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': 'GERD in the absence of endoscopic esophagitis is seen in: \nSelect and explain. \nA. Paially treated cases with PPI, B. Scleroderma, C. CRF, D. Cirrhosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: GERD is often diagnosed in the absence of endoscopic esophagitis. This phenomenon is seen in: Paially treated disease Abnormally sensitive esophageal mucosa. Next investigation in this setting would be: Reflux testing. It can demonstrate excessive esophageal exposure to refluxed gastric juice, the physiologic abnormality of GERD. (Ambulatory 24- to 48-hour esophageal pH recording using either a wireless pH-sensitive transmitter that is anchored to the esophageal mucosa or with a transnasally positioned wire electrode with the tip stationed in the distal esophagus) Ref: Harrison, E-18, P-2428', 'role': 'assistant'}]