Extensive bilateral corneal edema 6 weeks after cataract surgery: Keratopathy due to Asclepias physocarpa: a case report

Abstract

BackgroundSurgeons may be unaware of the ability of plant toxins to cause corneal damage. Therefore, corneal damage following intraocular surgery due to plant toxins may be misdiagnosed as postoperative infection.Case presentationA 74-year-old man presented with hyperemia and reduced visual acuity in both eyes 6 weeks after uneventful cataract surgery. We observed extensive hyperemia and corneal stromal edema with Descemet’s folds in both eyes.After obtaining a detailed patient history, we diagnosed plant toxin-induced corneal edema due to Asclepias physocarpa, which can induce corneal edema by inhibiting the Na+/K+ ATPase activity of the corneal endothelium.Antimicrobial and steroid eye drops and an oral steroid were prescribed accordingly. Symptons began to improve on day 3 and had almost completely resolved by day 6. At 1 month, the patient had fully recovered without any sequelae.ConclusionThe correct diagnosis was possible in the present case as symptoms were bilateral and the patient was able to report his potential exposure to plant toxins. However, if the symptoms had been unilateral and the patient had been unaware of these toxins, he may have undergone unnecessary surgical interventions to treat non-existent postoperative endophthalmitis.

Corneal endothelial dysfunction caused by Asclepias curassavica in a young farmer

“…In this case, cardenolides from the leaf of the Asclepias plant induced corneal edema several hours after the contact to the eye, as in other case reports 1 , 3 . Cardenolides can penetrate the intact cornea without damage to the epithelium, 1 , 2 and cause corneal endothelial toxicity by inhibiting the endothelial Na + /K + -ATPase pump function 1 .…”

“…steroid, may be helpful to alleviate ocular inflammatory symptoms, such as, conjunctival injection 1 . Treatment with topical steroid was often attempted because topical steroid might increase the activity of the remaining Na + /K + -ATPase pump that was not blocked by cardenolides and facilitate the recovery process 1 , 3 , 7 . An experimental study revealed that dexamethasone increased Na + /K + -ATPase pump activity in cultured corneal endothelial cells 7 …”

“…However, it took 9 months for the BCVA to improve to 20/20 from 20/400 at initial presentation 4 . In a case of bilateral Asclepias physocarpa exposure in a Japanese 74-year-old male patient, Matsuura et al 3 reported complete recovery of corneal edema in 6 days by rinsing with normal saline, topical levofloxacin 1.5% (6/day), bethamethasone 0.1% (6/day) and oral steroids (10 mg/ day).…”

“…To the best of our knowledge, only a few cases of corneal endothelial toxicity associated with Asclepias species have been reported 1, 2, 3, 4. However, all the reported cases were among old patients of 60 years or older.…”

“…Plants of the genus Asclepias (milkweed) of the Asclepiadaceae family are wildflowers native to the tropical America, 1 and globally distributed as ornamental plants 1 , 3 . Plants of the Asclepiadaceae family contain toxic cardenolides, also known as cardiac glycosides, in their stems, leaves, roots and latex for protection from their predators 1 .…”