INFILTRATIVE BOWEL DISEASE (IBD)

Infiltrative bowel disease, a common cause of chronic vomiting and diarrhea, may be either neoplastic or non-neoplastic. The most common symptoms include vomiting, diarrhea, loss of appetite, and weight loss. In both types of diseases the thickening of the intestinal wall may cause retention of foreign material and malabsorption.

Non-neoplastic (noncancerous) infiltrative bowel diseases are a group of disorders that cause infiltration of the gastrointestinal tract with inflammatory cells. In some areas this is due to parasitic, fungal or algal infections.

A variety of tests may be necessary because a diagnosis of inflammatory bowel disease (IBD) is one of exclusion that requires ruling out many other diseases that may cause intestinal inflammation or systemic disease.

When obvious infective agents are ruled out, intestinal inflammation is than classified by response to treatment or occasionally by intestinal biopsy. Some cases are due to intolerance to certain foods (food responsive enteritis), some are due to bacteria (antibiotic responsive diarrhea), others are due to retained foreign material, and some are due to an immune reaction to unknown agents.

The most common form of neoplastic intestinal inflammation is lymphosarcoma. This causes thickening of the intestinal walls and may result in malabsorption and slow intestinal motility. Focal forms of lymphosarcoma may cause obstruction. This tumor is thought to be related to feline leukemia virus (though the tests are usually FeLV negative). In some animals lymphoplasmacytic enteritis may progress to LSA.

The usual form is small cell lymphosarcoma of the bowel that is highly responsive to chemotherapy.  Occasionally a more primitive cell type occurs that is poorly responsive and rapidly becomes fatal.