Deciphering the Enigma: Lignocaine Resistance After Scorpion Envenomation

Lignocaine, an amide-type local anesthetic (LA), is routinely used in dentistry. Resistance to lignocaine is rare, and it can occur due to various reasons, such as genetic mutations or variations in the local environment where it is injected. One reason might be scorpion envenomation. We report a case of a 39-year-old female patient with a chief complaint of a gradual reduction in mouth opening for the past five years, with a history of scorpion bite. The patient had a scorpion bite 18 years back. She started developing symptoms of oral submucous fibrosis five years ago. The patient exhibited resistance to lignocaine, after which alternate agents were tried. We found that ropivacaine was effective as a LA, enabling airway management via cricothyrotomy and subsequent nasal intubation, following which bilateral fibrotomy, bilateral coronoidectomy, and bilateral nasolabial flap reconstruction were performed. The resistance to lignocaine is due to modifications in the sodium channels. Scorpion venom affects the local environment surrounding the nerve and has systemic effects as well. As an alternative to lignocaine, bupivacaine and ropivacaine can be tested for sensitivity. In patients with a recent history of scorpion bites, there is a higher chance of resistance to lignocaine. Therefore, evaluating the patients with a history of scorpion bites for resistance to lignocaine before any procedure is mandatory.