Neurological and neuro-ophthalmological manifestations of snake bite: a systematic review

Abstract

Objective: Snake bite is a major health concern, particularly in developing countries, affecting mainly rural farming communities. When venom primarily neurotoxin enters the body by a snake bite, it affects the nervous system, causing neurological symptoms like muscle weakness, paralysis, altered sensation, and coordination issues. This systematic review aims to study a detail evaluation of neurological and neuro-ophthalmological manifestations associated with snake bites. Methods: This review studied the type, severity, neurological and neuro-ophthalmological symptoms and signs, treatment, outcomes of treatment, and long-term complications of snake bites. Result: Snake venom, whether hematotoxic or neurotoxic, can cause neurological symptoms. Ptosis and limb weakness are frequently reported by patients in this review. Ophthalmoplegia, nystagmus, delayed neuropathy, and dysarthria are less commonly reported. Vision loss is moderately observed in snake bite cases. In neurotoxic snake bites, ptosis followed by neuroparalysis are the primary ocular symptoms, while hematotoxic snake bites can lead to various symptoms such as accommodation deficiency, ptosis, ophthalmoplegia, neck muscle weakness, and dysphagia. Most reviewed cases showed recovery without neurological deficits. Neurotoxic snake bites had higher mortality rates compared to hematotoxic bites. Factors linked to higher mortality in children with Early Morning Neuroparalytic Syndorme (EMNS) include younger age, ptosis, cardiac arrest, and limited availability of Pediatric Intensive Care Unit (PICU) beds. Prompt recognition, respiratory support, and PICU care can reduce mortality rates. Conclusions: Snake bite treatment involves administering antivenom (ASV) and providing supportive care, including mechanical ventilation if needed. Guidelines for handling snakes in locations such as zoos are crucial to prevent workplace snake bites. Establishing a snake bite registry in regions with high snake encounters is essential for proper case documentation and enables effective planning and strategy development for prevention and management of snake bites.