Typical idiopathic intracranial hypertension Optic nerve appearance and brain MRI findings. Jonathan A. Micieli, MD Valérie Biousse, MD

Transcription

1 Typical idiopathic intracranial hypertension Optic nerve appearance and brain MRI findings Jonathan A. Micieli, MD Valérie Biousse, MD

2 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

3 Figure 1. Right eye Left eye

4 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

5 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

6 Figure 3. Left eye Right eye 24-2 SITA-Fast Humphrey visual fields

7 Figure 3. Although there are a high number of false positives, visual fields appear normal with only mildly enlarged blind spots Left eye Right eye

8 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

9 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

10 Figure 5. MRV of the brain is shown here

11 Figure 6. Patient with a partially empty sella Example of a normal appearing sella 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

12 Figure 7. Sagittal T1 MRI shows mild tonsillar herniation Normal sagittal T1 MRI shown for comparison 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.

13 Figure 8. 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

14 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

15 Figure 10. MRV of the brain shows narrowing of the distal transverse sinuses, which is another common finding in patients with idiopathic intracranial hypertension

16 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

17 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

18 Figure 11. OS OD Presentation 3 months after presentation 6 months after presentation 1 year after presentation

19 Figure 12. OD OS OS OD OS OD OS OD OS OD Presentation 3 months after presentation 6 months after presentation 1 year after presentation Her optic disc edema resolved over a period of 1 year with weight loss and acetazolamide, which was discontinued

20 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