Jehanne Belange, MS4
The Article: Sterling, Budhram. “Traumatic retrobulbar hematoma: Case report of a new ultrasound finding and summary of the literature.” Visual Journal of Emergency Medicine 2019 16:100574
Background: Retrobulbar hematoma (RBH) is a rare vision-threatening complication of orbital trauma. The gold standard for diagnosing RBH is non-contrast CT. Obtaining a CT may be difficult, depending on the number of patients waiting for a scan. Since RBH can potentially cause loss of vision within an hour, ultrasound can be used to diagnose RBH. Since RBH is so rare, there it not a list of common findings seen on ultrasound to help facilitate making a diagnosis. This case helps provide a new finding and briefly touches on findings found in other cases.
Study: This was a case report from Baystate Medical Center Emergency Department that added a new finding to assess for retrobulbar hematoma. A 66-year-old woman presented to the emergency department with left preorbital swelling, ecchymosis, and lacerations after a mechanical fall. Physical exam shows an afferent pupillary defect (APD), visual acuity only to light/dark, intraocular pressure (IOP) of 60 mm Hg in the left eye, and 16 mmHg in the right eye.
A POCUS showed restriction of ocular movements and angular posterior aspect of the globe. Rapid CT showed significant edema and stranding of retrobulbar contents and an absence of global rupture. There was no retrobulbar fluid collection seen on POCUS or CT scan. The physician in the ED elected to perform a lateral canthotomy and cantholysis after considering the physical exam and imaging findings. The patient’s visual acuity improved to 20/40 before discharge.
Other case reports have seen findings of anechoic fluid collections, but this is not a consistent finding since blood can become isoechoic to other posterior structures. Another repeated finding found in a different case report was a “guitar pick” deformation of the posterior globe due to the increased retrobulbar pressure.
Takeaway: This case report suggests that in addition to clinical suspicion, a finding of retrobulbar fluid collection, deformity of the posterior globe, or restricted ocular movement can be helpful in the diagnosis of RBH. Since RBH is such a rare occurrence, large scale studies are not feasible to get a more accurate list of ultrasound findings. The finding from this case report does not change the management of a suspected RBH. Realistically if the clinical suspicion is strong enough, especially in this case where the patient had increased IOP, decreased visual acuity, and APD, lateral canthotomy can be performed.