Hemotoxic Snakebite Presenting with Bilateral Blindness Due to Ischemic Occipital Infarcts

Abstract

Cerebrovascular complications are rare following a Viperidae snake envenomation, let alone ischemic ones. This catastrophic hemorrhaging cascade is widely known to cause a wide array of manifestations. Its manifestations can range from skin bleeds to fatal intracranial or organ hemorrhages. Our patient had cortical blindness secondary to an ischemic occipital infarct following a hemotoxic snakebite - a seemingly distinct oxymoron. The physician should be mindful of the fact that a hemotoxic snakebite can deceptively bring in ischemic attacks as well. Toxic vasculitis, thrombotic angiopathies, widespread vasospasm and endothelial damage are believed to shoulder a part of the disease process that can bring about tissue ischemia. Key Messages Hemotoxic snake envenomation can have devastating effects. Apart from dealing with the threat of coagulopathy, the physician must also be alert to the ironical ischemic aftermath that can equally bring in misery. Our patient had one such complication-bilateral cortical blindness resulting from bilateral occipital ischemic infarcts. The physician must be aware that a hemotoxic snakebite can even instigate ischemic dilemmas, i.e. cerebrovascular infarcts, as well. How to cite this article Kodiatte Abraham A, Livingston J. Hemotoxic Snakebite Presenting with Bilateral Blindness Due to Ischemic Occipital Infarcts. Indian J of Crit Care Med 2019;23(2): 99-101.

Cortical Blindness and Thrombotic Microangiopathy Following a Hemotoxic Snake Envenomation: An Unusual Presentation

“…Cerebrovascular manifestations following snake envenomation are uncommon, and cortical blindness is rarely reported [3]. Possible etiologies for blindness following snake envenomation reported in the literature are snake venom ophthalmoplegia, acute angle closure glaucoma following capillary leak syndrome, vitreous hemorrhage, retinal hemorrhage, optic neuritis, post-neuritic optic atrophy, and occipital infarcts [5][6][7].…”

“…Our patient developed cortical blindness due to multiple bilateral infarcts. Ischemic infarcts can occur following snake envenomation due to disseminated intravascular coagulation, toxic vasculitis, and thrombotic microangiopathy, apart from hypercoagulable factors in snake venom [3]. Snake venoms are complex, heterogeneous poisons with multiple effects.…”

“…Common ocular manifestations are ptosis and external ophthalmoplegia, which are often the presenting signs of a neuroparalytic snake bite [2]. Although bilateral visual loss as an ocular presentation following snake envenomation is not uncommon, cortical blindness following a hemotoxic snake envenomation is rarely reported [3]. It is also important to point out that thrombotic microangiopathy following a hemotoxic snake envenomation often mistakenly attributes the hematologic derangement to disseminated intravascular coagulation (DIC) following venom-induced consumptive coagulopathy (VICC) [4].…”

“…Our patient presented with bilateral vision loss due to multiple occipital infarcts, and clinicopathologic evaluation was suggestive of thrombotic microangiopathy as evidenced by microangiopathic hemolytic anemia, renal failure, and thrombocytopenia. Apart from direct and established effects due to coagulopathy, the combination of toxic vasculitis, thrombotic microangiopathies, widespread vasospasm, and endothelial damage can cause tissue ischemia, leading to clinical presentation [3].…”