Optic Neuritis After a Snakebite: A Diagnostic Dilemma

Abstract

Background: Snakebite is one of the major causes of morbidity and mortality in India, particularly in rural regions. Of the 57 known venomous species of snakes in India, the 4 most dangerous snakes are the cobra, the common krait, the Russell viper, and the sawscaled viper. Of these, the snakes commonly implicated with neurotoxicity are the cobra and the common krait-both elapidae. Acute neuromuscular weakness with respiratory system involvement is the most lethal neurotoxic effect. Case Report: A 24-year-old female was brought to the emergency department in an unresponsive state with a history of snakebite on the left foot. The patient was intubated, mechanically ventilated, and promptly started on snake antivenom and anticholinesterase agents. The patient improved significantly and was extubated. On day 6, she developed blurred vision and slurred speech. She was diagnosed with bilateral optic neuropathy and treated with repeat snake antivenom and steroids. She improved significantly and was discharged on day 14. Conclusion: When a person is bitten by a venomous snake, antivenom is the mainstay of treatment, but clinicians must also consider possible reactions and complications. Optic neuritis following a snakebite is rare but does occur. The prognosis is generally good if clinical suspicion for such a complication is strong, the snake is identified, and the patient receives timely treatment with steroids.

Delayed Visual Loss in a Patient with Snake Bite: Case Report of an Unusual Neuro-Ophthalmic Presentation

“…In a similar case report from India, a 24-year-old female developed ON 6 days after ASV administration and improved on administration of steroids [4]. Similarly, another Indian case report described the development of bilateral retrobulbar neuritis on a 50-year-old male 2 weeks following a black-cobra bite.…”

“…Many ocular complications caused after injection of the snake venom are described in the literature, but there is little to no evidence that a direct toxic effect of snake venom causes ON [5]. Based on the reported cases of ON after snake bite, ASV is one of the causes of ON in patients after snake bite [4, 6]. These cases presented after 5–6 days following ASV administration.…”

“…After a snake bite, the clinical manifestation can range from mild local inflammation to severe systemic manifestation which can be hematotoxic, cytotoxic, or neurotoxic [3]. Neurotoxins related to optic neuritis (ON) after snake bite has been a rarely reported condition [4]. Here, we present a case of a 70-year-old female patient who developed bilateral painless sudden loss of vision following treatment for snake bite.…”

Bilateral Simultaneous Optic Neuritis Following Envenomations by Indian Cobra and Common Krait

“…The patient was treated with an intravenous infusion of dexamethasone for three days and a tapered oral prednisolone regimen over three weeks with gradual improvement in his vision. Similarly, another case of Indian cobra bite developed optic neuritis six days after the bite despite receiving the antivenom treatment [22]. This patient was treated with intravenous methylprednisolone for seven days followed by a prednisolone taper regimen, which improved their condition.…”

Comment on Senthilkumaran et al. Bilateral Simultaneous Optic Neuritis Following Envenomations by Indian Cobra and Common Krait. Toxins 2022, 14, 805

“…In our review of the online available literature [ 2 ], ten other case reports of optic neuropathies after a snakebite can be found [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Nine describe a similar syndrome of severe bilateral vision loss and papilledema with hemorrhages, several days (mostly six) after initial envenomation.…”