Hello...i understood your query... According to CDC definition diarrhoea more than 3-4 weeks is termed chronic. Since you have long history of diarrhoea and liquid stool..common cause of it may be Inflammatory bowel disease...though you found WBCs in stool...it may present concurrent infection with inflammatory bowel disease (IBD)... Cause might be infectious colitis (e.g. clostridium difficile), pancreatic disorder, Malabsorption Gastroenterologist just wanted to see endoscopically whether any features suggestive of IBD present or not.... two types of IBD ulcerative colitis and crohn s disease would have different findings like skip lesions, diffuse ulceration any many more which may be seen endoscopically....if found significant examination during endoscopy...he might take biopsy to confirm or support findings suggestive of IBD or other causes.. Apart from