Brief Answer:
Try dietary changes, rule out inflammatory bowel disease

Detailed Answer:

Hello,

I have gone through your current query and our previous discussion.
I see that he had a visit with the doctor and his doctor have ruled out obvious causes like inflamed appendix.
So, with his symptoms of persisting pain and diarrhea, the next important considerations include lactose intolerance, gluten intolerance and inflammatory bowel disease. It is easier to identify gluten intolerance among the three . Stopping gluten containing food for even a week can give relief of symptoms. On case of lactose intolerance, it can take up to few weeks after lactose is avoided in diet to show improvement.
So, try avoiding gluten and lactose in diet. There are also some blood tests and breath test to dentify these conditions. However, these tests are not completely reliable.

Another important consideration is inflammatory bowel disease, where body's own immune system act against the bowel. Stool analysis can screen for presence of inflammatory bowel disease. If the stool analysis suggest presence of inflammation, then colonoscopy is recommended.
Also, make sure to avoid spicy , fatty and fried food. Avoid too much processed sugar in diet. Avoid carbonated sodas.
If all these conditions are ruled out, then we need to consider irritable bowel syndrome.
Please be advised to follow up with his treating physician for necessary work up.

Hope this answers your question
Please let me know if you need further clarification
Regards
Dr.Lekshmi

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