Bilateral branched retinal artery occlusion following massive honeybee envenomation

Bee stings have been known to produce an immunoglobulin E (IgE)-mediated hypersensitivity reaction with resultant anaphylactoid and toxic manifestations.[1] Ocular involvement in the form of unilateral central retinal arterial occlusion following a bee sting has been reported twice in the previously reported literature.[2,3] A 64-year-old male complained of a sudden decrease in vision in both eyes, 1 week after suffering from multiple bee stings. He was admitted to the intensive care unit for the management of anaphylactic shock and thrombocytopenia after being stung by several bees. As patient complained about blurring of vision his reference was sent for ophthalmology opinion. Clinical examination revealed hyperpigmented patches along his lower eyelids following the resolution of eyelid angioedema [Figure 1a]. Visual acuity in the right eye was counting fingers close to the face and 20/60 in the left eye. Anterior segment examination showed the presence of pseudo-exfoliative material on the corneal endothelium. Fundus examination revealed ischemic retinal whitening, with partial involvement of the macula in both eyes more evident in the left eye compared to right eye suggestive of bilateral retinal artery occlusion (BRAO) [Figure 1b and c]. Optical coherence tomography macula of both eyes showed significant hyper-reflectivity and increased thickness of the inner retinal layers with an intact outer retinal architecture [Figure 1d and e]. Blood investigations revealed raised serum IgE levels, suggestive of hypersensitivity and raised D-dimer and ferritin levels suggestive of a hypercoagulable state, which could be a cause of bilateral BRAO. His complete blood count showed raised total leucocyte counts (18,660/mm3), low platelet count (80,000), rest of the coagulation profile was within normal limit. He was under intensive care unit for treatment of septicemia and angioedema with systemic antibiotics, steroids, blood thinners, intravenous fluids, antihistaminic, and other supportive medications. No additional treatment was offered to the patient for BRAO due to late presentation. Although exact pathogenesis of branch retinal artery occlusion is not known various theories such as transient vasospasm of the central retinal artery via the Kounis reaction, transient hypercoagulable state, thrombotic events either due to direct toxin effect or toxic vasculitis have been proposed.[2,3] Our case reports add to the possibility of hypercoagulability as etiology for retinal artery occlusion in event of high dose bee sting envenomation.Figure 1: (a) Bilateral hyperpigmented patches on lower lids following resolution of angioedema. (b) Right eye fundus photograph showing partial macular and retinal edema (arrow). (c) Left eye fundus photograph showing partial macular and temporal retinal edema (arrow). (d) Ocular coherence tomography of right eye showing hyperreflectivity in retina, increased thickness of retinal layers (arrow) with normal foveal contour suggestive of branch retinal artery occlusion. (e) Ocular coherence tomography of left eye showing hyperreflectivity in retina, increased thickness of retinal layers (arrow) with normal foveal contour and thinningTo the best of our knowledge, this is the first reported case of bilateral BRAO following massive honeybee envenomation. Patients with systemic collapse following multiple bee stings may be at risk of retina arterial infarction and their vision should be monitored to aid in timely diagnosis and management. Hence, an early ophthalmology consult in the setting on an intensive care unit in cases like these is of utmost importance. “What was known:” Occurrence of keratitis and central retinal arterial occlusion post bee sting. “What is added:” Risk of systemic hypercoagulability and risk of branch retinal artery occlusion post bee sting injury which could be devastating sequelae. 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 Nil. Conflicts of interest There are no conflicts of interest.