A Case of Recurrent Bilateral Central Retinal Vein Occlusion in an Otherwise Healthy Adolescent Male
Authors: Vandenheuvel Julia , Manco-Johnson Marilyn J , Zinn Daniel 
Published: November 2021

Abstract
Introduction: Central retinal vein occlusion (CRVO) is a rare finding in children. Well-known risk factors include hypertension and diabetes in older patients. CRVO has also been attributed to local causes such as compression or inflammation secondary to trauma, as well as systemic causes, such as thrombophilia or hyperviscosity etiologies. Here, we describe a case of recurrent bilateral CRVO in an otherwise healthy child.
Design/Methods: This is a retrospective case report reviewing a patient with recurrent bilateral CRVO. Ophthalmological and pediatric records were reviewed.
Results: A 10-year-old previously healthy male presented with sudden onset blurry vision of his left eye and was found to have CRVO with venous engorgement of the retina. He had a grandfather with polycythemia vera, but no other contributing family history. Initial coagulopathy workup was normal with a PTT of 29 sec, PT INR of 1.1 sec, fibrinogen of 291 mg/dL, Factor VIII of 174%, Von Willebrand Factor Antigen of 139%, Von Willebrand Factor Activity of 132%, Factor IX of 101%, and Factor XI of 112%. Computed tomography (CT) of the head was unremarkable. At the age of 13, he developed acute onset headache with blurry vision of his right eye. He had evidence of macular edema and CRVO of his right eye. Ophthalmology treated him three injections of vascular endothelial growth factor inhibitor, aflibercept, over four months with improvement in both macular edema and visual acuity. Daily aspirin prophylaxis was also initiated pending further hypercoagulability workup. Laboratory investigation for an inherited or acquired hypercoagulability including prothrombin mutation, AT III mutation, hyperhomocysteinemia, protein C & S, and antiphospholipid were negative. He initially had a positive cryoglobulin found to be negative on repeat evaluation. He underwent a comprehensive rheumatological and infectious workup that was unrevealing. Additionally, he had an elevated RBC of 6.09 mill/cmm, hemoglobin of 18.2 g/dL, and hematocrit of 52.0% but a targeted panel for inherited erythrocytosis and polycythemia was normal. The patient remained symptomatic with persistent episodes of blurred vision and lightheadedness. Further extensive hematologic workup revealed reduced thrombin inhibitor and elevated rates of thrombin formation. Lipoprotein (a) was 168 mg/dL. Interestingly, his mother had elevated rates of thrombin formation and a lipoprotein (a) level of 153 mg/dL. The patient is currently being treated with therapeutic rivaroxaban and whole exome sequencing (WES) for the patient and both parents are pending.
Conclusion: This case demonstrates a novel cause of recurrent bilateral CRVO secondary to reduced thrombin inhibition resulting in accelerated rates of thrombin formation and elevated lipoprotein (a) overall supporting a hypercoagulable state. Perhaps, there is a familial component predisposing recurrent thrombosis in this patient. Whole exome sequencing is pending to evaluate for a genetic predisposition to his findings. After completing a full course of therapeutic anticoagulation, he will likely require lifelong prophylaxis to reduce the risk of future thrombotic events and preserve his vision.

Disclosures
No relevant conflicts of interest to declare.