typical idiopathic intracranial hypertension · most common mri finding seen in idiopathic...
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Typical idiopathic intracranial hypertension Optic nerve appearance and brain MRI findings
Jonathan A. Micieli, MD
Valérie Biousse, MD
A 24 year old African American woman is referred for bilateral optic disc edema after visiting an optometrist to update her glasses. She is asymptomatic Her past medical history is significant for obesity (BMI 39.1) Visual acuity is 20/20 OD, 20/20 OS There is no relative afferent pupillary defect Color vision is 14/14 correct Ishihara plates OU
Figure 1.
Right eye Left eye
Figure 1.
Right eye Left eye
There is bilateral optic disc edema in both eyes. There are peripapillary wrinkles (also known as Paton’s lines) in both eyes (red arrow). The left eye also has pseudodrusen (blue arrow),
which are small discrete refractile bodies seen in patients with longstanding papilledema
Figure 2.
An OCT (optical coherence tomography) image of the optic disc is shown on the left to highlight the peripapillary wrinkles in the right eye.
The wrinkles are commonly seen with optic disc edema. As the disc swells, it displaces the retina causing it
to form a series of folds concentric to the edge of the optic disc
Figure 3.
Left eye Right eye
24-2 SITA-Fast Humphrey visual fields
Figure 3.
Left eye Right eye
Although there are a high number of false positives, visual fields appear normal with only mildly enlarged blind spots
The patient has bilateral optic disc edema and preserved visual function, suggesting
papilledema, which is optic disc edema due to raised intracranial pressure (ICP)
An MRI of the brain without and with contract and MRV of the head with contrast
were ordered to assess for any intracranial process (mass, hydrocephalus,
leptomeningeal enhancement) or venous sinus abnormality (thrombosis, dural fistula
or stenosis) that may lead to elevated ICP
Figure 4.
Sagittal T1 MRI of the brain without contrast Axial T2 FLAIR MRI of the brain without contrast Coronal T2 MRI of the brain without contrast
Figure 5.
MRV of the brain is shown here
Figure 6.
Sagittal T1 MRI of the brain without contrast shows a partially empty sella. There is intrasellar herniation of arachnoid mater and CSF (yellow), which flattens the pituitary gland (red) in the sella turcica (blue). This is the most common MRI finding seen in idiopathic intracranial hypertension. It is also seen in other causes of elevated ICP and may also be seen in the normal population
Patient with a partially empty sella Example of a normal appearing sella
Figure 7.
Mid-sagittal T1 MRI of the brain shows caudal displacement of the cerebellar tonsils. A line (red in the IIH patient and yellow in a normal control) is drawn from the basion to the opisthon defining the foramen magnum.
Sagittal T1 MRI shows mild tonsillar herniation Normal sagittal T1 MRI shown for comparison
Axial T2 FLAIR MRI shows flattening of the posterior globes in this patient (red arrow)
Normal axial T1 MRI shown for comparison
Flattening of the posterior globes may be seen in patients with elevated intracranial pressure and is due to a change in the pressure gradient between the perioptic CSF spaces and the intraocular pressure
Figure 8.
Figure 9.
Coronal T2 MRI shows distention of the CSF spaces around the optic nerves
Example of a normal coronal T2 MRI shown for comparison
Figure 10.
MRV of the brain shows narrowing of the distal transverse sinuses, which is another common finding in patients with idiopathic intracranial hypertension
A lumbar puncture was performed in the left lateral decubitus position and showed: Opening pressure of 39 cm of H2O Nucleated cells: 0 Red blood cells: 2 Protein and glucose within normal limits
The patient was diagnosed with idiopathic intracranial hypertension (IIH) according
to the modified Dandy criteria.
Modified Dandy criteria required for the diagnosis of IIH:
A) Papilledema
B) Normal neurological examination except for cranial nerve abnormalities
C) Neuroimaging: normal brain parenchyma without evidence of structural lesion
or venous sinus thrombosis
D) Normal CSF composition
E) Elevated lumbar puncture opening pressure (> 25 cm of H2O in adults)
She was prescribed acetazolamide and was started on a diet and weight loss
program under the guidance of her primary care physician
Presentation 3 months after presentation 6 months after presentation 1 year after presentation
Figure 11.
OD
OS
Presentation 3 months after presentation
6 months after presentation
1 year after presentation
Figure 12.
OD
OS
OS OD OD OD OD OS OS OS
Her optic disc edema resolved over a period of 1 year with weight loss and acetazolamide, which was discontinued
Summary points: ● Papilledema is defined as optic disc edema due to elevated intracranial pressure
and usually has preserved visual function (unless there is macular edema from severe disc edema or optic atrophy from longstanding papilledema)
● Classic MRI findings in IIH include a partially empty sella, flattening of the
posterior globes, distention of the CSF space around the optic nerves, tonsillar hernitation, skull base meningoencephaloceles, and distal transverse sinus stenosis without any evidence of an underlying structural lesion
Empty sella
Flattening of posterior globes Distention of CSF space
Distal transverse sinus stenosis