This 81-year-old man with a history of longstanding epilepsy presented after a generalized tonic-clonic seizure. The patient was asymptomatic prior to the event, and his family reported that the semiology was typical of past seizures. He was treated with benzodiazepines by emergency services and required intubation for airway protection. On initial neurological examination, he was comatose with intact brainstem reflexes and symmetrical, spontaneous limb movement. Computed tomography (CT) of the head showed bilateral, symmetrical superior ophthalmic vein (SOV) dilation, with a maximal diameter of 11 mm (Figure 1). In response to imaging abnormalities, CT angiography was performed, which revealed no cerebrovascular malformation. He had no chemosis, proptosis or cranial bruit; dilated fundoscopy was normal, and he improved to baseline health with supportive care. A repeat CT after extubation showed a reduction in SOV diameter, with a maximal diameter of 5 mm bilaterally (Figure 1).
Figure 1.
Computed tomography (CT) of the head showing bilateral superior ophthalmic vein (SOV) dilation associated with mechanical ventilation
Coronal (A) and axial (B) CT during intubation shows SOV dilation (arrowheads). Repeat coronal (C) and axial (D) CT completed approximately 48 hours following extubation shows reduced SOV diameter (arrowheads).
The SOV, the predominant venous outflow of the orbit, originates behind the superior oblique muscle tendon via the junction of cutaneous veins, courses posterolaterally over the optic nerve, exits the orbit via the superior orbital fissure and, ultimately, drains into the cavernous sinus. 1 In the largest retrospective case series to date, abnormal dilation of the SOV (defined as a diameter >3 mm in 2 or more contiguous coronal slices) was universally associated with intracranial or orbital structural pathology, and often with serious vascular disorders including dural- or carotid-cavernous fistula, arteriovenous malformation, and venous thrombosis. 2 Another study, however, demonstrated that SOV dilation can occur in patients during mechanical ventilation and be a reversible phenomenon, as was seen in this case. 3 The mechanism responsible for reversible dilation of the SOV in intubated patients is uncertain but may include increased central venous pressure related to mechanical ventilation. While SOV dilation from intubation appears to be a benign finding, further work is needed to define its physiology and to establish whether clinical correlates exist. Clinicians caring for critically ill patients should be aware that the differential diagnosis of SOV dilation includes reversible enlargement from intubation, as well as more serious vascular etiologies Figure 1.
Footnotes
Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
ORCID iD
Joseph M. Ferrara https://orcid.org/0000-0002-8925-0297
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