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|LETTER TO EDITOR
|Year : 2020 | Volume
| Issue : 4 | Page : 945-946
Gas in the eye, Holes in the Brain- Bubble Trouble
Boby Varkey Maramattom
Department of Neurology, Aster Medcity, Kochi, Kerala, India
|Date of Web Publication||26-Aug-2020|
Dr. Boby Varkey Maramattom
Department of Neurology, Aster Medcity, Kothad, Kochi, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Maramattom BV. Gas in the eye, Holes in the Brain- Bubble Trouble. Neurol India 2020;68:945-6
A 71-year-old man presented to us with right-sided headache. 2 months ago, he had undergone pneumatic retinal pneumopexy (PRP) with 4 ml of 20% perfluoropropane (C3F8) for a macular hole in the right eye. Three weeks later, during airflight, immediately after ascent, he developed severe right eye pain and headache and lost consciousness. Despite this the aircraft did not land but completed its 4 h flight. He regained consciousness 1 h after landing. On examination, there were no focal neurological deficits. Intraocular tension was normal. Magnetic resonance imaging brain showed enlarged spaces in the subcortex in the right internal carotid artery (ICA) territory [Figure 1].
|Figure 1: MRI showing right ACA/ MCA territory cavitary lesions. (a-c) T2 weighted images. Sagittal, Coronal and axial images. (d) Axial T2 weighted image. (e and f) Axial FLAIR images|
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After takeoff, commercial airplanes achieve cabin pressure equivalent to that at 6000–8000 feet elevation within 10–15 min even though their cruising altitude is 10,000–11,000 m (32–36,000 feet) with a cabin pressure of around 0.75–0.81 atm.
PRP commonly utilizes gases such as sulfur hexafluoride (SF6), perfluoroethane (C2F6), or perfluoropropane (C3F8). These gases expand to provide adequate tamponade without causing an abnormal intraocular tension (<20 mm Hg). C3F8 usually undergoes dissolution in 60–80 days. Twenty percent C3F8 is an isovolumic bubble at 1 atm, but expands at cabin pressure by 130%–140%. C3F8 is also known to cross the blood-aqueous barrier [Figure 2].
|Figure 2: Depiction of air pressure change with air travel and gas expansion|
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In our patient, rapidly expanding intraocular PFP during ascent would have caused the gas bubble to traverse the BAB. From there, it would have retrogradely propagated to the ophthalmic artery and thence into the ICA and its branches, causing massive tissue cavitation. This ocular expansion followed by intra-arterial passage explains his ocular and neurological symptomatology. Patients should be warned to avoid air travel for at least 8 weeks after ocular tamponade with PFP.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]