This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
[{'content': 'A 25 year old male with roadside accident underwent debridement and reduction of fractured both bones right forearm under axillary block. On the second postoperative day the patient complained of persistent numbness and paresthesia in the right forearm and the hand. The commonest cause of this neurological dysfunction could be all of the following except – \nSelect and explain. \nA. Crush injury to the hand and lacerated nerves, B. A tight cast or dressing, C. Systemic toxicity of local anaesthetics, D. Tourniquet pressure', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In local anesthetic toxicity there is circumoral (perioral) numbness and tongue paresthesia (not paresthesia & numbness in hand & fore arm).\nThis patient is having signs of peripheral nerve injury.\nThe involvement of the peripheral nerve is characterized by paresthesias, numbness, hypoesthesia, pain and neurological dysfunction.\nSo, this patient is having peripheral nerve injury. It could have happened d/t.\n\n\nOpen (crush) injury l/t laceration of nerves. As the patient underwent debriment so he is a case of open injury.\nNerve injury during debridement\nNerve injury during reduction & manipulation\nTourniquet pressure palsy\nNerve injury d/t tight bandage or cast', 'role': 'assistant'}]