EFFECT OF PREVIOUS SCORPION BITE(S) ON THE ACTION OF INTRATHECAL BUPIVACAINE

Background: Repeated clinical observations at our institution indicated a trend of inadequate or failed spinal anaesthesia in patients with a prior history of scorpion bites. To explore a possible association between scorpion envenomation and altered spinal anaesthetic efcacy, we conducted a prospective, comparative casecontrol study. Methods: A total of 90 patients aged 18 to 65 years, of either sex, scheduled for surgeries under spinal anaesthesia were included and divided equally into two groups: Group S (n=45) with a history of one or more scorpion bites, and Group C (n=45) with no such history. All patients received spinal anaesthesia with 3.5 mL of 0.5% hyperbaric bupivacaine. Parameters assessed included onset and peak of sensory and motor block (using the pin-prick method and Bromage scale), failure rates, and need for conversion to general anaesthesia. Statistical analysis was performed using the Chi-square test and independent sample t-tests. Results: Both groups were demographically comparable. In Group S, the onset of sensory (2.29 ± 1.56 min) and motor block (2.89 ± 1.79 min) was signicantly delayed compared to Group C (1.61 ± 0.78 min and 1.78 ± 0.78 min respectively; p < 0.05). Similarly, peak sensory (6.39 ± 2.76 min vs. 3.68 ± 0.89 min) and motor block times (7.81 ± 3.90 min vs. 4.44 ± 1.38 min) were prolonged in Group S (p < 0.001). In Group S, 5 patients experienced incomplete sensory block, 6 had incomplete motor block, and 3 patients had failure of both, requiring conversion to general anaesthesia. In contrast, all patients in Group C had satisfactory spinal block. Conclusion: Patients with a history of scorpion bites, particularly with multiple or recent episodes, demonstrated a signicant delay and resistance to spinal anaesthesia using bupivacaine. These ndings suggest a potential correlation between scorpion envenomation and reduced sensitivity to local anaesthetics administered intrathecally, warranting heightened clinical awareness and consideration during anaesthetic planning.