Case # 19: Under Pressure

A 27 year-old female presented to the emergency department with a two week history of headache, posterior eye pain, visual changes. She denied trauma, fever, focal neurological changes, or visual field deficits. She was seen by the optometrist earlier in the day and was sent to the ED for further evaluation.  Her neurological examination was normal. 

Eye exam: PERRL, EOMI, no injection/discharge, visual acuity 20/15 OS, 20/20 OD, IOP L19, R19

An ocular ultrasound is performed and the images below are seen. What do you see and what is your most likely diagnosis? What is your management?

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Left eye

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 Right eye

Answer and Learning Points

Answer

On both images of the right and left eye you see papilledema which is demonstrated as a bulging optic disc protruding into the posterior chamber.

CT Head non-contrast was obtained which showed " a partially empty pituitary sella which can be seen with intracranial hypertension, otherwise no acute findings." Ophthalmology was consulted. Their exam was unremarkable except for bilateral papilledema. An LP was performed which showed an elevated OP at 36. After large volume CSF removal the patient reported improvement in symptoms. Closing pressure was 22. The CSF studies were unremarkable. Patient was discharged with an MRI/MRV performed as outpatient and neuro-ophthalmology follow up. MRI brain showed mild flattening of the optic nerve heads which is nonspecific but could correlate with intracranial hypertension in the right clinical setting. 

Learning Points

    • Papilledema may be directly visualized with ultrasound as a bulging optic disc elevated more than 0.6mm from the retina. There are also studies that show a correlation between increased intracranial pressure and optic sheath nerve diameter greater than 5mm when measured 3mm posterior to the retina. (1-4)
    • A width of > 5mm has a pooled sensitivity of 90% and specificity of 85% for detecting an ICP > 20mmHg in trauma patients with head injuries (5-6)
    • It is important to note that the optic nerve sheath diameter should be measured when the sides are parallel, as it can be artificially increased otherwise.  (7)
    • When obtaining an ocular ultrasound use the high frequency linear probe on the ocular setting. If there is not an ocular setting, it is best to err on the high side with regard to gain.
    • Although controversial, some sources advise to avoid ocular ultrasound when concerned about globe rupture as any pressure on the eye could worsening the rupture.

References

    1. Marchese, R.F., et al. Identification of optic nerve swelling using point-of-care ocular ultrasound in children. Pediatric Emergency Care. 2018; 34(8):531-536. 
    2. Kimberly, H.H., Shah, S., Marill, K., & Noble, V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Academic Emergency Medicine. 2008; 15(2):201-4. 
    3. Amini, A., et al. Use of the sonographic diameter of optic nerve sheath to estimate intracranial pressure. The American Journal of Emergency Medicine. 2013; 31(1):236-9.
    4. Xu, W., Gerety, P., Aleman, T., Swanson, J., & Taylor, J. Noninvasive methods of detecting increased intracranial pressure. Child’s Nervous System. 2016; 32(8):1371-86. 
    5. Dubourg, J., et al. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis. Intensive Care Medicine. 2011;37(7):1059–1068.
    6. Rajajee, V., Vanaman, M., Fletcher, J.J., & Jacobs, T.L. Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocritical Care. 2011;15(3):506–515.
    7. Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 17th, 2020.

The following authors contributed to this post:

Amir Aminlari, MD; Danika Brodak, MD; Michael Macias, MD; Rachna Subramony, MD

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