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: Medicine
[{'content': 'Chvostek’s sign is elicited by \nSelect and explain. \nA. BP cuff in arm for 5 minutes, B. Facial nerve stimulation by tapping over the parotid, C. Tapping over extensor pollicis brevis, D. Tapping over flexor retinaculum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The Clinical manifestations of hypocalcemia are mostly due to neuromuscular irritability.\n\xa0The patients complains of paresthesias which are typically perioral or of the hands and feets\n\xa0Tetany is the classic manifestation of hypocalcemia, the manifestations are :\n\xa0Corpopedal Spasm o Laryngospasm o Seizures Latent tetany occurs which can be manifested by\nChvostek sign and \xa0Trousseau sign Electrocardiographic manifestations The classic E.C.G.\nchange with hypocalcemia is prolonged corrected QT interval Other possible E. C. G.\nfindings are o Prolonged ST interval o Peaked T waves o Arryhtmmias Heart block (hypocalcemia may impair cardiac contractility and decrease blood pressure) GI.\nT manifestations o Intestinal cramps and malabsorption NOTE: Corpopedal spasm: o Contraction the muscels of the hand and feet.\nThe wrists are flexed and fingers extended, with the thumbs adducted over the palms. Chvostek sign:\nTapping the facial nerve anterior to the external auditory meatus elicits a twitch of the upper lip or entire mouth.\nThis is not a very specific sign because it is positive in about 10% of patients without hypocalcemia. Trousseau sign:\n\xa0A blood pressure cuff is inflated slightly above the systotic blood pressure for more than 3 minutes.\nCorpopedal spasm occurs if hypocalcemia is present as a result of the ischemia of motor nerves.', 'role': 'assistant'}]