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: Pediatrics
[{'content': 'True statement about ductus Arteriosus is – \nSelect and explain. \nA. It undergoes anatomic closure within 24 hours of birth, B. Forms the ligamentum venosum in later life, C. It is induced to close by high levels ofprostaglandins, D. May cause a machinary murmur by its patency.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: This question deals with the changes in blood circulation that occur at birth :\n\nClosure of Ductus arteriosus\n\nThe closure occurs almost immediately after birth by contraction of its muscular wall, mediated by bradykinin. i.e.\n\nPhysiological closure.\n\nAnatomic closure occurs by proliferation of intima, and may take from 10-21 days (& not in 24 hrs. as given in choice \'A\').\nAfter obliteration, it forms ligamentum arteriosum. (& not the ligamentum venosum as given in choice \'ID\')\nLigamentum venosum, on the other hand, is formed by closure of the ductus venosus.\n\n"In neonates with congenital heart defects, till surgery is undertaken, PGE1 (Alprostadil) is used to maintain patency\xa0of ductus arteriosus".\nTherefore prostaglandins maintain patency of ductus arteriosus, and not induce it to close (as given in choice \'C\').\nProstaglandins maintain patency of ductus arteriosus\nNSAIDs - help in early closure of ductus arteriosus\n"Shunt murmur is a continuous machinery murmur".\nThe murmur is best heard at the 2nd left intercostal space and is also well heard below the left clavicle, where it maintains its continuous machinery character.', 'role': 'assistant'}]