Orbital compartment syndrome (OCS), also known as retrobulbar hematoma, is the development of a mass effect, usually from bleeding, that compromises blood flow to the retina and the rest of the eye. When intraocular pressure (IOP) is high enough, typically >30 mm Hg, ischemic damage may occur that can cause permanent vision loss.  For this reason, OCS is considered a true surgical emergency. 

The usual clinical presentation of OCS is pain and proptosis following a traumatic event that can progress to decreased visual acuity.  Pain is typically worse with eye motion.  In addition to proptosis, the physical examination may show decreased extraocular motion and elevated IOP on tonometry. For patients with an IOP >30 mm Hg, an ophthalmology consult should be called stat. For patients with an IOP >40 mm Hg, a lateral canthotomy and inferior cantholysis should be performed at the patient’s bedside. More severe cases may present with afferent pupillary defect (APD).

In any emergency involving the eye, it is paramount to establish the type of injury that has occurred. A CT may be considered when there is concern for other emergent conditions and it will not delay canthotomy. Tonometry should be avoided if a ruptured globe cannot be ruled out.


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In this case, a dedicated orbital CT image shows a retrobulbar hematoma and multiple facial fractures (Figure 2).

Figure 2. Orbital CT demonstrates retrobulbar hematoma and multiple facial fractures. Credit: Brady Pregerson, MD

The differential diagnosis for traumatic eye injuries includes corneal abrasion, foreign body, globe rupture, and blowout fracture. The CT imaging ruled out epidural hematoma, globe fracture, and blowout fracture, but the latter can be difficult to differentiate when there is orbital compartment syndrome.

In conclusion, clinicians should carefully check IOP, extraocular movement, and acuity in patients with trauma to the eye. Tonometry readings >30 mm Hg are concerning and >40 mm Hg warrant immediate surgical intervention with canthotomy at the bedside followed by ophthalmology consult. 

An ophthalmologist may occasionally recommend medical therapy, which may include mannitol, steroid, acetazolamide, and/or timolol drops. Prognosis can be poor if there is prolonged ischemia, especially if it lasts more than 90 minutes prior to canthotomy and cantholysis.

In this case, the patient’s IOP was 55 mm Hg.  A lateral canthotomy was performed and a repeat IOP dropped to 29 mm Hg.

Brady Pregerson, MD, is an emergency physician at Tri-City Medical Center in Oceanside, California and at Scripps Coastal Urgent Care in Oceanside, California.

Reference

Pregerson DB. Ophthalmology Trauma. In: Emergency Medicine 1-Minute Consult Pocketbook. 5th ed. 2017;5. http://www.erpocketbooks.com/emergency_medicine_reference_books/quick-essentials-emergency-medicine/

This article originally appeared on Clinical Advisor