A patient posted for vaginal hysterectomy was administered subarachnoid block, which failed, so was repeated in one space above. The block failed again, after waiting for 30 min. Patient gave a history of scorpion bite twice, once at the age of 17 years on her right foot and again about 8 months back. Thereafter, balanced general anaesthesia was given. On eighth post-operative day, after explaining about her possible special condition (?Resistance to local anaesthetic agents), the patient was given left median, ulnar and radial nerve blocks at the wrist and local infiltration near the anatomical snuff box. There was neither sensory nor motor block. The scorpion venom is known to affect the pumping mechanism of sodium channels in the nerve fibres, which are involved in the mechanism of action of local anaesthetic drugs, it may be responsible for the development of ‘resistance’ to the action of local anaesthetic agents.

No abstract