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: Surgery
[{'content': "In Raynaud's disease true is :a) Lower limb more involved than commonly upper limbb) More common in femalec) Sup. thrombophlebitisd) Associated with migraine \nSelect and explain. \nA. bd, B. d, C. ab, D. ac", 'role': 'user'}, {'content': "Answer: A \nExplanation: Raynaud's disease\n\nThe diagnosis of Raynaud's ds. is made when the secondary causes of Raynaud's phenomenon are ruled out.\nOver 50% of pts. with Raynaud's phenomenon have Raynaud's ds.\nDs. is more common in female (M : F ratio is 1 : 5)\nAge of presentation - 20 to 40 yrs.\nFingers are involved more frequently than toes\nRarely earlobes and tip of the nose may be involved\nRaynaud's phenomenon occurs frequently in patients who also have migraine headaches or variant angina. These associations suggest a common predisposing cause for the vasospasm\nOn physical examination the pts. are often entirely normal. The radial, ulnar and the pedial pulses are noinial.\nSclerodactyly (thickening and tightening of the digital subcutaneous tissue) may develop in few pts.\nIn general, pts. with Raynaud's disease appear to have a milder form of Raynaud's phenomenon. Fewer than 1% of these patients lose a part of digit.", 'role': 'assistant'}]