This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
A 70 kg young athlete was planned for surgery. During anaesthesia, vecuronium was not available, so repeated doses of succinylcholine was given intermittently up to 640 mg. During recovery, patient was not able to spontaneously respire and move limbs. What is the cause? 
Select and explain. 
A. Pseudocholinesterase deficiency, B. Phase II blockade, C. Muscle weakness due to repeated fasciculations, D. Undiagnosed muscular dystrophy
B: Phase II blockade
Answer: B: Phase II blockade 
Explanation: Continued presence of the drug causes persistent depolarization resulting in flaccid paralysis-phase blockade 1. Phase 2 blockade is slow in onset and results from desensitization of of the receptor to A-ch. Psuedocholinestrase enzyme deficiency usual dose results in prolonged apnea and paralysis which lasts for hours. From padmaja 4th edition Page no 86 And from KD Tripati 7th edition Page no 349