstruction, modality used in diagnosing and visualizing vascular
and venous stenosis . Controversy exists within literature pathologies in the cerebrum. DSA remains the gold
[8]
on whether venous sinus stenosis causes IIH or is a standard for visualizing and diagnosing vasculature for
consequence of the latter. A small study using magnetic several reasons, including its heightened spatial resolution
resonance venography (MRV) has demonstrated that 93% and superior temporal imaging quality (Figure 3) .
[16]
of 29 patients with IIH had bilateral transverse venous
Once a diagnosis of IIH is made, initial treatments
[9]
sinus stenosis . However, it is unknown if stenosis of the such as weight loss, lumbar punctures, and diuretics, such
transverse sinus is a cause or a result of increased overall as acetazolamide, are initiated . Acetazolamide with
[17]
ICP (Figures 1 and 2). Some have theorized that patients weight loss and a low-sodium diet has resulted in modest
with IIH have anatomically distinct dural venous sinuses . improvements in the visual function of patients with
[9]
Symptoms of IIH include headaches, migraines, pulse- IIH experiencing mild vision loss . Repeated lumbar
[18]
synchronous tinnitus, transient vision loss, double vision, punctures have been reported to be less effective. A study
and neck pain. Most patients present with visual changes, has shown that repeated lumbar punctures in patients
but 10% of patients experience blindness . with bilateral transverse sinus stenosis for 6 years and
[10]
3. Diagnosis and treatment subsequent CSF pressure normalization did not resolve
the patients’ IIH . In a 2021 study (n = 79), patients
[19]
IHH is diagnosed after the exclusion of other conditions who had higher lumbar puncture opening pressure before
that lead to increased ICP, such as tumors, hemorrhage, transverse sinus stent insertion showed a higher risk of
increased CSF secretion, or inadequate CSF absorption. failure. Other studies have also shown that a higher lumbar
Once these pathologies have been excluded, a diagnosis of puncture opening pressure confers a risk to CVSS failure
IIH can be made . or the need to retreat .
[11]
[20]
IIH is diagnosed using several criteria like the modified The next step for those who failed conservative
Dandy criteria or the diagnostic criteria for pseudotumor management is surgical intervention, including bariatric
cerebri syndrome. The original Dandy criteria were first surgery for obesity, CVSS, or ventriculoperitoneal shunting
proposed in 1937 to diagnose IIH. The report described (Table 1). For patients with severe optic neuropathy that
common symptoms of elevated ICP that were not brought may lead to permanent vision loss, optic nerve sheath
on by secondary causes, such as tumors. In addition to fenestration (ONSF) is recommended before conservative
typical symptoms of IIH, other manifestations such as treatment and CVSS . ONSF is less effective at treating
[21]
abnormalities in the fundus of the eye, drowsiness, gait headaches, which is the most common symptom in
issues, and a buzzing sensation in the ears have been IIH [13,19] . Moreover, compared with shunting, CVSS is
observed in these patients . The most recently modified more cost-effective because fewer revisions are needed
[12]

Volume 2 Issue 2 (2023) 2 https://doi.org/10.36922/an.284