IBS should only be considered as a diagnosis following a thorough GI work-up that fails to demonstrate any other diagnoses. Assuming that other disorders associated with chronic diarrhea have been completely ruled-out, then IBS becomes an "assumed diagnosis." (Also, sometimes referred to as a "wastebasket diagnosis," or a "diagnosis of exclusion.")

The initial management of IBS includes fiber supplementation with meals (I prefer Citrucel of Benefiber, as they are associated with less gas and abominal cramps than psyllium-based dietary fiber supplements). Also, keeping a diary of food intake may help your girlfriend to identify certain foods that significantly worsen her GI symptoms. In general, anti-motility agents, including Imodium, should be used a last resort, although they may be necessary in a very small minority of patients.

I would advise that you and your girlfriend ensure that other infectious and non-infectious causes of chronic diarrhea have been thoroughly and fully ruled-out prior to attributing her diarrhea to IBS.

Finally, severe and chronic diarrhea can certainly cause food malabsorption resulting in weight loss. Irrespective of the cause of her diarrhea, controlling her diarrhea could, indeed, allow her to gain back her previously lost weight.

Sincerely/ Robert A. Wascher, MD, FACS

http://doctorwascher.com